I'm still quaffing my HMB at 3g/day. I decided to make my own mix of stuff, it includes HMB, creatine and Vitamin K2 as well as my heart vitamins (Centrum Specialist Heart) ground to a powder. I like how I only need to take one thing 2x per day. The vitamin pills were too big for me, they have phytosterols in them for the heart but it makes the pills really big. So I just ground them up in a food processor and added to the other powders. I recently mixed up a 6-month supply.
I think it is helping but I don't really care what I think.. as Dudelsack mentions above it is hard to measure such things.