Table 6

Supplements promoted to assist with physique changes: gain in lean mass and loss of body fat mass

SupplementProposed mechanism of actionEvidence for efficacy25
Gaining LBM*
Protein
Usually comprised isolated proteins from various sources (whey and soy most common)
Recommended daily dose: 1.6 g protein/kg/day optimal (up to 2.2 g/kg/day with no adverse effects)
Recommended per-meal doses: 0.3–0.5 g protein/kg (3–4 times per day and in close temporal proximity to exercise, with postexercise being consistently shown to be effective)
Enhances lean mass gains when ingested during programmes of resistance training due to increased provision of building blocks (amino acids) and leucine as a trigger for a rise in muscle protein synthesis and suppression of muscle protein breakdownMeta-analyses focusing on younger and older participants have shown positive effects enhancing gains in muscle mass,161 162 but effects are not large.
LeucineStimulates muscle protein synthesis and suppresses protein breakdown (possibly through insulin)Short-term mechanistic data available,137 but no long-term trials showing efficacy163