Protein for runners: what's being used and what the research says
We report what runners are using and what the research says. We don't recommend taking any supplement. Talk to your GP or a registered sports dietitian before trying one.
Quick answer
Research suggests most runners don't need them. The international athletics federation's consensus puts daily targets for athletes at 1.3 to 1.7 g of protein per kg of body mass[1], and the AIS says most athletes meet their targets from food[2]. The ISSN says added protein does not appear to improve endurance performance[3].
- Research
- Emerging (proposed)Food can meet runners' daily needs. No clear gain in race times; meta-analyses of training adaptation disagree.
- Proposed by our editor; not yet confirmed by an expert reviewer.
- WADA status
- Permitted
- Distances in the research
- 800 m–5K: limited research10K–half: limited researchMarathon: limited researchUltra: limited research
What are protein supplements?
Protein supplements come as powders, bars and ready-to-drink shakes, made from milk proteins such as whey and casein, from egg, or from plants such as soy[2].
The Australian Institute of Sport lists isolated protein supplements in Group A as a sports food[2]. The international athletics federation prefers whole foods, but says supplements can help when food is impractical, such as straight after exercise[1].
Also called: protein shakes, protein powder, whey, casein, recovery shakes.
Why are protein supplements getting attention?
Protein's role in building and repairing muscle makes it an obvious focus for athletes, and protein supplements are among the most popular supplement products[2].
In a survey of recreational distance runners, the authors report an intake rate of 19% for carbohydrate and protein supplements, counted together[4].
How do protein supplements work?
Training raises protein needs: the AIS puts targets for athletes in heavy training at up to double those for inactive people, and says this applies to endurance athletes too[2].
Protein eaten over the day after key sessions helps the body build new proteins in response to training and replace damaged ones[1].
Do protein supplements help runners?
Not clearly for race performance. The ISSN says added protein does not appear to improve endurance performance[3]. A meta-analysis found carbohydrate plus protein beat carbohydrate alone overall, but in the six trials where drinks had the same calories, time to exhaustion didn't improve[5]. On training adaptation, one meta-analysis, which included patient groups, found small extra gains in aerobic fitness, lean mass and time trials[6]; a 2025 meta-analysis found only time to exhaustion improved, with most of its evidence low or very low certainty[7].
800 m to 5K (Limited research)
Elite orienteers who took whey around each session of a hard training week ran a 4 km test faster[8]. In trained runners, protein before sleep during a hard week made no difference to a 5 km time trial[9].
10K to half marathon (Limited research)
In 323 recreational runners after a 15 km road race, milk protein for three days didn't reduce muscle soreness or damage markers compared with a carbohydrate drink[10].
Marathon (Limited research)
In a small trial in recreational marathoners, protein during or after the race made no meaningful difference to recovery at 24 hours, though soreness and fatigue ratings were better over 72 hours[11].
Ultra (Limited research)
In 28 male ultra runners, amino acids before and during a 100 km race didn't change race time, damage markers or soreness[12]. The ISSN calls the controlled evidence in ultras conflicting[13].
