Do collagen supplements actually work?

Collagen supplements are now among the wellness sector’s top-selling products, with claims ranging from smoother skin to more resilient joints. But is there evidence that they deliver these effects?

A substantial new evidence review, combining findings from 113 clinical trials, indicates that they probably do for certain health measures.

As is often the case in nutrition research, however, the reality is not straightforward.

Collagen is a protein produced naturally by the body. It provides skin with structure and elasticity, supports muscles and bones, contributes to wound healing and helps protect organs. Its production declines with age, prompting many people to use supplements in an attempt to replenish it.

Yet collagen products are not all alike. Collagen obtained naturally from food may not be absorbed as effectively as the smaller forms found in most supplements.

These hydrolysed versions contain protein broken into short chains known as peptides. They are believed to enter the bloodstream more easily, allowing the body to carry these fragments to tissues where they could have biological effects, with potential benefits for skin, joints and muscles.

What the collagen supplements review found

The new review assessed research published up to March 2025. It drew on 16 systematic reviews, which together involved almost 8,000 participants. Overall, its findings were cautiously encouraging.

Taking collagen supplements was associated with moderate gains in muscle health and less pain among people with osteoarthritis.

Skin elasticity and hydration also improved. However, the effects accumulated over time, indicating that regular use over a longer period may be more important than a brief spell of supplementation.

Other results were more uncertain. Findings on skin hydration and elasticity varied according to when the studies took place: more recent studies reported smaller improvements in elasticity but larger improvements in hydration.

That variation matters, as it indicates that the evidence is still evolving.

Limits of the collagen evidence

The quality of the underlying research also needs careful consideration. Studies used very different methods, doses and outcome measures, making meaningful direct comparisons challenging.

Fifteen of the 16 reviews were assessed as being of low or critically low quality. This does not necessarily mean the supplements are ineffective, but reflects methodological shortcomings, including trials not being registered in advance and inadequate reporting of possible biases.

Many of the trials were short in duration and involved only small numbers of participants. This restricts the conclusions that can be drawn reliably about longer-term effects.

Not all collagen is equal

One difficulty is the enormous variation between collagen supplements. Some are sourced from animals including cows, pigs and chickens, while others come from marine sources such as fish, jellyfish and shellfish.

There are also so-called "vegan" collagen alternatives. While some research examined supplements taken orally, other studies assessed collagen dressings applied directly to skin.

Processing methods can also alter the size and composition of peptides in the finished product, affecting both their behaviour in the body and their absorption. Combining all of these different products within one analysis may conceal as much as it clarifies.

Personal variation is important as well. Sun exposure, smoking, sleep quality, environmental conditions and hormone levels can all influence skin ageing and its possible response to supplementation.

When studies do not account for these factors, it is difficult to establish whether observed changes are truly caused by collagen or instead reflect differences in participants’ lifestyles.

This review contributes to an expanding body of evidence suggesting that collagen supplements are more than simply costly placebos. There seem to be genuine, though modest, benefits, especially for skin hydration, joint pain and muscle health.

Important gaps remain in the research. Until more robust and standardised studies are available, it will remain difficult to identify what is responsible for these benefits or who is most likely to experience them.

Studies must specify clearly the collagen type used, the dose, the method of delivery and the characteristics of the people receiving it.

Heba Ghazal, Senior Lecturer, Pharmacy, Kingston University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.