Collagen for Runners: Does It Actually Work? What the New Science Says (From a Sceptic Who Changed His Mind)
- 3 days ago
- 22 min read
Written and published July 2026 | Andy Hood, ultra and endurance runner, 25 years of running, cancer survivor
Six months ago I raised my eyebrows at my wife. Now I'm standing in the kitchen at stupid o'clock, stirring a collagen supplement into a splash of water with a dash of fresh orange juice, and downing it with a smile. This is the story of how that happened, what the science actually says, and whether collagen for runners is worth the money or just clever marketing. Just please, whatever you do, don't tell my wife.
The short answer: collagen is the scaffolding that holds your tendons, ligaments, cartilage and bones together, and your body makes less of it every year from around your mid-20s. The old line, and one I fully believed, was that collagen supplements are marketing nonsense because the body can't absorb them.
The updated science is more interesting. It turns out the collagen you take doesn't get teleported to your dodgy knee, but it does appear to give your body a kick to ramp up its own collagen production, especially when you take it before you load the tissue with a run or a gym session. It's not a miracle. But it's not nothing either, and that's a genuine shift from where the evidence sat a few years ago.
🏃 Key takeaways
Your collagen is declining, and it's not in your head. Production peaks in your mid-20s and drops by roughly 1% a year after that. By your 50s you're down perhaps a quarter on your peak. For runners that shows up as stiffer tendons, achier joints and slower connective-tissue recovery.
"The body can't absorb it" is out of date. Hydrolysed collagen peptides are absorbed into the bloodstream. What you can't do is aim a swallowed molecule at a specific tendon. Instead, the peptides act as building blocks and, more interestingly, as a signal that kick-starts your own collagen production.
Timing is the bit the adverts skip. For the tendon-building effect, you take collagen with a little vitamin C 30 to 60 minutes before a run or gym session, so the building blocks are circulating in your blood while you actually load the tissue. The loading is what tells your body where to send them. Take it and then sit still with no exercise to follow, and most of it is, as one researcher put it, expensive urine.
It's an adjunct, not a magic bullet. The evidence is strongest for reducing joint pain and improving tendon stiffness alongside training. It won't build muscle, and the marketing wildly overstates the skin claims.
I'm a runner, not a doctor. This is my experience and the published research, not medical advice. Persistent pain belongs in front of a physio or GP, not a blog article.
Collagen for runners at a glance
The question | The honest answer |
Does the body absorb collagen? | Yes, hydrolysed peptides reach the blood within about an hour. But you can't direct them to a specific body part |
So how does it work? | Two ways: as raw building blocks, and as a signal that tells your own cells to make more collagen |
When should a runner take it? | 30 to 60 minutes before a run or gym session, with ~50mg vitamin C |
How much? | 10 to 15g of Type I peptides for tendon/bone; around 5g for specific Type II cartilage peptides |
What's it actually good for? | Joint pain, tendon stiffness and recovery, alongside loading. Modest skin benefits |
What won't it do? | Build muscle (it's an incomplete protein, worse than whey) or fix an injury on its own |
How long until I notice? | Give it 8 to 12 weeks. Tendon remodelling is slow |
Which type? | Type I (and III) for tendons, bone and skin. Type II or UC-II for cartilage and joints |
Contents
Why I'm writing this (blame my wife)
Six months ago my wife announced she'd ordered some collagen and was starting to take it daily. This was met with a raised eyebrow and a slightly smug little lecture from yours truly, because I'd recently listened to a BBC Sounds podcast on this exact topic.
Greg Foot covered collagen on Sliced Bread, the show that puts so-called wonder products under the microscope, and he did it properly, with a panel of experts. The verdict, in the show's own words, was marketing BS. The headline reason was the one everybody repeats: the body doesn't absorb the collagen you take. You eat a protein, your gut breaks it into its component parts, and the idea that swallowing collagen magically tops up the collagen in your skin or your knees is, well, wishful thinking dressed up in nice packaging.
So I felt fairly pleased with myself. Case closed. Save your money.
