What it is
Regulatory status: food or dietary supplement; product labels and allergen declarations vary by formulation
Mechanism evidence: human
At a glance
What it is, why people use it, the evidence, and what to know before trying it.
Why people use it
- Convenient dietary protein
- Lean-mass and strength support with resistance training
- Recovery nutrition
Evidence at a glance
Protein supplementation modestly improves lean-mass and strength gains when paired with prolonged resistance training, particularly when it helps total protein intake reach an adequate level. This does not establish that whey itself accelerates tendon or post-surgical healing, or that a specific brand or whey form is superior.
Confidence: moderate
Safety & interactions
Known side effects, interactions and use limits from reviewed sources.
Whey contains milk protein and can trigger reactions in people with milk-protein allergy. Lactose content is usually higher in concentrates than isolates, while sweeteners and other ingredients vary by product. People with significant kidney disease should individualize high-protein intake with their clinician.
- milk-protein allergy
- gastrointestinal symptoms depending on dose, lactose tolerance, and additives
Forms and variants
This review does not automatically apply to:
- goat whey protein
- collagen protein
- casein protein
- plant protein
- branded multi-ingredient protein blends