Key Takeaways (expand)
- Collagen is the most abundant protein in our bodies, making up about 30% of our total protein content.
- Collagen plays important structural roles, providing strength, elasticity, and support to connective tissues like the skin, bones, tendons, ligaments, and cartilage.
- Collagen also participates in cellular signaling, binding with specific receptors on cells to help regulate processes like cellular adhesion, differentiation, growth, and survival.
- It’s also abundant in muscles, blood vessels, corneas, and teeth.
- There are at least 28 distinct types of collagen with diverse structures and functions, though type I collagen is the predominant type in our bodies.
- All types of collagen are based on a triple helix structure, consisting of three long chains of amino acids—mainly glycine, proline, and hydroxyproline.
- Vitamin C, iron, copper, zinc, and silicone work synergistically to promote collagen production.
- Studies show significant anti-aging effects of dietary collagen, including reducing visible signs of aging, and improving skin hydration and elasticity.
- Collagen has also demonstrated health benefits for wound healing, joint and tendon health, body composition, bone health, cardiovascular health, and digestive health.
- Collagen could be helpful for improving muscle recovery and strength.
- In studies of collagen supplementation, amounts as low as 2.5 to 10 grams daily have been shown to produce measurable benefits.
- The best dietary sources of collagen include bone broth (or broth from other cartilage-containing animal parts), meat cuts rich in connective tissue, and skin-on anchovies or sardines.
Table of Contents[Hide][Show]
Collagen is a fibrous protein that plays a major role in the structure and function of the human body. It’s the most abundant protein in mammals, making up about 30% of the body’s total protein content. It provides strength, elasticity, and support to connective tissues, including skin, bones, tendons, ligaments, and cartilage! This protein acts like a scaffold, helping tissues maintain their shape and integrity. As we age, the production of collagen naturally decreases, which can lead to signs of aging like wrinkles and joint stiffness.
The word collagen is derived from the Greek “kólla,” which means glue. Indeed, not only does collagen act as a glue (holding our cells, tissues, and organs together), but the animal-based glues we use as adhesives are themselves made from collagen!
Foods high in collagen include broths made from bone or other cartilage-containing animal parts, meat cuts rich in connective tissue (such as oxtail, shanks, cheeks, jowl, ribs, chicken wings, tendon, tripe, hocks, skin, and brisket), fish and shellfish (particularly when they still contain their skin or scales, such as with anchovies or sardines), and pork rinds or chitlins. Collagen supplements can also supply additional collagen, including gelatin and collagen peptides.
The Biological Roles of Collagen
Collagen is a fascinating and incredibly diverse protein! In fact, there are at least 28 distinct types of collagen (numbered using Roman numerals in the order they were discovered), encoded by at least 46 genes, and categorized by their structure and function in the body.
No matter the type, all collagens are based on a molecular triple helix structure. This helix consists of three long polypeptide chains, called α-chains, composed of a repeating sequence of three amino acids. These polypeptide chains twist tightly around one another to form a stable, strong helix.
What makes this helix so sturdy? The answer has to do with glycine! Glycine comprises about a third of the amino acids in collagen (in fact, it’s the first amino acid in each repeating sequence of three amino acids that forms the α-chains). The small size of glycine allows the chains to pack closely together, and the hydrogen bonds between adjacent glycine molecules provide important stability. (Proline and hydroxyproline are commonly one of the other two amino acids in the repeating sequence.)
The collagen triple helix, also known as procollagen, goes through changes after it’s made to become a basic collagen molecule (called tropocollagen). Once this transformation happens, collagen molecules naturally come together to form larger structures. This process is influenced by the type of α-chains in the collagen (which determines its specific type), by other matrix molecules (like elastin, keratin, and proteoglycans), and by other nearby cells or structures.
The most abundant and widespread type of collagen in the human body is type I collagen, which makes up approximately 90% of all collagen. Type I collagen is categorized as a fibrillar collagen because the collagen molecules align to form structures called fibrils, which then self-assemble to form collagen fibers. Think of it like a rope (collagen fiber) made from twisted strands (collagen fibrils), each strand made of several twisted yarns (collagen triple helix), and each yarn built from smaller spun fibers (α-chains). This assembly gives type I collagen fibers amazing strength and flexibility, shock-absorbing biomechanical properties to bones, load-bearing abilities to tendons and ligaments, and elasticity to skin. Type I collagen is found in tendons, ligaments, skin, the cornea, fibrocartilage, organ capsules, the dura mater of the brain, the spinal cord, and skeletal muscle perimysium. It’s also the main organic component of bone.
While type I collagen is the predominant collagen in the body, most of the remainder are types II, III, IV, V and IX—each contributing unique properties to different tissues.
Type II collagen, for example, is another fibrillar collagen, making up a substantial amount of the protein in our cartilage. It’s crucial for the nucleus pulposus (the gel-like center of spinal discs), where it helps absorb shock, and for articular cartilage (the cushion-like tissue covering the end of joint bones), where it offers both strength and compressibility.
Type III collagen is also fibrillar, and tends to work alongside type I collagen to provide flexibility and strength in tissues like the skin, tendons, ligaments, vascular walls, and connective tissue surrounding skeletal muscle. It’s also a major component of the extracellular matrix—a complex network of molecules outside of cells that provides structural support and helps regulate cell behavior. Type III collagen is also found in the fine, fibrous networks of tissue (called reticular tissue) that support organs like the kidney, liver, and spleen.
Type V collagen is also fibrillar. Although it’s only present in small amounts in human tissues, it helps build the collagen architecture of types I and III, making it essential for forming healthy collagen tissues—including in bones, corneal stroma, and the interstitial matrix of muscles, liver, lungs, and placenta.
