It was back in March 2021 that I first tackled the topic of collagen supplements. It proved to be one of my most popular blog posts of the year. And for good reason. There is growing scientific evidence to support many of the health claims made about collagen. From improving skin health to even helping with sports injury recovery and osteoarthritis. In this post, I give an update on the growing scientific evidence for the use of collagen supplements. I’ll also describe the plausible biological mechanisms for how collagen can have a targeted benefit even after digestion.
If you haven’t caught my previous blog post on collagen supplements, let’s do a quick refresh. Collagen’s key role in the body is as a major structural protein. You’ll find it in many tissues including tendons, ligaments, cartilage, blood vessels and skin. It is so abundant, that it makes up almost 30 percent of our total protein mass.
The structure of collagen has a triple helix arrangement of long chains of amino acids. Think of collagen as like a rope with many fibres intertwined. This gives collagen a lot of strength. No wonder its leading role is as a scaffold, giving structure and strength to tissues such as skin and bones.
One of the things that makes collagen different to other proteins is its unique amino acid mix. For starters, every third residue is a glycine amino acid. And it mostly follows a common repeating sequence of just three amino acids: glycine, proline and hydroxyproline. It is that last guy, hydroxyproline, that is unique to collagen.
Hydroxyproline is made from proline and you need vitamin C to make it happen. The classic vitamin C deficiency disease of scurvy is a disease of very weak collagen. That explains the bruising and bleeding gums seen in this disease.
Collagen though is not one molecule. There are at least 28 distinct types. But it is types I, II and III collagens that are the most abundant. You’ll find type I collagen in the connective tissue of tendons, ligaments, corneas, bones and skin. Type III collagen usually is found along with type I collagen in the skin and blood vessels. Type II collagen is mostly found in cartilage.
Why hydrolysed?
When it comes to oral collagen supplements, it is hydrolysed collagen that dominates the market. Hydrolysed simply means the breaking down of a molecule with water. If you heat collagen, you denature the protein and are left with gelatin. Gelatin is a great gelling agent for use in food and beverages, but it is a large molecule and fairly insoluble.
Hydrolysed proteins are smaller in length, so they’re absorbed faster. Hydrolysed collagen is also much more soluble in water than gelatin. That makes hydrolysed collagen more convenient to put into drinks.
The collagen used in most supplements comes from many sources including cattle, pigs, chicken, and marine sources. It is a nice use of what would be a waste product in the processing of these animals and fish for human consumption.
Collagen metabolism 101
But why even bother with taking a collagen supplement? Surely all protein just becomes an amino acid soup in our body after digestion? It’s a common criticism I read about collagen supplements in the popular press. Article after article completely dismissing any benefit of it because of this digestion issue.
If collagen was completely digested to single amino acids, then such criticism would be valid. The thing is that is not the case.
Collagen peptides are absorbed into the bloodstream and are available as single amino acids and unique dipeptides and tripeptides. These small peptides have a unique fingerprint. They contain lots of hydroxyproline-proline and hydroxyproline-glycine containing sequences. Remember: hydroxyproline is unique to collagen so these tiny peptide fragments can only exist in the blood from collagen breakdown.
After consuming collagen, it is possible to measure levels of these unique collagen peptides in the blood. So, they certainly can pass through the digestion and absorption process. The collagen peptides and free amino acids then distribute around the body, especially to the skin. At least in rat studies, those collagen peptides can remain in place in the skin for up to 2 weeks.
It gets even more interesting. These collagen peptides can also function as signalling molecules. One theory is that collagen peptides in the blood are a marker for collagen breakdown. Think of these peptides as acting to signal the body that it needs to produce more collagen.
Collagen peptides can bind to receptors on the surface of fibroblasts. Fibroblasts are skin cells that are major factories for….collagen. And guess what the binding of collagen peptides to fibroblast receptors does? It stimulates them to produce collagen. But it is not just collagen these peptides stimulate the production of. You see more elastin (for skin elasticity) and hyaluronic acid (for water retention) made too.
Now let’s look at what clinical trials have to say happens when you take collagen as a supplement.
The evidence is growing
Back in my previous blog post when I first profiled collagen, I wrote how surprised I was when I went digging into the evidence for just how much there was. At the time, I could count 12 double-blinded randomised-controlled trials showing favourable benefits of hydrolysed collagen on skin elasticity, skin hydration, wrinkles and collagen density. And with every study reporting some degree of a positive finding.
Since that first post, an in-depth systematic review and meta-analysis has been published. In the paper, published in the International Journal of Dermatology, 19 clinical trials were included. All the clinical trials were randomised double-blinded placebo-controlled trials. That means both the participants in the study and the researchers assessing the effects were blinded to if a person got the collagen or a placebo. That removes a lot of bias.
