You get a copy of any fitness (particularly weight training) magazine and you are bombarded with different pre-workout supplements, post-workout supplements, anabolic stacks, nitrous oxide concoctions all “proven” to increase your workout/strength/growth potential.
The science behind a lot of these is sketchy to say the least, and they are often accompanied by pictures of famous lifters or body builders that “used” the product.
Personally, while they might add some benefit, the biggest thing that most of these do is empty your wallet. I prefer to take supplements of proven quality.
On top of a fairly balanced and clean diet (no processed foods), I supplement with the following products.
Whey/Casein Protein Powder
As both a lifter and having a mostly vegetarian diet I find it impractical to get all my protein needs fulfilled by food alone. Therefore I supplement with around 120g of protein a day.
Typically I have 60g of a whey/casein blend 30 minutes or so before a workout. Casein absorbs more slowly than whey and experimentally I found that this gives me a more consistent workout.
Post-workout I have about 60g of whey protein powder along with a protein rich meal. This provides a quick burst of protein to the repairing muscle which providing the slow release with the meal.
Creatine is a natural compound that is already found in the body, and is used to produce the fuel that the body needs to do its thing. The problem is the the body stores a limited amount of this fuel (ATP). A great detailed explanation of creatine can be found on Musclehack.
I add about 5-10g of creatine to my pre-workout shake.
L-Glutamine is one of the essential amino acids. Glutamine is important in keeping the immune system in good shape, but intense strength workouts deplete the body of this amino acid. Therefore I take about 5g of L-Glutamine in my post workout shake to restore levels.
I don’t drink coffee, and therefore am fairly sensitive to caffeine. I find that a quick shot of espresso before a workout really increases the intensity.
While I don’t take fish oil entirely for weight lifting purposes, it does have many health benefits. Use of fish oil results in lower triglycerides (stored body fat), lower blood pressure and healthier joints.