Beyond collagen types I, II, III, and V, other fibrillar collagens include types XI, XXIV, and XXVII. However, collagen can form non-fibrillar architectures as well! These non-fibrillar collagens are expressed in smaller amounts, and don’t create the typical fiber-like structures of other collagens. Instead, they form more organized sheet-like or network-like structures, helping anchor and organize tissues in the extracellular matrix.
For example, non-fibrillar type IV collagen helps form the glomerular basement membrane in the kidneys, which is crucial for filtering blood and preventing the loss of proteins like albumin. Non-fibrillar type VII collagen helps attach the outer layer of skin (epidermis) to the layer underneath (dermis). Non-fibrillar type IX collagen is a special type of cartilage collagen that works with type II collagen to help maintain the integrity and stability of cartilage and the vitreous humor (a gel-like substance in the eye that fills the space between the lens and retina). Meanwhile, type X collagen—also non-fibrillar!—helps control bone formation by regulating the mineralization of the bone matrix.
Clearly, the diversity in collagen structures—whether fibrillar or non-fibrillar—allows collagen to fulfill a vast array of biomechanical functions. So, while certain collagens may be more predominant in the body, all of them are important!
But, collagen’s wide-ranging roles are far more than just structural! Collagen also participates in cellular signaling, binding with specific receptors on cells to help regulate processes like cellular adhesion, differentiation, growth, and survival. Type I collagen, for example, interacts with a molecule called decorin, which can reduce the activity of transforming growth factor-beta (TGF-β), a cytokine involved in inflammation and cancer progression. Collagen also stores and releases a variety of cellular mediators (such as growth factors and cytokines) that are important for things like organ development, wound healing, and tissue repair. In bones, collagen stores insulin-like growth factors (IGFs), which regulate aging and help guide the bone remodeling process. More specifically, during the breakdown of bone by osteoclasts (bone-degrading cells), IGFs helps signal the creation of new bone by osteoblasts (bone-building cells). Yep… that means collagen is a major player for strong bones!
So, how does collagen from food or supplements contribute to the amazing functions of collagen inside of our bodies? The process is actually less straightforward than we might assume! When we ingest dietary collagen, our bodies can’t absorb it in its whole, fully intact form. Rather, our digestive systems break collagen down into smaller parts (primarily single amino acids and peptides, or strings of amino acids), which are then absorbed into the bloodstream and transported to various tissues. In some cases, these smaller components can be re-assembled to form collagen fibers—particularly in the case of the amino acids glycine, proline, and hydroxyproline. However, collagen-derived amino acids and peptides also possess many of their own unique functions, even if they don’t get used as collagen building blocks!
For example, collagen peptides can themselves stimulate collagen production, directly accumulate in cartilage, prompt the release of growth hormones involved in bone formation, upregulate extracellular matrix formation, promote the growth of fibroblasts (cells that help build connective tissue), and increase the production of hyaluronic acid (which helps keep skin and joints healthy). Some of the amino acids derived from collagen also have powerful health effects: for example, glycine is involved in neurotransmitter function, serves as a precursor for creatine and glutathione, has antioxidant properties, and helps regulate blood sugar—among many other functions!
It’s also worth noting that dietary collagen can be processed into different forms with distinct characteristics and bioavailability. Unprocessed, raw collagen is called native collagen, and is difficult to digest due to being insoluble. But, it degrades relatively quickly when cooked—beginning to denature once it’s heated to a mere 40°C (104°F), and nearly fully denatured once it reaches 60°C (140°F). The heat unravels all of the collagen architecture, breaking it down to its constituent α-chains, which can then further break apart via hydrolysis (breaking of chemical bonds in the presence of water).
Partially hydrolyzed collagen is better known as gelatin—yep, the same stuff in jiggly Jell-O or bone broth! When bone broth or gelatin cool, they gel because all those α-chain bits and pieces tend to at least partially reassemble.
Meanwhile, another type of processed collagen—collagen peptides or collagen hydrolysate (two generally interchangeable terms)—form when partially hydrolyzed collagen undergoes an additional step to break down the α-chain bits and pieces into even smaller polypeptides. In this case, enzymes are used to pre-digest the collagen in a process called enzymatic hydrolysis. Other collagen derivatives include low molecular weight collagen peptides (true peptides), specific bioactive collagen peptides (including dipeptides and tripeptides), and collagen tripeptides. Often, these are sold in dried form as collagen powder.
So, to summarize: gelatin and bone broth protein are denatured and partially hydrolyzed collagen. Collagen hydrolysates and collagen peptides are more fully (but not completely) hydrolyzed collagen, with enzymes used in the manufacturing process.
If you’re trying to figure out whether a collagen supplement is partially hydrolyzed or is enzymatically hydrolyzed into smaller polypeptides, here’s the trick: if it gels (once dissolved in hot water and then chilled), it’s the former. If it dissolves easily into cold water and doesn’t gel, it’s the latter!
Interactions with Other Nutrients
Some nutrients work synergistically to promote collagen production, either by serving as collagen precursors or by playing important biological roles in collagen synthesis.
Vitamin C and iron, for example, serve as a cofactor for prolyl hydroxylase and lysyl hydroxylase—enzymes responsible for the hydroxylation of proline and lysine, key components of the collagen molecule. This hydroxylation process is necessary for stabilizing the collagen triple helix structure and ensuring that collagen fibers are strong and functional. Vitamin C also controls the expression of several procollagen (AKA collagen precursor) genes, further promoting collagen production at the cellular level.
Copper serves as a cofactor for another enzyme involved in collagen synthesis: lysyl oxidase, which catalyzes the formation of cross-links in collagen (in turn stabilizing and strengthening the collagen matrix). Zinc is likewise a cofactor for several enzymes involved in collagen synthesis—particularly collagenase and prolyl hydroxylase, which promote the formation and stabilization of the collagen structure. Silicon, too, plays a key role in collagen production by facilitating the synthesis and organization of collagen fibers, as well as by enhancing the activity of hydroxylation enzymes.
