Coso: the male contraceptive with ultrasound

A testicular bath that removes sperm with ultrasound waves could revolutionize male contraception. Waiting for a male and reliable contraceptive method, Coso is positioned as the best to date.

The device works when men place their testicles in a small bowl-like device, which is filled with water. It then emits ultrasound waves that limit the production and mobility of sperm for up to two months.

Coso was designed by Rebecca Weiss, who wanted to create a form of male contraception after she contracted cervical cancer, which she linked to human papillomavirus and taking hormonal birth control pills. He said the device, known as COSO, is painless and reversible and should prevent unwanted pregnancies. But until now, ultrasound wave technology has only been tested as a contraceptive in animals, not humans.

How does it work?

Condoms and vasectomy are currently the only two contraceptives for men, while there are 12 adapted to women. Although there is ongoing research on a pill for men, none is yet available. Currently used to reduce pain and speed healing of deep tissue injuries, ultrasound was first proposed as a contraceptive in the 1970s and is believed to work by generating heat deep in testicular tissue . This alters the mobility of the sperm, preventing them from fertilizing a female egg and temporarily suppressing the creation of new sperm.

The COSO device must be filled with water, which is automatically heated to the temperature of a warm bath. The man then sits with his legs apart and puts his testicles into the water, which are then ultrasounded for two 15-minute treatments, two days apart.

The creator said that the contraceptive should be effective within two weeks and last at least two months . Fertility returns to normal six months after the last treatment. If approved, doctors would have to set up the device for each user before using it for the first time.

baño testicular coso

COSO testicular bath price

The COSO price is expected to be around €250 or €420 , although it could be less if it is declared as a medical device. The device is still a concept and is a long way from being released to the general public, as extensive clinical trials would be needed to prove it. The publication of COSO depends on the results of this clinical study, but Ms. Weiss predicts that “important milestones” will be reached in the next two to three years.

If the device gets the go-ahead, it would include an app that can be shared with a partner, tracks treatments and reminds men when to use the device again.

However, experts have warned that it can be difficult to prove that ultrasound used for birth control is safe, effective and does not cause long-term fertility problems. Couples may have a hard time knowing when they will be fertile again as the treatment wears off, doctors said.

So far, creator said the interest in the product has been overwhelming. The original intention was, on the one hand, to raise awareness of alternatives to male contraceptives and, on the other hand, to trigger controversial debates about COSO. The device won the German test for the James Dyson award and is being considered for the international stage of the competition.