As the mother of an 18 yr old I know what you mean.
With boys you can always appeal to their vanity, they want muscles right? or do they have them already? I would go with the whey protein, capsules or the powder. READ the MOOD CURE by Julia Ross,
and see that a lot of problems including mental/emotional are really protein (or amino acid deficiency). A little protein before bed can stop some dreams. TURKEY is full of l-tryptopan, and so is dairy. But since you said they are congested, I would try to get them to try 7 days without dairy and see if their heads clear up while using the WHEY or the EGG WHITE protein powder, it makes great smoothies with soy milk or almond milk and fresh/frozen fruit.
Hope this helps a little,
Joanne