Coffee, Metabolism, and Sex Hormones: What a New Finnish Study Reveals

Coffee is one of the most widely consumed beverages on the planet, and it’s long been linked to a lower risk of type 2 diabetes and cardiovascular disease. What’s been murkier is why, the biological mechanisms behind those benefits have stayed largely unexplained. A new study from the University of Oulu adds a fresh piece to the puzzle, tying habitual coffee drinking not just to healthier body composition, but to distinct shifts in sex hormones that differ between men and women.

 

Researchers followed 2,264 participants, all 46 years old, from the Northern Finland Birth Cohort 1966, a long-running dataset that’s become a goldmine for population health research. They looked at how self-reported coffee habits tracked with blood metabolites, cardiometabolic risk markers, and sex hormone levels.

The body composition findings were striking on their own: participants who drank more coffee had lower total and visceral fat, and more skeletal muscle, than lighter drinkers, even when their BMI was essentially the same. Heavier coffee consumption in both sexes was also tied to lower blood levels of branched-chain amino acids, compounds that tend to climb when insulin resistance sets in.

The hormone story was where things got more sex-specific. In men, higher coffee intake tracked with a healthier glucose-insulin balance, higher total and bioavailable testosterone, and more sex hormone-binding globulin (SHBG), alongside slightly lower free testosterone and free androgen index. In women, the hormonal picture was narrower: mainly higher SHBG and lower free androgens.

Lead author Luca Verroest, a doctoral researcher at the University of Oulu, noted that a distinct hormonal signature showed up even after accounting for BMI and lifestyle, and that it looked different in men than in women.

As with any observational study, these are associations, not proof that coffee itself is driving the changes. The team is now testing possible mechanisms in animal models, with human intervention studies as the eventual goal. It’s also worth noting where this research comes from: Finland is one of the heaviest coffee-drinking nations on Earth, averaging around 11.8 kg of coffee per person a year, so if there’s a population well-positioned to reveal coffee’s long-term effects, it’s this one.

Original paper: Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study — European Journal of Nutrition, 16 July 2026.

 

Source: Coffee, Metabolism, and Sex Hormones: What a New Finnish Study Reveals