He came up with it after years of studying steroid users in Boston-area gyms and comparing them not just to non-steroid users in the same gyms, but also to bodybuilders from different eras. For a 1995 study, Pope and his coauthors estimated the FFMIs of Mr. America winners from 1939 to 1959, before steroids were readily available. The group includes future B-movie star Steve Reeves, whose physique was so iconic that he was name-checked in The Rocky Horror Picture Show . The average FFMI was . (One of the highest was George Eiferman, Mr. America 1948, with a FFMI. His upper body was later the model for George of the Jungle, a 1960s cartoon character.) Even today, with all we’ve learned about training and nutrition, an FFMI in the mid 20s is still considered the ceiling for natural bodybuilders. Anything above 26 or 27 is suspect.
NOT NECESSARILY TRUE . Faced with an unnatural rise in estrogen, some steroid users will then take a class of drugs called aromatase inhibitors , which are designed to block the production of estrogen in women with breast cancer, Weinerman says. That's right: It's a breast cancer drug. And aside from the obvious danger in further messing with hormones, guys who turn to aromatase inhibitors can have side effects like joint and muscle pain, the loss of sex drive, and the loss of bone density, which can then result in osteoporosis, according to a Susan G. Komen Foundation report .
Testicular atrophy is one such issue, although many of the studies suggesting it does cause shrinkage are relatively outdated — from the 1980s. Nevertheless, the majority of it suggests that smoking weed lowers testosterone levels, either directly or through precursor hormones; or causes testicular atrophy in monkeys and dogs. A study from 2012 revives this idea, and finds some evidence in men living in the Niger delta area of Nigeria. In that study, 75 men who smoked marijuana were also likely to have shrunken testicles, infertility, and even male breasts.