Reversible Inhibition of Sperm Under Guidance

Reversible inhibition of sperm under guidance, known as RISUG and formerly studied under the name of its synthetic polymer styrene maleic anhydride, is a male contraceptive injection developed at the Indian Institute of Technology Kharagpur by a team led by Dr. Sujoy K. Guha. It is administered into the vas deferens under local anesthetic, where a polymer gel coats the vas walls and incapacitates sperm before ejaculation, working similarly to a vasectomy but remaining reversible. The technology holds patents in India, China, Bangladesh, and the United States, and phase III clinical trials in India were delayed by low volunteer enrollment before results were published in 2023. A US version developed from 2011 by the Parsemus Foundation under the name Vasalgel did not reach market despite years of promised commercialization, and in 2023 NEXT Life Sciences acquired the patent with plans to market the treatment as Plan A for Men.