The key studies, in order
- 2011Trial28 male ultra runners: 52.5 g of amino acids before and during a 100 km race didn't change race time, muscle damage markers or soreness. [12]
- 2015Trial18 elite orienteers, 1-week training camp: whey before and after each session improved a 4 km run test and lowered a muscle damage marker, against energy-matched carbohydrate drinks. [8]
- 2017ConsensusDaily intakes of 1.4-2.0 g/kg suit most exercising people. Added protein does not appear to improve endurance performance. No controlled evidence of harm in healthy exercisers. [3]
- 2018ConsensusProtein supplements provide 20-50 g per serve but may contain other ingredients that raise the risk of contamination. Athletes are responsible for anything found in their sample. [15]
- 2018TrialRecreational marathoners, 8 or 4 per group: protein during or after the race made no meaningful difference at 24 hours; soreness and fatigue ratings were better over 72 hours. [11]
- 2019ConsensusDaily protein targets of 1.3-1.7 g/kg for weight-stable athletes. Whole foods preferred; supplements useful when food is impractical. 2.4 g/kg a day during weight loss didn't raise kidney or bone risk. [1]
- 2019Trial32 trained runners, a week of hard training: whey before sleep didn't reduce the drop in 5 km performance or muscle damage markers, compared with carbohydrate. [9]
- 2019ConsensusFor ultra runners: about 1.6 g/kg of protein a day, up to 2.5 g/kg in demanding training. Controlled studies of protein during ultras have conflicting results. [13]
- 2020Meta-analysis30 trials: carbohydrate plus protein beat carbohydrate alone overall, but in 6 trials with calorie-matched drinks, time to exhaustion didn't improve. Most studies used cycling; about 80% of participants were men. [5]
- 2021Meta-analysis19 studies, 1,162 people including patient groups: protein during endurance training brought small extra gains in VO2peak and lean mass, and faster time trials. [6]
- 2021Trial323 recreational runners after a 15 km race: milk protein for 3 days didn't reduce soreness or damage markers compared with a carbohydrate drink. Funded by a dairy company. [10]
- 2021Survey119 recreational distance runners: the authors report intake rates of 43% for vitamins, 34% for minerals and 19% for carbohydrate or protein supplements, counted together. [4]
- 2025Meta-analysis23 trials, 1,146 people (78% men): time to exhaustion improved, but lean mass, VO2max, time trials and body fat didn't change significantly. Most evidence low or very low certainty; the authors note this contradicts an earlier meta-analysis. [7]
What the research can't tell us yet
Most trials used cycling: in a meta-analysis of protein added to carbohydrate, only four studies tested running, and about 80% of participants were men[5].
When drinks had the same calories, time to exhaustion didn't improve, but only six small trials tested this, and none used time trials[5]. Most evidence on training adaptation was rated low or very low certainty[7].
Some trials were funded by the dairy industry, including the 15 km race trial[10].
How are protein supplements used in studies?
Daily targets in position stands: 1.3 to 1.7 g per kg of body mass[1], 1.2 to 1.6 g/kg in heavy training[2], and 1.4 to 2.0 g/kg[3]. For ultra runners, the ISSN gives about 1.6 g/kg a day, and up to 2.5 g/kg during demanding training[13].
Studies of runners used, for example, 20 g of milk protein after a race and at breakfast, plus 40 g before sleep, for three days[10], or 0.3 g per kg before and after each session of a training camp[8].
| What studies used | When | Ref. |
|---|---|---|
| 20 g of milk protein, plus 40 g before sleep | After a 15 km race, then at breakfast and before sleep for 3 days | [10] |
| 0.3 g per kg of body mass of whey | Before and after each session of a 1-week camp | [8] |
| 0.5 g per kg of body mass of whey | Before sleep, during a hard training week | [9] |
| Gels with 20 g carbohydrate and 5 g protein | During a marathon | [11] |
What are the side effects, and who should be careful?
The ISSN says there is no controlled evidence that higher protein intakes harm healthy exercising people[3]. The international athletics federation says athletes eating 2.4 g/kg a day during weight loss aren't at increased risk of kidney or bone problems[1].
The AIS warns that some protein powders contain unneeded extra ingredients, some of which may be harmful or banned in sport, and that powders can contain contaminants such as heavy metals[2].
Protein can crowd out carbohydrate: in cyclists, a week of high-protein, lower-carbohydrate eating made a time trial take 20% longer[3].
Be careful if
- You have a kidney condition: the NHS advises people with chronic kidney disease to check with a doctor or pharmacist before taking nutritional supplements[14].
- Shakes are replacing carbohydrate-rich food: a high-protein, lower-carbohydrate diet slowed cyclists' time trials[3].
- You're tested under anti-doping rules: protein supplements can contain undeclared prohibited substances[15].
Are protein supplements allowed in competition?
Food proteins such as whey and casein are not on the World Anti-Doping Agency's Prohibited List[16].
The IOC notes that protein supplements may contain other ingredients that raise the risk of contamination[15], and under anti-doping rules, athletes are responsible for anything found in their sample[15].
Independent quality-assurance schemes, often called batch testing, check supplement products for prohibited substances[15]. WADA says using a product from one of these schemes can reduce, but not eliminate, the risk of an anti-doping violation[16], and the IOC says no product can be guaranteed entirely safe[15]. The AIS adds that batch testing checks for substances banned in sport, not other contaminants such as heavy metals[2].
Myth or evidence?
