If you're trying to put on size, the best thing you could do (other than eating appropriately) is move from a straight whey to some type of protein blend that has not only whey, but different types of casein. Whey is a quick digesting protein that is lower in calories. If you're trying to put on any type of mass, quality calories are your friend. If you're having trouble gain weight, try a weight gainer and eat, eat and eat some more. A creatine supplement could be helpful too. Either regular creatine monohydrate or a mix like Cell Tech.
As for supplements and the military, stay away from the original Jack3d formula. I'm pretty sure that the stimulant used in that (geranium root, aka 1,3 dimethylamyaline) is military banned. The C4 would be a better alternative as they pulled that ingredient out a while back. Also, Jack3d Micro would be fine.
FYI I am a store manager for a supplement store. I'd be happy to answer any other questions. I don't know everything but I've been in the industry a while.

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