And the results of this systematic review were impressive. A clear and consistent benefit of hydrolysed collagen on skin hydration, skin elasticity, skin density and wrinkles.
Marine/fish collagen was the most common source of collagen used in the trials. But bovine, porcine and chicken were all popular as well. Doses used ranged from 0.6 g to 12 g per day for 1 to 3 months.
No, not all research is funded by collagen companies
The recent meta-analysis also reported that they could not see any evidence of a publication bias. Publication bias is a sign that positive studies were more likely to be published – at the expense of less favourable research which is buried.
That point on publication bias is a critical one. That’s because a common criticism I see of collagen supplements in dismissing any benefit they can have is that the positive evidence is because the research is industry-sponsored. That’s a dog whistle that it can’t be trusted.
Firstly, that is an absolute lazy argument when it comes to critiquing scientific evidence. Research should be evaluated on the merits of the study, not who funded it.
And do you know what else? Among those 19 clinical trials covered in the review, seven of them were not funded by a manufacturer of collagen supplements. Nor did any of the research team in those studies have any conflicts of interest to declare. And those ‘untainted’ studies were just as likely to report a positive benefit as studies funded by industry.
Other benefits of collagen
I’ve focussed this update on the benefits of hydrolysed collagen on skin health, but the research evidence in other areas such as osteoarthritis and recovery joint from injuries is growing. And the research looks promising so far and why such supplements are gaining wider adoption.
But it is not all about skin and joints. There is some interesting preliminary research showing that hydrolysed collagen may be effective at improving insulin sensitivity, glucose and lipid levels, and reducing hypertension in people with type 2 diabetes. So, watch this space as the research develops.
How much to take
If you want to trial collagen yourself, look past all the glossy promotion of expensive powdered supplements touted by Insta influencers. Just evaluate a supplement based on price. For that, look at how much actual collagen is in it and work out the price per gram. That is the best way to shop around to make valid comparisons.
Some supplements may have an extensive list of other ingredients such as vitamins, minerals and herbals. But it is the collagen that is the star of the show here so just focus on that.
Collagen from any animal or fish source are your options and just a few grams a day will be enough. Doses as low as 1 gram per day have shown benefits in clinical trials. Taking more than 10 grams per day is overkill. And it may be better to take it between meals to avoid interference from other protein sources.
And ignore claims made about ‘vegan collagen’. It is a scam. Yes, you read that correctly. What is promoted as ‘vegan collagen’ does not have any of the unique hydroxyproline peptides. It is normally just an amino acid soup with a lot of other vitamins, minerals and botanicals thrown in. It is promoted as a ‘collagen booster’ but don’t go looking for any human clinical research to support these claims. There is zilch.
There is lab-made collagen being developed which is done by microbial fermentation, but this is a niche early-stage development product. It is expensive and GMO. I have no issue with GMOs, but I doubt few people who follow a vegan diet would be up for it.
What it all means
For hydrolysed collagen, it reads like a shopping list of health benefits that sound too good to be true. But for those who are regular readers of this blog, you would know that I have a high evidence threshold for making claims. And at least with collagen, there definitely appears to be something to the story – especially for skin health. All for something that is naturally part of foods and has little evidence of any adverse problems.
Melissa says
Hi Tim,
Thank you so much for providing a podcast that I can trust.
I noticed a slight variation on collagen supplement product labels. Some say they contain ‘Hyaluronic Acid’ and others say “Hydralyte Plus’ is this all the same as hydrolysed collagen?
Thank you.
Tim Crowe says
Thanks for your comment Melissa. Neither of those ingredients are ‘hydrolysed collagen’. Hyaluronic acid is an additional ingredient that may help with skin hydration while Hydralyte Plus is just an oral hydration electrolyte drink – bit of a waste of money to have that in there when water will be fine. All you need to focus on is how much hydrolysed collagen is in your supplement per serve.
Anna Whitley says
Hi Tim,
Thanks so much for this summary. Like you I was a collagen sceptic and now have to admit I was wrong in regards to the evidence!
One of my interest areas in my work is related to nutrition interventions for pressure injuries and chronic wounds, where arginine has obviously been the go-to amino acid for a while. Do you know if there is much evidence around collagen supplementation and healing of these types of wounds? Should Dietitians be looking more closely at this?
Thanks!
Tim Crowe says
Thanks for your comment Anna! Yes, apart from the arginine research there have been some clinical trials with hydrolysed collagen as well and the results look positive so far.. Here is some of it
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6065362/
https://pubmed.ncbi.nlm.nih.gov/16557055/
https://www.sciencedirect.com/science/article/pii/S2352385916300317
Rebecca Voisin says
Hi Tim,
Really curious to know if you’ve read anything about collagen supplements for joint hypermobility disorders.
