The Claim
Insulin does not significantly increase skeletal muscle protein synthesis in healthy humans under conditions of unchanged amino acid availability, but increases skeletal muscle protein synthesis by 13.44 nmol (100 ml leg vol.)⁻¹ min⁻¹ when amino acid delivery is increased.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Insulin does not increase muscle protein synthesis in healthy people unless more amino acids are delivered to the muscles. When amino acid delivery increases, insulin raises muscle protein synthesis by 13.44 nmol per 100 ml of leg volume per minute.
See the scientific wording
Insulin does not significantly increase skeletal muscle protein synthesis in healthy humans when amino acid availability is unchanged, but stimulates synthesis by 13.44 nmol (100 ml leg vol.)⁻¹ min⁻¹ when amino acid delivery is increased, demonstrating its anabolic effect is conditional on substrate availability.
Insulin alone does not build muscle protein. When amino acids are present in the blood and enter muscle cells, insulin helps pull more amino acids inside and turns on a molecular switch called mTORC1. This switch tells the cell's protein-making machines to start building new muscle proteins. Without enough amino acids, the switch stays off, and insulin cannot trigger protein building.
What the research says
1 studyInsulin doesn't make muscles grow by itself—it needs protein (amino acids) to help. When amino acids are around, insulin helps build muscle; without them, it doesn't.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.