My husband and I started taking Doc's best a few months ago, starting with 1-2 capsules daily. After taking only 1 capsule daily my husband started commenting about how much stronger he felt during his morning bicycle rides (he's an outdoor cyclist and rides about 100 miles a week). He started taking 2 capsules and noticed even more improvement. He's now taking 3 capsules daily and can't believe how much more strength he feels during a ride. He doesn't feel tired like before when his heart rate goes way up while climbing the big hills. By the way, he is 78-1/2 years old! Thank you for this excellent product.