I had a horrible allergic reaction three times, and the last two were really bad. I finally narrowed it down to it being caused by the Zantrex Black. Heart palpitations, extreme nervousness, turned beat red with a rash. My head felt like it was on fire. Thank goodness I had Benadryl on hand for two bad episodes; I thought I was going to die. I won't be ever taking this product again.
I had to rate, so I gave it one star only because that was the lowest I could rate it at.
Bottom Line: No, I would not recommend this to a friend