NTA but the study is pointless. Miniscule natural fluctuations of testosterone don’t increase sexual desire. The average fluctuation was 14.25 ng/dl. The subjects were aged 18-26. The average testosterone for this age range is probably around 500-700 ng/dl, so that’s a <3% fluctuation at the lower end. It’s minuscule.

They should have structured it by doing things that purposefully elevate testosterone naturally, that way the fluctuations would have been greater.