Nine amino acids must come from the diet and support protein synthesis, enzymes, hormones and tissues.
Covered through protein needs and protein quality; no universal single dose for healthy people.
All complete animal proteins; plant-based needs are met through adequate variety and quantity from legumes, soy, grains, nuts and seeds.
Usually part of general protein-energy undernutrition with muscle loss, weakness and poor wound healing.
Leucine triggers muscle-protein synthesis but replaces neither complete protein nor resistance training.
No single amino acid can be read reliably from hair or nails.
Severe restriction, malnutrition, illness and very low total protein intake.
Assess total protein, protein sources, energy intake, weight and muscle status.
Complete protein first. EAA/BCAA are usually unnecessary with adequate protein; situational in sport or clinical care.
High doses of single amino acids can affect balance and medicines.