When you’re hurt, the internet sells you a recovery stack. The trials say something plainer: eat enough, keep your protein up, keep moving what you can, and be sceptical of anything promising to stop your muscles shrinking in a cast. Here’s what holds up, graded, for injuries to muscle, tendon and joint, and for concussion.
The grades in this post: Strong means good randomised trials agree. Mixed means trials disagree or are small and short. Mechanistic means the biology makes sense but it hasn’t been shown to change outcomes in people. None means there’s no usable evidence in people.
Two mistakes I see after an injury
Over the years I’ve watched two things happen when clients get hurt, usually both at once.
The first is eating less because you’re moving less. It feels logical. You’re not training, so you cut back. But healing costs energy. Inflammation, tissue repair and the extra effort of getting around on crutches or with a limp all use fuel. Cut too hard and you take away the raw material at the moment the body most needs it.
The second is buying the stack. Leucine, BCAAs, collagen, turmeric, high-dose everything. Some of it has a rationale. Very little of it has been shown to change what matters: how much muscle you keep, and how quickly you get back.
What a cast does to muscle, and how fast
Muscle starts to go within days of being immobilised. In a 2026 trial, three days in a full leg cast cut the daily rate at which the thigh muscle rebuilds itself by about 15% in young adults and 23% in older ones, and the muscle shrank by about 1% in those three days (Churchward-Venne 2026). After a week in a cast, young men lost about 3.6% of the lean mass in that leg, and its strength fell by about 28% (Edwards 2020). After two weeks, thigh muscle size fell by about 10% and power by about 25% (Hespel 2001).
Strong Consistent small controlled trials. The direction and speed of the loss are well established.
The older you are, the more this matters. Ten days of bed rest in healthy older adults produced a substantial loss of leg muscle (Kortebein 2007, a short JAMA report; I haven’t quoted a figure because I haven’t been able to read it). That’s why a week in hospital can cost an older person months of strength.
Being in a cast or largely immobile also raises the risk of a blood clot in the leg. Know the warning signs: see Blood clots.
What helps during immobilisation, graded
| What | What the trials found | Grade |
|---|---|---|
| Enough energy | Energy use falls when you’re immobile, but less than people think: inflammation, healing and the effort of getting around limit the fall (Tipton 2011; Tipton 2015) | Mechanistic physiology and expert review; no trial of “eat more” vs “eat less” during injury |
| Enough protein | Don’t let protein fall when you eat less overall. In middle-aged men with a leg immobilised for two weeks, 20 g a day of milk protein reduced the shutdown of some muscle-building signals, but the study didn’t show muscle kept (Zeng 2021). Expert opinion on going higher has changed: see below | Mechanistic plus expert review; no trial shows extra protein keeps muscle in a cast |
| Leucine supplements | Two trials, no benefit: 15 g a day for 7 days in young men (Edwards 2020); 5 g with each main meal for 3 days in young and older adults (Churchward-Venne 2026). Neither muscle mass nor muscle building was protected | Strong for “doesn’t work” (two consistent RCTs) |
| Creatine during the cast | Loading for 5 days before and during a week in a cast didn’t preserve muscle or strength (Backx 2017) | Strong for “doesn’t work” (one RCT, 30 men) |
| Creatine during rehab | After two weeks in a cast, creatine taken through 10 weeks of rehab training brought muscle size and power back faster (Hespel 2001, 22 people) | Mixed one small RCT, positive; fits what creatine does in training generally |
| Omega-3 (fish oil) | Young women taking omega-3 for 4 weeks before and during 2 weeks with a leg immobilised lost 8% of muscle volume vs 14% on sunflower oil, and were back to where they started after 2 weeks of normal activity (McGlory 2019, 20 women) | Mixed one small RCT, positive, young women only |
| Egg-yolk “myostatin blocker” (Fortetropin) | Stopped the rise in blood myostatin but didn’t prevent muscle loss (Lim 2023) | Strong for “doesn’t work” on what matters (one RCT) |
The pattern: the supplement built on the most persuasive biology (leucine “switches on” muscle building) failed in the cast, twice. Two with a less obvious story (creatine in rehab, omega-3) have one small positive trial each. A good mechanism isn’t a result.
