Coffee drinkers carried less body fat and more muscle than people who drank little or none, even when their body mass index was the same. That is the headline finding from a new analysis of 2,264 middle-aged Finns, published July 16, 2026 in the European Journal of Nutrition.
But when the researchers looked at circulating sex hormones, the picture split by sex. In men, higher coffee intake tracked with a more favorable glucose and insulin profile and with higher total and bioavailable testosterone. In women, the hormonal signal was weaker and largely limited to shifts in binding proteins and free androgens.
The study was led by Luca Verroest, a doctoral researcher at the University of Oulu, and drew on the Northern Finland Birth Cohort 1966, a long-running population study of people all born the same year and followed into midlife.
What the researchers measured
Participants reported their average daily cup count, and were grouped into four categories: none, 1 to 2, 3 to 4, and five or more cups per day. Blood samples were then screened for a wide panel of metabolites, cardiometabolic risk markers and sex hormones.
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In both men and women, higher coffee intake was tied to lower circulating branched-chain amino acids. These are protein building blocks that, when chronically elevated, have been linked to insulin resistance and a higher risk of type 2 diabetes. The pattern fits earlier work suggesting regular coffee drinkers tend toward a leaner body composition.
The split between men and women
The clearest sex hormone signal showed up in men. Each additional cup of coffee per day was associated with higher total and bioavailable testosterone and with more sex hormone-binding globulin, the protein that shuttles sex hormones through the blood. At the same time, free testosterone and the free androgen index edged slightly down, according to the study.
In women, the associations were more limited. Higher coffee intake was tied to more sex hormone-binding globulin and to lower measures of free androgens, but the researchers did not see the same broad hormonal pattern as in men.
"Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones," Verroest said in a statement from the university.
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What it does and does not show
This was a cross-sectional analysis, meaning the researchers looked at one snapshot in time. That design can flag associations, but it cannot show that coffee itself caused any of the differences. People who drink more coffee may also differ in diet, activity or sleep in ways that shape body composition and hormones.
The authors describe their results as population-level endocrine patterns rather than proof that drinking more coffee will change any individual person's hormone levels in a clinically meaningful way, as news-medical.net reported. They call for longitudinal work and intervention trials to test whether specific compounds in coffee drive the effects.
Everyone in the cohort was 46 years old, so the findings speak most directly to middle-aged adults, and the authors say intervention trials are the next step before the results could shape any dietary advice.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.