Meanwhile, other nutrients help form the building blocks of collagen itself! Ornithine, arginine, and glutamine all serve as precursors for the amino acids in collagen, in turn helping increase collagen production within the body.
Collagen in Health and Disease
Numerous studies have shown that increasing collagen intake can mitigate the effects of aging, improve cardiovascular and bone health, support a healthy body composition, and more! While more research is needed to elucidate the best form of collagen and optimal dose to maximize therapeutic value for various health challenges, here’s a look at some of the best-studied benefits of collagen supplementation.
Collagen and Skin Health
One of collagen’s best-studied roles is in dermatology, particularly in combatting visible signs of aging. The dry weight of young, healthy skin is at least 75% collagen, but this decreases as we age. In fact, a 2006 study measured a 68% decrease in the amount of type I procollagen in the skin of people over 80 years old compared to people between the ages of 18 and 29!
Numerous studies have shown that collagen peptide supplementation improves skin elasticity, reducing the appearance of fine lines and wrinkles. In fact, a 2019 systematic review of eight studies showed that collagen hydrolysate supplementation at doses of 2.5 to 10 grams per day for eight to 24 weeks showed measurable improvements in skin elasticity and moisture, as well as decreases in fine lines and wrinkles. These benefits to visible signs of skin aging are attributable to increased collagen density in the skin and a reduction in collagen fragmentation.
A 2020 systematic review of 10 studies, focusing on collagen’s mechanisms of action, found that collagen consumption results in measurable, clinical improvements in skin health—specifically by directly affecting fibroblasts, M2-like macrophages, and oral tolerance-related mechanisms.
A 2023 systematic review and meta-analysis, encompassing 26 randomized controlled trials, found that supplementation with hydrolyzed collagen significantly improved skin hydration and elasticity relative to placebo. Where skin hydration was concerned, the effects were most pronounced when supplementing for at least eight weeks, and when using collagen derived from fish, possibly due to the specific amino acid profiles and high bioavailability of marine collagen.
Another systematic review and meta-analysis from 2023, this one encompassing 14 randomized controlled trials, reached similar conclusions—finding that hydrolyzed collagen supplementation improved skin hydration, elasticity, wrinkle appearance, firmness, and visually assessed radiance.
A 2024 randomized controlled trial of adults aged 40 to 60 years tested the effects of a collagen plus vitamin C supplement (containing 8000 mg of hydrolyzed marine collagen and 60 mg of ascorbic acid). Participants in the intervention consumed the supplement either once daily or once every other day, for a period of 12 weeks. By the end of the study, daily supplementation had successfully increased the collagen content and quality in the skin, which in turn was associated with improvements in hydration, elasticity, and wrinkles. (By contrast, every-other-day supplementation delivered less pronounced benefits.)
A 2023 clinical trial found that 12 weeks of oral collagen supplementation led to significant improvements in skin elasticity, roughness, and dermis echo density, with these benefits persisting four weeks after ceasing supplementation!
And, a 2024 double blind, randomized, placebo controlled trial of 112 adult women found that taking 10 g of hydrolyzed collagen peptides daily for eight weeks significantly improved the elasticity, hydration, and roughness of the skin, while also reducing facial soft tissue sagging.
Collagen and Wound Healing
Wound healing is a complex process that involves the immune system, and collagen is essential for wound healing. First, exposed collagen fibers from damaged blood vessel walls help recruit platelets to the site of injury to begin the clotting process. During the proliferative phase of wound healing, collagen is secreted by fibroblasts to form new connective tissue, providing a scaffold for contraction of the wounded area by myofibroblasts. During the remodeling phase of wound healing, collagen fibers are reorganized to return tissue to a more normal architecture. In fact, scars are largely made of collagen. A 2006 study of long-term care residents showed that pressure ulcers healed twice as fast in the group receiving a 15-gram collagen hydrolysate supplement three times daily for eight weeks.
Collagen and Joint and Tendon Health
Collagen plays a crucial role in supporting joint and tendon health, offering a range of benefits that can help maintain mobility, reduce discomfort, protect against joint-related diseases, support healing from tendon injury, and more.
When it comes to osteoarthritis—a common degenerative joint condition that causes the breakdown of cartilage—the benefits of collagen are particularly impressive! A 2019 meta-analysis of placebo-controlled trials found that for osteoarthritis patients, collagen supplementation led to significant decreases in patients’ total WOMAC scores (an assessment of the severity of knee and hip osteoarthritis), stiffness scores, and pain intensity (as measured by the Visual Analog Scale, or VAS). Furthermore, a 2023 meta-analysis of randomized controlled trials, encompassing a total of 507 patients with osteoarthritis of the knee, found that collagen supplementation conferred significant pain-relieving benefits compared to placebo.
Some studies have also shown direct protective effects of collagen supplementation on cartilage quality in osteoarthritic individuals, highlighting the most likely mechanism. For example, a 2011 study of people with mild to moderate knee osteoarthritis showed that 10 grams of collagen hydrolysate taken daily for 24 weeks significantly improved a measure of cartilage quality (called the dGEMRIC score, measured by MRI), while those receiving placebo saw a continued deterioration of cartilage.
Collagen supplements may improve joint health in other contexts as well. A 2008 study in athletes with activity-related joint pain showed that 10 grams daily of collagen hydrolysate, taken for a total of 24 weeks, substantially reduced joint pain—including at rest, standing, walking, carrying objects, and lifting!
