This is long but interesting read.
http://musculardevelopment.com/articles/research-and-review/1548-anabolic-steroids-and-sexual-behavior.html?showall=1&limitstart=#.VFwggr5vZSWDan Gwartney, M.D
Through the course of history and across the span of evolution, few things hold the interest of individuals as much as sex.1 Though individuals may survive without succumbing to the desires of the flesh, for the species, it’s essential. The drive for sexual intercourse is hard-wired into nearly every being.
Back to Basics
Sexual behavior is easily studied in animals. Scientists are beginning to understand, down to the level of hormones, receptors, genes and neurotransmitters, how sexual behavior is regulated in humble creatures, such as rats.2 It’s a simple matter to inject a female rat with hormones that place her in estrus, a physiologic state which causes her to become attractive to male rats and receptive to sexual intercourse. For the male rat, it’s even easier; male rats will respond to the physical and behavioral cues of the female. Never satisfied to merely observe the normal interaction between rats, scientists have performed a vast number of interventions on rats and other animals to determine the basis for their sexual behavior. These interventions range from simple to drastic, including brain surgery and castration (surgical removal of the testicles).
Much to the chagrin of male rats everywhere, castration allows for a clear picture of the effect of androgens upon male sexual behavior. Castration eliminates most sexual response in male rats and other species, rendering them impotent as well, which is why many emperors and sheiks had eunuchs (castrated men) serving as guards and servants to their wives and mistresses.
Scientists learned it’s possible to restore androgen levels through the use of testosterone, restoring sexual behavior and function.3,4 The restoration of sexual behavior and function through the use of testosterone replacement therapy is also used in human clinical practice.5 Men suffering from a failing libido or erectile difficulty are placed on testosterone (injections, patches or creams), though the introduction of Viagra and similar drugs has reduced the demand. Testosterone replacement therapy has restored the vitality and libido of many aging men.
With the notoriety of anabolic steroids and their close chemical resemblance to testosterone, scientists investigated the effects of these drugs upon sexual behavior in castrated rats. Rather than getting a clear cut answer, as might be expected from these powerful androgens, a full look at the data suggests that one cannot simply assume that all steroids will affect sexual behavior in a manner similar to testosterone.
Sexual behavior is a complex series of physical, psychological and social cues and responses designed to combine the act of mating (sex) with the best reproductive environment.2,6,7 This is particularly evident in lower animal forms, where the female is only receptive to mating during the time of her ovulation (releasing an ovum or egg cell to be fertilized by sperm). Most people are familiar with this phenomenon through their experience with pet dogs or cats that “go into heat.” Suddenly, every unpenned mutt or stray tomcat in the neighborhood shows up ready to mount, eyes rolling and tongue lolling for his chance at siring the next litter.
Public Erections are Generally Discouraged
With humans, the process is more complicated, discounting public examples of debauchery such as Mardi Gras or fraternity parties. Sexual behavior includes several phases, including: desire, arousal, intercourse and latency. Desire refers to the underlying yearning for a sexual encounter; no specific time, place or person; just a desire for sex. For people in a monogamous relationship, desire is conditioned to refer to a single person— the significant other. Arousal is more specific and immediate. Arousal refers to wanting sex immediately with the subject of the aroused person’s focus. This may relate to a promising date eating across the table or an actress in a television show. In addition to mental and emotional changes, physical changes also are evident at this point, including flushing of the skin, dilated pupils and penile erection.
Again, people are conditioned to respond to social cues and the environment. It’s considered funny or excusable if an adolescent boy becomes excited in the presence of girls and women or while climbing the rope in gym class, but for adult men, public erections are generally discouraged. Intercourse refers to the sexual act, which ranges from complex rituals to hurried encounters. Latency is the amount of time elapsing between the completion of one sexual act until the male achieves his next state of sexual readiness.
