Podcast episode 33 (in German)
Whey protein: leucine, the timing myth and who really benefits
August 10, 2026
Whey is the best-selling supplement in the world and one of the best studied. The episode explains why leucine is the actual switch, why the anabolic window hardly holds up and who benefits most from the powder: people over 50.
What it is about
Whey is milk whey protein, a by-product of cheese-making that enters the blood quickly and contains a particularly large amount of leucine. Leucine signals to the body whether there is enough protein for muscle building; above a threshold, the mTOR signaling pathway switches on. The episode assesses how plant protein performs in a direct comparison, why the timing effect after training was mainly a quantity effect and how much protein strength athletes need per day. It dispels the concern about healthy kidneys and takes acne seriously as a personal issue. What remains is an efficient food that most people do not need, but that can help older people counter muscle loss together with strength training.
Key points
- Whey contains around 10 to 11 percent leucine; the threshold for muscle building is about 2 to 3 grams of leucine per meal, which corresponds to about 20 to 25 grams of powder.
- A meta-analysis of 12 studies and 26 effect estimates found practically no difference in muscle protein synthesis between plant and animal protein.
- In people over 65, an advantage for animal protein remains; with pea protein, a third to a half more powder is needed for the same amount of leucine.
- A meta-analysis by Schoenfeld adjusted for total intake, after which the timing effect almost entirely disappeared; the window extends more like 4 to 6 hours before and after training.
- For strength athletes, the episode cites 1.6 to 2.2 grams of protein per kilogram of body weight, roughly 130 to 175 grams a day at 80 kilograms; most people reach this with normal food.
- The German consumer organization Stiftung Warentest tested 21 protein powders and concluded that they are superfluous for recreational athletes.
- From about 50 onwards, the body loses muscle and responds less well to protein: where 20 grams flip the switch at 25, it takes more like 30 to 40 grams at 75.
Where the data stop
The data on muscle protein synthesis are short-term measurements over a 5-hour window. Only one study in the meta-analysis looked longer, and synthesis over hours is not the same as muscle mass over 12 weeks, as the authors themselves write. Protein alone also builds nothing: the stimulus comes from strength training, the protein only supplies the material. On the benefit in old age, the episode cites a 2025 review in the Journal of Cachexia, Sarcopenia and Muscle.
For acne the mechanism is plausible, because milk protein raises IGF-1 and insulin, and a 2024 case-control study found an association in young men; those without a tendency to acne usually notice nothing. For healthy kidneys, a systematic review found nothing substantial. Anyone with kidney disease should clarify protein intake with a physician.
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Published on August 10, 2026.
The topic in the database
- Highest-quality protein with the best amino acid profile. Ideal post-workout.Whey Protein
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-10-09.