When can collagen supplements help? Breaking down the science
Collagen powders, gummies and "beauty" drinks promise glowing skin, thicker hair and stronger nails. But what does the science actually say? Here is where collagen may help, where the evidence is not there yet, and why the basics matter most.
How collagen works in the body
Collagen is the main structural protein in skin, tendons, ligaments and bone. When you take a collagen supplement, it is digested into amino acids and small peptides like any other protein. It does not travel straight to your skin or joints. Your body decides where those building blocks go, based on what it needs most.
Oestrogen helps maintain collagen, which is one reason collagen loss speeds up around perimenopause and menopause, and why these products are often marketed to women in midlife.
Types of collagen
- Type I: the most common type, found in skin, bone, tendons and ligaments.
- Type II: the main collagen in cartilage, which cushions the joints.
- Type III: found alongside Type I in skin and blood vessels.
Most supplements are hydrolysed collagen (collagen peptides) from cow, pig or fish, and mainly provide Types I and III. As these are broken down during digestion, the type on the label matters less than it seems. Undenatured Type II collagen, usually from chicken cartilage, is taken in much smaller doses and is mostly marketed for joints.
What about vegan collagen? Collagen only comes from animals, so vegan collagen does not exist. Vegan "collagen boosters" contain nutrients like vitamin C and zinc that help your body make its own, which you can also get from a varied diet.
Where collagen may help
Tendon and ligament rehab. In a small study, taking 15 g of gelatin with vitamin C (which the body needs to build stable collagen) an hour before a short bout of exercise roughly doubled a blood marker of collagen production.2 This is why the two are sometimes paired with rehab programs. The study measured a marker, not injury outcomes, so it is promising but not a standalone fix.
Joint pain. A 2024 meta analysis of 11 trials in knee osteoarthritis found collagen reduced pain and improved function compared with placebo.7 Results varied a lot between studies, so Arthritis UK describes the evidence as promising but does not yet recommend collagen as a routine treatment.8
Where the evidence is not there yet
A 2025 meta analysis of 23 trials found collagen appeared to improve skin hydration, elasticity and wrinkles when all studies were pooled. When only independent or high quality studies were included, the benefits disappeared.1 For hair, there is very little human research.
| Area | What the research shows | Evidence |
|---|---|---|
| Tendons and rehab | Collagen with vitamin C before exercise increased collagen production markers | Promising |
| Joint pain (osteoarthritis) | Reduced pain and improved function, but results varied between studies | Promising |
| Bone density | One 12 month trial in postmenopausal women showed improvement3 | Promising |
| Nails | One small study, no placebo group4 | Early |
| Skin | No benefit in independent or high quality studies | Not yet |
| Hair | Very limited human research | Not yet |
| Muscle building | Less effective than complete proteins like whey5 | Not ideal |
Hair, skin and nails: core nutrients come first
When energy or protein intake is low, your body directs its resources to essential functions, such as your organs and immune system. Hair growth is particularly sensitive to this, so changes in your hair, skin and nails can sometimes reflect a gap in your nutrition, although they have many other possible causes.
Deficiencies in iron and zinc, and inadequate protein or energy, are all linked with hair shedding. Correcting a true deficiency helps, but there is little evidence supplements help when your levels are already adequate.6
The key message: A collagen supplement cannot make up for a diet that is not meeting your core needs. Start there first.
In general, foundations to consider before supplements
- Eat enough overall. Consistently eating too little affects hair, skin, hormones and energy.
- Meet your protein requirements, with foods such as eggs, yoghurt, fish, chicken, tofu or legumes.
- Ask your GP about checking iron, especially if you have heavy periods.
- Include zinc from meat, seafood, legumes, nuts and seeds.
- Eat a variety of colourful fruit and vegetables for vitamin C.
- Wear sunscreen. UV exposure is one of the biggest drivers of skin ageing.
The bottom line
Collagen shows promise for tendon and ligament rehab when paired with vitamin C and exercise, and possibly for joint pain. For skin, hair and nails, the evidence does not yet match the marketing. Most studies have run for at least 8 to 12 weeks, and third party testing offers more assurance of a product's quality. Overall, meeting needs for energy, protein, iron, zinc and vitamin C remains the foundation for healthy hair, skin and nails.
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Book a Free Discovery CallThis article is for general education and is not a substitute for individual medical or dietetic advice. Speak with your healthcare team before starting a new supplement.
References
- Myung SK, Park Y. Effects of collagen supplements on skin aging: a systematic review and meta-analysis of randomized controlled trials. Am J Med. 2025;138(9):1264-1277. PMID: 40324552.
- 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;105(1):136-143. PMID: 27852613.
- König D, Oesser S, Scharla S, Zdzieblik D, Gollhofer A. Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women: a randomized controlled study. Nutrients. 2018;10(1):97. PMID: 29337906; PMCID: PMC5793325.
- Hexsel D, Zague V, Schunck M, Siega C, Camozzato FO, Oesser S. Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails. J Cosmet Dermatol. 2017;16:520-526. PMID: 28786550.
- Oikawa SY, Kamal MJ, Webb EK, McGlory C, Baker SK, Phillips SM. Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial. Am J Clin Nutr. 2020;111(3):708-718. PMID: 31919527; PMCID: PMC7049534.
- Guo EL, Katta R. Diet and hair loss: effects of nutrient deficiency and supplement use. Dermatol Pract Concept. 2017;7(1):1-10. PMID: 28243487; PMCID: PMC5315033.
- Simental-Mendía M, Ortega-Mata D, Acosta-Olivo CA, Simental-Mendía LE, Peña-Martínez VM, Vilchez-Cavazos F. Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials. Clin Exp Rheumatol. 2024. PMID: 39212129.
- Arthritis UK. Collagen for joints. arthritis-uk.org.