Which makes it a little surprising that I now find myself with a bag of collagen, adding it to a little water and a dash of fresh OJ, and drinking it every day. What on earth happened?
Two things happened, almost identical in effect and completely unrelated.
The first was my wife. She's a runner too, and she's long suffered with painful knees. A few months into taking collagen daily, she started telling me her knees felt a lot better. Not cured, not miraculous, but noticeably better. She also reckoned her skin, hair and nails were stronger and brighter. Now, I'm a sceptic by nature, and the placebo effect is real and powerful. But my wife is not one for supplement fads, and she was quietly, consistently convinced.
The second was, of all things, another episode of Sliced Bread. I was driving along when Greg revisited collagen to look at what the updated science was telling us. And that update genuinely piqued my interest, because it wasn't the same story as before.
I'm in my 50s. As you'll see in a moment, my collagen production is on the slide, exactly as the biology predicts. Could that be affecting my running? Quite possibly. As an ultra and endurance runner I ask an enormous amount of my body, and after cancer in 2021 and emergency surgery this year, I ask even more of it than I used to. Any legitimate help I can give it is welcome.
Here's the part that got my attention. Greg and his experts explained that it does still seem to be true that your body isn't taking the collagen from your pills, gummies or drinks and slotting it straight into your tendons. But, and this is the bit that made me turn the radio up, the trials are increasingly showing that the collagen you take gives your body a kick to increase its own production.
That's a meaningfully different claim. And it's enough of a shift that I've stopped being smug and started paying attention.
So here I am, a month in, writing this for anyone else who's wondering whether to bother. I'll update you again after three months to tell you honestly whether I've noticed anything. And I'd be grateful if this stayed between us, because if my wife finds out I've quietly started taking the thing I mocked her for, the ridicule will be more than I can bear.
What collagen actually is, and what it does for a runner
Let's do the biology quickly and painlessly, because you can't judge the supplement without understanding the substance.
Collagen is the most abundant protein in your body, roughly a third of your total protein. It's the structural scaffolding of your skin, your bones, your tendons, your ligaments and your cartilage. If your muscles are the engine, collagen is a lot of the chassis.
It's built mostly from three amino acids, glycine, proline and hydroxyproline, and it's manufactured by cells called fibroblasts. Think of them as little collagen factories dotted throughout your connective tissue. In your tendons specifically, the equivalent cells are called tenocytes, but the principle is the same: cells that build and maintain the scaffolding.
Crucially, those factories need more than just raw material. They need tools, and the most important tool is vitamin C. This isn't a marketing add-on to justify a higher price. Vitamin C is genuinely essential for building collagen. The clue is in scurvy, the old sailors' disease caused by vitamin C deficiency. At its core, scurvy is a collagen-building failure: joints deteriorate, tendons weaken, connective tissue falls apart. That's how central vitamin C is to the whole process. Two other minerals, copper and zinc, play supporting roles in cross-linking and keeping the factories running.
Keep that factory metaphor in your head, because it's the key to understanding why swallowing collagen isn't as daft as I first thought, and also why it's not as simple as the labels suggest. A factory needs raw materials, working tools, and a reason to ramp up production. Hold that thought for section five.
When your collagen starts to decline, and why your 50s matter
Here's the uncomfortable bit for those of us with a few decades on the clock.
Your collagen production peaks in your mid-20s to early 30s. After that, the balance tips. You start breaking down more collagen than you build, and production falls by roughly 1% a year. It's cumulative, and at first it's completely invisible.
The rough milestones quoted across the research look like this:
By your mid-30s, you're around 15% down on your peak.
By your 40s, it becomes noticeable. Skin takes longer to snap back, and, more relevantly for us, knees feel a bit crunchier after a hard session.
By your 50s, you've lost somewhere around a quarter of your youthful collagen.
By 60, roughly half of it has gone.
Two things are happening at once, which is why it's sometimes called a double hit. Your fibroblasts become fewer and less active, so less collagen comes in. At the same time, enzymes that break collagen down become more active, so more goes out. Less in, more out, year after year.
