A new scientific study has raised questions about the relationship between dairy protein consumption and testosterone levels in men, bringing renewed attention to the nutritional and hormonal effects of milk and other protein-rich foods. Research published in the International Journal of Food Sciences and Nutrition in September 2026 found an association between higher animal protein consumption and lower testosterone levels, while greater plant protein intake was associated with higher levels.
The study, conducted by researchers from the University of Eastern Finland, examined 2,546 men aged between 42 and 60 years. Researchers analysed participants’ dietary habits alongside blood measurements of testosterone and sex hormone-binding globulin (SHBG), a protein that regulates the availability of sex hormones in the body.
Using four-day food records, the research team assessed the amount and sources of protein consumed by participants, including dairy, meat and plant-based foods. The findings highlighted differences in how various dietary protein sources were associated with male hormone levels.
However, researchers cautioned against interpreting these findings as evidence that drinking milk directly reduces testosterone.
Dairy Protein and Testosterone: What Did Researchers Find?
The study identified a relationship between animal protein consumption and lower testosterone concentrations.
Men with the highest animal protein intake had average testosterone levels approximately 1.2 nanomoles per litre (nmol/L) lower than those with the lowest intake.
In contrast, participants consuming higher amounts of plant protein had testosterone levels approximately 1.1 nmol/L higher than men in the lowest plant protein consumption group.
Dairy protein consumption was also associated with lower testosterone and SHBG concentrations. Meat protein intake, meanwhile, was associated with lower SHBG levels but did not demonstrate a clear relationship with total testosterone.
These findings suggest that protein sources may have different associations with hormonal profiles. Nevertheless, the research was observational, meaning it examined existing dietary patterns and hormone measurements rather than testing the effects of deliberately increasing or reducing milk consumption.
Does Drinking Milk Directly Reduce Testosterone?
One of the most important distinctions in the research is the difference between an association and a causal relationship.
The researchers did not conduct an experiment in which participants were instructed to drink milk and subsequently tested for changes in testosterone. Instead, they compared dietary records with hormone measurements.
Consequently, the study cannot establish that dairy consumption causes testosterone levels to decline.
The research also focused on Finnish men aged 42–60 years. Its findings cannot automatically be applied to younger men, different populations or individuals with different dietary and lifestyle patterns.
Furthermore, the observed differences in testosterone concentrations were relatively modest. Other factors, including body composition, physical activity, sleep, overall nutritional intake and underlying health conditions, may also influence hormonal levels.
Additional controlled research will be necessary to understand whether dairy protein has a direct physiological effect on testosterone production or whether the observed association reflects other dietary and lifestyle factors.
Nutritional Importance of Milk in the Human Diet
Despite the findings, milk continues to be an important source of essential nutrients. Dairy products provide high-quality protein, calcium, phosphorus, vitamin B12 and other nutrients that contribute to normal body functions.
Milk protein contains essential amino acids and is commonly consumed to support muscle maintenance, recovery and overall nutritional requirements.
Calcium and phosphorus also contribute to bone development and maintenance, making dairy products an important component of many balanced diets.
From a dairy nutrition perspective, the findings should not be interpreted as a reason for men to eliminate milk or dairy products from their regular diets. Individuals choosing to reduce dairy consumption should ensure that they obtain sufficient protein, calcium and other essential nutrients from alternative food sources.
Lifestyle Factors Also Influence Male Hormonal Health
Testosterone levels are influenced by several interconnected factors, including age, body weight, sleep quality, physical activity and general metabolic health.
Men experiencing persistent symptoms such as reduced sexual desire, unexplained fatigue or decreased muscle strength should consult a healthcare professional rather than making dietary changes based solely on observational research.
Clinical assessment and appropriate blood testing can help determine whether testosterone levels are below the expected range.
What the Findings Mean for the Dairy Industry
The research adds to ongoing scientific discussions about dairy protein, nutritional composition and human health. For the dairy industry, it also highlights the importance of communicating scientific findings accurately and distinguishing between observed associations and established health effects.
Milk remains a widely consumed source of high-quality protein and essential nutrients. While the relationship between dairy protein and testosterone requires further investigation, the latest findings do not establish that drinking milk lowers testosterone in men.
Further studies will be important in understanding how different protein sources influence hormonal health and how dairy products fit into balanced dietary patterns.
