Performance/Weight/Longevity

Protein

Widely researched sports nutrition supplement providing amino acids to support muscle synthesis, recovery, body composition, and satiety.

score

evidence

Safe

risk

Our methodology: How we evaluate supplements and turn the underlying research into a single rating.

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Overview

Forms

Safety

Stack

Quick Take

Strong evidence for building and preserving muscle with training; useful for satiety during weight loss.

Protein is a macronutrient of amino acids essential for tissue repair. Supplemental forms include whey (fast-absorbing), casein (slow-release), and blends of pea, soy, or rice. It stimulates muscle protein synthesis via the mTOR pathway. Meta-analyses confirm it augments strength and lean mass with resistance training, preserves muscle during dieting, and supports satiety. It also reduces sarcopenia risk in older adults. Most likely to benefit: athletes, dieters, and adults over 60 with low intake.

Potential benefits

Enhances strength with training

Supports lean mass preservation

Reduces sarcopenia in older adults

Accelerates post-exercise recovery

Supports satiety and weight control

Protocol

Amount

20-40 g per serving

Frequency

1-3 times daily

When

Within 2 hours post-workout; any time to meet daily protein targets

Onset Time

Acute protein synthesis in 1-2 h; strength gains in 8-12 weeks.

Who Should Consider

Resistance-training athletes

Adults in a calorie deficit

Adults 60+ with low protein intake

Vegetarians and vegans

Endurance athletes in heavy training

Food Sources

Chicken breast (~31 g protein per 100 g)
Greek yogurt (~10 g per 100 g)
Eggs (~6 g each)
Lentils (~9 g per 100 g cooked)
Salmon (~20 g per 100 g)
Tofu (~8 g per 100 g)

How It Works

Protein provides essential amino acids that activate the mTOR signaling pathway, stimulating muscle protein synthesis. Leucine and other branched-chain amino acids act as key signals for anabolism. Sufficient protein intake shifts nitrogen balance positive, supporting tissue repair and lean mass maintenance.

Updated 5/19/2026