Medically reviewed by Dr. Reina Punj, MBBS, PG Diploma in Endocrinology (University of South Wales), Lead Physician, Excelgenics Clinical Panel.
The benefits of marine collagen that have been studied most are for skin. Several trials have reported better skin hydration and elasticity in people who took hydrolysed collagen peptides, usually 2.5–10 g a day for 8–12 weeks. However, a 2025 meta-analysis found these benefits mainly in industry-funded and lower-quality trials, and good evidence for hair, nails, joints or weight is lacking. This article explains what marine collagen is, what the research on marine collagen benefits actually shows, and the honest limits of that evidence.
For how collagen supplements work and what to look for on a label, see our Marine Collagen Supplements Guide.
What is marine collagen?
Collagen is the most abundant protein in the body. It gives structure and strength to skin, bone, tendons and cartilage, and the body makes less of it as we age. Marine collagen comes from fish skin or scales and is mainly type I collagen, the type found most in human skin.
In supplements, marine collagen is usually hydrolysed: broken down into smaller pieces called collagen peptides, which dissolve easily and are easier to digest. It is sold as powders, tablets and capsules, often combined with hyaluronic acid, vitamin C and antioxidants. Because it comes from fish, marine collagen is not vegetarian or vegan.
Benefits of collagen for skin: what the trials found
Most research on the benefits of collagen for skin has looked at three things: hydration (how much moisture the skin holds), elasticity (how well it springs back) and wrinkles. These trials usually lasted 8–12 weeks and used collagen peptides from a range of animal sources, not only fish.
The largest recent analysis is a 2025 systematic review and meta-analysis in The American Journal of Medicine by Myung and Park. It pooled 23 randomised controlled trials with 1,474 participants. Its findings were:
- Across all trials: collagen supplements were linked with significant improvements in skin hydration, elasticity and wrinkles.
- By funding: trials funded by companies showed significant effects, while trials without company funding showed no significant effect on any of these outcomes.
- By quality: high-quality trials showed no significant effect; only lower-quality trials showed better elasticity.
The authors concluded that there is currently no clinical evidence to support using collagen supplements to prevent or treat skin ageing. The Harvard T.H. Chan School of Public Health makes a similar point: most collagen research is funded or partly funded by industry, which makes the true effect hard to judge.
So the fair summary is this: some trials have found modest skin changes in the people studied, but the evidence is not as strong as marketing suggests, and the results cannot be assumed for every product.
Marine collagen benefits: where the evidence is weak or missing
| Claimed benefit | What the evidence shows |
|---|---|
| Skin hydration and elasticity | Mixed: positive results mainly in industry-funded and lower-quality trials |
| Hair growth or thickness | We could not find good-quality research supporting this |
| Stronger nails | Little good-quality research |
| Joints | Some trials of other collagen types have reported less joint discomfort, but very little research has tested marine collagen for joints |
| Weight loss | We found no good evidence; collagen is a protein and provides calories like any other protein |
For joints, most research has used different ingredients, such as undenatured type II collagen (UC-II) from chicken cartilage, which works in a different way and at a much smaller dose. Results for one type of collagen cannot be applied to another.
How much collagen did the studies use?
Most skin trials used 2.5–10 g of collagen peptides a day, which is why many collagen products are powders. Capsules hold much less.
For example, Radia Marine Collagen + Hyaluronic Acid provides 500 mg of marine collagen peptides (type I & III) per 2-capsule daily serving, together with low-molecular-weight hyaluronic acid 100 mg, grape seed extract (95% OPC) 100 mg, vitamin C 65 mg, CoQ10 60 mg, lycopene 10 mg, vitamin E 10 mg, zinc 5 mg, black pepper extract 5 mg and astaxanthin 4 mg. That is less collagen than the doses used in skin trials, between a fifth and a twentieth of them, so trial results should not be assumed to apply. It is fish-derived, so it is not vegetarian and is not suitable for anyone with a fish allergy. It contains CoQ10, which can interact with warfarin and insulin, and black pepper extract (piperine), which can change how some medicines are processed; speak to your doctor first if you take regular medication.
Supporting your skin's own collagen
Your body makes collagen from the protein in your diet, and it needs vitamin C to do so. Vitamin C contributes to normal collagen formation for the normal function of skin, a nutrient function recognised by the European Food Safety Authority (EFSA). Habits matter at least as much as any supplement:
- Sun protection: sun exposure speeds up collagen breakdown, so daily sunscreen and shade do a great deal for skin.
- Not smoking: smoking, including second-hand smoke, is linked to faster collagen loss.
- Diet: enough protein, plus fruit and vegetables rich in vitamin C.
- Sleep and alcohol: poor sleep and too much alcohol are also linked to collagen loss.
Who should be careful with marine collagen?
Collagen supplements are generally well tolerated in trials; some people notice mild stomach upset or a feeling of fullness. Avoid marine collagen if you have a fish allergy. If you are pregnant or breastfeeding, take regular medicines (especially blood thinners or diabetes medicines) or have a medical condition, speak to your doctor first. Read more in marine collagen side effects.
Frequently asked questions
What are the benefits of marine collagen for skin?
Some trials have found improved skin hydration and elasticity with 2.5–10 g of collagen peptides a day over 8–12 weeks. A 2025 meta-analysis found that higher-quality and independently funded trials did not show these benefits, so the evidence is still uncertain.
Is marine collagen better than other collagen?
No collagen source has been clearly shown to be better for skin. Marine collagen suits people who prefer to avoid beef or pork, but it is not suitable for people with a fish allergy.
Does marine collagen help hair growth?
We could not find good-quality research showing that collagen supplements improve hair growth. If you are losing hair, see a doctor, as hair loss can have medical causes.
How long does marine collagen take to work?
Studies usually measure skin changes after 8–12 weeks of daily use, and results vary. Read more in how long it takes to see skin changes from supplements.
Can vegetarians get marine collagen benefits?
Marine collagen comes from fish, so it is not vegetarian. Collagen exists only in animal tissue. Vegetarians can support their body's own collagen formation with enough protein and vitamin C-rich foods.
References
- Myung SK, Park Y. Effects of collagen supplements on skin aging: a systematic review and meta-analysis of randomized controlled trials. The American Journal of Medicine. 2025;138(9):1264–1277. doi:10.1016/j.amjmed.2025.04.034
- Harvard T.H. Chan School of Public Health, The Nutrition Source. Collagen. nutritionsource.hsph.harvard.edu
- Choi FD, Sung CT, Juhasz MLW, Mesinkovska NA. Oral collagen supplementation: a systematic review of dermatological applications. Journal of Drugs in Dermatology. 2019;18(1):9–16. jddonline.com
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to vitamin C. EFSA Journal. 2009;7(9):1226. doi:10.2903/j.efsa.2009.1226
- National Center for Complementary and Integrative Health (NIH). Coenzyme Q10. nccih.nih.gov
- Bhardwaj RK, Glaeser H, Becquemont L, et al. Piperine, a major constituent of black pepper, inhibits human P-glycoprotein and CYP3A4. Journal of Pharmacology and Experimental Therapeutics. 2002;302(2):645–650. doi:10.1124/jpet.102.034728
This article is for general education and is not medical advice. Food supplements are not intended to diagnose, treat, cure or prevent any disease. Consult a qualified healthcare professional before starting any supplement, particularly if you are pregnant, breastfeeding, have a medical condition or take medication.
