Gym-goers who regularly drink protein shakes are being urged not to immediately blame the supplement for changes in their hair. There is currently no evidence that protein shakes directly cause hair loss, but experts say they may speed up thinning in men who are already genetically prone to androgenic alopecia, according to the Mirror.
There is no strong clinical evidence that pure whey protein directly causes hair thinning in men, but a popular theory suggests that heavy use of the supplement could accelerate the process in men who are already predisposed to the condition.
What is whey protein
Whey protein is one of the most common sports supplements. It is typically added to shakes by people trying to increase their protein intake, build muscle or recover after exercise. Not every protein shake contains whey, however. Alternatives include plant-based protein, other dairy proteins and egg white protein.
A new literature review, published in the September 2026 issue of the journal JAAD Reviews, examined the potential effects of whey protein on hair. It looked specifically at possible effects on hormones, insulin-like growth factor 1 (IGF-1) and androgen-dependent pathways.
What the review found
The researchers stressed that the evidence remains limited and contradictory, and that there are currently no robust clinical studies proving whey protein consumption directly causes hair loss. Dr Emre Cinik, founder of the Dr Cinik Hair Clinic, said that distinction matters.
Cinik said it had not been proven that whey protein makes people go bald, and that someone drinking a regular protein shake should not suddenly throw out the tub after seeing a scary headline. He said what was interesting about the new review was that researchers were asking whether biological mechanisms could potentially link whey consumption to hair condition in certain people.
Look at the bigger picture
Cinik said people who have noticed changes in their hair after starting a new gym routine should still look at their situation as a whole rather than assuming genetics alone is to blame. If someone already has a genetic predisposition to androgenic alopecia and notices hair changes after several changes to their diet, supplements and training routine, he said it makes sense to consider all of those changes when assessing hair loss.
Do not blame the powder automatically
The review analysed existing experimental, clinical and observational studies on whey protein and hair. The researchers concluded that possible effects could include changes in whey's amino acid composition and in IGF-1 and other hormonal pathways, but noted that dedicated clinical trials are still lacking.
That means it cannot currently be said that someone's daily protein shake is the cause of a receding hairline or increased shedding. Cinik said one of the biggest mistakes is confusing timing with proof.
He gave an example of someone who starts going to the gym in January, begins drinking whey protein, cuts their calorie intake significantly and loses a lot of weight. Three months later they notice much more hair coming out in the shower and decide the protein powder is to blame, when several changes are happening at once, some of which already have an established link to hair loss.
Britain's National Health Service (NHS) lists weight loss, stress, illness and iron deficiency among the possible causes of temporary hair loss. Significant weight loss can also trigger telogen effluvium, a form of excessive shedding that usually becomes noticeable several months after the initial trigger rather than straight away. The American Academy of Dermatology says losing 9kg or more can be a stress factor linked to excessive hair shedding.
Cinik added that if someone has started an intense fitness programme and is eating significantly less in an effort to lose weight quickly, that is important information. He said stopping whey protein while continuing an extremely restrictive diet will not necessarily remove what is actually causing the hair loss.
Check what changed three months ago
The hair expert said people experiencing sudden hair loss should think about more than what they ate or drank that morning, since hair often reacts slowly to changes elsewhere in the body, meaning the trigger could have happened weeks or months before the shedding is noticed.
He said that if hair suddenly seems to be falling out everywhere, rather than gradually receding at the temples or thinning at the crown, people should think back over the previous two to three months. He suggested asking whether they had lost significant weight, sharply increased their training intensity while cutting calories, been ill, gone through a very stressful period, or started several supplements at once. He said those questions are more useful than picking the newest product on the kitchen shelf and assuming it is the culprit.
The pattern of hair loss matters too
Studies show that male pattern baldness typically progresses gradually, most often affecting the temples, the front hairline and the crown. Telogen effluvium usually causes more diffuse shedding across the whole scalp. Sudden bald patches, scalp inflammation or rapid, unexplained hair loss should not simply be put down to whey protein without a proper assessment.
Cinik advised using the same lighting and angle every few weeks, saying this gives far more reliable results than checking the hairline in different mirrors each morning and trying to remember how it looked the day before. He said that if thinning is clearly progressing, people should find out the cause rather than spending months switching between protein powders, shampoos and supplements based on theories from the internet.
Do not cut protein unnecessarily
The expert also warned against reacting to the new review by cutting protein intake without good reason. Hair is largely made of a structural protein called keratin, and balanced overall nutrition is important for normal hair growth.
The NHS advises people concerned about hair loss to see their GP to establish the cause before going to a commercial hair clinic, noting that most cases of male baldness are inherited from family members. A natural hormone called dihydrotestosterone (DHT) shrinks hair follicles over time, making hair shorter and thinner until it stops growing altogether.
The NHS says losing 50 to 100 hairs a day is normal. Typical baldness becomes more common with age, and most men notice some hair thinning by the age of 60.
