Cannabis and Testosterone Levels
"Myth: Marijuana causes sterility and lowers testosterone
Government experts also concede that pot has no permanent effect on the male or female reproductive systems.(14) A few studies have suggested that heavy marijuana use may have a reversible, suppressive effect on male testicular function.(15) A recent study by Dr. Robert Block has refuted earlier research suggesting that pot lowers testosterone or other sex hormones in men or women.(16) In contrast, heavy alcohol drinking is known to lower testosterone levels and cause impotence. A couple of lab studies indicated that very heavy marijuana smoking might lower sperm counts. However, surveys of chronic smokers have turned up no indication of infertility or other abnormalities.
Less is known about the effects of cannabis on human females. Some animal studies suggest that pot might temporarily lower fertility or increase the risk of fetal loss, but this evidence is of dubious relevance to humans.(1) One human study suggested that pot may mildly disrupt ovulation. It is possible that adolescents are peculiarly vulnerable to hormonal disruptions from pot. However, not a single case of impaired fertility has ever been observed in humans of either sex."
[url]http://paranoia.lycaeum.org/marijuana/facts/mj-health-mythology.html#myth13[/url]
"HE FACTS
There is no evidence that marijuana impairs male reproductive functioning.
The Jamaican and Costa Rican field studies detected no differences in hormone levels between marijuana users and non-users.
In epidemiological surveys of marijuana users, no problems with fertility have emerged as important.
In 1974, researchers reported diminished testosterone, reduced sexual function and abnormal sperm cells in males identified as chronic marijuana users. 34 In a laboratory study, the same researchers reported an acute decrease in testosterone, but no chronic effect after nine weeks of smoking; they did not evaluate sperm volume or quality. 35 In other laboratory studies, researchers have been generally unable to replicate these findings, 36 although by administering very high THC doses - up to 20 cigarettes per day for 30 days - one study found a slight decrease in sperm concentrations. 37 In all studies, test results remained within normal ranges and probably would not have affected actual fertility. "
[url]http://www.erowid.org/plants/cannabis/cannabis_myth6.shtml[/url]