There's a hormonal driver too. Growth hormone and a hormone called IGF-1 both fall from your mid-20s, and both normally tell fibroblasts to get to work. For women, oestrogen directly stimulates collagen production, which is why loss accelerates sharply around menopause, with some research suggesting up to 30% of skin collagen can be lost in the first five years. For us blokes, the decline is more of a steady, linear slide, but it's just as real.
I've written before about the seven ways a man's body changes when he runs into his 50s, covering testosterone, muscle loss, bone density and slower recovery. Collagen decline sits neatly alongside all of them. It's part of the same story: the raw materials and the machinery of your connective tissue quietly becoming less efficient. And just like those other changes, the interesting question isn't whether it's happening, but how much you can influence it.
What less collagen means when you run
This is where it stops being a skincare conversation and becomes a running one.
Your tendons get stiffer and slower to warm up. Tendon is predominantly Type I collagen. As its quality and turnover decline, tendons become less elastic and need longer to get going. If you've read my stuff before, you'll know my Achilles greet me every morning as though they've run a hundred miles in the night without telling me. That tightness is partly this.
Recovery slows down. Tendon has a notoriously poor blood supply at the best of times, and it turns over slowly, which is why tendon injuries are so frustratingly stubborn and can drag on for a year or more. Less efficient collagen synthesis doesn't help the situation.
Your joints feel it. Cartilage, the shock absorber in your knees and hips, is mostly Type II collagen. Thinner, more brittle cartilage is part of the crunchy-knee experience that turns up with age and mileage. This is exactly the area my wife noticed a change in.
Your bones rely on it too. Bone isn't just a lump of mineral. It's a collagen scaffold reinforced with calcium, which is why the collagen story links straight back to bone density, a genuine issue for runners as we age.
And your injury margin shrinks. More than half of all sports injuries are soft-tissue problems: sprains, strains, and tendon and ligament trouble. Anything that legitimately improves collagen synthesis and tendon stiffness could, in theory, widen the gap between the load you put through a tendon and the load it can handle. For an ultra runner who spends the year hammering that margin, that's an appealing idea.
Now, the honest caveat, because I'm not in the business of scaring you into buying powder. Most running aches are multi-factorial. Training load, footwear, strength work, sleep and fuelling all feed in. Collagen is one possible lever, not the lever. Anyone telling you a supplement is the answer to your knee pain is selling something.
"But the body doesn't absorb it" — the myth, the update, and what changed my mind
Right. This is the heart of it, and it's where I have to eat a little humble pie.
The claim that convinced me collagen was nonsense goes like this: "You can't absorb collagen, so eating it does nothing. Your gut just digests it like any other protein." It sounds authoritative, it's repeated everywhere, and it has a grain of truth in it.
Here's the more complete picture, which is the bit the first version of the story missed.
Native, intact collagen really is hard to absorb. It's a long, tightly wound triple helix, and your gut can't take it on board whole. So far, so sceptical.
But supplements don't use intact collagen. They use hydrolysed collagen, also called collagen peptides or collagen hydrolysate. The protein has been broken down using heat, water and enzymes into much smaller fragments. And those fragments are absorbed. Small peptides, including distinctive ones containing hydroxyproline, show up in the bloodstream within about an hour of taking them, reaching peak levels well above baseline within a couple of hours. This is measured, not marketed.
So what do they do once they're in there? Two things, and the second is the interesting one.
They act as building blocks. They raise the pool of glycine, proline and hydroxyproline that your body draws on to make new collagen. More raw material for the factories.
They act as a signal. And this is the part Greg's experts were getting at. Those circulating peptides appear to behave like little messengers that tell your fibroblasts to up their game and produce more collagen. They nudge your own machinery into gear.
