Whey protein is a supplement that some people use to increase their protein intake or to help boost muscle protein synthesis and lean muscle mass growth.
Milk consists of two proteins: casein and whey. Whey separates from the milk during cheese making.
Whey protein is a nutritionally complete protein, as it contains all essential amino acids. Though it is low in lactose, it may not be suitable for everyone.
There are many benefits associated with consuming whey protein. Here, we explain what the benefits might be and look at some of the side effects and potential risks.
Research suggests that whey protein may have several health benefits.
Muscle growth
Whey protein is a popular protein supplement for people trying to gain muscle. A 2019 review notes that it is well-suited for this purpose because whey has a high leucine content. Leucine is an amino acid that helps build and repair muscle.
Previous research suggests that using whey protein alongside resistance training can help people build the maximum amount of muscle when they exercise.
Lowering cholesterol
A 2025 review and meta-analysis of past research found evidence that whey protein may help improve cholesterol levels.
The authors looked at 20 previous trials and found whey protein supplements reduced triglyceride levels while increasing high-density lipoprotein (HDL).
Triglycerides are fats that circulate in the blood, and high levels can raise the risk of several conditions. In contrast, HDL cholesterol is also known as “good” cholesterol, and higher levels can be beneficial.
Cardiovascular health
Whey proteins and the peptides they contain may have numerous benefits for cardiovascular health. A
- lower blood pressure
- reduce inflammation
- improve vascular stiffness
- increase nitric oxide
However, not all studies have reached the same conclusions, and much of the research that the authors examined has involved different methods and dosages.
More research is necessary to determine if whey protein could help lower the risk of cardiovascular disease.
Anticancer effects
According to a 2024 study, some studies have suggested whey protein may have anticancer properties.
Specifically, whey protein triggers apoptosis, which refers to the death of atypical cells. Whey protein may also help reduce the muscle atrophy that often accompanies cancer treatment.
Nutritional support
Some groups of people cannot get enough protein from other sources. In these cases, whey protein can be a suitable supplement.
For example, people with phenylketonuria need to avoid phenylalanine, an amino acid present in many foods.
A specific component of whey protein, glycomacropeptide, is one of the few sources of protein that does not contain phenylalanine.
Whey protein supplements may also help people with low body weights to gain weight. It can also help those with a loss of appetite to get enough protein.
While whey protein has several benefits, a 2020 review found that less research has examined its potential risks.
However, the authors found evidence to suggest that the use of whey may cause acne or affect the microbiome.
With long-term and excessive use, whey protein may also result in kidney or liver damage. This appears to be particularly associated with physical inactivity.
Whey protein may also be unsuitable for people with milk allergies. Some types of whey protein contain lactose, making those unsuitable for people with lactose intolerance.
Consuming very high doses of whey protein may cause digestive symptoms, such as cramping or nausea.
There are three primary types of whey protein:
- Whey protein concentrate (WPC): WPC contains low levels of fat and low levels of carbohydrates. The percentage of protein in WPC depends on how concentrated it is. Higher concentrations can be 89% or more.
- Whey protein isolate (WPI): WPIs are further processed to remove all the fat and lactose. WPI is usually less than or equal to 90%.
- Whey protein hydrolysate (WPH): Health experts consider WPH to be the “predigested” form of whey protein as it has already undergone partial hydrolysis — a process necessary for the body to absorb protein. It does not require as much digestion as the other types, but it can have varying amounts of protein.
WPH is popular for its use in medical protein supplements and infant formulas because of its improved digestibility and reduced allergen potential.
The amount of whey protein people can take to gain muscle depends on their body weight and activity level.
A 2019 study says that, at rest, a single serving of around 0.24 grams per kilogram (g/kg) of body weight is enough to maximize muscle protein synthesis. For intensive workouts, a single dose of 0.4 g/kg or more may be better.
This is in addition to the daily requirement of protein, which for people building muscle or doing intense physical training is around 1.6 g/kg of body weight daily. Individuals can get this protein from meat, fish, dairy, legumes, soy, or other plant sources as part of their diet.
The minimum daily requirement for protein for most people is 0.8 g/kg per day, but most health experts agree this is not enough for those who are building muscle or who are athletes.
Combining whey protein with other proteins, creatine, and carbohydrates may offer additional benefits for individuals doing resistance training.
Whey is one of two proteins that occur in dairy and may have several health benefits. It is a popular protein supplement for people trying to build muscle or improve their nutrition.
Whey proteins and peptides may also have the ability to help lower triglycerides, improve cardiovascular health, and may have anticancer properties.
However, this supplement may not be suitable for everyone, and at high doses over long periods of time, it could have some risks.
People who want to improve their health or their fitness through dietary changes may benefit from speaking with a doctor or dietitian for advice on what will work for them.