Testosterone cream gives young women more stamina, more muscles and more body hair

If healthy athletic women rub 10 milligrams of testosterone on their legs every day, their testosterone level does not yet rise to the level that you expect in men. Yet this increase provides a little more muscle mass, a little less body fat and demonstrably more endurance. Swedish researchers report this in the British Journal of Sports Medicine.Study

Some women produce a lot more testosterone than normal due to a birth defect. Among top athletes you will find those women 140 times more often than in the rest of the population. [J Clin Endocrinol Metab. 2014 Nov;99(11):4328-35.] Swedish researchers at the Karolinska Institutet wondered whether such abnormalities actually make women perform better in sports.

The researchers divided 48 normal, healthy and active women aged 18-35 into 2 groups. During the 10 weeks that the experiment lasted, the women put 1 milliliter of cream on the outside of their thighs every night. The women in the placebo group used a cream without bioactive substances, the women in the experimental group rubbed 10 milligrams of testosterone on their skin on a daily basis.The researchers used AndroFeme, a product made by Australian Lawley Pharmaceuticals. [lawleypharm.com.au] AndroFeme is intended for post-menopausal women.

Results
In the women who used the testosterone cream, the testosterone level increased by a factor of 4.8. This level is lower than you'd expect in men. Healthy men have a testosterone level of at least 12 nanomoles per liter - and preferably higher.









At the top right you see that testosterone had no effect on the torque [say strength] that the women could develop while doing leg extensions. They also did not jump higher [at the top left].What testosterone cream did increase, was the women's aerobic endurance of. In a test where the women had to run on a treadmill on an increasingly higher slope [bottom left], and a test where the women had to cycle for 30 seconds as fast as they could [bottom right], testosterone increased the time to exhaustion and the maximum speed respectively.





The total muscle mass increased by 2 percent due to the testosterone cream, though the women did not get any heavier. The increase in muscle mass was offset by a decrease in fat mass.

Side effects
In the testosterone group, bodily changes that could be the result of the use of testosterone, such as acne and facial and body hair, were three times more common than in the placebo group. More than 70 percent of the women in the testosterone group reported these changes.

Conclusion
"Our study supports a causal effect of testosterone on physical performance, as measured by running time to exhaustion, in young healthy women", write the researchers. "Thus the ergogenic effect of short term moderately increased testosterone concentration seemed to apply for aerobic performance only."

"Testosterone also promoted a leaner body composition with an increase in muscle mass although body weight was unchanged."

Source:
Br J Sports Med. 2019 Oct 15. pii: bjsports-2018-100525. doi: 10.1136/bjsports-2018-100525. [Epub ahead of print].