Grapefruit juice decreases insulin resistance. My fasting insulin was very high at 27. After taking grapefruit juice 3 times per day, cinnamon and metformin it droped to >2. That's as good as you can get. Grapefruit didn't do it all but I'm sure it had a huge impact.
You could of had high insulin and high glucose levels and the grapefruit juice reduced them. High insulin and glucose are not exactly good for your sex drive. Many cutting diets use grapefruits to help cut weight.
The chemicals in Grapefruit juice have been proven to change the bio availability and half life of endless medications in numerous studies have been done showing the effects. All I can say is grapefruit juice might be one of those miracle foods for some people.
List of drugs affected by grapefruit - Wikipedia, the free encyclopedia