I been taking Citraplex which increases metabolism, but I would still get sleepy around the afternoon. Like any higher metabolism stimulant, the body tends to adapt over time so it is not effected as strongly.
When I used CarbManager, the effects were noticeable. I actually felt energetic, instead of the "forced" energy that comes from higher metabolism stimulants. All the higher metabolism stuff does for me is make my heart pound more strongly (where I can feel it constantly) but I don't really have energy all day. CarbManager gave me that energy especially when I workout. I do 45 minutes of cardio 6 days a week then lift weights for about 15-20 minutes, splitting up muscle groups for different days to allow muscle to recover and grow better.
Wiith CarbManager I would get to 45 minutes of cardio and I would feel like "that was 45 mins.?".
I been starting to do an hour easily and could do much more.
I should mention that I don't use low carb diets. I eat somewhat healthy, ground turkey on white bread for lunch/dinner and breakfast I'll have cereal or waffles. I also drink a lot of Orange Juice and I think CarbManager seems to regulate the insulin better, because I don't get sleepy from a lot of carbs or unrefined sugar (like in fruits) now, whereas usually if I had a sandwich I would get sleepy from the carbs in the bread.
Only after taking it for 14 days, I have not noticed any other effect other than having plenty of energy for about 10-12 hours a day. (Especially when I do cardiovascular exercise) The lean muscle mass claim I think would be hard to measure. Because it takes a significant time to create that muscle mass, and it could be just as likely that your own exercise routine has contributed to it, as CarbManager has.
$50 is a bit expensive but it's not so expensive that a lot of people wouldn't buy it, which I'm sure was the idea.. get as much money from consumers as you can lol.