Similarly, a 2013 double-blind placebo-controlled study tested the effects of undenatured type II collagen on people who had no prior history of arthritis, but experienced joint discomfort with physical activity. After 90 days of taking 40 mg of supplemental collagen daily, there were statistically significant improvements in average knee extension; after 120 days, the group taking collagen was able to exercise for significantly longer than the placebo group before experiencing joint discomfort.
Research suggests a beneficial role of collagen in tendon health, too—particularly for Achilles tendinopathy, a condition that causes swelling, pain, and stiffness in the Achilles tendon (which connects the calf muscles to the heel bone). A 2019 randomized controlled trial found that compared to placebo, giving Achilles tendinopathy patients collagen supplements (2.5 grams of hydrolysed specific collagen peptides for three months) accelerated the benefits of a bi-daily calf strengthening program and return-to-running program, helping them heal more quickly! However, larger studies with more statistical power are needed to confirm these findings.
Collagen and Body Composition
Collagen can benefit body composition in several ways, including the maintenance of muscle mass and reduction of excess body fat.
Loss of muscle mass as we age, called sarcopenia, is a major cause of functional decline and loss of independence in older adults. Dietary collagen can be a major boon here! A 2015 randomized controlled trial of elderly sarcopenic men compared the effects on muscle mass from lifting weights three times per week, with or without taking 15 grams daily of collagen peptides for three months. The group taking collagen gained significantly more muscle (an average gain of 4.2 kg compared to 2.9 kg) and lost more fat (an average loss of 5.4 kg versus 3.4 kg). A similar randomized controlled trial from 2019 was performed in postmenopausal women, with the collagen peptide group gaining 1.8% fat-free mass (and loss of fat mass) compared to 0.9% in the placebo group.
More recently, a 2023 randomized, double-blind, placebo-controlled trial tested the effects of 12 weeks of collagen peptide supplementation (15 grams daily) in adults aged 50 and above, in combination with physical activity.
Young, healthy men can benefit from collagen supplementation too. A 2019 trial in young sports students showed that those that took a 15 grams collagen peptide supplement increased muscle mass and strength more than placebo after 12-weeks of strength training. And a 2019 study of recreationally-active young men also showed similar results, with the addition of collagen peptides increasing the effectiveness of strength training over 3 months. And a 2016 study looking at vitamin C-enriched gelatin, with either 5 grams or 15 grams of gelatin, as a pre-workout supplement in healthy young men showed a dose-dependent increase in markers of collagen synthesis in their blood an hour after exercise compared to placebo, which may help prevent musculoskeletal injuries.
Collagen and Bone Health
Collagen provides the scaffold for mineralization of bones, so it’s no surprise that loss of collagen is associated with osteopenia and osteoporosis. Conversely, increased collagen intake could help support stronger bones! In a 2018 randomized controlled trial of postmenopausal women taking 5 grams of collagen peptides for a year, bone mineral density of both spine and femoral neck increased significantly compared to the placebo group. And in a 2015 randomized controlled trial of a combined supplementation of elemental calcium, vitamin D and 5 grams of a collagen-calcium chelate for a year in osteopenic postmenopausal women, the collagen-containing supplement resulted in much less bone mineral density loss than the group receiving just calcium and vitamin D, with concurrent reduction in bloodborne markers of bone breakdown.
Collagen and Cardiovascular Health
Could collagen be heart-healthy? The answer appears to be yes! In fact, several different studies have found that collagen supplementation could help improve cardiovascular risk factors. A 2013 trial tested the effects of collagen hydrolysate supplementation (2.9 grams daily for 18 weeks) on patients with elevated blood pressure (either mild hypertension, or the very upper end of normal blood pressure). The results showed that the collagen-consuming group had lower blood pressure, lower brachial-ankle pulse wave velocity (a marker of vascular damage and indicator of arterial stiffness), and higher nitrogen oxide (a vasodilator). Likewise, a 2017 open-label, single-dose trial of healthy adults tested the effects of collagen tripeptide supplementation (16 grams daily, split into two doses, for a total of 6 months) on the development of atherosclerosis. The collagen supplements led to significant reductions in the LDL to HDL ratio (among those with a baseline ratio of at least 2.5), toxic advanced glycation end-products, and the cardio-ankle vascular index (a measurement used to assess arterial stiffness).
And, a 2023 systematic review and meta-analysis of randomized controlled trials, encompassing a total of 12 different studies, found that collagen peptide supplementation significantly decreases serum LDL levels and systolic blood pressure, along with fat mass.
So, while we’re currently lacking data on collagen consumption for hard endpoints like heart attack and stroke, the evidence certainly points to a protective effect in terms of known risk factors!
Collagen, Muscle Recovery, and Strength
Yep, collagen could even be a boon for muscle recovery and strength! A 2023 randomized controlled trial found that adding collagen supplements to an exercise regimen (30 minutes of resistance and endurance training, three times per week) for a total of 12 weeks led to significant improvements in markers reflecting muscle recovery—particularly explosive, reactive, and maximal strength. The researchers hypothesized that these effects were due to collagen facilitating remodeling of the extracellular matrix, in turn enhancing the generation of explosive force and supporting muscular adaptations.
Collagen and Digestive Health
Some research has confirmed a gut-health-supportive role of collagen! A 2022 trial of healthy women found that supplementation with 20 grams daily of collagen peptides, for a period of eight weeks, led to reductions in bloating and improvements in mild digestive symptoms. (While mechanistic and animal evidence is abundant on this topic, more studies in humans are needed!)
Collagen and Nail Health
Although the research is limited, some evidence suggests that collagen could benefit the health of our nails! A 2024 randomized controlled trial of 85 adult women found that compared to placebo, 5 grams of daily collagen led to visible improvements in nail color after only 28 days.
Didn’t know collagen was such a superhero? Maybe your friends will enjoy this too!
