Is l-carnitine supplements good for weight loss? i am look to lose fat and become more effective in the gym.

?why not diet?: While the carnitine supplement you describe is safe at your age when used as directed, it still has considerable calories and shouldn't be looked at as a weight loss item. This is basically a protein powder, so instead, get more proteins in your diet - have a juicy steak, a grilled chicken breast, e yogurt parfait, etc. You get the extra protein and it tastes good too! keep it up at the gym.