As many of you know, in the past I’ve taken a critical stance on dietary collagen protein and recommended against it as a supplement. Science evolves, however, and given the new research that has come out since I first took my stance, I thought it an appropriate time to revisit the topic and potentially reevaluate my opinion.

To help with this, I reached out to Dr. Keith Baar, the senior author on the paper that is primarily responsible for this article. First though, let me recap the stance I’ve held so the context of my conversation with him is clear!

A Quick Recap on Collagen Supplements

My argument against collagen has been centered around two related points:

First, collagen is a poor-quality protein from a dietary standard as it is extremely limited in the amino acids it contains. Collagen is abundant in glycine, proline, and hydroxyproline—all of which are inessential (our body can produce them itself)—and deficient in all the essential amino acids. With this in mind, hypothetically our ability to produce collagen should not be limited by amino acid availability (since collagen mostly doesn’t contain any we can’t produce ourselves), at least provided we supply our body with adequate protein.

Second, no trial has compared a dietary collagen supplement to a high-quality protein. Since a high-quality protein supplies both the inessential amino acids that collagen is rich in as well as the essential ones it lacks, it’s plausible that a high-quality protein would be equally (or more) effective than dietary collagen at boosting collagen production.

There are a few more points I’ve made as well, but they are secondary to these first two. In particular, the second one has been my “sticking point” because it is more easily testable than the first and would provide a clear answer to the question; if collagen is more effective, it would show up in the data (and vice versa)!

New Research by Dr. Keith Baar

A couple years ago, Dr. Baar and his team released a paper that demonstrated the efficacy of dietary collagen in promoting collagen synthesis in two parts, the first using an engineered ligament and the second with blood levels of procollagen I N-terminal peptide (PINP). The PINP blood test showed that in vivo collagen formation increased after collagen supplementation, with the caveat that PINP is more a marker of bone metabolism than connective tissue since bone has a greater turnover rate than tendons or ligaments. The engineered ligament test (an in vitro test) helped fill in the gap by demonstrating that a ligament would also take up the appropriate amino acids if exposed to them, in this case through serum drawn from participants who had recently consumed a gelatin supplement.

(It’s also important to note that the trial used a special exercise and timing protocol for the supplementation. The key is that our tendons and ligaments are poorly vascularized, so we need to improve blood flow with exercise to sufficiently expose them to our amino acid-enriched blood.)

I believe I wrote about the paper at the time, but didn’t change my opinion because the trial compared dietary collagen to maltodextrin (a carbohydrate). While it did demonstrably show that dietary collagen has a positive effect on physiological collagen synthesis, it didn’t address whether it would be better than just having a serving of protein since we wouldn’t expect maltodextrin to have any effect on collagen synthesis while we would expect a protein (even a low-quality protein) to have at least some effect.

Though it wasn’t sufficient at the time to convince me, recently there’s been a surge in popularity for collagen protein supplements and I wanted to be sure I wasn’t missing anything. So, I reached out to Dr. Baar to see if he could provide some insight. Here’s what we wrote to me:

Thanks for the question. I like your analysis and explanation for why you argue against dietary collagen. In principle, I agree with everything you’ve said. There hasn’t been a trial comparing collagen to whey protein. We are doing that at the moment, but these studies are not easy. It is really hard to measure collagen synthesis in people.



The only data I know of as to why collagen might be useful compared to whey protein for connective tissue comes from Luc van Loon. He has found that when you take whey protein, glycine levels in the blood drop significantly, to the point that glycine (every third amino acid in collagen) could limit collagen synthesis. The data haven’t been published yet, but it is really interesting and suggests that having some glycine rich protein may be necessary for collagen synthesis.



In the meantime, my view is that since there are no counter indications, collagen is not known to cause kidney, liver, or other issues, if it might increase collagen synthesis and help someone stay healthy there is no downside. I tell people that it might be helpful to take before loading and many tell me stories of how it changes their lives. But I realize that this could all be a placebo effect. If in the end the research comes back negative, collagen intake has nothing to do with collagen synthesis, they won’t have lost anything or put themselves at risk. If in 5 years we look back on clear evidence that it works, they will have had a small jump on the crowd.

Dr. Baar also emphasized the need for more studies, which require funding. He said that many (if not most) collagen producers have reached out to his lab in regard to funding research, but when the question comes up about what would happen if the results are negative, he responds that they would publish regardless and the companies typically don’t write back. Unfortunately, this type of research isn’t “interesting” to federal funding agencies, so as a result it’s hard to secure adequate funding to perform large numbers of studies (or large studies).

Where to Go From Here

I really appreciate Dr. Baar’s insight and neutral approach, and I don’t disagree with his argument. It could be that in five years we have the data to suggest dietary collagen protein is superior to high-quality proteins in terms of collagen synthesis and you’ll have had five years of benefit. Alternatively, five years from now the data could suggest collagen doesn’t work any better than another protein (or is inferior) and you’ll have wasted some money but will otherwise be healthy and unharmed. You can make a reasonable argument both directions, so we’ll just have to wait for the research to give us more direction in the future; the important thing is to be open to the possibility you’re wrong and willing to change your mind!

In any case, keep in mind that supplements are just that: supplements. The most important nutritional factors in collagen synthesis and repair will continue to be adequate calories and protein (without which you will impair overall physiological protein synthesis), and improving the strength of your connective tissue will still demand appropriate loading and rest.

I still recommend against using any collagen-based protein (gelatin, beef protein isolate, hydrolyzed collagen peptides, etc.) as a protein supplement—that is, don’t replace the protein in a meal with it, or use it in a protein shake instead of a more conventional whey, casein, soy, or whatever. Collagen lacks sufficient quantities of the essential amino acids to be a good source of protein, including leucine (the metabolic “signal” amino acid for muscle protein synthesis), and replacing a regular protein with collagen-based protein is akin to reducing your overall daily protein intake.

Thank you to Dr. Baar for taking the time to respond to me, and if any of you reading this know of any potential sponsors for his research I’m sure he’d appreciate hearing from you! You can contact me and I’ll pass along your information. And, as always, if you have questions or comments please don’t hesitate to send them my way.