The expert view on protein has moved. In 2011 the main reviewer in this area, Kevin Tipton, wrote that there was “little rationale” for raising protein during immobilisation. By 2015 he suggested 2–2.5 g per kg a day “seem to be warranted”, and at the very least that the absolute amount shouldn’t fall when you eat less (Tipton 2011; Tipton 2015). Neither position rests on a trial showing muscle kept. The part both agree on, and that I’d hold to, is: don’t let it fall.
What actually protects muscle is using it. Move whatever you’re allowed to move, train the uninjured side, and start loading the injured side as soon as your physio or surgeon says you can. Rest has its place in the first days, and there are damage limitation exercises for when you can’t do much. Nothing in the table comes close to loading.
Tendons and ligaments: the collagen question
Collagen supplements are sold hard for joints and tendons (I’ve written about the wider claims in Collagen Is Everywhere). The evidence for injury is early and specific.
- Gelatin with vitamin C before exercise. In 8 men, 15 g of vitamin C-enriched gelatin an hour before six minutes of skipping doubled a blood marker of collagen production, and blood serum taken afterwards made lab-grown ligaments stronger (Shaw 2017). Mixed One small crossover trial; a blood marker and engineered tissue, not injured people. The timing matters in the theory: the collagen building blocks need to be in the blood when the tendon is being loaded.
- Collagen peptides with calf rehab for Achilles tendinopathy. In a 6-month pilot crossover trial (20 patients, Australian Institute of Sport), people improved more on an Achilles function score during the three months they took collagen peptides alongside their calf-strengthening programme than during the placebo months (Praet 2019). Mixed A pilot RCT; the authors say it needs repeating in a larger trial. The product was a branded one (Tendoforte), and its maker, Gelita, paid for the study. The paper says the sponsor had no role in the analysis or the write-up, and the authors declare no conflicts.
My reading: collagen with loading is plausible and cheap, and the early trials point the right way. Collagen instead of loading has nothing behind it. The exercise is the treatment; the collagen may help it work. If you’re using a collagen-type protein powder, see Protein Powder: Win, Loss or Better Than Nothing?, including why the beef protein I recommend behaves like collagen.
Inflammation is part of healing
The instinct after an injury is to suppress inflammation hard: ice, anti-inflammatories, a turmeric habit. But the inflammatory response is how repair starts. Tipton’s review puts it plainly: “excessive anti-inflammatory measures may impair recovery” (Tipton 2011). Mechanistic Expert review and physiology. That doesn’t mean never take a painkiller your GP or pharmacist recommends. It means a recovery plan built around stamping out inflammation is aiming at the wrong target.
Concussion and brain injury
Call 999 if someone has hit their head and has been knocked out and not woken up; can’t stay awake or keep their eyes open; has a fit (seizure); has fallen from more than 1 metre or 5 stairs; has problems with vision or hearing; has a black eye without hitting their eye; has clear fluid from their ears or nose, bleeding from their ears or bruising behind them; has new numbness or weakness; has problems walking, balancing, understanding, speaking or writing; hit their head at high speed, such as in a road accident; has a head wound with something in it or a dent in the head; has a bruise, swelling or large cut on the head and is under 1; or their behaviour has changed, such as being more irritable or distracted, or losing interest in things around them.
Get urgent help from NHS 111 if you’ve recently had a head injury and are being sick, feel dizzy, have a condition or take medicine that thins the blood, were drinking alcohol or taking drugs at the time, or have any other symptoms you’re worried about. Call 111 for advice about a child under 5.
See a GP if symptoms last more than 2 weeks, or you’re not sure it’s safe to drive or go back to work, school or sport.
