Some users of anabolic androgenic steroids (AAS) secretly consume aromatase inhibitors (AI) and selective oestrogen receptor modulators (SERM). Cyber-forums can be potential sources of information. Our aim was to determine the cycles used, and to identify the adverse drug reactions (ADRs) experienced, reported in a bodybuilding forum.

We collected discussions on a French forum for AAS users (MESO-Rx®), from January 2013 to 2019 on concerning clomiphene, tamoxifen, anastrozole, exemestane and letrozole were collected. Characteristics of the users, duration of cures, treatments, dosages, point of purchase and occurrence of ADRs were analysed.

Among the 1792 posts published on the forum, 845 concerned SERM and 571 concerned AI, i.e. 2180 drugs used (several cycles included concomitant consumption). Our population was exclusively male, with an average age of 28.2±6.3years, and had been practising weight training for 6.7±5.6years. The SERMs were mainly used to “revive the hypothalamohypophyseal axis” and the AIs to “fight against androgen aromatisation”. The median treatment duration was 22 days for SERM, 70days for anastrozole, 84days for exemestane and 30days for letrozole, with a mean dose of 69mg/d for clomiphene, 22mg/d for tamoxifen, 0.4mg/d for anastrozole, 10mg/d for exemestane, 2mg/d for letrozole. The main way of obtaining these drugs was through the internet. 157 ADRs were identified: 95 for SERMs and 62 for AI. The most represented were acne, musculoskeletal, mood and reproductive disorders. Impaired quality of life (according to the patient) was described in 54% of the SERM posts and 26% of the AI posts.

Patient narratives posted on forums can be a useful tool in the context of doping, to better understand practices, motivations and possibly to bring up pharmacovigilance signals.