Health Effects of Collagen Deficiency
Because the body can assemble its own collagen from other molecules, collagen isn’t considered an essential nutrient, and therefore no true “deficiency” exists in terms of dietary intake. However, a variety of factors can either impair collagen production in the body (e.g., deficiencies in nutrients that serve as co-factors for collagen synthesis), or raise our collagen requirements (such as lifestyle factors or medical conditions that increase collagen breakdown). So, while the body doesn’t face a deficiency in the traditional sense, low dietary intake and/or increased collagen breakdown can make us more susceptible to the effects of collagen loss, contributing to visible signs of aging, joint discomfort, loss of mobility, problems with blood flow, shrinking or weakening muscles, poor wound healing, and weakened connective tissues.
How Much Collagen Do We Need?
There’s no established recommended daily intake level for collagen. However, in studies of collagen supplementation, amounts as low as 2.5 to 10 grams daily have been shown to produce significant, measurable health benefits. Doses between 10 and 20 grams may have more dramatic and wide-ranging effects.
Extra collagen could be particularly helpful during times of increased collagen breakdown or repair, such as from physical injuries, burns, surgery, hormonal changes (such as menopause), certain cancer therapies, or exercise with high joint impact. Certain lifestyle factors can also raise our collagen requirements, including smoking, high alcohol intake, or excessive UV exposure from sunlight. Medical conditions affecting collagen in the body may also increase our collagen needs: for example, rheumatoid arthritis, osteoarthritis, or lupus. And of course, because our collagen levels naturally decrease with age, consuming extra collagen as we get older could be particularly beneficial!
It’s worth noting that while the collagen amounts typically used in studies don’t often exceed 20 grams daily, we can consume quite a lot more without jeopardizing the amino acid balance of our diet as a whole. Because collagen is an incomplete protein completely lacking in the essential amino acid tryptophan, it has a Protein Digestibility-Corrected Amino Acid Score (PDCAAS) of zero, even though it’s highly (98.8%) digestible. Researchers have used PDCAAS calculations to show that collagen peptides can make up to 36% of our dietary protein while ensuring indispensable amino acid requirements are met. That means that if you’re aiming for 150 grams of protein daily, you can safely get a little over 50 grams of that from collagen!
Citations
Expand to see all scientific references for this article.
Abrahams M, O’Grady R, Prawitt J. Effect of a Daily Collagen Peptide Supplement on Digestive Symptoms in Healthy Women: 2-Phase Mixed Methods Study. JMIR Form Res. 2022 May 31;6(5):e36339. doi: 10.2196/36339.
Alcock RD, Shaw GC, Burke LM. Bone Broth Unlikely to Provide Reliable Concentrations of Collagen Precursors Compared With Supplemental Sources of Collagen Used in Collagen Research. Int J Sport Nutr Exerc Metab. 2019 May 1;29(3):265-272. doi: 10.1123/ijsnem.2018-0139.
Barati M, Jabbari M, Navekar R, Farahmand F, Zeinalian R, Salehi-Sahlabadi A, Abbaszadeh N, Mokari-Yamchi A, Davoodi SH. Collagen supplementation for skin health: A mechanistic systematic review. J Cosmet Dermatol. 2020 Nov;19(11):2820-2829. doi: 10.1111/jocd.13435.
Barbul A, Lazarou SA, Efron DT, Wasserkrug HL, Efron G. Arginine enhances wound healing and lymphocyte immune responses in humans. Surgery. 1990 Aug;108(2):331-6; discussion 336-7.
Bello AE, Oesser S. Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature. Curr Med Res Opin. 2006 Nov;22(11):2221-32. doi: 10.1185/030079906X148373.
Bianchi FM, Angelinetta C, Rizzi G, Praticò A, Villa R. Evaluation of the Efficacy of a Hydrolyzed Collagen Supplement for Improving Skin Moisturization, Smoothness, and Wrinkles. J Clin Aesthet Dermatol. 2022 Mar;15(3):48-52.
Bischof K, Stafilidis S, Bundschuh L, Oesser S, Baca A, König D. Influence of specific collagen peptides and 12-week concurrent training on recovery-related biomechanical characteristics following exercise-induced muscle damage-A randomized controlled trial. Front Nutr. 2023 Nov 16;10:1266056. doi: 10.3389/fnut.2023.1266056.
Boyera N, Galey I, Bernard BA. Effect of vitamin C and its derivatives on collagen synthesis and cross-linking by normal human fibroblasts. Int J Cosmet Sci. 1998 Jun;20(3):151-8. doi: 10.1046/j.1467-2494.1998.171747.x.
Bruyère O, Zegels B, Leonori L, Rabenda V, Janssen A, Bourges C, Reginster JY. Effect of collagen hydrolysate in articular pain: a 6-month randomized, double-blind, placebo controlled study. Complement Ther Med. 2012 Jun;20(3):124-30. doi: 10.1016/j.ctim.2011.12.007.
Campos LD, Santos Junior VA, Pimentel JD, Carregã GLF, Cazarin CBB. Collagen supplementation in skin and orthopedic diseases: A review of the literature. Heliyon. 2023 Mar 28;9(4):e14961. doi: 10.1016/j.heliyon.2023.e14961.
Choi FD, Sung CT, Juhasz ML, Mesinkovsk NA. Oral Collagen Supplementation: A Systematic Review of Dermatological Applications. J Drugs Dermatol. 2019 Jan 1;18(1):9-16.
Clark KL, Sebastianelli W, Flechsenhar KR, Aukermann DF, Meza F, Millard RL, Deitch JR, Sherbondy PS, Albert A. 24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Curr Med Res Opin. 2008 May;24(5):1485-96. doi: 10.1185/030079908×291967.
