Purpose <p>Androgen abuse has been suggested to adversely affect sleep-disordered breathing, but prospective real-world data in androgen abusers are lacking. The aim of this study was to evaluate the effects of androgen abuse on sleep-disordered breathing.</p> Methods <p>Adult men planning a self-initiated androgen cycle were evaluated before, at approximately week 8 of their cycle, and approximately three months after cycle cessation. Sleep was assessed using ambulatory WatchPAT monitoring. The primary outcome was change in the peripheral arterial tone–derived apnea–hypopnea index (pAHI). Secondary outcomes included peripheral arterial tone-derived respiratory distress index (pRDI) and oxygen desaturation index (pODI), sleep architecture and subjective sleep questionnaires as measured through the Epworth Sleepiness Scale (ESS) and Insomnia Severity Index (ISI). Longitudinal changes were analyzed using linear mixed-effects models.</p> Results <p>Twenty-three participants were included. Median cycle duration was 12&#xa0;weeks with a median weekly dose of 678&#xa0;mg. During the androgen cycle, pAHI did not increase significantly, whereas pRDI did increase (mean increase of 3.0 events/hour). At post-cycle follow-up, pAHI, pRDI, and pODI were significantly increased compared with baseline (mean increases of 2.7, 4.4, and 3.0 events/hour, respectively). Sleep architecture was largely preserved, although a modest reduction in deep sleep and an increase in heart rate was observed during androgen abuse. No significant changes were observed in total ESS or ISI scores across time points.</p> Discussion <p>These findings suggest that androgen abuse may exert subtle effects on sleep-disordered breathing parameters but are unlikely to translate into overt or clinically meaningful sleep apnea in most androgen abusers.</p> Clinical trial registration number <p>Registration number P2117, study number NL77191.028.21.</p>