So here's the reconciliation, and it's exactly what the podcast was describing. It's not that nothing gets absorbed. It's that you can't post a swallowed collagen molecule straight to your left Achilles and have it slot neatly into place. What actually happens is closer to giving your body a kick: the peptides get in, they supply materials, and they signal your own cells to build more. The "it doesn't get absorbed" shorthand was really trying to say "it doesn't go where you point it", which is true. But the newer research on the signalling effect is what turns this from a flat "no" into a cautious "actually, there might be something here."
That's what changed my mind. Not the marketing, not the influencers, and definitely not wanting to admit my wife was onto something. It was the mechanism finally making sense.
The bit that matters most for runners: timing and loading
If you take one thing from this article, take this, because it's the detail that separates the runners who get something out of collagen from the ones who just have expensive wee.
The landmark research here comes from the lab of Dr Keith Baar at the University of California, Davis. His team gave people vitamin C-enriched gelatin an hour before a short bout of jumping, then measured markers of collagen synthesis in the blood.
The results were striking. Markers of new collagen synthesis doubled after exercise, and then doubled again when the collagen and vitamin C were taken beforehand. Three findings came out of that work and the studies that followed, and they've genuinely changed how this is understood:
Loading and collagen were both required. Collagen without exercise did very little. The run, the jump, the gym session is what directs your body's building response to the tissue you're actually stressing. Your body doesn't waste resources; it repairs what you've just loaded.
Timing mattered. Taken before exercise, not after, so the raw materials are already circulating when you load the tissue and blood flow to it increases.
It's been repeated with collagen peptides, not just gelatin, so it's about the amino acids, not one particular product.
The mechanism, in plain runner's terms: when you load a tendon, blood flow to it rises and your body sends the signal to build. If the building blocks happen to be circulating in your bloodstream at that exact moment, you get a bigger repair-and-build response in precisely the tissue you've been working. Which is why the advice has landed on collagen plus vitamin C, taken 30 to 60 minutes before you run or lift, rather than collagen on its own whenever you remember.
One nuance, because I promised you honesty and not sales copy. The specific blood marker in that famous 2017 study is actually more a measure of bone collagen turnover than tendon, so the "it's your tendons" conclusion is inferred from a wider body of laboratory and engineered-tissue work rather than proven by that single study. It doesn't undo the finding, but it's the kind of detail that should make you trust me a bit more and the supplement adverts a bit less.
The different types of collagen, and which one you actually want
Walk into a health shop and you'll be hit with Roman numerals. Here's what you actually need to know, kept to the types that matter for a runner.
Type I is the big one. It's about 90% of the collagen in your body and it dominates skin, bone, tendons and ligaments. Most collagen peptide powders are Type I, or a Type I and III blend. If tendons and bone are your concern, this is your type.
Type II is the main collagen in cartilage and joints. If your concern is joint cushioning and cartilage, this is the relevant one.
Type III turns up alongside Type I in skin and connective tissue, and usually comes bundled in with it in bovine products.
There's one more distinction worth understanding, because it trips people up and it changes what you should buy.
Hydrolysed Type I collagen peptides (or Type I and III) are taken in grams, typically 10 to 15g. They work by the building-block and signalling route I described above, and this is what most of the tendon, bone and skin research uses.
Specific Type II-optimised peptides (such as FORTIGEL, the one in my tub) are also hydrolysed and taken in grams, around 5g a day, but they're formulated to target cartilage, nudging the cells that build and maintain it. This is the joint and cartilage play.
Undenatured Type II collagen (UC-II) is different again, taken in milligrams, around 40mg, and works via the immune system to calm the attack on your own cartilage. Another joint product, but a completely different dose and mechanism.
The practical point: if you buy a tub of Type I peptides expecting a cartilage effect, or a joint product expecting a tendon effect, you may have bought the wrong tool for the job. Match the type to the goal.
And a quick word on source, because it confuses people. Marine collagen, from fish skin and scales, is mostly Type I and often processed to a small particle size, which is why it gets marketed as more absorbable. Bovine collagen, from cattle, gives you Types I and III, or I, II and III if it's from bone. Chicken collagen is rich in Type II. The "marine is more bioavailable" claim mostly evens out once you compare like for like, so don't pay a huge premium for it on that basis alone.