First, the part that isn’t nutrition. Current international guidance has moved away from strict rest. After a concussion, a day or two of relative rest, then early light activity and reduced screen time, help recovery more than lying in a dark room (Patricios 2023; Davis 2024, from the 2022 Amsterdam consensus). Return to sport is staged and supervised.
Then the supplements. Two systematic reviews looked at everything tried: omega-3, melatonin, creatine, pine bark and others.
- 15 studies, 1,139 people: the strongest evidence is for omega-3 taken before repeated head impacts in athletes, not for treating a concussion after it happens. Melatonin and one other supplement may help symptoms that persist; more trials are needed (Feinberg 2023).
- 19 studies of 13 supplements: “none of the interventions reviewed offer strong enough evidence to justify regular use in clinical practice” (Siahaan 2025).
Omega-3 in contact sport, looked at closely. In American football, a blood marker of nerve-fibre damage (neurofilament light) rises over a season. One non-randomised two-team study found a branded fish oil blunted that rise (Heileson 2021). A randomised trial from another group found it didn’t, though players with the highest blood omega-3 tended to have lower levels (Mullins 2022), and the brain scans from that trial “did not provide strong evidence” of protection (Raikes 2022). Mixed Blood markers and scans, not symptoms or long-term outcomes.
Severe brain injury is managed in hospital, and feeding is part of intensive care (the Brain Trauma Foundation guideline covers it; Carney 2017). Nothing in this article replaces that. One line of research is worth knowing about: in 39 children and teenagers with traumatic brain injuries, many serious enough to need intensive care, creatine for six months was followed by less headache, dizziness and fatigue and better recovery scores (Sakellaris 2006; Sakellaris 2008). Mixed But it was open-label (everyone knew who was taking it), small, from one group, and hasn’t been repeated. Interesting, not established, and not a concussion trial.
How much? What the trials used
Trial amounts as tested, and the rules I use. If you have kidney disease, take medication, are pregnant or are recovering from surgery, check with your GP or surgical team first.
| How much | Where it comes from | Grade | |
|---|---|---|---|
| Protein, normal life | 1.2–1.6 g per kg of body weight a day | With resistance training, extra protein stopped adding muscle at about 1.6 g/kg a day (Morton 2018, 49 trials). The 1.2 lower end is my working range. | Strong meta-analysis |
| Protein while immobilised | Keep your daily grams at least the same, even if you eat less overall. Tipton’s later review suggests 2–2.5 g/kg | Tipton 2015 (review). No trial has shown extra protein keeps muscle in a cast | Mechanistic expert opinion |
| Kidney check | Before going above 1.6 g/kg, know your kidney function (eGFR, on a routine blood test) | My rule for anyone eating at the top of the range | Practice |
| Creatine in rehab | The rehab trial started at 20 g a day and stepped down to 5 g a day, through 10 weeks of rehab. For everyday amounts, see the How much box in the creatine article | Hespel 2001 | Mixed one small RCT |
| Omega-3 | 5 g a day of omega-3 fatty acids, starting 4 weeks before the immobilisation | McGlory 2019 | Mixed one small RCT; a trial amount, far higher than most capsules give. If you take blood thinners, ask first |
| Gelatin with vitamin C | 15 g of vitamin C-enriched gelatin, an hour before a short bout of loading (three times a day for three days in the trial) | Shaw 2017 | Mixed one small crossover trial; blood marker only |
| Collagen peptides for an Achilles tendon | 2.5 g twice a day, 30 minutes before the calf exercises, for 3 months | Praet 2019 (Tendoforte; study funded by its maker, Gelita) | Mixed one pilot RCT |
Why injury can justify a different number. My everyday protein range is for a healthy body living a normal life. A cast or a boot is a short, abnormal state: the muscle becomes less responsive to protein, you’re healing tissue, and you’re often eating less. I already make one exception to my ceiling (up to 2.4 g/kg when someone is in a calorie deficit and training hard), for the same reason: a different state, a different need. Injury fits that logic. What the evidence doesn’t yet show is that the extra protein keeps more muscle. So my rule is: never let protein fall during an injury, and go higher only as a time-limited step, with your kidneys checked.
