***Androgens, Estrogens, and Libido: New Evidence***

[HawaiianPride.]

By William Llewellyn

Androgens, Estrogens, and Libido: New Evidence

Although the response is a highly individualized thing (and therefore may vary greatly between one person and the next), some steroids are more commonly known for interfering with male libido and sexual functioning than others. Nandrolone decanoate is perhaps the most well-known offender. You may have heard of the infamous side-effect called "deca dick," often cited as the #1 reason not to use this drug alone.

Deca, however, is far from the only steroid associated with this side effect. Primobolan and oxandrolone are also common offenders, as are others. It should not be a surprise that steroids can produce sexual side effects in users. Sexual functioning is highly dependent on the actions of sex hormones. All anabolic /androgenic steroids are, of course, derivatives of basic sex hormones.

When we try to identify why it is that some steroids are more prone to causing sexual side effects than others, the most common answer is that some are less "androgenic" than others. This is the term for being more masculinizing, or supportive of male sexual development and functioning. Drugs like Anadrol , methandrostenolone , and the natural male androgen testosterone tend to be more "androgenic" (although only testosterone is technically classified as an androgen).

These steroids also are less likely to produce sexual side effects in men, and more likely to produce masculinizing side effects when administered to women. So our basic association seems to make sense. On the other side, those steroids most commonly associated with sexual side effects tend to be weakly androgenic. Again, the "low androgenic potency" model for predicting sexual side effects seems to fit, at least much of the time.

Recent evidence, however, has been making us rethink the androgenic potency model for explaining why some steroids are better supporters of male libido than others. More to the point, it seems that the estrogenic activity of the steroid must also be taken into account. On this line of thought, we have seen several studies supporting a direct role for estrogen in male sexuality.

For example, experiments with rats have shown that the aromatization of testosterone to estrogen (or even the direct administration of estrogen in some experiments) is necessary for male animals to properly develop neural circuits in sexual areas of the brain.1 It has also been shown that estrogen is needed for animals to exhibit traditional male behavior such as aggression, urine marking, and territoriality.

Another series of experiments that were just published also found that estrogen and androgens are necessary to support sexual motivation in male rats.2 The researchers used several different hormonal protocols to determine this. For example, testosterone + an aromatase inhibitor failed to maintain sexual activity. When testosterone was administered without the aromatase inhibitor, normal male sexual activity was noted.

The same type of association was seen with dihydrotestosterone (DHT), a steroid that cannot aromatize to estrogen. When given alone, DHT interrupted sexual activity. DHT is several times more androgenic than testosterone, so androgenic activity alone was insufficient. When estrogen was combined with DHT, however, normal sexual activity was restored. So at the end, only those protocols involving both hormones were shown to maintain sexual activity.

At one time, the whole sex steroid topic appeared to be very simple. The male body required testosterone to support its reproductive system. The female system needed estrogen. It seems, however, that this old model is far too simplistic, and is now being drastically reworked.

In some regard, it may be that men need estrogen for their reproductive systems as much as we need testosterone. The same can be said of women and testosterone. We know that androgens are female sex steroids, too. In fact, it is clearly correct to say that the reproductive systems of both sexes operate with the use of both androgens and estrogens combined. Men and women just have vastly varying levels of sex steroids, and thus different dominant hormones, but both are necessary.

While this may be mostly an academic argument, it may have some practical ramifications, too. Most notably, it might make individuals consider the full spectrum of sex steroid activity when fine-tuning their cycles to adjust for side effects. On that note, we see that the three "libido-supporting" steroids we identified earlier also happen to be three of the most estrogenic steroids.

Testosterone and methandrostenolone both aromatize to estrogens, while oxymetholone is inherently estrogenic. Perhaps both the androgenic and estrogenic natures of these steroids are responsible for their abilities to support libido. In that case, one might think of estrogenicity the next time libido issues arise. Perhaps one of the non-aromatizable androgens like Proviron , Halotestin , or DHT would not be a quick fix.

Testosterone and "Sports Porn"

This falls under a highly interesting category. It involves another link between psychological state and testosterone production in men. Researchers at Brock University in Ontario Canada recently found that viewing a videotape of a past victory was a strong trigger for physiological androgen change in elite male hockey players.3

When blood samples were taken after such viewing, the men had a whopping 42-44 percent increase in testosterone levels . When the video was neutral or of a game that was lost, however, the response was only a minor increase in testosterone (6-17 percent). Admittedly, the performance-enhancing effects of short acute increases in testosterone are unclear.

There is some suggestion, however, that acute increases in testosterone might equate this to an increase in aggression and competitive behavior. If true, such viewing might translate into stronger play during competition. Of course this is highly speculative, and viewing previous victories pre-game may also have no overall effect on the win or loss ratio of a team.

Improved Testosterone Pellet

For those considering this course of androgen therapy, studies were just published on Testopel subcutaneous testosterone implant pellets (Slate Pharmaceuticals) that seem to support improved safety over previous testosterone pellets from Organon.4 These pellets are implanted under the skin via a small in-office procedure, and release testosterone in a steady level for a period of three to six months before needing to be replaced.

While the minor procedure may be off-putting to some, it does have the benefit of allowing the person to forget their androgen therapy for long stretches of time. For some men, the daily gels and patches, or weekly/bi-weekly injections, are very inconvenient. Traditionally, however, the pellets from Organon had a somewhat high rate of infection (up to 6.8 percent). As much as 12 percent of the pellets would also work their way out of the site of deposit and up into the skin (extrusion).

This new study, however, shows the Testopel pellets to have an infection and extrusion rate of only .3 percent. The Testopel pellets appeared to be well-tolerated according to this study, and as such might be an increasingly valid option for men undergoing androgen replacement therapy.

References:

1. Estrogen masculinizes neural pathways and sex-specific behaviors. Wu MV, Manoli DS et al. Cell, 2009 Oct 2;139(1):61-72.

2. Sexual incentive motivation in male rats requires both androgens and estrogens. Attila M, Oksala R, Agmo A. Horm Behav, 2009 Sep 19. [Epub ahead of print].

3. Watching a previous victory produces an increase in testosterone among elite hockey players. Carré JM, Putnam SK. Psychoneuroendocrinology, 2009 Oct 3. [Epub ahead of print].

4. Subcutaneous Testosterone Pellet Implant (Testopel) Therapy for Men with Testosterone Deficiency Syndrome: A Single-Site Retrospective Safety Analysis. Cavender RK, Fairall M. J Sex Med, 2009 Sep 29.

[lovbyts]

The same type of association was seen with dihydrotestosterone (DHT), a steroid that cannot aromatize to estrogen. When given alone, DHT interrupted sexual activity. DHT is several times more androgenic than testosterone, so androgenic activity alone was insufficient. When estrogen was combined with DHT, however, normal sexual activity was restored. So at the end, only those protocols involving both hormones were shown to maintain sexual activity.

Does this basically mean we have to choose between our hair or sex?