It is true that vegan men have 13% HIGHER testosterone levels than meat eaters and 8% higher than vegetarian men.
This 2000 Cancer Research Campaign study: Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2374537/pdf/83-6691152a.pdf) has the results.
The study included 696 men of whom 226 were meat-eaters, 237 were vegetarians and 233 were vegans, recruited between 1994 and 1997 that had given blood samples.
According to the study, those samples indicated that:
All mean hormone concentrations are adjusted for age, smoking status, vigorous exercise, time of day of venipuncture, time since last eaten at venipuncture and time between venipuncture and blood processing. Mean hormone concentrations are presented with and without adjustment for BMI (Table 2). Vegan men had on average 9% lower IGF-I levels than meat-eaters (P< 0.01) and 8% lower levels than vegetarians (P< 0.01); adjustment for BMI made little difference to these values. Prior to adjustment for BMI, SHBG levels in vegans were 16% higher than in meat-eaters (P<0.0001), and 12% higher than in vegetarians (P= 0.0008); adjustment for BMI reduced these differences to 6% (P= 0.02) and 10% (P= 0.004), respectively. Vegans had 13% higher testosterone concentration than meat-eaters (P= 0.0001) and 8% higher than vegetarians (P=0.001); adjustment for BMI reduced these differences to 6% (P=0.07) and 7% (P= 0.02), respectively.
Of additional note, there were also substantial differences in plasma total cholesterol, with vegans having 17% lower mean values than meat-eaters, and 10% lower values than vegetarians, and adjustment for BMI made little difference to these values.
Men and women alike THRIVE on a whole food plant based vegan diet. If you are interested to know more about fit vegans, please see the page Vegan Fit.
(The Vegan Bodybuilder in the above image is Nimai Delgado. His Instagram is: https://www.instagram.com/nimai_delgado/)
You can read more about Erectile Dysfunction, Cardiovascular Disease and Diet here: https://www.arespectfullife.com/2018/04/25/erectile-dysfunction-cardiovascular-disease-and-diet/