Black Tea and DHT: Where the 72% Figure Comes From

The widely repeated claim that black tea lowers DHT by 72% comes from a 2003 experiment at Harvard-affiliated Beth Israel Deaconess Medical Center. The finding was striking, but its setting matters: researchers were studying prostate tumors in mice.

What the researchers measured

The mice carried human prostate-cancer cells. Those in the black-tea group received tea infusion as their drinking fluid, prepared with 15 grams of leaves per liter of water. Researchers measured hormones in the blood alongside tumor outcomes.

• DHT was 72% lower in the black-tea group than in controls, a statistically significant difference.
• Testosterone averaged 34.4% higher, but that difference was not statistically significant.

Read Zhou and colleagues’ full study in the Journal of Nutrition.

This is a promising animal finding for investigating how tea affects androgen metabolism. It was not a human study, and it measured circulating DHT rather than scalp DHT or hair growth. The 72% figure therefore cannot be compared directly with a finasteride result in people.

The next question is which tea compounds could account for the effect. Our theaflavin and DHT review follows that question into a separate enzyme experiment.