Neither L Carnitine nor Berberine work like caffeine, yohimbine, or fat burners. They do NOT: Spike your heart rate Jack up your nervous system Cause jitters or crashes Mask Yohimbe Supplements to Support Men's Vitality* Irwin Naturals Best Yohimbine for Erectile Dysfunction: What Actually Works in Practice l carnitine Walgreens Stark Pharm Stark L Carnitine & Yohimbe , Acetyl L Carnitine, 120 Veggie Caps (500 mg per Cap)