The best-known use of whey protein supplements is for the purpose of increasing muscle mass and strength.
Whey protein is popular among athletes, bodybuilders, fitness models, as well as people looking to improve their performance in the gym.
The ways by which whey protein promotes muscle/strength gain include:
- Building blocks: It provides protein and amino acids, which serve as building blocks for increased muscle growth.
- Hormones: It increases the release of anabolic hormones that can stimulate muscle growth, such as insulin (12Trusted Source).
- Leucine: It’s high in the amino acid leucine, which is known to stimulate muscle protein synthesis at the molecular and genetic level (13Trusted Source, 14Trusted Source).
- Fast absorption: Whey protein is absorbed and utilized very quickly compared to other types of protein (15Trusted Source).
Whey protein has been shown to be particularly effective at increasing muscle growth when consumed right before, after or during a workout. Muscle protein synthesis is usually maximized in the time period after training (16Trusted Source, 17Trusted Source, 18Trusted Source, 19Trusted Source).
However, a recent review of the evidence concluded that total daily protein intake is the most relevant factor in muscle growth. Whether protein is consumed around the workout or not doesn’t seem to matter much (20Trusted Source).
When compared to other types of protein, such as soy protein, whey protein has usually performed slightly better (21Trusted Source, 22Trusted Source).
When compared to casein, the evidence is more mixed. Whey appears to be effective in the short-term, but casein stimulates muscle growth over a longer period, making the net effect similar (23Trusted Source, 24Trusted Source, 25Trusted Source, 26Trusted Source, 27Trusted Source).
Also, keep in mind that unless your diet is already lacking in protein, supplementing with whey protein is unlikely to have a significant effect on your results.
In a 12-week study in older adults with adequate protein intake, who did resistance training, there was no difference in muscle growth when supplementing with whey protein or carbohydrates (28Trusted Source).
Therefore, the evidence of whey protein on muscle and strength is mixed, and the results may vary greatly between individuals.
If you’re already eating plenty of meat, fish, eggs and dairy — all high in quality protein — the benefits of adding whey will probably be minimal.