Powders, pills, gels and bone broth: the forms explained
Same active ingredient, very different practicality.
Hydrolysed powder is the workhorse. It dissolves in water, juice, coffee or a smoothie, and it makes hitting a proper 10 to 15g dose easy. It's what most research uses.
Capsules and tablets are convenient but usually only pack a gram or two per serving, so reaching a research dose means swallowing a fistful. Fine for topping up, impractical as your main source.
Liquid shots and gels are pre-mixed and easy on the go. Check the actual gram dose per sachet, and watch for added sugar.
Gelatin is the cooked form, the stuff that sets a jelly or a cooled bone broth. It's literally what Baar's original study used, but it has to be dissolved in something warm and it sets when cold, so it's fiddlier than peptides that stay dissolved.
Bone broth and gelatinous cuts like oxtail are the wholefood route. Genuine collagen, but the dose is wildly variable. Some shop-bought bone broth contains as little as half a gram per cup, so you'd be drinking it by the bucket to match a supplement.
Worth knowing: a modern lean-meat diet, all chicken breast and no skin, bone or offal, gives you almost no dietary collagen. Our ancestors ate the whole animal. Most of us don't, which is part of why the supplements exist at all.
Whatever form you choose, pair it with vitamin C. A splash of orange juice as your mixer does the job, which is exactly why mine goes down with a dash of fresh OJ. It's not an affectation, it's the cofactor doing its work.
How to take collagen as a runner: the practical protocol
Pulling the evidence together, here's the best-supported approach for the connective-tissue benefits that runners care about.
10 to 15g of hydrolysed collagen peptides. Benefit for collagen synthesis appears to plateau around 15g, so more than that is just spending money.
Plus around 50mg of vitamin C. Up to 100mg is fine. Orange juice works perfectly as the carrier.
In water or juice.
Taken 30 to 60 minutes before your run or gym session, or before targeted rehab exercises if you're rehabbing something specific.
Consistently. Five to seven days a week. Consistency beats perfection every time.
Give it 8 to 12 weeks before you judge it. Tendon remodelling is slow, and chronic issues take longer still.
If your goal is different, the doses shift. For general skin and wellbeing, 2.5 to 10g a day, and timing doesn't matter, so just take it whenever you'll remember. For cartilage and joint discomfort, the specific Type II peptides such as FORTIGEL are studied at around 5g a day, and UC-II at roughly 40mg. For bone, about 5g a day for a year or more, alongside calcium and vitamin D. The pre-exercise timing really only matters for the Type I tendon and connective-tissue loading effect. For the cartilage and joint peptides, and for skin and bone, daily consistency is the whole game, so pick a time you'll actually stick to and give it three months.
The honest bit: what the evidence does and doesn't show
You know by now that I won't hand you a one-sided sales pitch. So here's where the research is solid and where it isn't.
Reasonably solid:
Hydrolysed collagen peptides are absorbed and do raise blood levels of collagen's amino acids. Not in doubt.
Collagen plus vitamin C plus loading increases markers of collagen synthesis. Good mechanistic evidence.
In healthy athletes, collagen combined with resistance training increases tendon cross-sectional area and stiffness. Recent systematic reviews grade this fairly strongly. A stiffer tendon transmits force better and may be more resilient.
For joint pain, several trials and reviews show modest but fairly consistent reductions in activity-related discomfort, including in athletes with knee pain and in Achilles tendinopathy when collagen is paired with calf-strengthening work.
Weaker or contested:
The evidence in genuinely injured tendons is thinner than in healthy ones. Reviews call it promising but low-to-moderate quality, needing bigger trials. Don't over-extrapolate a structural change in a healthy tendon to pain relief in an injured one.
Collagen is an incomplete protein and is inferior to whey for building muscle. If muscle growth is your goal, this isn't your tool.
Almost all the benefits show up alongside training. Collagen on its own, without loading, is where the evidence thins right out.
