Professor Belinda Winder, a leading forensic psychologist who has evaluated the use of sex drive-suppressing drugs in UK prisons, told the Guardian that approximately one in four sex offenders—roughly 3,750 current prisoners—would be considered for the treatment.
The medications, which reduce libido in men, are already used on a voluntary basis in some correctional facilities. The program is currently being expanded to 20 prisons across England and Wales, and Winder said a broader rollout could begin by late 2028.
Advocates argue the drugs can help prisoners manage what experts call "problematic sexual arousal" (PSA). Winder described one patient who said the medication allowed him to follow a film plot for the first time without being distracted by sexualized thoughts. "I remember talking to one guy a few weeks after he started taking the medication. He said: 'It's amazing. I followed a film plot. I wasn't just looking for when I could see bra straps, when I could see nipples, when someone's going to bend over so I could see their bum,'" Winder recalled.
However, the use of libido-suppressing drugs, sometimes referred to as "chemical castration," remains controversial. Critics question the ethics of requiring such treatment as a condition of parole, even when participation is nominally voluntary. Some argue that the coercive context of the prison system undermines true informed consent, and that altering brain chemistry to control behavior raises fundamental questions about autonomy and human rights.
The UK approach mirrors practices in several other countries where parole boards have made chemical suppression a condition of release. Proponents counter that for some offenders, the drugs provide a crucial tool for reducing reoffending risk and enabling reintegration into society.
In the UK, the program is currently limited to male prisoners. No similar initiative has been announced for female offenders, though some researchers have noted that problematic sexual arousal occurs across genders.
Winder said the 2028 timeline assumes successful completion of the current pilot phase and subsequent evaluation. "We need to ensure the medications are safe and effective, and that prisoners are fully informed about side effects," she said.
Side effects can include fatigue, weight gain, depression, and reduced bone density, though advocates note that patients can discontinue use at any time if they experience adverse effects.
The expansion plan comes as the UK prison system faces severe overcrowding, with officials seeking evidence-based ways to reduce reoffending rates among the roughly 15,000 sex offenders currently incarcerated in England and Wales.