A total of 420 heterosexual couples worldwide are included in this study.
Of these, there are 50 couples in Sweden where the man lubricates a gel on shoulders and upper arms every day.
- Had a hard time believing that it was just a gel, it sounded almost ridiculously easy, says Carl Enderstein.
"Difficult to let go of control"
The study follows both people in the couples and for Jonas' wife Rebecca Redmansdotter, it was initially a bit unusual to let Jonas be responsible for the contraceptive.
- I'm a control freak and it was a bit difficult to let go of control but Jonas really showed that he took his responsibility so it worked very well, she says.
She is positive that a contraceptive for men is being developed, but believes that it is better suited for couples.
- Single women will probably not trust it as much.
If the man does not take care of himself, it is the woman who gets to take the slap, she says.
Larger muscles and short stubble
But side effects then?
The list of common side effects of hormonal contraceptives for women is long, what does it look like with the contraceptive gel?
The increased amount of testosterone has been shown in larger muscles, increased sex drive, sweating and short stubbornness, but neither Jonas nor Carl have experienced it as a major problem so far.
Hear Jonas and Carl talk about their time in the study in the clip above.