Keep taking it then.
Tons of people take supps that dont work for their supposed purpose, otherwise glutamine wouldnt have nearly as large of a following as it does for bodybuilding purposes
glutamine has its uses when severly overtraining- like when getting ready for a contest or extreme intense training. -has other benefits as well- soothes the srtomach - that said I take it when I am sick or over trained or in pre contest
as far as L-carnitine helping with fatloss, do you believe more muscle helps with fat loss?
check out this article
http://www.bodybuilding.com/fun/l_carnitine_l_tartrate.htm
Back when i took alcar for 2 years strait @ 3 grams daily I took it before my first meal-its great before cardio as well alcar (or any l-cartinine) in my opinion plus cla is a nice stack (I havent used cla in years although i still think its effective)
*I was 220lbs back then- 5-7 years ago so of course take into weight into account-that is why i took 3 grams instead of 2. but yeah 2-3 grams is a good dose depending on your weight. Some days I took 6 grams - 3 and 3 split before work(i worked as a bouncer back then) and got a brain buzz out of this world