Coffey JW, Fiedler-Nagy C, Georgiadis AG, Salvador RA. Digestion of native collagen, denatured collagen, and collagen fragments by extracts of rat liver lysosomes. J Biol Chem. 1976 Sep 10;251(17):5280-2.
de Almagro MC. The Use of Collagen Hydrolysates and Native Collagen in Osteoarthritis. 2020; 7(6). AJBSR.MS.ID.001217. doi: 10.34297/AJBSR.2020.07.001217.
Demir-Dora D, Ozsoy U, Yildirim Y, Yilmaz O, Aytac P, Yilmaz B, Dogan Kurtoglu E, Akman A, Tezman S, Inaloz HS, Erenmemisoglu A. The Efficacy and Safety of CollaSel Pro® Hydrolyzed Collagen Peptide Supplementation without Addons in Improving Skin Health in Adult Females: A Double Blind, Randomized, Placebo-Controlled Clinical Study Using Biophysical and Skin Imaging Techniques. J Clin Med. 2024 Sep 11;13(18):5370. doi: 10.3390/jcm13185370.
Dewi DAR, Arimuko A, Norawati L, Yenny SW, Setiasih NL, Perdiyana A, Arkania N, Nadhira F, Wiliantari N. Exploring the Impact of Hydrolyzed Collagen Oral Supplementation on Skin Rejuvenation: A Systematic Review and Meta-Analysis. Cureus. 2023 Dec 9;15(12):e50231. doi: 10.7759/cureus.50231.
Elam ML, Johnson SA, Hooshmand S, Feresin RG, Payton ME, Gu J, Arjmandi BH. A calcium-collagen chelate dietary supplement attenuates bone loss in postmenopausal women with osteopenia: a randomized controlled trial. J Med Food. 2015 Mar;18(3):324-31. doi: 10.1089/jmf.2014.0100.
Fu Y, Therkildsen M, Aluko RE, Lametsch R. Exploration of collagen recovered from animal by-products as a precursor of bioactive peptides: Successes and challenges. Crit Rev Food Sci Nutr. 2019;59(13):2011-2027. doi: 10.1080/10408398.2018.1436038.
García-Coronado JM, Martínez-Olvera L, Elizondo-Omaña RE, Acosta-Olivo CA, Vilchez-Cavazos F, Simental-Mendía LE, Simental-Mendía M. Effect of collagen supplementation on osteoarthritis symptoms: a meta-analysis of randomized placebo-controlled trials. Int Orthop. 2019 Mar;43(3):531-538. doi: 10.1007/s00264-018-4211-5.
Gelse K, Pöschl E, Aigner T. Collagens–structure, function, and biosynthesis. Adv Drug Deliv Rev. 2003 Nov 28;55(12):1531-46. doi: 10.1016/j.addr.2003.08.002.
Harkness ML, Harkness RD, Venn MF. Digestion of native collagen in the gut. Gut. 1978 Mar;19(3):240-3. doi: 10.1136/gut.19.3.240.
Harris ED, Rayton JK, Balthrop JE, DiSilvestro RA, Garcia-de-Quevedo M. Copper and the synthesis of elastin and collagen. Ciba Found Symp. 1980;79:163-82. doi: 10.1002/9780470720622.ch9.
Hong H, Fan H, Chalamaiah M, Wu J. Preparation of low-molecular-weight, collagen hydrolysates (peptides): Current progress, challenges, and future perspectives. Food Chem. 2019 Dec 15;301:125222. doi: 10.1016/j.foodchem.2019.125222.
Horn MA, Trafford AW. Aging and the cardiac collagen matrix: Novel mediators of fibrotic remodelling. J Mol Cell Cardiol. 2016 Apr;93:175-85. doi: 10.1016/j.yjmcc.2015.11.005.
Iwai K, Hasegawa T, Taguchi Y, Morimatsu F, Sato K, Nakamura Y, Higashi A, Kido Y, Nakabo Y, Ohtsuki K. Identification of food-derived collagen peptides in human blood after oral ingestion of gelatin hydrolysates. J Agric Food Chem. 2005 Aug 10;53(16):6531-6. doi: 10.1021/jf050206p.
Jalili Z, Jalili F, Moradi S, Bagheri R, Moosavian SP, Naeini F, Mohammadi H, Mojtaba Ghoreishy S, Wong A, Travica N, Hojjati Kermani MA, Jalili C. Effects of collagen peptide supplementation on cardiovascular markers: a systematic review and meta-analysis of randomised, placebo-controlled trials. Br J Nutr. 2023 Mar 14;129(5):779-794. doi: 10.1017/S0007114522001301.
Jendricke P, Centner C, Zdzieblik D, Gollhofer A, König D. Specific Collagen Peptides in Combination with Resistance Training Improve Body Composition and Regional Muscle Strength in Premenopausal Women: A Randomized Controlled Trial. Nutrients. 2019 Apr 20;11(4):892. doi: 10.3390/nu11040892.
Karna E, Miltyk W, Wołczyński S, Pałka JA. The potential mechanism for glutamine-induced collagen biosynthesis in cultured human skin fibroblasts. Comp Biochem Physiol B Biochem Mol Biol. 2001 Aug;130(1):23-32. doi: 10.1016/s1096-4959(01)00400-6.
Kim DU, Chung HC, Choi J, Sakai Y, Lee BY. Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study. Nutrients. 2018 Jun 26;10(7):826. doi: 10.3390/nu10070826.
Kirmse M, Oertzen-Hagemann V, de Marées M, Bloch W, Platen P. Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men. Nutrients. 2019 May 23;11(5):1154. doi: 10.3390/nu11051154.
Kouguchi T, Ohmori T, Shimizu M, Takahata Y, Maeyama Y, Suzuki T, Morimatsu F, Tanabe S. Effects of a chicken collagen hydrolysate on the circulation system in subjects with mild hypertension or high-normal blood pressure. Biosci Biotechnol Biochem. 2013;77(4):691-6. doi: 10.1271/bbb.120718.
