Muscle & Aging
How Much Protein Do Older Adults Actually Need?
The short answer
In a 6-month controlled-feeding trial, older men whose usual intake already met the standard recommendation (0.8 g/kg/day) saw no additional lean-mass benefit from raising it to 1.3 g/kg/day (difference 0.31 kg; 95% CI -0.46 to 1.08; p=0.43). But in sarcopenic older adults specifically, reaching 1.2-1.5 g/kg/day — whether through diet counseling or a supplement — was linked to measurable gains in muscle mass index that a lower intake did not produce. A separate feeding study found that once total intake exceeded the recommendation, the source mattered: whey and pea protein raised the body's muscle-building signal, while collagen at the same amount did not. No trial in this search tested protein needs specifically in adults 85 and older.
Quick answers
- What is it?
- How much protein older adults actually need to preserve muscle.
- Why are people interested in it?
- Older adults are commonly told to eat more protein, and want to know if the standard recommendation is really too low for them.
- What has actually been studied?
- A 6-month controlled-feeding trial in 92 older men comparing the standard RDA against a higher intake, a 12-week trial in 56 sarcopenic older adults targeting 1.2 to 1.5 g/kg/day, and a mechanistic trial comparing whey, pea, and collagen protein.
- How strong is the evidence?
- It depends on the population — in older men already meeting the standard recommendation, raising intake further added no lean-mass benefit, but in sarcopenic older adults, reaching a higher target tracked with measurable muscle gains.
- What don't we know yet?
- Whether one protein source outperforms another once total intake is adequate, how obesity changes protein requirements during weight loss, and protein needs specifically in adults 85 and older.
- Where can I read the original research?
- Sources at the bottom of this page: Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men: A Randomized Clinical Trial and The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial.
The short answer: It depends on what "need" means and who's being measured. In a 6-month controlled-feeding trial, older men whose usual protein intake already sat within the standard recommendation of 0.8 g/kg/day saw no extra benefit to lean body mass from pushing intake up to 1.3 g/kg/day — the RDA, in that specific population, appeared sufficient. But in sarcopenic older adults, separate trials found that reaching 1.2-1.5 g/kg/day tracked with measurable gains in muscle mass that lower intakes did not produce. And once intake rises above baseline, the source seems to matter: a controlled study found whey and pea protein raised the body's muscle-building signal while collagen, at an identical added amount, did not. No trial retrieved in this search tested protein needs specifically in adults 85 and older — a population reviews flag as understudied.
What the research shows
A trial that found the standard recommendation was enough
The most tightly controlled test of this question came from a 2018 randomized clinical trial published in JAMA Internal Medicine. Researchers recruited 92 men aged 65 and older with physical function limitations whose usual protein intake was already at or below the U.S. recommended dietary allowance (RDA) of 0.8 g/kg/day. Using a 2×2 factorial design with custom-prepared, controlled meals, participants were randomized to six months of either 0.8 g/kg/day or 1.3 g/kg/day of protein, combined with either weekly testosterone injections or placebo. The primary outcome — change in lean body mass — did not differ between the 0.8 and 1.3 g/kg/day groups (difference 0.31 kg; 95% CI -0.46 to 1.08; p=0.43), regardless of whether participants also received testosterone. Muscle strength, power, physical function, quality of life, fatigue, and well-being also showed no difference by protein dose. The one measurable effect of higher protein was on fat mass, which fell more in the higher-protein group (difference -1.12 kg; 95% CI -2.04 to -0.21; p=0.02). The authors concluded that in this population, the RDA was sufficient to maintain lean body mass, and that protein above the RDA did not promote additional muscle gain or enhance the anabolic response to testosterone.
But in sarcopenic adults, hitting a higher target tracked with muscle gains
A different picture emerged in adults who already had diagnosed sarcopenia. A 2020 open-label, parallel-group trial in Clinical Nutrition enrolled 56 sarcopenic older adults and set a shared protein target of 1.2-1.5 g/kg/day for everyone — reached either through dietary counseling toward an ordinary protein-rich diet (28 participants) or through a leucine- and vitamin D-enriched whey protein supplement (28 participants). Both groups increased total protein and energy intake over 12 weeks, and appendicular muscle mass index improved in both — with no significant difference between the counseling-only and supplement groups. The supplement group did show a larger improvement in gait speed at 12 weeks, particularly among participants under 75. The authors framed the finding simply: muscle mass index improved as long as the 1.2-1.5 g/kg/day target was reached, regardless of how people got there.
