Finally, we looked at the proprietary blends of our remaining boosters, and dug into their ingredient lists. Supplements frequently include ingredients known for their “folk-lore” value; they’re believed to work, even when there isn’t any scientific background to prove it. Though we didn’t ding points if an ingredient wasn’t proven to be good (just so long as it wasn’t proven to be bad), we didn’t want to include any ingredient with evidence of causing harm.
Bottom line: testosterone boosters aren’t right for a lot of people. We dive deep into ingredient research below, but typically, testosterone boosters contain at least one (and often three or more) different ingredients that each impact your circulatory system — both the heart and blood. If you’re taking any kind of blood-thinner medication, or you have a history of heart disease, these supplements can get really dangerous, really quickly. The simple fact of the matter is that hormones are tricky things to mess with, and a doctor should be your first port of call to help you safely achieve your goals — whether they’re related to fitness, weight, or libido.

"Some say it's just a part of aging, but that's a misconception," says Jason Hedges, MD, PhD, a urologist at Oregon Health and Science University in Portland. A gradual decline in testosterone can't explain a near-total lack of interest in sex, for example. And for Hedges' patients who are in their 20s, 30s, and early 40s and having erectile problems, other health problems may be a bigger issue than aging.
The final two studies looked directly at soy vs testosterone levels. The first looked at introducing consumption of soya flour on testosterone levels. They found that those who ate the Soy flour lowered their T levels during the study (43). And the second study looked at the consumption of soy protein isolates (powder) in healthy men. They found that testosterone levels decreased upon consumption of soy powder (45).
Sharma, R., Oni, O. A., Gupta, K., Chen, G., Sharma, M., Dawn, B., … & Barua, R. S. (2015, August 6). Normalization of testosterone level is associated with reduced incidence of myocardial infarction. European Heart Journal, 36(40), 2706-2715. Retrieved from