Supplement analysis backed by scientific evidence · PT

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Moderate evidencePhysical performance

Milk Protein Isolate

Whole milk protein with the lactose and fat removed, keeping the natural roughly 80:20 casein-to-whey ratio. It is a good, slow-and-fast blended protein source, though few trials test this exact ingredient rather than milk or whey.

Evidence last reviewed: August 2026

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What the science says

  • Lean mass with resistance training Moderate evidence

    A randomized trial in novice male weightlifters found that fat-free fluid milk after resistance exercise produced greater lean mass accretion over 12 weeks than soy or carbohydrate. The trial was small and used milk rather than the isolated powder.

  • Protein supplementation generally Strong evidence

    A meta-analysis and meta-regression of 49 randomized trials found supplemental protein increases fat-free mass and strength gains during resistance training. Milk protein was among the most commonly used supplements in those trials.

  • Animal versus plant protein Moderate evidence

    A systematic review and meta-analysis of randomized trials found a small advantage for animal protein over plant protein for lean mass, mainly in younger adults. The difference is modest and largely disappears when total protein and leucine are matched.

Dosage & safety

Studied dose20–40 g per serving. The casein fraction slows digestion, which makes it a reasonable choice before longer gaps between meals or before bed.
SafetyWell tolerated by most. Contains milk protein, so it is unsuitable for milk allergy; residual lactose is low but not always zero. No specific risks beyond those of any concentrated protein source.

Scientific references

Where to buy

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