Lee SK, Posthauer ME, Dorner B, Redovian V, Maloney MJ. Pressure ulcer healing with a concentrated, fortified, collagen protein hydrolysate supplement: a randomized controlled trial. Adv Skin Wound Care. 2006 Mar;19(2):92-6. doi: 10.1097/00129334-200603000-00011.
León-López A, Morales-Peñaloza A, Martínez-Juárez VM, Vargas-Torres A, Zeugolis DI, Aguirre-Álvarez G. Hydrolyzed Collagen-Sources and Applications. Molecules. 2019 Nov 7;24(22):4031. doi: 10.3390/molecules24224031.
Li S, Niu G, Wu Y, Du G, Huang C, Yin X, Liu Z, Song C, Leng H. Vitamin D prevents articular cartilage erosion by regulating collagen II turnover through TGF-β1 in ovariectomized rats. Osteoarthritis Cartilage. 2016 Feb;24(2):345-53. doi: 10.1016/j.joca.2015.08.013.
Lin CR, Tsai SHL, Huang KY, Tsai PA, Chou H, Chang SH. Analgesic efficacy of collagen peptide in knee osteoarthritis: a meta-analysis of randomized controlled trials. J Orthop Surg Res. 2023 Sep 16;18(1):694. doi: 10.1186/s13018-023-04182-w.
Lis DM, Baar K. Effects of Different Vitamin C-Enriched Collagen Derivatives on Collagen Synthesis. Int J Sport Nutr Exerc Metab. 2019 Sep 1;29(5):526-531. doi: 10.1123/ijsnem.2018-0385.
Liu D, Nikoo M, Boran G, Zhou P, Regenstein JM. Collagen and gelatin. Annu Rev Food Sci Technol. 2015;6:527-57. doi: 10.1146/annurev-food-031414-111800.
Lugo JP, Saiyed ZM, Lau FC, Molina JP, Pakdaman MN, Shamie AN, Udani JK. Undenatured type II collagen (UC-II®) for joint support: a randomized, double-blind, placebo-controlled study in healthy volunteers. J Int Soc Sports Nutr. 2013 Oct 24;10(1):48. doi: 10.1186/1550-2783-10-48.
McAlindon TE, Nuite M, Krishnan N, Ruthazer R, Price LL, Burstein D, Griffith J, Flechsenhar K. Change in knee osteoarthritis cartilage detected by delayed gadolinium enhanced magnetic resonance imaging following treatment with collagen hydrolysate: a pilot randomized controlled trial. Osteoarthritis Cartilage. 2011 Apr;19(4):399-405. doi: 10.1016/j.joca.2011.01.001.
Meschiari CA, Ero OK, Pan H, Finkel T, Lindsey ML. The impact of aging on cardiac extracellular matrix. Geroscience. 2017 Feb;39(1):7-18. doi: 10.1007/s11357-017-9959-9.
Mohammad AW, Suhimi NM, Aziz AGKA, Jahim JM. Process for Production of Hydrolysed Collagen from Agriculture Resources: Potential for Further Development. Journal of Applied Sciences, 2014;14: 1319-1323. doi: 10.3923/jas.2014.1319.1323
Molenda M, Kolmas J. The Role of Zinc in Bone Tissue Health and Regeneration-a Review. Biol Trace Elem Res. 2023 Dec;201(12):5640-5651. doi: 10.1007/s12011-023-03631-1.
O’Dell BL. Roles for iron and copper in connective tissue biosynthesis. Philos Trans R Soc Lond B Biol Sci. 1981 Aug 14;294(1071):91-104. doi: 10.1098/rstb.1981.0091.
Oertzen-Hagemann V, Kirmse M, Eggers B, Pfeiffer K, Marcus K, de Marées M, Platen P. Effects of 12 Weeks of Hypertrophy Resistance Exercise Training Combined with Collagen Peptide Supplementation on the Skeletal Muscle Proteome in Recreationally Active Men. Nutrients. 2019 May 14;11(5):1072. doi: 10.3390/nu11051072.
Ohara H, Matsumoto H, Ito K, Iwai K, Sato K. Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources. J Agric Food Chem. 2007 Feb 21;55(4):1532-5. doi: 10.1021/jf062834s.
Osawa Y, Mizushige T, Jinno S, Sugihara F, Inoue N, Tanaka H, Kabuyama Y. Absorption and metabolism of orally administered collagen hydrolysates evaluated by the vascularly perfused rat intestine and liver in situ. Biomed Res. 2018;39(1):1-11. doi: 10.2220/biomedres.39.1.
Panwar P, Lamour G, Mackenzie NC, Yang H, Ko F, Li H, Brömme D. Changes in Structural-Mechanical Properties and Degradability of Collagen during Aging-associated Modifications. J Biol Chem. 2015 Sep 18;290(38):23291-306. doi: 10.1074/jbc.M115.644310.
Park J, Kim M, Shin H, Ahn H, Park YK. Low-Molecular Collagen Peptide Supplementation and Body Fat Mass in Adults Aged ≥ 50 Years: A Randomized, Double-Blind, Placebo-Controlled Trial. Clin Nutr Res. 2023 Oct 31;12(4):245-256. doi: 10.7762/cnr.2023.12.4.245.
Paul C, Leser S, Oesser S. Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance. Nutrients. 2019 May 15;11(5):1079. doi: 10.3390/nu11051079.
Pinnel SR, Murad S, Darr D. Induction of collagen synthesis by ascorbic acid. A possible mechanism. Arch Dermatol. 1987 Dec;123(12):1684-6. doi: 10.1001/archderm.123.12.1684.