What I’d actually do
- Don’t diet while you heal. Eat to appetite, with some protein at every meal. If you’ve lost your appetite, that’s the time for nourishing, easy food, not restriction.
- Keep protein steady even if you eat less overall.
- Move everything you’re allowed to move, and start loading the injured part as soon as your clinician says so. That’s what protects muscle. How you load it matters as much as what you load: see Same Exercise, Different Animal.
- Supplements, in order of evidence: creatine during rehab (not to prevent loss in the cast); omega-3 if you know you’re going to be immobilised (one small trial); collagen or gelatin with vitamin C before your rehab exercises for tendon problems (early evidence). Leucine and BCAAs: skip them.
- Concussion: follow the staged return; don’t expect a supplement to speed it up.
What testing can and can’t add. If recovery is slower than expected, it’s worth checking the things that genuinely slow healing: iron, vitamin D, protein intake, blood sugar control in diabetes, and whether you’re eating enough at all. A blood test answers those questions. No test predicts which supplement will make you heal faster.
How strong is the evidence?
| Claim | Grade | Main source |
|---|---|---|
| A cast causes fast muscle and strength loss | Strong | Churchward-Venne 2026; Edwards 2020; Hespel 2001 |
| Leucine protects muscle in a cast | Strong doesn’t | Edwards 2020; Churchward-Venne 2026 |
| Creatine protects muscle in a cast | Strong doesn’t (one RCT) | Backx 2017 |
| Creatine speeds recovery during rehab | Mixed | Hespel 2001 (22 people) |
| Omega-3 reduces muscle loss when immobilised | Mixed | McGlory 2019 (20 young women) |
| Extra protein keeps muscle in a cast | Mechanistic | Zeng 2021; Tipton 2015 (review) |
| Collagen or gelatin helps tendons heal with loading | Mixed | Shaw 2017; Praet 2019 (pilot) |
| A supplement speeds concussion recovery | None strong enough to recommend | Feinberg 2023; Siahaan 2025 |
| Omega-3 protects the brain in contact sport | Mixed | Heileson 2021; Mullins 2022; Raikes 2022 |
Sources
- Backx EMP et al. Creatine loading does not preserve muscle mass or strength during leg immobilization in healthy, young males: a randomized controlled trial. Sports Med 2017;47:1661–71. PMID 28054322. doi:10.1007/s40279-016-0670-2
- Carney N et al. Guidelines for the management of severe traumatic brain injury, fourth edition. Neurosurgery 2017;80:6–15. PMID 27654000. doi:10.1227/NEU.0000000000001432
- Churchward-Venne TA et al. Leucine supplementation does not attenuate the decline in daily muscle protein synthesis rates or muscle mass during short-term limb immobilization in young or older adults. Am J Clin Nutr 2026;123:101205. PMID 41580240. doi:10.1016/j.ajcnut.2026.101205
- Davis GA et al. Pediatric sport-related concussion: recommendations from the Amsterdam consensus statement 2023. Pediatrics 2024;153:e2023063489. PMID 38044802. doi:10.1542/peds.2023-063489
- Edwards SJ et al. High-dose leucine supplementation does not prevent muscle atrophy or strength loss over 7 days of immobilization in healthy young males. Am J Clin Nutr 2020;112:1368–81. PMID 32910813. doi:10.1093/ajcn/nqaa229
- Feinberg C et al. Nutritional supplement and dietary interventions as a prophylaxis or treatment of sub-concussive repetitive head impact and mild traumatic brain injury: a systematic review. J Neurotrauma 2023;40:1557–66. PMID 36680752. doi:10.1089/neu.2022.0498
