Collagen Supplements: What the Research Says and How to Choose

Updated September 2026

Collagen is the most abundant protein in the body, giving structure to skin, bones, tendons and cartilage. Our natural collagen production slows with age, which is one reason collagen supplements have become so popular. The research is encouraging, but more nuanced than the marketing suggests.

The main types of collagen

• Type I is the most abundant type, found in skin, bone and tendons.
• Type II is the main collagen in cartilage, the cushioning in your joints.
• Type III works alongside Type I in skin and blood vessels.

Does taking collagen actually do anything?

When you take collagen, it's digested into amino acids and small peptides. Some of these peptides reach the bloodstream, and researchers believe they may act as signals to the cells that produce collagen in the skin.

In a double blind, placebo controlled trial, 69 women aged 35 to 55 took 2.5 g or 5 g of specific collagen peptides daily for eight weeks. Both groups showed a significant improvement in skin elasticity compared with placebo.¹ A 2019 systematic review of oral collagen for skin concluded that results are promising for skin elasticity and hydration, while calling for larger, independent studies.²

Worth knowing: many studies use specific branded peptides and some are industry funded, so results can't automatically be applied to every product on the shelf.

Marine vs bovine collagen

Marine collagen comes from fish skin and is mainly Type I. It suits pescatarians, but isn't suitable if you have a fish allergy.

Bovine collagen comes from cattle hide and provides Types I and III.

Both are usually hydrolysed (broken down into peptides) to improve absorption. There's limited head to head evidence that one source works better than the other, so choose based on your diet, allergies and preferences.

Why your collagen might not seem to be working

• Not enough time. Most skin studies measure results at eight to twelve weeks, not days.
• Inconsistent use. Benefits in studies come from daily intake.
• Dose too low. Most skin studies use between 2.5 g and 10 g a day.
• Missing vitamin C. Vitamin C contributes to normal collagen formation in the body.
• Lifestyle factors. Sun exposure and smoking both break down collagen. Daily sunscreen does more for your skin's collagen than any supplement.

What to look for on the label

• Hydrolysed collagen peptides
• A clear dose per serve, ideally in the 2.5 g to 10 g range used in research
• The source (marine or bovine) and any allergens clearly listed
• Independent testing, including for heavy metals

The bottom line

Collagen isn't a miracle product, but the evidence for skin elasticity and hydration is building. Choose hydrolysed peptides at a researched dose, take them daily for at least two to three months, and pair them with vitamin C and sun protection.

Where Keeper fits: Keeper Body Boost contains 5 g of marine collagen (Type I) per sachet, with 250 mg of vitamin C, which contributes to normal collagen formation, plus creatine and HMB. Contains fish. Every batch is third party tested. See our testing standards.

References

1. Proksch E et al. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double blind, placebo controlled study. Skin Pharmacol Physiol. 2014.
2. Choi FD et al. Oral collagen supplementation: a systematic review of dermatological applications. J Drugs Dermatol. 2019.

This article is general information only and isn't a substitute for advice from your healthcare professional.