Serotonin and Testosterone reduction
Serotonin, SSRIs, and Testosterone: Brief Citation Sheet for Clinical Review
Clinical bottom line:
Current evidence supports a biologically plausible link between serotonergic signaling and reduced testosterone production, with the strongest direct evidence coming from Leydig-cell and animal studies. In humans, there is evidence that SSRIs can disrupt the hypothalamic-pituitary-testicular axis and are associated with lower gonadotropins, lower testosterone, and sexual dysfunction in some men.
Key references
1) Direct Leydig-cell evidence
Tinajero JC, Fabbri A, Dufau ML. Regulation of corticotropin-releasing factor secretion from Leydig cells by serotonin: inhibition of testosterone production. Endocrinology. 1992;131(2):556-564.
Key finding: Serotonin stimulated CRF secretion and inhibited basal and hCG-stimulated cAMP generation and testosterone production in cultured rat Leydig cells.
2) Serotonergic inhibition of Leydig-cell function
Tinajero JC, Fabbri A, Dufau ML. Serotonergic inhibition of rat Leydig cell function by propranolol. Endocrinology. 1993;133(1):257-264.
Key relevance: Follow-up mechanistic work on serotonergic inhibition of Leydig-cell steroidogenic signaling.
3) Serotonin secretion and androgen suppression pathway
Tinajero JC, et al. Serotonin secretion from rat Leydig cells. Endocrinology. 1993.
Key finding: In rat Leydig cells, serotonin binds 5-HT2 receptors and stimulates CRF secretion, which in turn inhibits gonadotropin-induced cAMP formation and androgen production.
4) Human endocrine data in men with SSRI-associated sexual dysfunction
Safarinejad MR. Evaluation of endocrine profile and hypothalamic-pituitary-testis axis in selective serotonin reuptake inhibitor-induced male sexual dysfunction. J Clin Psychopharmacol. 2008;28(4):418-423.
Key finding: Compared with normal controls, men taking SSRIs had significantly lower LH, FSH, and testosterone, with reduced gonadotropin response to GnRH testing.
5) Recent review of endocrine effects of SSRIs
Ruiz-Santiago C, Rodríguez-Pinacho CV, Pérez-Sánchez G, Acosta-Cruz E. Effects of selective serotonin reuptake inhibitors on endocrine system (Review). Biomed Rep. 2024.
Key takeaway: The review concludes that SSRIs may adversely affect sexual function and fertility by dysregulating endocrine axes, including effects on the gonads, and recommends closer endocrine monitoring in long-term users.
In summary:
Available evidence indicates that serotonergic signaling can inhibit testosterone production at the testicular level in experimental models, and SSRI exposure has been associated in human studies with suppression of the hypothalamic-pituitary-testicular axis, lower gonadotropins, lower testosterone, and sexual dysfunction in some patients.
Direct mechanistic evidence exists that serotonin can suppress Leydig-cell steroidogenesis in experimental systems.
Human evidence is stronger for SSRI-associated endocrine disruption than for a simple universal claim that “serotonin lowers testosterone” in all people.
In men presenting with new-onset sexual dysfunction, emotional blunting, fertility concerns, or hypogonadal symptoms during SSRI treatment, it is reasonable to consider medication effects in the differential. This is an inference supported by the human endocrine findings and review data.