5 things runners hear about protein supplements. Pick an answer to see what the research says.
1.Distance runners need more protein than people who don't exercise.
Show the answer
Evidence. The AIS puts targets for athletes in heavy training at up to double those for inactive people, including endurance athletes[2].
2.You need protein shakes to get enough protein.
Show the answer
Myth. The AIS says most athletes meet their targets from food alone[2].
3.Protein before or during a race makes you faster.
4.Protein after a hard run cuts muscle soreness.
5.Protein powders can contain contaminants or banned substances.
Have you tried protein supplements?
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What readers have said so far
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Frequently asked questions
- How much protein do distance runners need each day?
- The international athletics federation's consensus gives 1.3 to 1.7 g per kg of body mass a day[1], and the ISSN 1.4 to 2.0 g/kg[3]. For ultra runners, the ISSN gives about 1.6 g/kg a day, and up to 2.5 g/kg during demanding training[13].
- Do runners need a protein shake to hit that target?
- The AIS says most athletes reach their daily target from food and takes a food-first approach[2]. The athletics federation sees shakes as useful when food is impractical, such as straight after a session[1].
- Will extra protein make me faster?
- The ISSN says added protein does not appear to improve endurance performance[3]. A meta-analysis found benefits mainly when protein added extra calories: in six trials with calorie-matched drinks, time to exhaustion didn't improve[5].
- Does protein after a race reduce muscle soreness?
- In 323 runners after a 15 km race, milk protein didn't reduce soreness compared with a carbohydrate drink[10]. A small marathon trial found better soreness and fatigue ratings over 72 hours, but no meaningful difference at 24 hours[11].
- Is a high-protein diet bad for a healthy runner's kidneys?
- The athletics federation's consensus says athletes eating 2.4 g/kg a day during weight loss aren't at increased risk of kidney problems[1]. That applies to healthy athletes; the NHS advises people with kidney disease to check with a doctor or pharmacist before taking supplements[14].
References
- [1]
Burke LM, Castell LM, Casa DJ, et al. International Association of Athletics Federations consensus statement 2019: nutrition for athletics. International Journal of Sport Nutrition and Exercise Metabolism, 2019.
Consensus statementDaily protein targets of 1.3-1.7 g/kg for weight-stable athletes. Whole foods preferred; supplements useful when food is impractical. 2.4 g/kg a day during weight loss didn't raise kidney or bone risk.
doi.org/10.1123/ijsnem.2019-0065 - [2]
Australian Institute of Sport AIS Sports Supplement Framework: Group A and linked fact sheets. Australian Sports Commission, 2026.
Consensus statementLists isolated protein supplements in Group A as a sports food. Most athletes meet their daily protein targets from food; some powders contain contaminants or unneeded ingredients.
www.ausport.gov.au/ais/nutrition/supplements/group_a - [3]
Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, 2017.
Consensus statementDaily intakes of 1.4-2.0 g/kg suit most exercising people. Added protein does not appear to improve endurance performance. No controlled evidence of harm in healthy exercisers.
doi.org/10.1186/s12970-017-0177-8 - [4]
Wirnitzer K, Motevalli M, Tanous D, et al. Supplement intake in half-marathon, (ultra-)marathon and 10-km runners: results from the NURMI study (step 2). Journal of the International Society of Sports Nutrition, 2021.
Survey119 recreational distance runners: the authors report intake rates of 43% for vitamins, 34% for minerals and 19% for carbohydrate or protein supplements, counted together.
doi.org/10.1186/s12970-021-00460-2 - [5]
Kloby Nielsen LL, Tandrup Lambert MN, Jeppesen PB The effect of ingesting carbohydrate and proteins on athletic performance: a systematic review and meta-analysis of randomized controlled trials. Nutrients, 2020.
Meta-analysis30 trials: carbohydrate plus protein beat carbohydrate alone overall, but in 6 trials with calorie-matched drinks, time to exhaustion didn't improve. Most studies used cycling; about 80% of participants were men.
doi.org/10.3390/nu12051483 - [6]
Lin YN, Tseng TT, Knuiman P, et al. Protein supplementation increases adaptations to endurance training: a systematic review and meta-analysis. Clinical Nutrition, 2021.
