As reported in the Sun newspaper 1 scientists are recruiting couples to take part in a clinical trial testing a new male contraceptive gel. This gel could be a huge step forward in contraception by helping men take greater responsibility for birth control. Scientists hope that the new gel will be more effective than condoms and just as effective as the contraceptive pill for women.
How does the gel work?
The gel is called NES/T, and it contains hormones which cause a man’s sperm count to fall. The NES/T gel contains a compound called segesterone acetate, which has the brand name Nestorone.
This compound contains progestogen which acts on the brain to reduce testosterone production in the testes. Testosterone is responsible for normal sperm production. But the effects of progestogen slow down the rate of sperm production until it is non- existent with continued use of the gel after four months.
Blocking testosterone could have wider negative effects on the body, including loss of libido and muscle mass. However the scientists have countered this by including testosterone in the NES/T gel. By replacing the testosterone in this way, scientists believe they can prevent any loss of libido and reduce any harmful side effects.
Are the effects reversible?
Yes, the drop in sperm count is not permanent. Scientists believe that sperm counts should return to normal after stopping daily use of the gel for six months.
Couples are currently being recruited for the clinical trial
Scientists are recruiting eighty couples in Manchester and Edinburgh. Men will need to use the gel daily until their sperm count drops to zero. Scientists believe that this could take four months.
After this point, the couples will use the gel as their only form of contraception, and it would replace any other contraceptive methods they use for over a year. Scientists would regularly test how effective the gel is and monitor any side effects. Men will need to attend a clinic each month so that scientists can monitor the change in their sperm count.
How do you apply the gel?
Men should apply the gel to their arms, shoulders and back every day. The gel travels directly into the bloodstream from the skin. Scientists will provide the men in the study with the gel in a pump form which administers the correct daily dose.
The only other current options for contraception in men are vasectomies and condoms. Therefore the NES/T gel could be a huge step forward in terms of convenience if these trials are successful.
What does the current evidence say about the gel?
Previously scientists have studied the effects of a gel containing a combination of nestorone and testosterone in a study of 99 men. The results were significantly positive, with 88.5% of men experiencing a reduction in their sperm count over the course of 20-24 weeks without major side effects 2.
Previous studies have investigated hormone-based methods of contraception for men
Professor Richard Anderson from Edinburgh University, who is leading this new trial, has also conducted previous research into contraceptive methods for men based on hormones.
In 2016 he led a study which tested a contraceptive injection for men. The injection contained progestogen and testosterone. The trial had promising results in terms of preventing pregnancies, and scientists found that the injection was almost 96% effective. This made it more effective than condoms and almost as effective as the contraceptive pill for women.
However men experienced side effects including acne, depression and increased libido. These were judged as unacceptable and the trial was stopped early. But despite these side effects, at the end of the trial 75% of men said that they were willing to continue having the injection if they had the option 3.
The trial will reveal any side effects of the gel
Side effects are expected with any medical intervention, and the same applies to methods of contraception. The combined contraceptive pill for women has many side effects including mood swings and headaches. It also increases the risk of more serious problems such as blood clots.
Scientists hope that this gel could eventually be an alternative to the contraceptive pill for women. This would allow men to take more responsibility for birth control, particularly in cases where women cannot take the contraceptive pill for medical reasons.
The gel does not replace condoms
The NES/T gel lowers sperm count to reduce the chances of getting pregnant. However it does not have any effect against Sexually Transmitted Infections (STIs). Therefore men would still need to use condoms.
When will it be available to buy?
Scientists will need two years to conduct the study. If the results are successful, they believe that there will be a great deal of interest in developing the NES/T gel commercially for the general public. Therefore the gel could be available on the market in the next three to five years, depending on the results of this clinical trial.
How can I get involved in the study?
Men who are aged between 18 and 50 years old and are in a stable relationship with a woman aged between 18 and 34 years old are invited to apply to take part in the study. Call 0161 276 3296 for Manchester, and 0131 242 2669 for Edinburgh as soon as possible.
The NES/T gel sounds very promising and it is an important step forward in developing new and practical methods of male contraception. The clinical trials will provide valuable evidence about how effective the gel is, and whether it is a viable option as a contraceptive method. However even if the NES/T gel has positive results in clinical trials, it will still take three to five years before it is widely available for use.
- Wooller S. Arm and a Legover! Gel that men rub on their limbs could become the new male contraceptive. 2019 Jan 31. The Sun. Available from: https://www.thesun.co.uk/news/8327633/gel-male-contraceptive-rub-arms/ ↩
- Ilani N, Roth MY, Amory JK, Swerdloff RS, Dart C, Page ST, Bremner WJ, Sitruk-Ware R, Kumar N, Blithe DL, Wang C. A new combination of testosterone and nestorone transdermal gels for male hormonal contraception. Journal of Clinical Endocrinology and Metabolism. Internet. 2012. 97(10):3476-3486. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22791756 ↩
- Behre HM, Zitzmann M, Anderson RA, Handelsman DJ, Lestari SW, McLachlan RI, Meriggiola MC, Misro MM, Noe G, Wu FC, Festin MP, Habib NA, Vogelsong KM, Callahan MM, Linton KA, Colvard DS. Efficacy and safety of an injectable combination hormonal contraceptive for men. Journal of Clinical Endocrinology and Metabolism. Internet. 2016. 101(12):4779-4788. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27788052 ↩