Proof.Fit

Leucine

17 benefits mapped to clinical evidence across supplements.

Benefit Evidence

Main Effects
Muscle growth

MPS + leucine

Muscle size/gain +

Strong
3,420
Body composition

+lean mass, body weight

-muscle loss, protein breakdown

Strong
3,421
Healthy aging

Muscle gain + performance

Mortality/cognition benefits

-

Strong
6,625
Illness recovery

Anabolism + recovery

Less catabolism, shorter stay

BCAA/leucine support healing

Strong
1,879
Metabolism

Glucose/insulin ↓

Liver fat/IR ↓

Strong
4,453
Strength

Strength +5-15%

Strength +20 kg

Strong
1,773
Blood sugar

↑ insulin, ↓ glucose

↓ insulin resistance

Moderate
699
Exercise recovery

MPS recovery +30-145%

Less breakdown/soreness

Moderate
568
Workout performance

MPS + performance

Strength + recovery

Moderate
623
Immune support

Immune markers +

Inflammation down, immunity up

Moderate
362
Fat burn

Fat loss +4.7 kg

Fat oxidation +33.6 g/d

Moderate
248
Endurance

Endurance +18.1 m

Muscle preservation +1,019 g

Moderate
380
Skin repair

Protein balance + synthesis

Wound repair + collagen

Moderate
340
Appetite suppression

Leucine/AA ↑ satiety, CCK

Whey/BCAA ~13% intake ↓

Weak
106
Bone health

Vitamin D/PTH: +2% BMD

Leucine EAA: BMC preserved

Weak
440
Focus & concentration

Cognition +10.6%

Attention/reaction time

Protein synthesis

Weak
71
Muscle soreness

Reduced soreness; no detail

Lower soreness, +5% strength

Weak
41