It’s 30 minutes until your next workout. Quick, what should you take to ensure high-performance energy levels, monstrous strength and ample supplies of nutrients to kick-start muscle growth processes?

We stumped some of you, didn’t we? Plenty of bodybuilders start bashing the weights after hitting a fast-food drive-through, after wolfing down a protein bar or even while running on empty. Most guys simply don’t give a lot of consideration to their nutritional attack–even guys who will spend hours meticulously planning out exercises, sets and reps are often guilty of putting zero thought into the food and supplements that will actually fuel their training session.

That’s a mistake, and one you can put an end to right here. We’ve mapped out the nine top supplements for bodybuilders in preworkout mode, along with the best carb foods for stoking your body’s growth and energy furnace. Use this as your guide, and you’ll have improved power, energy levels, endurance and focus next time you train.

#1 WHEY PROTEIN

First on your list is supplying your body with critical amino acids needed not only as building blocks for muscle growth, but for energy during training. If your body uses the amino acids from whey protein, it won’t have to break down existing muscle protein to get aminos for fuel, which obviously could compromise your muscle size.

THE RESEARCH SAYS Drinking a whey protein shake immediately before you lift is even better for stimulating muscle growth than waiting until after the workout is over. Taking in a small amount of whey protein (without carbs) before you do cardio may also help you burn more fat when you exercise.

TIMING AND DOSAGE Having a whey protein before exercise is your best bet, as it is a quick-digesting protein, which means your body will get the aminos it needs, fast. Go with 20 grams (g) of whey protein isolate, hydrolysate or concentrate along with 30-50 g of carbs within 30 minutes of your workout.

#2 ARGININE

This amino acid is the main ingredient in almost every nitric oxide (NO) boosting product available. Arginine is readily converted in the body to NO.

THE RESEARCH SAYS Nitric oxide dilates blood vessels, which helps get more blood flow to working muscles. Enhancing blood flow to muscles right before a workout helps to deliver more nutrients, such as amino acids from whey protein, glucose and fats, and the anabolic hormones that rise during training, such as testosterone, growth hormone and insulinlike growth factor-I (IGF-I). Greater blood flow also means more water delivery to exercising muscles; since a muscle pump is essentially a result of muscle cells filling up with water from blood, more water supplied to the muscles results in a greater muscle pump.

TIMING AND DOSAGE No matter whether the product you take supplies L-arginine, arginine alpha-ketoglutarate, arginine ketoisocaproate, arginine malate or arginine ethyl ester, go with 3-5 g about 30-60 minutes before workouts. For maximal effect, on nontraining days take a dose in the morning and before bedtime.

#3 CARNOSINE

Carnosine is an amino acid supplement that is actually a dipeptide–two amino acids (beta-alanine and histidine) bound together. You can supplement with either carnosine or with beta-alanine and histidine for the same effects–greater muscle strength and endurance. That’s because, in muscle fibers, beta-alanine and histidine are combined to form carnosine.

THE RESEARCH SAYS Muscle fibers that have the highest levels of carnosine can produce the greatest amount of force and can produce the greatest amount of force and can contract for longer periods. Studies of athletes show that it is possible to increase muscle levels of carnosine by more than 80% with supplementation, but it can forestall fatigue. In the gym, this means you can get more reps with a given weight before reaching failure, or lift more weight for a certain amount of reps. Carnosine appears to work by buffering the byproducts that build up in muscles during exercise–those byproducts eventually cause muscles to fatigue. Carnosine also has been found to provide antioxidant properties, meaning it scavenges free radicals that could damage muscle cells; this protection helps muscle recovery.

TIMING AND DOSAGE Take 1-1 1/2 g of carnosine 30-60 minutes before workouts.

#4 CARNITINE

The supplement carnitine is considered an amino acid, but it’s not typical. It’s actually made from the amino acids lysine and methionine; vitamins C, B3 and B6; and iron. Carnitine is important for fat metabolism, as it is involved in carrying fat into the machinery in muscle, heart and brain cells, known as mitochondria, that burn it for fuel. Taking carnitine before workouts prompts your body to use more fat during the session.

THE RESEARCH SAYS University of Connecticut researchers have been integral in discovering carnitine’s importance to bodybuilders. One of their studies suggests that carnitine, like arginine, enhances blood flow to exercising muscles. However, the mechanism is likely different from arginine, which indicates that taking both supplements can offer additive benefits (i.e., it would be more valuable to take both of them rather than just one or the other). A more recent study from UConn suggests that carnitine enhances the number of androgen receptors in muscle cells responsible for binding testosterone in the muscle and initiating its effects on muscle growth and strength.