Arthritis relief: Can collagen supplements help?

Collagen supplements are marketed as supporting joint health. Research scientist Tim Crowe digs into the science and finds potential good news.

Interest in collagen supplements continues to grow – and for good reason. The body of scientific evidence supporting some of the health claims about collagen supplements, especially for skin
and joint health, is stacking up. Let’s take a look at some emerging science about their use for arthritis relief.

Collagen 101

Collagen is the most abundant protein in our body, present as a major structural protein in many tissues including tendons, ligaments, cartilage, blood vessels and skin.

There are 28 distinct types of collagen. The most abundant are types I, II and III. Type I collagen is found in tendons, ligaments, corneas, bones and skin. Type III collagen is typically found alongside type I collagen in the skin and blood vessels. While type II collagen is mostly found in cartilage.

Hydrolysed collagen is the most common form in the supplement market. When native collagen is heated, it denatures (changes structure) to form gelatin. However, gelatin has low solubility so hydrolysing collagen increases solubility and absorption.

It’s all about the peptides

When collagen is eaten it is digested and absorbed into the bloodstream where it produces amino acids and unique peptides which redistribute to the skin and act as signalling molecules to skin cells called fibroblasts which produce collagen, elastin (which is needed for skin elasticity) and hyaluronic acid (for water retention).

This may be the mechanism by which collagen consumption directly affects our skin. And similar types of pathways exist in cells that produce collagen found in cartilage and tendons.

Collagen for skin health

Results from 19 clinical trials showed supplementation with hydrolysed collagen had a statistically significant effect on skin hydration, skin elasticity, skin density and wrinkles. Effective collagen doses ranged from 0.6g to 12g per day for one to three months.

There has been even more research since those trials.

A late 2023 systematic review analysed 26 randomised controlled trials of oral collagen supplements’ effects on skin hydration and skin elasticity.

Like prior reviews, a significant benefit was seen, with almost every study pointing in the right direction for a positive benefit.

Of those 26 studies on skin health, 11 had no funding from the collagen industry, nor did any of the research team report a conflict of interest. Those ‘untainted’ trials were just as likely to show a benefit as those with industry links.

Arthritis relief: Can collagen supplements help?

Arthritis is the swelling and tenderness of one or more joints, often with pain and stiffness, which typically worsen with age. The most common types are osteoarthritis and rheumatoid arthritis.

Osteoarthritis is characterised by a breakdown in cartilage which covers the ends of bones where they form a joint. It’s more common in women and usually affects people from 45 onwards. It often affects the knees, hands, hips and back, causing loss of the protective cartilage.

In rheumatoid arthritis, the immune system attacks the joints, beginning with their lining.

The differences between these two are worth noting, because collagen supplements could help with both forms, but through different mechanisms.

Collagen for osteoarthritis

Osteoarthritis is common – afflicting more than 500 million people worldwide. Treatment involves pain-relieving anti-inflammatory medications along with regular exercise and healthy weight.

Where the interest in collagen supplements arises is from the observation that cartilage is mostly made up of collagen – in particular type II – while in skin types I and III collagens are predominant.

But just because cartilage is made up of mostly collagen, does that mean taking a collagen supplement will help repair it?

Extensive research already done on collagen supplements and skin health shows specific effects of oral hydrolysed collagen. So, it isn’t a crazy stretch to think there could be some benefit on the joints too. Interestingly, from in vitro cell culture studies exposing chondrocyte cells (the cells responsible for cartilage production) to collagen shows an increase in collagen production.

What do clinical trials have to say?

Although there have been fewer clinical trials on collagen supplementation for osteoarthritis published than for skin health, there are enough to assess a possible benefit.

The initial collection of research in humans came from a 2018 systematic review. Five randomised controlled trials involved over 500 people with osteoarthritis taking oral collagen supplements or a placebo for 10 to 48 weeks. Four of the studies used hydrolysed collagen taken at between 2g to 10g per day while the fifth study used 40mg of undenatured type II collagen.

What the review uncovered was a clear significant reduction in arthritis symptoms reflected in the pooled data and in the individual studies which mostly all reported a significant benefit. There was a lot of variability among studies, due to differences in doses of collagen used as well as the length of treatment.

With just five studies included, this review is by no means a ‘slam dunk’ for the benefit of collagen in osteoarthritis, however, it gives a very positive signal. But the review only included research published before 2018. So what has happened since then?

The latest research

A 2023 review summarised six randomised controlled trials and three observational studies on hydrolysed collagen and osteoarthritis.

The studies varied greatly in design, dosages, collagen source and treatment length, but all showed some degree of improvement in osteoarthritis symptoms. Most studies were blinded, so this removes some level of bias. Self-reported improvements in physical function, quality of life and pain showed the greatest improvement.

Interestingly, one study from the review looked specifically at proteoglycan content in knee cartilage which saw an increase in its content. Proteoglycan is used as a proxy measure of cartilage production so this provides some evidence that collagen supplementation could be restoring some of the collagen lost in osteoarthritis. Hydrolysed collagen via its absorbed peptides is also proposed to have an anti-inflammatory action. This could also be an explanation for an improvement in some of the arthritis symptoms seen in the research.

The research is looking positive, so far, and while ‘more research is always needed’, it would be unwise to dismiss claims about the benefit of hydrolysed collagen in osteoarthritis at this stage.

What is this ‘undenatured collagen’ stuff?

Undenatured simply means the collagen protein hasn’t been unwound and degraded, so it is the pure, fully functional protein without any structural deformation. Isolating this from an animal source needs very careful treatment because acid, heat and enzymes destroy the protein. Not a problem if you’re talking about hydrolysed collagen as you want the peptides, but undenatured collagen is a different beast.

Type II collagen that is isolated (usually from chicken sternums) is the predominant form found in cartilage. When you consume undenatured protein, it can have a specific immune-mediated mechanism of action known as oral tolerance.

Oral tolerance allows us to tolerate and not mount an immune response against ingested substances like food antigens or harmless microorganisms found in the gut. In theory, this can lead to a decrease in autoimmune reactions against collagen in cartilage. This contrasts with the effects of hydrolysed collagen which are thought to have positive effects on cartilage collagen synthesis.

There has been quite a bit of research into undenatured type II collagen in osteoarthritis. A 2023 systematic review included eight randomised controlled trials, and it was again possible to see collagen supplementation reducing symptoms.

Considering the effects of undenatured type II collagen could be via the immune system, it raises the question of how it may work for rheumatoid arthritis which originates in the immune system. In vitro and animal studies suggest undenatured type II collagen can have anti-inflammatory effects, but the evidence is looking stronger for collagen supplements and osteoarthritis at this stage.

The bottom line

The health benefits may sound too good to be true, but this is a rare case where there is a good base of science to support many of the claims made about collagen supplements.

In the end, you can trial collagen for skin or joint health and make your own personal assessment. Even with plenty of clinical trials showing postive results, every person’s response in those trials was different, so the final judge of the benefits is going to be the person taking it.