The consensus is that psychostimulants like Adderall diminish testosterone.
Adderall is comprised of mixed amphetamine salts and is used in the treatment of ADHD and narcolepsy. Given that millions of children and adolescents with ADHD take prescription psychostimulants, we should consider how Adderall and Ritalin impact growth and development (especially during adolescence).
One issue discussed in the medical literature is that Adderall may slightly stunt terminal height.
This effect may be related to appetite suppression or sleep disruption. Psychostimulants like Adderall can cause insomnia and impair sleep quality.
Human growth hormone (HGH) is released during slow wave sleep (SWS) and is an important determinant of height.
Read my article on enhancing slow wave sleep and improving sleep quality to promote nighttime growth hormone release.
Testosterone is an endogenous anabolic steroid and sex hormone secreted by the male testes and to a lesser extent the adrenal glands.
How does Adderall treatment affect testosterone secretion?
One study conducted in rats[^1] indicates that treatment with amphetamine diminished the secretion of testosterone, both in vitro and* in vivo*.
The authors hypothesized that amphetamine suppressed testosterone release by activating testicular cyclic AMP (adenosine monophosphate), an important cellular second messenger.
It is well established that human chorionic gonadotropin (hCG) stimulates testosterone release. The authors also reported that in rats, amphetamine diminishes the stimulatory effect of hCG on testosterone. Amphetamine also enhances the effect of hCG on cyclic AMP signaling.
Plasma luteinizing hormone (LH) levels were not affected by amphetamine administration, indicating that amphetamine impairs testosterone release through an LH-independent mechanism.
The study concluded that:
…amphetamine inhibits the spontaneous and hCG-stimulated secretion of testosterone from the testes through a mechanism involving an increase in cyclic AMP production.
A second study corroborated these results, finding that amphetamine inhibits testosterone production through the mechanism involving increased cyclic AMP production, impaired calcium channel activity and decreased activities of 3beta-HSD, P450c17, and 17-KSR in testicular interstitial cells.
Although it remains unclear to what extent these studies in animal models can be translated to humans, it seems likely that Adderall (mixed amphetamine salts) does impair testosterone release in humans.
Adolescent men who are concerned about this side effect of Adderall my wish to consider alternative medications like Wellbutrin (buproprion), Strattera (atomoxetine), Kapvay (clonidine), or Intuniv (guanfacine).
[^1]: Tsai SC, Chiao YC, Lu CC, et al. Inhibition by amphetamine of testosterone secretion through a mechanism involving an increase of cyclic AMP production in rat testes. Br J Pharmacol. 1996;118(4):984-8. Link
[^2]: Tsai SC, Chen JJ, Chiao YC, et al. The role of cyclic AMP production, calcium channel activation and enzyme activities in the inhibition of testosterone secretion by amphetamine. Br J Pharmacol. 1997;122(5):949-55 Link