The first day I took Bioperine I in the morning, with my vitamins and with my treatment (designed for regulate my heart beats). My pulses decreased falling from 60 to 48. SO ... What I'm saying here is there was a side effect because my treatment was more efficient and every one who's taking piperine extract should be aware of that. And obviously, Bioperine is increasing bio availibility, and here's a proof it's working on a larger scale. As for a secondary benefit, I'm taking now half a pill of my treatment and it seems to be working properly. So just take care and be aware it could happen for you on molecules you're taking for your desease, not only vitamins are concerned here. Bioperine is doing exactly what it's designed for, perhaps too much better, that's why I rated 5 stars.

Very good product, with a short time efficiency. Roughly after a week, I noticed changes. First my mind was clearer. At the end of the day, I feel my brain less tired as my job needs to keep concentrate all the time. I'm also more refreshed when I wake up, and I noticed better sleeping. On an another aspect, shipping to France was quick and cheap.