I don't mean to sound like a know-it-all, b/c I'm still relatively new to lifting, but I LOVE Jacked. So much that when I first started using it, I didn't cycle. Not good. It lost efficacy after about 10 days. Now I cycle 4 days on, 2 days off and it's been holding great for about 7 weeks. Another good one is GAT's Jet Fuel, but it's pricey. I could lift my house on that stuff.