There are many products in the supplement industry that are used in pursuit of muscle accretion, strength gains, or fat loss. One such product is a testosterone booster. Testosterone boosters are generally avoided by females (and sometimes recommended against), due to the fear that they will cause androgenic side effects (which they will NOT), because of ignorance on how the product affects the female physiology.
Then there is the other side of the coin, where females look to (and males recommend) a testosterone booster, believing that by elevating their testosterone levels they will get faster gains and experience the same results as a male with increased testosterone. Both ideas are inaccurate.
This article will focus on the latter, discussing the endogenous female response of testosterone to resistance exercise; and which hormone(s) should be optimized to provide muscle accretion, strength gains, or fat loss in women.
Alongside resistance training anabolic hormones play an important role in hypertrophy, strength gains, and leanness. Two of the anabolic hormones in the body are testosterone and growth hormone (GH) (Kraemer, 1988).
Females have less testosterone than males (normal male total testosterone values are 0.95-4.3 pg/dl, compared to the 0.7-3.6 pg/dl of females). They also have less free testosterone (males’ bioavailable testosterone is 0.3-5% (average of 2%), with their free testosterone values between 270-1100 ng/dl; compared to only 6-86 ng/dl in females).
Whilst testosterone levels in females may influence physiological adaptations to resistance training, studies indicate that muscle accretion and strength gains happen with OR without an increase in testosterone (Kraemer & Ratamess, 2005). Subjects of Hickson, Hidaka, Foster, Falduto & Chatterton (1994) increased both muscle mass and strength over a 16-week period of resistance training, with NO change in testosterone levels.
With the exception of Cumming, Wall, Galbraith, Belcastro (1987) and Nindl, et al. (2001), most studies using acute or short-term (i.e. 10-16 weeks) resistance training has shown to have NO significant (if any) change in total or free testosterone at rest, or pre and post training in females (Kraemer, et al., 1998; Hickson, et al., 1994). Despite this, females are still able to gain significant muscle and strength or lose fat effectively.
Although research has been inconsistent with resistance training effects on female resting testosterone levels (Kraemer & Ratamess, 2005), chronic resistance training (i.e. >6 months) has been shown to increase resting (and post-exercise) free testosterone in females (Häkkinen, Pakarinen, Kraemer, Newton & Alen, 2000; Marx, et al., 2001), suggesting that long-term training is required to elicit a hormonal response.
Studies also indicate that there is no difference in testosterone levels between heavily trained female athletes and sedentary controls (Tegelman, et al., 1990). However, increases in strength and power have been correlated with pre-training testosterone levels (Krahenbuhl, Archer & Pettit, 1978), leading Hakkinen, et al. (2000) to hypothesize that testosterone levels in females are indicative of their trainability (although not necessarily of their results).
It has been suggested that other anabolic hormones, such as growth hormone may be responsible for hypertrophy, strength gains, and leanness in females (Kraemer & Ratamess, 2005), since such results are achieved without changes in testosterone levels.
Females naturally have higher growth hormone levels than males (Engstrom, Karlsson & Wide, 1998; Wideman, Weltman, Hartman, Veldhuis & Weltman, 2002).
Exercise is a physiological stimulus for growth hormone release, with resistance training inducing significant GH secretion. The magnitude of exercise induced GH release in females is greater than that in males (Wideman, et al., 2002).
Multiple set resistance exercise increases and prolongs the growth hormone response in females compared to single sets (Mulligan, et al., 1996); and resistance training with higher volume elicits a greater GH response than low volume training (Kraemer, et al., 1993). The largest female GH responses are observed with longer resistance sessions with high total work using moderately to heavy weights (>70% 1RM) and shorter recovery periods (Kraemer, et al., 1993).
Whilst acute resistance training has been shown to elevate resting levels of GH in females, chronic resistance training has not. However, chronic resistance training still elicits a similar exercise induced growth hormone response pre and post acute resistance training (McCall, et al., 1999).
Muscle accretion, strength gains, or fat loss in a female are NOT dependent upon their testosterone levels. There are many factors involved in each goal achievement, including an increase in all anabolic hormones. Products that increase GH (or both GH and testosterone) would be a better option than utilizing just a testosterone booster, for the female looking to optimize hypertrophy, strength, or leanness.
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I don't understand why the introduction talked all about supplemental products like testosterone boosters, yet the other paragraphs didn't mention them at all. I was really curious as to how they worked differently in a male vs. a female.
An increase in testosterone WILL make building muscle easier and strength gains WILL come faster. I personally gained 10 lbs of mass in 3 months through HRT (low dose of testosterone) without any exercise whatsoever (fat content and diet unchanged) and experienced much more upper body strength.
More recent studies (i.e., Kraemer, et al., 2001) show that even "short-term" (7 weeks) intervals of exercise led to a significant increase in DHEA, DHEAS, cortisol, testosterone, and leptin in females.
Also, the amount adipose tissue (body fat) usually goes down after consistent exercise. Females usually have more body fat anyway, but it's actually a huge source of estrogen production and aromatization (when testosterone is converted into estrogen). So assuming a female lowers her body fat percentage through exercise, this may also lower estrogen production as well as the conversion of testosterone in her body to estrogen. In other words, it should increase testosterone and lower estrogen simply through fat loss. This occurs in males as well, which is why overweight men (with high amounts of estrogen producing adipose tissue) are prone to estrogenic effects as well as athletes who abuse anabolic steroids (the excess testosterone is converted to estrogen through aromatization and they end up with breast tissue etc.).
Overall, I somewhat feel like this article really missed the mark in some areas.
Here's the info for the Kraemer, et al., 2001 article:
Kraemer, R., Acevedo, E., Synovitz, L., Herbert, E., Gimpel, T. & Castracane, V. (2001). Leptin and steroid hromone responses to exercise in adolescent female runners over a 7-week season. European Journal of Applied Physiology 86(1):85-91.
The rest of the information can be found readily through a search engine.