Once you're above baseline, the protein source appears to matter
A 2024 mechanistic trial in the American Journal of Clinical Nutrition tested what happens at the cellular level when protein intake rises above the RDA, and whether the source changes the outcome. Thirty-one healthy older men, average age 72, ate a controlled diet at the RDA for a week, establishing a baseline muscle protein synthesis rate of roughly 1.46%/day. They then added 50 g/day of either whey, pea, or collagen protein for a second week. Muscle protein synthesis rose significantly with both whey (1.59%/day, p<0.001) and pea protein (1.59%/day, p<0.001) — but stayed unchanged with collagen. Whey and pea also produced higher post-meal blood amino acid levels and stronger activation of anabolic signaling pathways than collagen did. The implication: simply hitting a gram-per-kilogram number may not be the whole story — where those grams come from appeared to change whether the body's muscle-building machinery actually responded.
Where the recommendations sit, and why they may be shifting
A 2024 review in Current Opinion in Clinical Nutrition and Metabolic Care addressed protein needs in older adults dealing with obesity specifically, noting that no trial has directly established a protein requirement for obesity as such. But the review concluded that during weight loss, the "rebuilding of the body is likely to need at least 1.2 g/kg body weight/day," especially in older adults — and cautioned that an obese but healthy, active older adult might have protein needs closer to normal. A separate 2018 review of nutrition in the "very old" (85 and above), covering data from the Newcastle 85+ Study and the Life and Living in Advanced Age study in New Zealand, described diet — including protein — as a modifiable risk factor for sarcopenia and functional decline in this age group, but flagged a "major gap" in evidence for how much protein specifically supports physical and cognitive function once someone reaches their mid-eighties and beyond, since most trials, including all four above, enrolled participants substantially younger than that.
What we don't know yet
Whether one protein source outperforms another once total daily intake is already adequate. The mechanistic trial found whey and pea outperformed collagen for muscle protein synthesis at a single added dose, but no retrieved trial tracked whether that acute difference translates into different long-term muscle outcomes.
Optimal per-meal distribution versus total daily amount. None of the trials retrieved here directly tested whether spreading protein evenly across meals, versus consuming most of it at one meal, changes outcomes in older adults specifically.
How obesity changes protein requirements during active weight loss. The 2024 review found no trial has directly tested protein requirements in older adults with obesity; its 1.2 g/kg/day figure was extrapolated from broader evidence, not measured directly in that population.
Protein needs in adults 85 and older. Every RCT retrieved in this search enrolled participants younger than 85 on average. The review covering the "very old" explicitly described this as an evidence gap rather than a settled question.
Whether higher protein intake changes hard outcomes like falls, hospitalizations, or mortality. The trials here measured lean mass, strength, and muscle protein synthesis — intermediate markers — not downstream clinical events.
Sources
- Bhasin S, Apovian CM, Travison TG, et al. Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men: A Randomized Clinical Trial. JAMA Internal Medicine, 2018;178(4):530-541. DOI
- McKendry J, Lowisz CV, Nanthakumar A, MacDonald M, Lim C, Currier BS, Phillips SM. The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial. The American Journal of Clinical Nutrition, 2024;120(1):34-46. DOI
- Lin CC, Shih MH, Chen CD, Yeh SL. Effects of adequate dietary protein with whey protein, leucine, and vitamin D supplementation on sarcopenia in older adults: An open-label, parallel-group study. Clinical Nutrition, 2020;40(3):1323-1329. DOI
- Weijs PJM. Protein requirement in obesity. Current Opinion in Clinical Nutrition and Metabolic Care, 2024;28(1):27-32. DOI
- Granic A, Mendonça N, Hill TR, Jagger C, Stevenson EJ, Mathers JC, Sayer AA. Nutrition in the Very Old. Nutrients, 2018;10(3):269. DOI
Article records maintained via PubMed. Peptide Proof reports what studies found. It does not provide medical advice, dosing guidance, or treatment recommendations.
Topic: Energy & Performance · Aging & Longevity
Sources
- Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men: A Randomized Clinical Trial
- JAMA Internal Medicine, 2018 · n=92 · DOI
- The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial
- The American Journal of Clinical Nutrition, 2024 · n=31 · DOI
- Effects of adequate dietary protein with whey protein, leucine, and vitamin D supplementation on sarcopenia in older adults: An open-label, parallel-group study
- Clinical Nutrition, 2020 · n=56 · DOI
- Protein requirement in obesity
- Current Opinion in Clinical Nutrition and Metabolic Care, 2024 · DOI
- Nutrition in the Very Old
- Nutrients, 2018 · DOI
Get the evidence, not the hype.
New research briefs, plainly written and fully sourced. No dosing advice, ever.