More greens, higher testosterone? What a Finnish study found

Published on 30 October 2026 - 6:27 GMT+1

Sport, smoking and alcohol are often discussed as factors that can affect men’s testosterone levels. But diet — and whether protein comes from plants or animals — could also play a role, according to new research from Finland.

A study of 2,546 men found that those with the highest intake of animal protein had lower testosterone concentrations than those who consumed the least, while the opposite was true for men with the highest intake of plant protein.

Testosterone is a key male sex hormone, involved in sexual function, muscle development and bone health. Its levels vary with age, body weight and other factors, making it difficult to isolate the contribution of any single part of a person’s diet.

Higher dairy-protein intake was associated with lower total testosterone and sex hormone-binding globulin concentrations. Meat-protein intake, meanwhile, was associated with lower sex hormone-binding globulin concentrations but not with total testosterone.

Higher intake of plant protein from vegetables and sources other than cereal products was associated with higher total testosterone.

Researchers at the University of Eastern Finland analysed data from men aged 42 to 60 living in eastern Finland. Their diets were recorded over four days between 1984 and 1989, and their blood samples were used to measure total testosterone and sex hormone-binding globulin, a protein that influences testosterone concentrations in the blood.

Men in the highest animal-protein intake group had average total testosterone concentrations that were 1.2 nanomoles per litre lower than those in the lowest-intake group. For plant protein, the association ran in the opposite direction: men in the highest-intake group had concentrations 1.1 nanomoles per litre higher than those in the lowest-intake group.

The researchers adjusted their analyses for age, body mass index and several other dietary, lifestyle and health-related factors.

The Finnish study does not establish that animal protein lowers testosterone or that switching to a plant-based diet raises it.

The research was cross-sectional, meaning it examined associations rather than demonstrating cause and effect.

“Although the observed differences in testosterone concentrations were statistically significant, they were relatively small,” Miika Wynne-Ellis, a doctoral researcher at the University of Eastern Finland, said in the university’s announcement of the findings.