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Strong evidencePhysical performance

Whey Protein

High-quality, fast-absorbing milk protein. Effective for hitting daily protein targets and supporting muscle growth.

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What the science says

  • Supports muscle mass gain Strong evidence

    A meta-analysis with over 1,800 participants showed that protein supplementation significantly increases lean mass and strength gains during resistance training, especially when total daily protein intake reaches around 1.6 g/kg.

  • Aids post-workout recovery Moderate evidence

    The leucine in whey stimulates muscle protein synthesis. The real-world benefit depends more on total daily protein than on the exact timing of intake.

Dosage & safety

Studied dose20–40 g per serving, as needed to reach the daily protein target (1.6–2.2 g/kg for people who train).
SafetySafe for most people. Those with lactose intolerance may prefer whey isolate or hydrolysate.

How to take it

TimingTiming does not matter — total protein across the day drives the result, not the post-workout window.
With food?With or without food; it is food.
Worth knowingA shake only helps if you would otherwise miss your daily protein target — if you already hit it from meals, it adds nothing.

Frequently asked questions

Does whey protein work for building muscle?

Yes, when paired with resistance training — the evidence is strong. A meta-analysis of over 1,800 participants found protein supplementation such as whey increases lean mass and strength gains, especially when total daily protein reaches around 1.6 g/kg.

How much whey protein per day?

Use 20–40 g of whey protein per serving, only as much as you need to reach your daily protein target of about 1.6–2.2 g/kg if you train. If your meals already get you there, a whey shake adds nothing.

Do I need to drink whey protein right after a workout?

No. With whey protein, total protein across the day drives the result, not the post-workout window, so take it whenever it fits your routine.

Is whey protein OK if I am lactose intolerant?

Whey protein is safe for most people, and if lactose is a problem, whey isolate or hydrolysate is usually the better choice.

Scientific references

Where to buy

California Gold Nutrition, Sport, Whey Protein Isolate, Unflavored, 1 lb (454 g)

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