Prototype testosterone implant, 1998-1999.
© Science Museum / Science & Society Picture Library
In 1998 and 1999 Edinburgh University conducted trials designed to develop an oral male contraceptive. A pill (containing desogestrel) was taken four times daily, and two implants (containing testosterone) were inserted under the skin on the abdomen, which lasted for three months. The implants were needed because the pill stopped the production of both sperm and testosterone (which could not be taken orally). The Edinburgh trials reduced the sperm count of 60 men to zero.