Testosterone is a steroid hormone that contributes to muscle mass, bone density, and overall energy levels in both men and women. Concerns about dietary factors influencing this hormone are common, and tea, a globally consumed beverage, is often the subject of inquiry. Whether tea lowers testosterone is complex, as the effect depends heavily on the specific type of tea, the concentration of its compounds, and the individual’s hormonal status. Scientific evidence suggests that while most common teas have little impact on testosterone at typical consumption levels, a few specific varieties show clear effects, particularly in certain populations.
The Specific Effects of Common Tea Varieties
Spearmint and peppermint teas, derived from the Mentha plant family, are the varieties most consistently linked to reduced androgen levels. Human clinical trials, primarily involving women with Polycystic Ovary Syndrome (PCOS), have shown a measurable anti-androgenic effect. Drinking spearmint tea twice daily for a month led to significant decreases in both free and total testosterone levels. This reduction is relevant for women with excess androgens, helping to alleviate symptoms like hirsutism, or excessive hair growth.
The effects of traditional teas like green tea and black tea are far less conclusive regarding testosterone suppression in healthy individuals. Green tea, rich in epigallocatechin gallate (EGCG), has shown mixed results across different studies. While high-dose extracts demonstrate testosterone-lowering effects in animal and cell-culture models, human clinical trials using standard consumption amounts often show no significant change in circulating testosterone levels. Some observational studies suggest long-term green tea drinkers may have slightly higher total testosterone, possibly linked to the tea’s anti-inflammatory properties.
Black tea lacks compelling human evidence for testosterone suppression. Compounds in black tea, such as theaflavins, have been theorized to influence hormone metabolism. However, any potential hormonal effects from moderate black tea consumption are negligible for the average healthy consumer.
Biochemical Mechanisms of Action
The potential for tea to influence testosterone levels is based on the action of various plant compounds, primarily polyphenols and catechins, on two distinct biological pathways.
5-Alpha Reductase (5-AR) Inhibition
One key mechanism involves the enzyme 5-alpha reductase (5-AR), which is responsible for converting testosterone into the more potent androgen, Dihydrotestosterone (DHT). Certain compounds found in both green tea (EGCG) and black tea (theaflavins) are known to act as inhibitors of this enzyme in laboratory settings. By inhibiting 5-AR, these compounds theoretically reduce the conversion of testosterone to DHT. This could lead to an increase in circulating testosterone while lowering the overall androgenic effect. The strong anti-androgenic effect observed with spearmint tea is also attributed to 5-AR inhibition.
Sex Hormone-Binding Globulin (SHBG) Modulation
The second primary mechanism involves Sex Hormone-Binding Globulin (SHBG), a protein produced mainly by the liver that binds to sex hormones, including testosterone, making them biologically inactive. If tea compounds increase the production or binding affinity of SHBG, it would result in a reduction of free testosterone, which is the active form the body can use. While certain plant compounds are known to modulate SHBG, some earlier studies suggested green tea might increase it. However, a large-scale randomized human trial using high-dose green tea extract found no overall effect on SHBG levels. Therefore, the most biologically relevant mechanism appears to be the direct inhibition of the 5-AR enzyme, which alters the balance between testosterone and DHT.
Dosage, Duration, and Clinical Relevance
The findings regarding tea and testosterone are highly dependent on the dosage and duration of consumption, limiting the clinical relevance for the average tea drinker. Many strong testosterone-lowering results come from in vitro (test tube) or animal studies. Researchers in these settings use highly concentrated tea extracts or inject pure compounds like EGCG at levels far exceeding what a person would consume in a daily cup of tea. For example, animal studies using high concentrations of EGCG have shown direct inhibition of testosterone production in testicular Leydig cells.
The context of the research is also significant, with the most definitive human results belonging to spearmint tea consumed by women with specific hormonal imbalances like PCOS. In these cases, drinking two cups of spearmint tea daily demonstrated a clear effect after a few weeks. However, the results from studies on healthy men consuming standard amounts of green or black tea are generally inconsistent or show no significant hormonal change.
The effects seen in test tubes or animal models do not always translate directly to human physiology, especially considering the rapid metabolism and lower bioavailability of tea compounds in the human body. For the average person consuming one to three cups of common tea varieties daily, the impact on circulating testosterone levels is likely minimal. The available evidence suggests that any significant alteration of testosterone requires either a specific type of tea, such as spearmint, or the consumption of highly potent extracts at supra-nutritional levels.