Praet SFE, Purdam CR, Welvaert M, Vlahovich N, Lovell G, Burke LM, Gaida JE, Manzanero S, Hughes D, Waddington G. Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients. Nutrients. 2019 Jan 2;11(1):76. doi: 10.3390/nu11010076.
Pritchard A, Nielsen BD. Silicon Supplementation for Bone Health: An Umbrella Review Attempting to Translate from Animals to Humans. Nutrients. 2024 Jan 24;16(3):339. doi: 10.3390/nu16030339.
Proksch E, Segger D, Degwert J, Schunck M, Zague V, Oesser S. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study. Skin Pharmacol Physiol. 2014;27(1):47-55. doi: 10.1159/000351376.
Pu SY, Huang YL, Pu CM, Kang YN, Hoang KD, Chen KH, Chen C. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients. 2023 Apr 26;15(9):2080. doi: 10.3390/nu15092080.
Razak MA, Begum PS, Viswanath B, Rajagopal S. Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review. Oxid Med Cell Longev. 2017;2017:1716701. doi: 10.1155/2017/1716701. Epub 2017 Mar 1. Erratum in: Oxid Med Cell Longev. 2022 Feb 23;2022:9857645. doi: 10.1155/2022/9857645.
Reilly DM, Kynaston L, Naseem S, Proudman E, Laceby D. A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen. Dermatol Res Pract. 2024 Jul 10;2024:8752787. doi: 10.1155/2024/8752787.
Ricard-Blum S, Ruggiero F. The collagen superfamily: from the extracellular matrix to the cell membrane. Pathol Biol (Paris). 2005 Sep;53(7):430-42. doi: 10.1016/j.patbio.2004.12.024.
Ricard-Blum S. The collagen family. Cold Spring Harb Perspect Biol. 2011 Jan 1;3(1):a004978. doi: 10.1101/cshperspect.a004978.
Samadi A, Movaffaghi M, Kazemi F, Yazdanparast T, Ahmad Nasrollahi S, Firooz A. Tolerability and efficacy assessment of an oral collagen supplement for the improvement of biophysical and ultrasonographic parameters of skin in middle eastern consumers. J Cosmet Dermatol. 2023 Aug;22(8):2252-2258. doi: 10.1111/jocd.15700.
Sato K. The presence of food-derived collagen peptides in human body-structure and biological activity. Food Funct. 2017 Dec 13;8(12):4325-4330. doi: 10.1039/c7fo01275f.
Schwartz Z, Schlader DL, Ramirez V, Kennedy MB, Boyan BD. Effects of vitamin D metabolites on collagen production and cell proliferation of growth zone and resting zone cartilage cells in vitro. J Bone Miner Res. 1989 Apr;4(2):199-207. doi: 10.1002/jbmr.5650040211.
Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017 Jan;105(1):136-143. doi: 10.3945/ajcn.116.138594.
Shi HP, Fishel RS, Efron DT, Williams JZ, Fishel MH, Barbul A. Effect of supplemental ornithine on wound healing. J Surg Res. 2002 Aug;106(2):299-302. doi: 10.1006/jsre.2002.6471.
Song H, Zhang S, Zhang L, Li B. Effect of Orally Administered Collagen Peptides from Bovine Bone on Skin Aging in Chronologically Aged Mice. Nutrients. 2017 Nov 3;9(11):1209. doi: 10.3390/nu9111209.
Sugihara F, Inoue N, Venkateswarathirukumara S. Ingestion of bioactive collagen hydrolysates enhanced pressure ulcer healing in a randomized double-blind placebo-controlled clinical study. Sci Rep. 2018 Jul 30;8(1):11403. doi: 10.1038/s41598-018-29831-7.
Taga Y, Iwasaki Y, Shigemura Y, Mizuno K. Improved in Vivo Tracking of Orally Administered Collagen Hydrolysate Using Stable Isotope Labeling and LC-MS Techniques. J Agric Food Chem. 2019 Apr 24;67(16):4671-4678. doi: 10.1021/acs.jafc.9b00571.
Tomosugi N, Yamamoto S, Takeuchi M, Yonekura H, Ishigaki Y, Numata N, Katsuda S, Sakai Y. Effect of Collagen Tripeptide on Atherosclerosis in Healthy Humans. J Atheroscler Thromb. 2017 May 1;24(5):530-538. doi: 10.5551/jat.36293.
Varani J, Dame MK, Rittie L, Fligiel SE, Kang S, Fisher GJ, Voorhees JJ. Decreased collagen production in chronologically aged skin: roles of age-dependent alteration in fibroblast function and defective mechanical stimulation. Am J Pathol. 2006 Jun;168(6):1861-8. doi: 10.2353/ajpath.2006.051302.
Vleminckx S, Virgilio N, Asserin J, Prawitt J, Silva CIF. Influence of collagen peptide supplementation on visible signs of skin and nail health and -aging in an East Asian population: A double blind, randomized, placebo-controlled trial. J Cosmet Dermatol. 2024 Nov;23(11):3645-3653. doi: 10.1111/jocd.16458.
Wang H. A Review of the Effects of Collagen Treatment in Clinical Studies. Polymers (Basel). 2021 Nov 9;13(22):3868. doi: 10.3390/polym13223868.
Zdzieblik D, Oesser S, Baumstark MW, Gollhofer A, König D. Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial. Br J Nutr. 2015 Oct 28;114(8):1237-45. doi: 10.1017/S0007114515002810.
Zhu S, Huang M, Feng G, Miao Y, Wu H, Zeng M, Lo YM. Gelatin versus its two major degradation products, prolyl-hydroxyproline and glycine, as supportive therapy in experimental colitis in mice. Food Sci Nutr. 2018 Apr 16;6(4):1023-1031. doi: 10.1002/fsn3.639.
