My book The Pill Problem discusses many side effects that women can experience from taking oral contraceptives (OCs). One chapter addresses the sexual side effects that are common which include decreased desire for sex, greater difficulty becoming aroused, vaginal dryness resulting in painful sex and difficulty or inability to achieve orgasm.
These sexual side effects are due to the fact that women taking oral contraceptives have lower levels of dehydroepiandrosterone (DHEA), lower levels of testosterone and elevated levels of sex hormone binding globulin (SHBG) compared to non-users. These hormonal changes inhibit a woman’s ability to build strength and muscle mass.
The relationship of testosterone to muscle growth is well-known. Many active young women use oral contraceptives and numerous studies report that women using oral contraceptives have lower levels of testosterone compared to non-users. However, no one knew what effect these oral contraceptive induced hormonal changes had on a woman's body composition and exercise performance. A recent study evaluated the the effects of oral contraceptives on female muscle mass and the results are quite shocking. The title of this study is Oral Contraceptives Impair Muscle Gains In Young Women.
Seventy-three healthy women between the ages of 18-31 were divided them into two groups. Group 1 consisted of 34 women who were using oral contraceptives and Group 2 consisted of 39 women who were not taking OCs. The study consisted of a 10-week whole-body resistance exercise training (RET) program in which the women exercised three times per week under the supervision of an exercise physiologist.
The exercises performed were chest press, lat pull down, leg extension, triceps extension, arm curl and abdominal crunch. Standard exercise machines were used and each volunteer performed 3 sets of 6 to 10 repetitions for each exercise at 75% of their maximum strength. Body composition was measured using hydrostatic weighing which is also referred to as "underwater weighing."
The study found that the women who were NOT using oral contraceptives gained significantly more lean muscle mass compared to the women taking oral contraceptives. The women using oral contraceptives were also found to have lower blood levels of testosterone, lower levels of DHEA and elevated levels of the stress hormone cortisol.
The researchers stated the following, "We were surprised at the magnitude of differences in muscle gains between the two groups, with the non-OC women gaining more than 60% greater muscle mass than their OC counterpart." This study was published in The Journal of the Federation of American Societies for Experimental Biology (FASEB).