The skin claims, in particular, are routinely overstated by the marketing. Real, but modest.
On safety, collagen is generally very well tolerated, with few known interactions. It's a food-derived protein. That said, if you've got a persistent injury or an underlying health condition, talk to a professional rather than treating a supplement as a fix.
What I'm taking, and why
For the sake of transparency, I'm taking U Perform Active Sport Collagen Powder, an unflavoured powder mixed into a little water with a dash of fresh orange juice.
I landed on U Perform for a specific reason that matters more to me than it might to a casual user: their collagen is Informed Sport batch-tested. For anyone competing, or anyone like me who takes what goes into their body seriously, that certification means every batch is screened for banned substances and contamination. It's not an added extra reserved for elites, it's their standard, and as someone who's had enough medical adventures for one lifetime, that assurance is worth a lot.
Now, a bit of honesty about what this particular product is, because it's not quite the same as the pre-run tendon protocol I described above, and I'd rather explain than gloss over it. Active Sport Collagen Powder uses a single, specific collagen peptide called FORTIGEL, a Type II-optimised hydrolysate aimed squarely at cartilage and joints. The clinical evidence for it is about easing activity-related joint discomfort and supporting cartilage, with results quoted from around 12 weeks at a 5g daily serving. In other words, it's targeting exactly the thing my wife noticed in her knees, which is presumably no coincidence and a large part of why I ended up with this one.
Two practical notes. First, unlike the Type I tendon research, this cartilage peptide isn't built around pre-exercise timing, so with this product consistency matters more than the clock. I take mine before a run out of habit, but the key is simply taking it every day. Second, this powder is pure FORTIGEL with no added vitamin C, so my dash of fresh OJ isn't just for the taste, it's me adding the cofactor myself. Turns out my kitchen habit was better science than I realised.
I'm one month in as I write this. I'm not going to insult you by claiming a dramatic transformation after four weeks, because that's not how cartilage or tendon remodelling works, and you'd rightly stop trusting me. What I can tell you is that it's easy to take, it goes down pleasantly, and I've folded it into my daily routine. Whether I notice anything meaningful is exactly what the three-month update is for, and I'll report back honestly, good or bad.
If you want to match your own product to the research, first work out which goal you're buying for, because the types answer different questions: Type I peptides (often with vitamin C, taken before loading) for tendons and bone; specific Type II peptides like FORTIGEL, or UC-II, for cartilage and joints. Then look for a proper clinical dose, a clearly stated peptide type and source, and, if you compete, third-party testing like Informed Sport.
FAQs: collagen for runners
Does the body actually absorb collagen? Yes. Hydrolysed collagen peptides break down into small fragments that reach the bloodstream within about an hour. What you can't do is aim a swallowed molecule at a specific tendon. Instead the peptides supply raw materials and appear to signal your own cells to build more collagen.
Is collagen just marketing BS? It's a fair question, and a few years ago the honest answer leaned towards yes. The updated science is more nuanced. The mechanism has shifted from "it tops up your collagen directly", which was never true, to "it gives your body a kick to make its own", which has growing evidence behind it, especially when paired with training.
When should a runner take collagen? For tendon, joint and connective-tissue benefits, 30 to 60 minutes before a run or gym session, with a little vitamin C. For skin or general wellbeing, any time of day, as long as you're consistent.
How much collagen should I take? It depends on the type and goal. For Type I peptides aimed at tendons and bone, around 10 to 15g, with benefit plateauing near 15g. For specific Type II cartilage peptides like FORTIGEL, the studies use around 5g a day. More isn't better, so match the dose to the product.
Marine or bovine collagen, which is better for runners? Marine is mostly Type I and processed small, which suits skin. Bovine gives you Types I and III, or I, II and III from bone. The differences are smaller than the marketing implies. Pick based on type and dose, not the source hype.
Do I really need the vitamin C? The research pairs collagen with roughly 50mg of vitamin C, because it's an essential cofactor for building collagen. A splash of orange juice covers it. Cheap insurance.
