What supplements actually help with muscle mass and strength over 40?

The supplements with the strongest evidence specifically for muscle mass and strength in men over 40: (1) creatine monohydrate 3–5 g/day, Solid (1), the most studied supplement in existence; (2) whey protein to achieve 1.6–2.2 g/kg/day total protein, Solid (1); (3) vitamin D to achieve serum 40–60 ng/mL (deficiency impairs muscle function directly through vitamin D receptors in myocytes), Solid (1) for deficiency correction; (4) omega-3 fatty acids 2–4 g/day EPA+DHA, Promising (2) for attenuating muscle protein breakdown during energy restriction (Smith et al., Am J Clin Nutr, 2011).

HMB (beta-hydroxy beta-methylbutyrate) has a brief mention: meta-analysis shows modest muscle mass preservation benefit in older adults, particularly in sarcopenic populations, Promising (2) for men over 70, Early (3) for men 40–55 with adequate protein intake. BCAA supplementation above adequate total protein intake, Unsupported (5) for additional muscle benefit.

Honesty Scale: As rated per supplement.

What to do: Build the stack in order: adequate total protein first (non-negotiable), then creatine (cheap, safe, effective), then vitamin D if deficient, then omega-3. Everything else is secondary.

For the full picture, read The Strength/Grip Deep Dive