Some quotes of interest
In the trial, 42 women with PCOS related hirsutism were assigned to drink spearmint tea or a placebo herbal tea twice daily for 30 days. Blood tests measuring hormone levels were taken at the beginning, the mid way point and at the end of the experiment. The results indicate that the women receiving the spearmint demonstrated significant reductions in free and total testosterone levels and increases in luteinizing hormone and follicle stimulating hormone concentrations.
It’s interesting to note that a study in male rats found the exact same hormonal shifts that were exhibited in the women with PCOS, namely, a reduction in testosterone. Potentially negative effects on the testicles of the rats were also detected. This testicular disturbance could possibly be important with regard to fertility. (7)
Other experiments have raised red flags with regard to large dosages of mint tea and possible harm to the kidneys and liver (in a rat model). (8,9) Concerns have also been raised about peppermint teas ability to interact with the liver in such a way that it may negatively affect the metabolism of medications. (10) These concerns need to be taken seriously, especially since peppermint tea is one of the most widely consumed herbal beverages among pregnant women. (11,12)
Regardless of effects, I wouldn't order again, because I don't care much for the flavour. I don't like the idea of reduced testosterone.