Gan E, Pattman S, Pearce S, Quinton R. A UK epidemic of testosterone prescribing, 2001-2010. Clinical Endocrinology. A UK epidemic of testosterone prescribing, 2001-2010 - Gan - Clinical Endocrinology - Wiley Online Library Context Testosterone replacement therapy is the standard treatment for male hypogonadism. There has lately been increased marketing in the medical media promoting testosterone replacement for men with erectile dysfunction or for older men with low serum testosterone, despite the lack of long-term safety and efficacy data. Therefore, we aimed to examine trends in testosterone prescribing in UK primary care over the last 10 years. Methods Data about the use of testosterone preparations from the Departments of Health Prescription Cost Analysis for community pharmacies 2001-2010, for England, Scotland and Wales were collated. Community requests for serum total testosterone assay in males to the Biochemistry Department at the Newcastle upon Tyne Hospitals Trust were also examined over the same time period. Results The number of prescriptions for testosterone preparations increased by nearly 90% from 157,602 to 298,134 dispensed items annually, over a 10-year period. However, due to a particularly significant (five-fold) increase in prescribing of (more expensive) transdermal preparations, the cost to the NHS showed a 267% escalation, from £3.2 to £11.7 million, annually over the same period. Local requests from primary care in the Newcastle and North Tyneside area for serum testosterone measurement in males also increased, from 347 requests in 2000 to 823 requests in 2010, a 137% increase. However, the number of men with likely unequivocal hypogonadism (testosterone less than 6.0 nmol/l) remained constant at 5.2% in 2000 and 6.3% in 2010. Conclusion Many men in the UK might be receiving testosterone replacement therapy with neither clearly-established indications, nor robustly-diagnosed hypogonadism. A national registry for men treated with testosterone and further evidence to improve current guidance (national and/or international) on the indications for testosterone replacement would be beneficial.