Whey Protein Isolate
A highly purified whey fraction with 90%+ protein, minimal lactose and fat. Suitable for those with lactose intolerance who want fast-digesting protein.
A well-studied, foundational ingredient
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Effects reported in research
Rapidly stimulates muscle protein synthesis (MPS) post-exercise
Low lactose and fat content reduces digestive discomfort
High leucine content efficiently activates mTORC1 signaling
Dosage & timing
- 20–40 g per serving, ideally within 30–60 minutes post-exercise.
- Adjust within daily protein targets (1.6–2.0 g/kg body weight).
Cautions
- •Contraindicated for those with milk protein allergy.
- •Consult a doctor if you have kidney disease.
- •Higher cost than concentrate — consider your budget.
Supporting research
Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men
Journal of Applied Physiology, 2009
ホエイ（加水分解）・カゼイン・ソイプロテインを摂取した後の安静時・運動後の筋タンパク質合成（MPS）を比較したRCT。ホエイは急速吸収・高ロイシン含量によりカゼイン・ソイより運動後MPSを有意に高めた。カゼインは吸収が遅く夜間の徐放性補給に適している。ソイはホエイとカゼインの中間的な特性を示した。
Protein supplementation augments resistance-training-induced gains in muscle mass and strength (meta-analysis)
British Journal of Sports Medicine, 2018
A synthesis of 49 RCTs (1,863 participants). Protein supplementation significantly increased gains in lean mass and 1RM from resistance training; benefits plateaued beyond about 1.6 g/kg/day of total protein.
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