Referring back to animal studies, it was clear that testosterone levels correlated with all phases of sexual behavior. Castration resulted in very little curiosity in or attraction to sexually receptive females, markedly reduced attempts at intercourse and long latency periods.3,4 Providing high doses of testosterone increased sexual behavior above that of normal rats.8 This effect is seen in humans— male and female, comparing people with low testosterone to normal adults to adolescents.5,9-12 Obviously, there are many exceptions to this general rule, as humans modify their behavior to conform to public expectations, religious beliefs and social mores.13
Effects of Anabolic Steroids
Most bodybuilders who use moderate doses of testosterone esters report improved libido and sexual behavior.14 Unfortunately, some users following the “more is better” philosophy find that excessively high levels of steroid use can actually interfere with sexual behavior during a cycle. There are no published studies to aid in determining the maximum threshold of steroid use that can be tolerated without affecting sexual behavior, but it appears that 500-600 milligrams of the testosterone, enanthate weekly provides an anabolic effect without sexual detriment.10,15
In regard to the multitude of other steroids, the picture is less than clear. Animal studies have shown that the modifications of anabolic steroids from the parent hormone, testosterone, affect the drugs’ impact on sexual behavior.16 Oddly, the potency of an anabolic steroid in the gym has little relevance to its ability to maintain sexual behavior.
In evaluating the effect of anabolic steroids on sexual behavior, it’s important to remember steroid use typically shuts down the user’s natural testosterone production, making him dependent on the steroids to support all functions related to testosterone, not just muscle growth.17,18
Several steroids have been evaluated relative to sexual behavior, including: testosterone esters, nandrolone (Deca), oxymetholone (Anadrol), stanozolol (Winstrol), methandrostenolone (Dianabol) and methyltestosterone. In animals, it was determined that testosterone, nandrolone and to a much lesser degree, methandrostenolone, could maintain sexual behavior in castrated rats, whereas the other drugs didn’t restore sexual behavior.3,4 Even in rats who retained their testicles, high doses of stanozolol, oxymetholone and methyltestosterone eliminated sexual behavior, whereas the other steroids had no effect.16 These observations fly in the face of what would be expected, as oxymetholone is a potent anabolic steroid and methyltestosterone is often thought of as an oral form of testosterone by clinicians.19 Nandrolone has been associated with erectile difficulties and isn’t a potent androgen; instead, nandrolone is often selected for cycles as it has relatively little androgenic effect.20
Upon reviewing the literature, it appears that each steroid has its own behavior profile.3,16 In part, this may be explained by the ability of the drug to be aromatized or to directly stimulate estrogen and/or progesterone receptors. Stanzolol and oxymetholone aren’t aromatized, meaning they’re not converted into estrogenic hormones; testosterone is, as can be nandrolone.19-21 Further, nandrolone appears to directly stimulate both estrogenic and progestinic receptors.2,20
The Reward Factor
The role of estrogen in sexual arousal and copulatory behavior is not fully understood, but it’s known that estrogen receptors in the preoptic area of the brain stimulate sexual arousal.2,22 The source of the estrogen acting on this part of the brain comes from local conversion of testosterone to an estrogen via the aromatase enzyme complex. By down-regulating natural testosterone production and replacing it with a non-aromitizable androgen, it stands to reason that estrogenic stimulation of the preoptic area of the brain would be decreased, accounting for some of the decrease in sexual behavior. It would be interesting to track sexual arousal and behavior in normal men being treated with an aromatase inhibitor. It’s known that Arimidex raises testosterone in men, so a decrease in sexual behavior would be particularly interesting in such a setting.23,24
It appears that sex-hormone binding globulin (SHBG) may play a role in the effect of steroids on sexual behavior. The traditional understanding of steroid-receptor interactions involve receptors that exist inside the cell, rather than on the outer membrane. Most other drugs affect membrane-associated receptors. However, recent research suggests that steroids and SHBG interact with membrane-associated receptors, changing the cellular response that occurs when they’re activated.25 In the presence of high steroid levels, the arousal state of the individual is peaked, increasing receptiveness to sexual cues. This change is reversed by neurotransmitter events associated with ejaculation/orgasm, which reduce arousal back to its baseline state. Interestingly, most of the steroids noted to lessen sexual behavior are known for reducing SHBG as well.21
It’s of further interest that the steroids associated with reduced or eliminated sexual behavior are drugs that don’t appear to have a reward effect. The term reward effect refers to the addictive potential of a drug. Studies have shown that hamsters will preferentially self-administer testosterone and nandrolone, but that stanazolol and oxymetholone don’t promote use/self-administration.26,27 It’s possible that the 17-? alkylation used in modifying oral steroids interferes with the drug’s ability to act as a neurosteroid, even while maintaining its anabolic potency.
