Supplements

When you are trying to improve your performance, gain size or lose weight their are some thing that will help.

1. Follow a good nutritional diet. There is no replacement for eating right.

2. Proper training. Make sure your training plan is approriate and that you out forth the required work. 

3. Rest. Your body repairs itself with adequate nutrition and rest so make sure you get enough sleep. 

If you are training for a specific purpose there are additional things that can assist you, if the above are adhered to. The International Society of Sport Nutrition has listed these as apparently effective and generally safe:

Muscle building-weight gain powders, creating, protein, essential amino acids

Weight loss-low calorie foods, caffeine

Performance enhancement-water, sports drinks, carbs, creatine, caffeine, post exercise carb and protein mix

Depending on your goals, training, and nutrition, some of those supplements can help with achieving the goals.