Are Protein and Amino Acid Supplements Necessary? Who May Need Them and Who Probably Does Not

What official figures say

These are population reference values, not targets for any one person. Do not mix g/kg, g/day and % of calories; see Protein units explained and Protein intake levels by age, sex and country.

Groups who may have higher needs or difficulty reaching them

This is the list a clinician would use to start a conversation, not a list of people who must supplement.

• Older adults. The PROT-AGE Study Group (2013 position paper, adults over 65) recommended average intake at least 1.0 to 1.2 g/kg a day, higher for people who exercise or have acute or chronic disease. [3] Those with severe kidney disease who are not on dialysis may need to limit protein. [3] See Protein for older adults and Strength training and protein for older adults.
• People doing regular resistance training. The International Society of Sports Nutrition (2017) says 1.4 to 2.0 g/kg a day is sufficient for most exercising people, and that whole foods can supply it. [4] In a 2018 meta-analysis of 49 trials, supplements gave a small average gain in lean mass; gains were smaller with age. [5] Another meta-analysis (2012, 22 trials) also found gains in muscle mass and strength in younger and older people. [6] See Protein for muscle, training and recovery.
• People eating no animal foods. A 2019 review found legumes, nuts and seeds are enough for protein adequacy in adults on vegetarian or vegan diets. [7] A powder is optional. See Protein for vegans and vegetarians.
• Pregnancy. Needs rise in the second half of pregnancy per the Health Canada table above. [2] Talk to your prenatal care provider before using any powder or amino acid product. See Pregnancy and breastfeeding.
• Illness, surgery or poor appetite. The PROT-AGE paper says most older adults with acute or chronic disease need more dietary protein. [3] This is clinician or dietitian territory; see Protein after illness and surgery.
• Chronic kidney disease. Needs may be lower or, on dialysis, higher; NIDDK advises working with a dietitian or health care professional. [8] See Protein and kidney disease.
• Children and teens. MedlinePlus notes protein is important for growth and that amounts differ by age. [1] See Protein for children and teens.

Who probably does not need them

The sources we read do not define a group that should not use protein supplements, and they do not measure benefit for people who are not training. Proper evidence not found for added benefit of protein powder in sedentary adults eating varied protein foods: the supplement trials we read were all in people doing resistance training (reviews of 22 and 49 trials). [6][5] That is a gap in what we read, not proof of no benefit.

Amino acid supplements

Protein and amino acid products are not the same thing. Amino acids are the building blocks of protein; nine are essential. [9] An ISSN position stand (2023) on essential amino acid (EAA) supplements says free-form EAAs stimulate muscle protein synthesis more than an equal amount of intact protein, and that without exercise EAA supplements can improve functional outcomes in people with "anabolic resistance". [10] Two cautions: those are short-term muscle-building measures, not proof of long-term health benefit, and the paper's conflict-of-interest statement lists commercial interests, including patents on EAA compositions, for some authors. [10] For single amino acids (for example glutamine, arginine or tryptophan) use their own pages, because each has different evidence and risks. See BCAAs vs EAAs vs complete protein and Essential amino acids.