Cheers,
Rebecca
Tim Crowe says
Hi Rebecca. There’s very little in the way of clinical trials in this area (probably zero as never seen anything). And while it does get promoted as a way to treat it, I can’t see a strong rationale why it would be effective as you are dealing with genetic issues upstream of collagen production related to collagen integrity. But of course, no issue if someone wants to try collagen – it is a food afterall.
Melissia says
Hi Tim,
Have you come across any research regarding collagen supplementation causing GI distress or exacerbating IBS-D symptoms in sufferers? For the last 3 years I’ve tried different brands, amounts, and forms and each time within a day or two I am in sever GI distress (I do ah e IBS-D). Each town it’s the only change to diet/supplements and within a few days of stopping to symptoms subside. Clearly regardless of research it simply may not be something I can take.
Tim Crowe says
Hi Melissia. in all the clinical trials I’ve looked at not a single one has reported an adverse event. That doesn’t mean that an individual could not have some adverse effect, only that it is extremely rare – we are talking about a natural protein found all throughout the animal world and in our food supply (albeit we eat very low amounts of collagen naturally present in food in our modern diets).
Troy Walker says
Hi Tim,
Liked this article so much I shared it on my LinkedIn page. Well done.
Can I ask you two things, my first question being a presumptive yes:
1 – Do you supplement on collagen hydrolysate?
2 – You mention
“Taking more than 10 grams per day is overkill. And it may be better to take it between meals to avoid interference from other protein sources.”
I know you’ve said may to be cautious but what is the rationale for taking it separately to other protein sources, won’t they all be digested, absorbed and assimilated or is the data showing the amino acids may compete for uptake with other amino acids like leucine and impact on say muscle protein synthesis?
Thanks again, keep up all your good work.
Tim Crowe says
Good to hear from you Troy and thanks for sharing! When I look at all the science and the almost zero downsides, hydrolysed collagen is one of the few supplements I take. The advice to take collagen in between meals is more so that it removes any potential effect of AA interaction on peptide absorption, although I cannot really point to any research that would show this would be an issue to any significant extent really, just being conservative that’s all that you ensure you absorb all the peptides. But whatever works for a person for when they prefer to take it during the day.
Troy Walker says
Thanks Tim much appreciated!
So a potential absorption concern we could diminish with proteases on competing amino acids following ingestion? Makes sense, just checking I”m not misinterpreting you.
Louise Bonney says
Great article, thanks Tim, I’m interested in how long and how often you would need to take collagen for? I recently had a ligament injury and was taking collagen at the time and the physiotherapist was impressed with the rate of healing. I’ve since stopped taking it but I’m wondering how often you’d need to take it for benefits to be seen, is it a daily ongoing dose?
Thank you
Tim Crowe says
Thanks for your comment Louise and great you got such good results with your injury – certainly I know of many sports dietitians and physios that are now using it in this setting. While I never give advice specific to a person’s personal circumstance, if someone is taking collagen for injury repair and recovery as the main reason, then it would make sense that once recovered, you don’t need to take it anymore. For more ongoing things like skin health, it is a long-term game with the supplements for ongoing benefit although clinical trials rarely run more than 3 months.
Gerard says
Hi Tim,
You mention putting it in coffee to take, but as protein denatures at 45C (according to a quick Google search) I presume I’m missing something, or it starts breaking down but the reaction is slow?
Thanks
Gerard
Tim Crowe says
Good question Gerad and yes, heat does indeed denature protein, but hydrolysed collagen has already been denatured so not an issue! 🙂 Hydrolysed collagen is just very short chains of the original collagen molecule which is why it is soluble in liquids like coffee. Gelatin (which is just denatured collagen) is not hydrolysed so still has long amino acid chains and for that, it is not very soluble in liquids which is a positive for its culinary uses.
michele says
which brand do you recommend
Tim Crowe says
I don’t recommend any brands – they are all essentially the same and source their collagen from a small pool of suppliers. As it is the hydrolysed collagen that is the active ingredient then any other ingredients and flavours just makes them more expensive so choose based on price per gram of collagen.
Michelle says
Hi Tim,
Great review and really interesting to read that many of the claimed benefits of collagen are backed up by science.
I see a few collagen supplements on the market that combine Vitamin C with Collagen. Is there any added benefit of relating to this combination?
Cheers
Tim Crowe says
Thanks for your comments Michelle. Vitamin C is important in collagen production – no question at all and why it is added – but unless someone has a pretty poor diet, they will be getting plenty of vitamin C from their diet.
Michelle says
Thanks Tim, I appreciate your quick reply.
James says
Hi Tim. Great article – thank you for looking into this very ‘hot’ topic. Many people make ‘gummies’ from collagen powders using for example fruit juice and collagen powder which needs to be heated or add the powder to hot drinks. You mentioned heat denatures the proteins in collagen powder. Does this affect absorption and efficacy? I assume it would not?