A final aspect to consider is the changes in sexual behavior that occur during steroid withdrawal, or off-cycle. As was mentioned earlier, supraphysiologic anabolic steroid use shuts down natural testosterone production.17 This period can vary greatly between individuals and even between cycles for the same person. It’s not unheard of for a bodybuilder or athlete to suffer depression, reduced libido and impotence for months or years after ending steroid use.18,28 Fortunately, this condition appears to resolve over the course of time.29,30 Clinicians have found the drugs used by bodybuilders for decades are successful in treating the condition, with Clomid, hCG and other drugs restoring testicular function in a matter of days to weeks.31,32 Interestingly, hCG is associated with an increase in estrogen as well as testosterone, perhaps accounting for some of its potency in restoring sexual function.
It should be noted that this discussion only pertains to adult males. The effect of anabolic steroids on the sexual behavior of adolescents is a poorly understood phenomenon, as adolescents demonstrate different neurological response to and metabolism of anabolic steroids, in addition to other drugs.33,34 Anabolic steroid use in this age group appears to be part of a constellation of high risk behaviors and poor social conditioning, rather than performance enhancement. Anabolic steroids shouldn’t be used in this age group.
In retrospect, it’s not surprising that the individual steroids behave differently in regard to their effects on sexual behavior.13,29 Bodybuilders know well how differently anabolic steroids act in building muscle. Additionally, there are clear-cut differences in regard to the side effect profile, with some being associated with estrogenic problems in high doses, while others may cause androgenic concerns. Though many users are happy to relate their increased libido and potency in the locker room, others quietly suffer reduced sex drive and transient impotence. It appears that non-aromatizable steroids are most often associated with decreased sexual arousal in animals, though these findings don’t clearly dictate their effect on humans, who are more complex and socially affected in sexual matters.6,7,35 Further, steroids that reduce SHBG or are modified by 17-? alkylation, may also have a negative effect on sexual behavior during a cycle. All steroids, when used in the supraphysiologic doses required for an anabolic effect will reduce or eliminate natural testosterone production. At the end of a high dose or prolonged cycle, there will typically be a delay in restoring testicular function and sexual behavior, which may persist for months to years. Clomid, hCG and other drugs have successfully treated this condition. Interestingly, nandrolone (Deca) has been shown to maintain sexual behavior, but is often blamed for problems with impotence, a condition known in the gym as “Deca dick.”
Better Left to Instinct
Left undisturbed, nature has provided mechanisms to promote sexual behavior, which has allowed for the species to survive and thrive. Human intervention has disturbed this balance and anabolic steroids may directly impact sexual behavior. It appears that a reasonable, moderately dosed, testosterone-based cycle isn’t associated with any negative changes in sexual behavior and may improve arousal and sexual frequency. Cycles that exceed 600 milligrams of testosterone ester weekly, including non-aromatizable steroids or oral androgens, may be associated with a reduced sex drive. Aromatase inhibitors may also interfere with sexual behavior even in moderately dosed testosterone-based cycles.
This is a topic that will definitely be studied more deeply in the future. Obviously, bodybuilders and athletes will be watching with great interest.
