The cold, honest truth is that there's no magic pill that'll make you faster, stronger, thinner, or healthier all by itself. To chase down your fitness goals, the most indispensable ingredients are exercise and a healthy diet. Nonetheless, without the right workout supplements, there's a good chance you won't maximize the benefits of all the work you put into your exercise routine. And depending on the type of athlete you are and what you want to gain from your workouts, the supplements you should take can vary. So which workout supplements are right for you? Read through our guide to find out.

If You Want to Build Muscle

Whey Protein

• What It Is: Whey makes up a big chunk of the protein found in milk. It's one of the purest forms of a protein supplement available, especially if you go for whey-protein isolate, which contains an even bigger portion of protein per serving. It comes in a powder form that can be mixed into water, milk, smoothies, and even foods like oatmeal.

• Why You Should Take It: Since proteins are the body's basic muscle building block, whey is usually the first natural choice for athletes looking to gain muscle. Bodies digest it easily and quickly, and when taken after a resistance-training workout, whey helps supply blood to your weary muscles and kick-starts protein synthesis (i.e., muscle development).

Creatine

• What It Is: Creatine is a molecule found naturally in the body. It's built up of a trio of amino acids. Like whey protein, it usually comes in a powder that can be mixed into drinks before and/or after workouts.

• Why You Should Take It: In short, it builds muscle quickly. Taking creatine can increase the volume of the cells in your muscles and boost water content in them. This not only gives you a short-term "pump," but also stretches and primes those cells for further, more lasting muscle growth.

Beta Alanine

• What It Is: Like creatine, beta alanine is naturally occurring, a nonessential (meaning the body can reproduce it on its own) amino acid found in the body. It often comes in both tablet and powder form. Together with other amino acids in your body, beta alanine controls the amount of acid that enters your muscles. The more acidic a muscle is, the less it can contract, so basically, beta alanine helps keep your muscles ready for work.

Why You Should Take It: Since it's so crucial in preventing acid buildup (and the subsequent fatigue and cramping) in your muscles, beta alanine is great for lasting through lengthy weight- or resistance-training sessions.

If You Want to Burn Fat

Green-Coffee-Bean Extract

• What It Is: As you may have guessed from the name, this supplement comes from coffee beans when they're still green, or before they're roasted. The main compound in green coffee beans that's associated with health benefits is the antioxidant chlorogenic acid.

• Why You Should Take It: In general, the research on how effective this and other fat burning supplements are on their own is still ongoing, but the results so far have been promising. Studies have been conducted that have seen subjects using green-coffee-bean extract lose as many as 18 pounds over a five-month period.

Green-Tea Extract

• What It Is: What makes green tea different from other varieties, say, oolong or black tea, is how unaltered it is. Unlike other teas, green tea isn't withered or oxidized. This keeps all the good stuff—like catechins, which can be important in an athlete's weight-loss efforts—intact.

• Why You Should Take It: Those catechins are examples of natural thermogenics, or substances that boost the calorie-burning process and help drive weight loss. One catechin in particular, epigallocatechin gallate, has been shown to keep athletes' metabolism up, which can stretch out how long your body burns fat during and after exercise.

Garcinia Cambogia

• What It Is: Garcinia cambogia, also known as the tropical fruit malabar tamarind, is a popular supplement used in weight-loss routines. The main ingredient associated with weight loss is something called hydroxycitric acid (HCA).

• Why You Should Take It: Like many supplements claiming to have weight-loss benefits, there's still no consensus on garcinia cambogia. However, HCA has been linked in many studies to appetite suppression, and it has also been thought to be an effective blocker of the citrate lyase enzyme, which builds fat in the body.

If You're Training for a Race

L-Glutamine

• What It Is: Glutamine is a naturally occurring amino acid, and your body makes a lot of it. All told, it accounts for more than 20% of all of the body's circulating amino acids, and it comprises upward of 60% of free amino acids in skeletal muscles.

• Why You Should Take It: With the long distances and grueling workouts runners go through in prepping for a race, L-glutamine can come in handy during training. It's lauded for its ability to keep muscles from becoming sore during long periods of exercise. Additionally, L-glutamine has been shown to strengthen the immune system and protect against the upper-respiratory infections that sometimes haunt marathoners and long-distance runners.

Fish Oil

• What It Is: It's self-explanatory, but these capsules are filled with oils found in fish and fish products, such as tuna, salmon, and cod liver. Inside a fish-oil supplement lie the much ballyhooed omega-3 fatty acids, which carry many health benefits.

• Why You Should Take It: Fish oil is championed as an all-around supplement that almost any athlete can benefit from, but it can be particularly good for an athlete on a running routine. Its anti-inflammatory properties can keep you from stiffening or becoming injured, hasten muscle recovery following runs, and even lessen the amount of oxygen you go through during exercise—the latter helping make the work you're doing feel a little easier.

Betalain

• What It Is: Betalains are the color pigments found in beets, and they come in two colors: purple/red and yellow/gold.

• Why You Should Take It: Turns out, your mom was right when she urged you to eat your beets. The betalains in beets help synthesize nitric oxide, which in turn increases the blood flow to your muscles. The final result is more energy to expend on keeping your legs moving.

If Your Workouts Need a Jolt of Energy

Branched-Chain Amino Acid (BCAA)

• What It Is: BCAAs comprise three amino acids: leucine, isoleucine, and valine. They're found in high-protein food sources, such as beans, eggs, and meats.

• Why You Should Take It: These amino acids can help keep fellow amino acid tryptophan—yes, the stuff that makes you feel sleepy on Thanksgiving—from entering the brain. This helps prevent the brain from recognizing fatigue, which can keep you going during workouts.

Caffeine Anhydrous

• What It Is: Simply put, it's dehydrated caffeine. You can find it in pill, tablet, or powder form.

• Why You Should Take It: Plenty of athletes extol the energy-spiking virtues of coffee before a workout, and caffeine anhydrous works the same way. But it can do more than just keep you from yawning your way through a workout at the end of your day: it's also been known to decrease the pain felt in muscles during exercise, and it can boost your endurance, too.

Vitamin B12

• What It Is: Vitamin B12 is one of eight B vitamins found in the body. It's essential in every cell's metabolism, and it's involved in the synthesis of fatty acids.

• Why You Should Take It: It's arguably one of the most important vitamins for your body when it comes to energy; a shortage of B vitamins leads to a shortage of the body's version of fuel, ATP. Since B12 is found in foods like cheese, shellfish, eggs, and poultry, using a B12 supplement or injection can be especially helpful for vegans or vegetarians.