Also, I assume the research thus far has only included supplement doses rather than homemade bone broths etc. ?
Tim Crowe says
Thanks for your comment James. Heating isn’t an issue for collagen as it is already denatured and hydrolysed and absorbed well and is why adding it to coffee is a popular way to take it as a supplement. All the clinical trials with collagen use it mostly in a supplemental form – bone broth is a very variable and source of collagen so can’t be controlled as well to use as a reliable source.
Suzanne says
Hi Tim,
Thank you for your excellent podcast and I particularly enjoyed this one on collagen. My question is, I presume from your review that using gelatin as a dietary supplement would not produce the same results described above due to its different chemical structure. Is that correct? Is using gelatin in cooking of any nutritional benefit other than as a source of protein?
Thanks
Suzanne
Tim Crowe says
HI Suzanne. Gelatin should give similar results as will still be broken down in our gut by protease enzyems, but the reason all the supplements are based on hydrolysed collagen is to do with solubility so it can go into foods or powdered supplements designed to be made up in water.
Suzanne says
Great thank you so much for the fast reply !
Tracey says
Hi Tim,
I am confused about the serving size and ingredients included in different collagen products.
If the product contains 100% hydrolysed collagen peptides (bovine), I assume this is the best value for money as it doesn’t contain anything else.
Why do some companies recommend a 25g serving size when you say over 10g is a waste of money? I assume it’s because 25g is for muscle building while your review was based on skin and joint benefits?
Thanks very much
Tim Crowe says
Hi Tracey. All things being equal, then 100% collagen should be cheaper, but that doesn’t account for premiums the company may build into it based on their marketing spin. So, I recommend choosing collagen purely based on the price per 100 grams of the actual protein and ignore everything else unless there are other nutrients of interest to you or you prefer certain ones that have more pleasing flavours.
There isn’t much research with doses above 10 g/day and yes, unless someone is taking it to target muscle growth too, then not much rationale for such high doses about this. And here, any source of protein will do the job to ‘top up’ dietary intake rather than needing to turn to collagen as the additional source as nothing that special about collagen when it comes to muscle growth.
Tracey says
Thanks very much! This is the first time I’ve ever submitted a question to a forum and I’m impressed with the speed of your reply and the details. Thanks again.
Peggy says
Hello Tim,
really appreciate and value your work. thank you for it! I just stumpled upon this article regarding collagen – do you have an opinion on it? https://www.statnews.com/2022/01/20/painfully-weak-evidence-supporting-collagen-supplements-for-arthritis/ Is it really that the evidence is so weak or is he refering to the level of evidence in regards of Osteoarthritis? Thank you!
Tim Crowe says
Thanks for your comments Peggy! Yes, I saw this article and the key point is he is only referring to the evidence for OA which is only based on 5 trials so some of his points are valid and I agree the research is still ’emerging’ in this area and why I gave it only a small focus in my article. Though with a small number of trials in the OA meta-analysis each with a different design, the variability is magnified. Regarding skin health which was the main focus of my article, it is a very different matter as there are 19 RCTs in the latest meta-analysis (and several more trials I am aware of that were not included) and many of these were not funded by industry.
Peggy says
Great, thank you so much!
Isaac Robertson says
I have been using these supplements for over 6 months now. As a result, I have noticed my skin is firmer and wrinkles are less visible. My hair has also stopped falling out so much. I think it’s something in the collagen that helps you to build muscle tissue. I recommend taking them daily.
Andrew Howie says
Tim thanks for the review. The question is why use supplements vs whole food. How much meat or fish is necessary to have an impact on health issues?
Jo says
Hello, I notice you mention ‘marine/fish collagen’ as the most common, but ‘vegan collagen’ is a scam.
I’m wondering if ‘marine’ is from algae or another plant source and therefore would be vegetarian/vegan?
If collagen is only available from animal sources, do you know which type has the least environmental impact/makes best use of a by-product?
Thanks
Tim Crowe says
Plants don’t make collagen nor do algae – there are no natural sources of collagen that can be considered vegan. You will only get it from animals and fish, jellyfish, starfish, and sponges (hence the term marine to cover all these). All the collagen produced is essentially a by-product from the processing of the animal/fish for consumption so environmental impact isn’t really a consideration seeing at the collagen is there already – that is the fish aren’t caught or the animals killed for their collagen. But from the small amount of reading I’ve done on this, marine sources may have a lower overall environmental impact.
donna bull says
Thanks so much for this review, Tim. Do you know how long it is likely to be after commencing collagen supplements that results might be noticed? Also, is there any superior benefit of powdered forms over tablets or gummies?
Tim Crowe says
Thanks for your comment Donna. Clinical trials show benefits within a few weeks. Almost every clinical trial uses powdered collagen usually made up in a drink. I can see no reason why gummies would or would not be better though they are a more expensive way to take collagen.