Why Amino Acids Matter More After 40

Muscle mass is one of the strongest predictors of health-span and functional independence. 

Beginning in the fourth decade of life, adults lose approximately 3–8% of skeletal muscle mass per decade, with accelerated decline after age 60. This age-related muscle loss is associated with increased insulin resistance, higher fall risk, greater fracture incidence, and increased all-cause mortality.

Muscle tissue is metabolically active and serves as a primary site for glucose disposal. Preserving muscle mass is therefore a strategy for maintaining metabolic health. Adequate amino acid intake is foundational to this preservation.

Muscle protein synthesis (MPS) requires essential amino acids (EAAs), particularly leucine. With aging, muscle becomes less responsive to smaller doses of protein- a phenomenon known as anabolic resistance. 

Research suggests older adults require approximately 30–40 grams of high-quality protein per meal to maximally stimulate MPS. Total daily protein intake for active adults over 40 is often recommended at 1.2–1.6 g/kg/day, higher than the current RDA of 0.8 g/kg/day, which is designed to prevent deficiency rather than optimize function.

Combined with resistance training, adequate essential amino acid intake helps counteract muscle decline and supports longevity by preserving strength, metabolic health, and independence.

Recovery and Strength Mix - $49.99

References

  1. Mitchell WK, Williams J, Atherton P, Larvin M, Lund J, Narici M. Sarcopenia, dynapenia, and the impact of advancing age on human skeletal muscle size and strength; a quantitative review. Front Physiol. 2012;3:260.

  2. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52:376–384.

  3. Phillips SM, Fulgoni VL 3rd, Heaney RP, Nicklas TA, Slavin JL, Weaver CM. Commonly consumed protein foods contribute to nutrient intake, diet quality, and nutrient adequacy. Am J Clin Nutr. 2015;101:1346–1352.