- Heileson JL et al. The effect of omega-3 fatty acids on a biomarker of head trauma in NCAA football athletes: a multi-site, non-randomized study. J Int Soc Sports Nutr 2021;18:65. PMID 34579748. doi:10.1186/s12970-021-00461-1
- Hespel P et al. Oral creatine supplementation facilitates the rehabilitation of disuse atrophy and alters the expression of muscle myogenic factors in humans. J Physiol 2001;536:625–33. PMID 11600695. doi:10.1111/j.1469-7793.2001.0625c.xd
- Kortebein P et al. Effect of 10 days of bed rest on skeletal muscle in healthy older adults. JAMA 2007;297:1772–74. PMID 17456818. doi:10.1001/jama.297.16.1772-b
- Lim C et al. Fortetropin supplementation prevents the rise in circulating myostatin but not disuse-induced muscle atrophy in young men with limb immobilization: a randomized controlled trial. PLoS One 2023;18:e0286222. PMID 37220119. doi:10.1371/journal.pone.0286222
- McGlory C et al. Omega-3 fatty acid supplementation attenuates skeletal muscle disuse atrophy during two weeks of unilateral leg immobilization in healthy young women. FASEB J 2019;33:4586–97. PMID 30629458. doi:10.1096/fj.201801857RRR
- Morton RW et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med 2018;52:376–84. PMID 28698222. doi:10.1136/bjsports-2017-097608
- Mullins VA et al. Effects of fish oil on biomarkers of axonal injury and inflammation in American football players: a placebo-controlled randomized controlled trial. Nutrients 2022;14:2139. PMID 35631280. doi:10.3390/nu14102139
- NHS. Head injury and concussion. Page last reviewed 29 May 2025; read 13 October 2026. nhs.uk
- Patricios JS et al. Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport, Amsterdam, October 2022. Br J Sports Med 2023;57:695–711. PMID 37316210. doi:10.1136/bjsports-2023-106898
- Praet SFE et al. Oral supplementation of specific collagen peptides combined with calf-strengthening exercises enhances function and reduces pain in Achilles tendinopathy patients. Nutrients 2019;11:76. PMID 30609761. doi:10.3390/nu11010076
- Raikes AC et al. Effects of docosahexaenoic acid and eicosapentaenoic acid supplementation on white matter integrity after repetitive sub-concussive head impacts during American football: exploratory neuroimaging findings from a pilot RCT. Front Neurol 2022;13:891531. PMID 36188406. doi:10.3389/fneur.2022.891531
- Sakellaris G et al. Prevention of complications related to traumatic brain injury in children and adolescents with creatine administration: an open label randomized pilot study. J Trauma 2006;61:322–29. PMID 16917445. doi:10.1097/01.ta.0000230269.46108.d5
- Sakellaris G et al. Prevention of traumatic headache, dizziness and fatigue with creatine administration: a pilot study. Acta Paediatr 2008;97:31–34. PMID 18053002. doi:10.1111/j.1651-2227.2007.00529.x
- Shaw G et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr 2017;105:136–43. PMID 27852613. doi:10.3945/ajcn.116.138594
- Siahaan AMP et al. Dietary supplementation roles in concussion management: a systematic review. Tzu Chi Med J 2025;37:157–66. PMID 40321955. doi:10.4103/tcmj.tcmj_241_24
- Tipton KD. Nutrition for acute exercise-induced injuries. Ann Nutr Metab 2010;57 Suppl 2:43–53 (published online February 2011). PMID 21346336. doi:10.1159/000322703
- Tipton KD. Nutritional support for exercise-induced injuries. Sports Med 2015;45 Suppl 1:S93–104. PMID 26553492. doi:10.1007/s40279-015-0398-4
- Zeng N et al. Daily protein supplementation attenuates immobilization-induced blunting of postabsorptive muscle mTORC1 activation in middle-aged men. Am J Physiol Cell Physiol 2021;320:C591–601. PMID 33471625. doi:10.1152/ajpcell.00284.2020