How long before I notice anything? Give it 8 to 12 weeks. Tendon remodelling is slow, and chronic issues take longer again. Anyone promising results in days is overselling.
Can I just drink bone broth instead? In theory. In practice the dose is small and highly variable, so you'd need several strong cups a day to match a supplement.
Will collagen build muscle? No. It's an incomplete protein and worse than whey for muscle growth. It's a connective-tissue play, not a muscle one.
Can collagen help my runner's knee or Achilles? The evidence is most encouraging for joint pain and for tendon issues when collagen is combined with proper loading, like eccentric calf work for the Achilles. It's an adjunct to good rehab, not a replacement for it. Persistent pain should be seen by a physio.
The bottom line
I started this journey as a smug sceptic armed with a podcast, ready to save everyone their money. I'm ending it, for now, as a cautious convert who's genuinely interested in where the evidence goes next.
Here's where I've landed. The old dismissal, that collagen is pointless because you can't absorb it, was based on an incomplete picture. The updated science suggests the peptides do get in, and that they give your body's own collagen production a nudge, particularly when you take them before you load your tendons and joints with a run or a session in the gym. It's not a miracle, the marketing oversells it, and it works best as one small, sensible part of a bigger picture that still runs on training, strength work, sleep and decent food. But for a runner in his 50s whose collagen is quietly declining and who asks a great deal of his body, a cheap, well-tested, evidence-informed nudge is worth a proper try.
So I'm giving it three months, taking it before my runs, with my dash of orange juice, and I'll come back and tell you the truth about whether it made a blind bit of difference.
If you've been going back and forth on this yourself, I hope this has helped you make an informed decision rather than an influencer-led one. Drop me a comment or a message and let me know if you're trying it too.
Lace up and enjoy your miles.
And remember, not a word to my wife.
This article shares my personal experience and publicly available research. It is not medical advice. I'm a runner, not a doctor. If you're experiencing pain or symptoms that concern you, please speak to a physio or your GP.
Sources and further reading
Shaw G, Lee-Barthel A, Ross MLR, Wang B, Baar K. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. American Journal of Clinical Nutrition, 2017. (The landmark timing and loading study.)
Baar K. Minimizing Injury and Maximizing Return to Play: Lessons from Engineered Ligaments. Sports Medicine, 2019.
Khatri M, Naughton RJ, Clifford T, Harper LD, Corr L. The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review. Amino Acids, 2021.
Praet SFE, Purdam CR, et al. Oral supplementation of specific collagen peptides combined with calf-strengthening exercises enhances function and reduces pain in Achilles tendinopathy patients. Nutrients, 2019.
Zdzieblik D, Oesser S, Gollhofer A, König D. Improvement of activity-related knee joint discomfort following supplementation of specific collagen peptides. (Athletes with functional knee pain.)
Collagen supplementation on tendon-related structural and performance outcomes: a systematic review. (2025/26, finding strong evidence for tendon cross-sectional area and stiffness, and against a muscle-strength effect.)
Absorption of bioactive peptides following collagen hydrolysate intake: a randomized, double-blind crossover study. Frontiers in Nutrition, 2024.
BBC Sounds, Sliced Bread with Greg Foot, episodes on collagen (original and follow-up).
About the author: Andy Hood
Andy Hood is an ultra and endurance runner, cancer survivor, and unapologetic advocate for men's health. After a diagnosis tried to take his running shoes off, he laced them back up and turned the experience into a mission: designing bold, attention-grabbing ultras each year to raise awareness and funds, particularly around testicular cancer. That mission includes his cheeky-but-serious menswear brand, Check Ya Balls, kit with a message that quite literally saves lives. Follow his runs, read his race reports, and grab a pair of Check Ya Balls at runningwestwardho.co.uk.
This article may include affiliate codes or links. I may receive a commission if you purchase products or services from any of the companies mentioned, at no cost to you. This goes towards running this blog, bringing you interesting articles and supporting my charity fundraising with over £27,000 raised to date.
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