Collagen Supplements for Arthritis

Nearly a millennium ago, a medieval nun suggested eating gelatin to reduce joint pain. Unfortunately, when it was put to the test in a multicenter, randomized double-blind placebo-controlled trial, it didn’t work. A dozen years later, looking at knee and hip osteoarthritis, there was still no overall evidence for collagen supplements working better than placebo. However, the latest compilation of studies purported to show a benefit for improving osteoarthritis symptoms. In one symptom index, it appeared to help with stiffness, but not pain or disability. But, an improvement in overall symptoms and a different index of pain were statistically significant.

If, however, you exclude the smallest study, whose authors were employees of a collagen company, all of the results lost clinical importance, meaning the overall effects were unnoticeably small. In fact, every single one, was funded by collagen companies, or directly run by company employees.

Another thing you’ll notice about these data is that with this one exception, the smaller the study, the larger the effect. This pattern is a common sign of publication bias—the tendency to do a whole bunch of small trials, but publish only the ones that work to your advantage and secretly shelve the rest. Coupled with all of the conflicts of interest, concerns have been raised that additional small studies may have been conducted but conveniently disappeared. And then other fishy findings are that smaller doses appeared to have larger effects, as did using it for a shorter amount of time. OK, but the last study was published in 2016. What’s happened since then?

A comprehensive systematic review published in 2022 was surprised to note that the last study done on collagen supplements for rheumatoid arthritis was published more than a decade ago, and the last osteoarthritis study was still that 2016 one. Why? Well, one possible reason is the high incidence of adverse side effects reported in those taking collagen supplements, or another reason may be that they simply don’t work very well.

I mean, if collagen company executives truly believed they were selling something that worked, why don’t they do more studies? If they thought collagen had a decent chance of working, they could make out like bandits. The fact that they haven’t sponsored such a trial suggests they’re not so confident it would actually show benefit.

One study has been published since 2016, the biggest yet, with more than 150 people. Funded by a collagen company, researchers found a significant drop in knee pain, and a significant improvement in knee function among those randomized to collagen supplements. But, they also found a significant drop in knee pain and improvement in knee function in those randomized to the placebo, with no real difference between them. So, the fact that effectively a sugar pill worked as well as the collagen supplements suggests that collagen doesn’t work.

But that does raise another point. If you look at what was used for controls in the collagen studies it was basically just sugar or sawdust. And the same with the skin studies I talked about in the last video. So, even if collagen was found to be helpful in some way, there is no proof that collagen has any effects, beyond just being a source of amino acids like any other protein. So, if any purported collagen effect is just a matter of increased amino acid availability, then why not just like have some extra hummus or something?