Quick answer
Count all your protein, not just the shake. Adults need at least 0.8 g per kg of body weight a day, and people who train are advised to get 1.4 to 2.0 g per kg. Per shake, sports guidance is 20 to 40 g; with pea protein, about 38 g matches the leucine in 25 g of whey.1,2,3
Key facts
- Above about 1.6 g per kg a day in total, extra protein added no more lean mass in pooled training trials.4
- Intakes up to about 2.0 g per kg a day raised no safety concerns in NIH's review.1
- For a 70 kg adult, the sports guideline of 0.25 g per kg per serving is about 18 g of protein.2
- Pea protein carries less leucine than whey, so a pea shake needs to be about half as large again.3
Daily amounts by body weight
The Recommended Dietary Allowance (RDA) for protein is 0.8 g per kg of body weight a day for healthy adults and 0.85 g per kg for teens. The ISSN says this amount is not enough for people in regular training.1,2
The International Society of Sports Nutrition says 1.4 to 2.0 g of protein per kg of body weight a day is enough for most people who exercise to build and keep muscle. NIH gives a similar range for athletes, 1.2 to 2.0 g per kg.1,2
In a pooled analysis of 49 training trials, protein supplements added no more lean mass once total protein intake passed about 1.6 g per kg of body weight a day. The estimate was uncertain, with a likely range of about 1.0 to 2.2 g per kg.4
An international expert group on protein in older people (PROT-AGE) recommends at least 1.0 to 1.2 g per kg of body weight a day for adults over 65, and 1.2 g or more for those who exercise.5
| Body weight | RDA (0.8 g per kg) | Training (1.4 to 2.0 g per kg) | Over 65 (1.0 to 1.2 g per kg) |
|---|---|---|---|
| 55 kg (121 lb) | 44 g | 77 to 110 g | 55 to 66 g |
| 70 kg (154 lb) | 56 g | 98 to 140 g | 70 to 84 g |
| 85 kg (187 lb) | 68 g | 119 to 170 g | 85 to 102 g |
| 100 kg (220 lb) | 80 g | 140 to 200 g | 100 to 120 g |
The calculator works these out for any weight. Adults over 65 who exercise are advised 1.2 g per kg or more.5
How much per shake
For people who train, the ISSN suggests about 0.25 g of high-quality protein per kg of body weight per serving, or 20 to 40 g, containing 0.7 to 3 g of leucine.2
Older muscle needs a larger serving for the same response. An analysis cited in the 2018 meta-analysis found the response to one serving leveled off at about 0.24 g per kg in younger adults and 0.40 g per kg in older adults, and older men needed about 40 g of whey after exercise to reach the highest response.2,4
Plant proteins usually carry less leucine than dairy, so a pea shake needs to be bigger to match whey. In a laboratory analysis, 38 g of pea protein held the same 2.7 g of leucine as 25 g of whey; for soy the figure was 40 g.3
How much should come from a powder?
In national survey data from 2007 to 2008, American men ate about 100 g of protein a day on average and women about 69 g.1
Start with what you already eat. If food gives you 90 g a day and your target is 110 g, one 20 g shake closes the gap; if you already reach about 1.6 g per kg, the trials found nothing more to gain from extra protein.2,4
In the trials pooled in 2018, the protein groups took 4 to 106 g a day on top of their usual diet. Younger adults averaged 42 g a day and older adults 20 g.4
When more stops adding muscle
Extra protein supports small added gains in strength and lean mass from resistance training when your usual intake is below about 1.6 g per kg of body weight a day*4
Moderate evidence
A meta-analysis of 49 randomized trials (1,863 people) found protein supplements added about 2.5 kg to one-rep-max strength and 0.3 kg of fat-free mass over training alone, with no further gain above about 1.6 g of protein per kg a day in total. The trials averaged 36 g of supplement a day (range 4 to 106 g) and mostly used whey or milk protein, so 20 or 21 g of a fava and yeast blend is only a partial match; hence moderate, not strong.
Amount studied: 4 to 106 g of supplemental protein a day (36 g on average) during 6 to 52 weeks of resistance training
The 1.6 g figure is an estimate with a wide margin, not a hard limit, and the authors suggested about 2.2 g per kg for people trying to gain as much muscle as possible. It comes from healthy adults doing resistance training at least twice a week for 6 weeks or more.4
What's in ours
What’s in ours
- Collagen Peptides: Protein, 18 g per serving, from the label
- Collagen Peptides: Protein, 18 g per serving, from the label
- Plant Protein: Protein, 20 g per serving, from the label
- Plant Protein: Protein, 21 g per serving, from the label
One serving of our Plant Protein sits at the low end of the per-shake range, and it is fava bean and yeast protein rather than pea, so its leucine content is not known. Collagen counts only in part toward daily protein, because it lacks tryptophan.2,6
Upper amounts, and who should ask first
No tolerable upper intake level has been set for protein, because the risk of harm from protein in food is very low. NIH still advises caution with high intakes from foods and supplements combined, since data are limited, and reports no safety concerns up to about 2.0 g per kg a day.1
High-protein diets of two to three times the RDA do not appear to harm kidney function, bone health or hydration in healthy people, and trained adults eating up to about 3.3 g per kg a day for up to a year showed no change in kidney or liver markers. People with severely reduced kidney function may need to limit protein.1,2,5
- Ask first if you have kidney disease or have been told to limit protein
- Ask first if you are pregnant, nursing or under 18
Questions people ask
Is 50 g of protein powder a day too much?
Not for most healthy adults if your total stays within the studied range. Trials gave up to 106 g of supplement a day, and NIH reports no safety concerns up to about 2.0 g per kg from all sources. Above about 1.6 g per kg in total, extra protein added no more lean mass.1,4
See what we make
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Sources
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. Updated April 1, 2024. Opened 2026-10-07.
- Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. Opened 2026-10-01.
- Gorissen SHM, Crombag JJR, Senden JMG, et al. Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids. 2018;50(12):1685-1695. Opened 2026-10-07.
- 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(6):376-384. Opened 2026-10-01.
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. Opened 2026-10-07.
- Paul C, Leser S, Oesser S. Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance. Nutrients. 2019;11(5):1079. Opened 2026-10-07.
- Office of Dietary Supplements, National Institutes of Health. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.