Letrozole versus testosterone. a single-center pilot study of HIV-infected men who have sex with men on highly active anti-retroviral therapy (HAART) with hypoactive sexual desire disorder and raised estradiol levels

J Sex Med. 2007 Mar;4(2):502-8. doi: 10.1111/j.1743-6109.2007.00451.x.


Introduction: Since the advent of Highly Active Anti-Retroviral Therapy (HAART), men with HIV experience good quality of life and expect to have normal sexual function. However, it appears that men infected with HIV commonly complain of sexual problems. There is evidence that men on HAART develop low sexual desire that is associated with raised estradiol levels. It has been postulated that abnormal metabolism seen in this group of men increases the aromatization of testosterone to estradiol. We hypothesized that letrozole, an aromatase inhibitor that inhibits the conversion of testosterone to estradiol, would be beneficial in these men.

Aim: The aim of this study was to compare the effects of testosterone vs. an aromatase inhibitor, letrazole, in HIV-infected men with raised estradiol and low sexual desire.

Methods: Thirteen men who have sex with men on HAART with low sexual desire as well as raised estradiol levels (>120 pmol/L) were randomly allocated to receive either parenteral testosterone (Sustanon 250 intramuscular injection) (N = 6) or letrozole 2.5 mg orally daily (N = 7) for 6 weeks.

Main outcome measures: Sex steroid hormone assays, sex hormone-binding globulin, virological, hematological, and biochemical parameters were measured before and after treatment. Each subject was given the Spector Sexual Desire Inventory and the Depression/Anxiety Stress Scale before and immediately after treatment. Subjects were also asked to estimate the number of actual sexual acts before and after treatment. Results. Inventory data showed a rise in dyadic desire in both treatment arms. Mean actual sexual acts rose from 0.33 to 1.5 in the testosterone group and from 0.43 to 1.29 for the letrozole group. Luteinizing hormone increased in seven of seven men on letrozole. Serum testosterone increased in seven of seven men on letrozole. There were no adverse events from either medication.

Conclusion: Letrozole may be useful in the management of men on HAART who have low sexual desire.

Publication types

  • Controlled Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Antiretroviral Therapy, Highly Active / adverse effects*
  • Aromatase Inhibitors / administration & dosage*
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Erectile Dysfunction / chemically induced*
  • Erectile Dysfunction / drug therapy
  • Estradiol / blood
  • Homosexuality, Male*
  • Humans
  • Letrozole
  • Male
  • Middle Aged
  • Nitriles / administration & dosage*
  • Pilot Projects
  • Statistics, Nonparametric
  • Testosterone / administration & dosage*
  • Treatment Outcome
  • Triazoles / administration & dosage*


  • Aromatase Inhibitors
  • Nitriles
  • Triazoles
  • Testosterone
  • Estradiol
  • Letrozole