Meta-analysis19 studies, 1,162 people including patient groups: protein during endurance training brought small extra gains in VO2peak and lean mass, and faster time trials.
doi.org/10.1016/j.clnu.2020.12.012 - [7]
Xiao Y, Deng Z, Sun W, et al. Effects of protein supplementation on body composition, physiological adaptations, and performance during endurance training: a systematic review and meta-analysis. Frontiers in Nutrition, 2025.
Meta-analysis23 trials, 1,146 people (78% men): time to exhaustion improved, but lean mass, VO2max, time trials and body fat didn't change significantly. Most evidence low or very low certainty; the authors note this contradicts an earlier meta-analysis.
doi.org/10.3389/fnut.2025.1663860 - [8]
Hansen M, Bangsbo J, Jensen J, et al. Effect of whey protein hydrolysate on performance and recovery of top-class orienteering runners. International Journal of Sport Nutrition and Exercise Metabolism, 2015.
Randomised controlled trial18 elite orienteers, 1-week training camp: whey before and after each session improved a 4 km run test and lowered a muscle damage marker, against energy-matched carbohydrate drinks.
doi.org/10.1123/ijsnem.2014-0083 - [9]
Larsen MS, Clausen D, Jørgensen AA, et al. Presleep protein supplementation does not improve recovery during consecutive days of intense endurance training: a randomized controlled trial. International Journal of Sport Nutrition and Exercise Metabolism, 2019.
Randomised controlled trial32 trained runners, a week of hard training: whey before sleep didn't reduce the drop in 5 km performance or muscle damage markers, compared with carbohydrate.
doi.org/10.1123/ijsnem.2018-0286 - [10]
Ten Haaf DSM, Flipsen MA, Horstman AMH, et al. The effect of protein supplementation versus carbohydrate supplementation on muscle damage markers and soreness following a 15-km road race: a double-blind randomized controlled trial. Nutrients, 2021.
Randomised controlled trial323 recreational runners after a 15 km race: milk protein for 3 days didn't reduce soreness or damage markers compared with a carbohydrate drink. Funded by a dairy company.
doi.org/10.3390/nu13030858 - [11]
Saunders MJ, Luden ND, DeWitt CR, et al. Protein supplementation during or following a marathon run influences post-exercise recovery. Nutrients, 2018.
Randomised controlled trialRecreational marathoners, 8 or 4 per group: protein during or after the race made no meaningful difference at 24 hours; soreness and fatigue ratings were better over 72 hours.
doi.org/10.3390/nu10030333 - [12]
Knechtle B, Knechtle P, Mrazek C, et al. No effect of short-term amino acid supplementation on variables related to skeletal muscle damage in 100 km ultra-runners: a randomized controlled trial. Journal of the International Society of Sports Nutrition, 2011.
Randomised controlled trial28 male ultra runners: 52.5 g of amino acids before and during a 100 km race didn't change race time, muscle damage markers or soreness.
doi.org/10.1186/1550-2783-8-6 - [13]
Tiller NB, Roberts JD, Beasley L, et al. International Society of Sports Nutrition position stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 2019.
Consensus statementFor ultra runners: about 1.6 g/kg of protein a day, up to 2.5 g/kg in demanding training. Controlled studies of protein during ultras have conflicting results.
doi.org/10.1186/s12970-019-0312-9 - [14]
NHS Chronic kidney disease: living with. NHS, 2026.
RegulatorPeople with chronic kidney disease should check with a doctor or pharmacist before taking nutritional supplements, which can affect the kidneys.
www.nhs.uk/conditions/kidney-disease/living-with/ - [15]
Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. British Journal of Sports Medicine, 2018.
Consensus statementProtein supplements provide 20-50 g per serve but may contain other ingredients that raise the risk of contamination. Athletes are responsible for anything found in their sample.
doi.org/10.1136/bjsports-2018-099027 - [16]
World Anti-Doping Agency The Prohibited List. World Anti-Doping Agency, 2026.
RegulatorThe substances and methods prohibited in sport. Food proteins such as whey are not on it.
www.wada-ama.org/en/prohibited-list
Who wrote and reviewed this
Written by Grant MacMillan, Editor, RunV. Not yet reviewed by an expert.
Last checked against its references . Next review due . How pages are reviewed · How we grade research
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