Max Size male enhancement formula is a blend of 20 natural and herbal ingredients including 500mg of Yohimbe (3% alkaloids) which yields up to 15mg of Yohimbine HCL. Yohimbine HCL is the sole natural supplement listed in the Physicians Desk Reference to treat male impotence. Higher amounts have shown in studies to create side effects without increase in performance and/or function. Each 2,000mg serving contains unique ingredients ...(cnidium monnier, and xanthomelia scabrosa—found nowhere else in this product category are widely acknowledged as precursors for PDE-5 inhibition which serves as the body's building blocks to naturally larger and firmer erections). Ingredients: Xanthoparmelia Scabrosa, Cnidim Monnier, Yohimbe, Maca, L-Arginine, Avena Sativa, Catuba, Panaz Ginseng, Muira Puama, Taurine, Nettles, Orchic Powder, Oyster Shell, Tribulus Terrestris, Astragalus, Pumpkin, Sarsaprilla, Boron (from boron chelate) Manufactured by M.D. Science Lab *These statements have not been evaluated by the Food And Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease, Individual Results May Vary.