S/x on Dr/gs Reference
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Clinical evidence

Opioids (heroin, fentanyl, methadone)

Mu-opioid agonist·Recreational / illicit · Medication side-effects

Effect across the cycle

DesireInhibitory: Chronic use sharply reduces libido via androgen deficiency.
ArousalInhibitory: Suppressed arousal and genital response with sustained use.
PerformanceInhibitory: Erectile dysfunction is common on maintenance therapy.
ClimaxBiphasic: Single doses may delay ejaculation; chronic use causes anorgasmia.
ExperienceBiphasic: Acute euphoric 'rush' vs chronic anhedonia and blunting.
MemoryMixed: Sedation degrades encoding at higher doses.

Mechanism

Mu-receptor agonism inhibits hypothalamic GnRH, lowering LH/FSH into hypogonadotropic hypogonadism, with direct gonadal suppression and hyperprolactinemia (opioid-induced androgen deficiency, OPIAD). Acute 'rush' can be described in orgasmic terms; chronic use robustly suppresses function.

Pharmacokinetics
Methadone (full agonist) suppresses testosterone more than buprenorphine (partial agonist).
Reversibility
Often reversible with cessation, buprenorphine switch, or testosterone therapy.

Sex differences & notes

Reported dysfunction ranges roughly 34–85% in heroin users and 14–81% on methadone maintenance; ~70% of men on chronic opioids are androgen deficient.

Key sources

  • Andrology 2025 systematic review (Kafel et al.)
  • J Endocrinol Invest 2018 (OPIAD 19–86%)
  • Sexual Medicine Reviews 2025 (opioid reward)