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The Ultimate Guide to Preworkout Supplements – Part 2


Get pumped: We’re continuing our breakdown of the top 15 preworkout supplements. Read part 1 here.


Carnitine is an amino acid that contributes to heart, muscle, and brain function. Besides providing benefits for athletic performance, it acts as an antioxidant in the body, removing harmful free radicals that accelerate signs of ageing and disease. Carnitine plays an important role in fat oxidation–the process by which the body converts fat into energy. (x)

Increase energy

Though it’s not yet clear exactly how carnitine improves exercise endurance, research suggests that through the fat oxidation process, carnitine increases levels of ATP, a substance that provides energy for your body during high-intensity activity. (x)

While prolonged low-intensity workouts don’t have much of an effect on carnitine levels in your muscles, high-intensity workouts lasting only 10 minutes can decrease carnitine by about 40%, which could make you feel tapped out mid-set. (x) Supplementing with carnitine may give you the energy you need to work out longer and harder. One study found that it prolonged the amount of time muscles resisted fatigue by 25%. (x)

Delay muscle soreness and fatigue

Carnitine may also reduce levels of lactic acid, a substance responsible for that trademark burn you feel in your muscles when you’re on your last few reps. (x) That burn is good news–it means you’re working your muscles to their max, which is what gives you results–but it also leads to fatigue (and fewer reps). Taking carnitine before you hit the gym may reduce fatigue, meaning you can work out longer and harder.


A water-soluble nutrient related to B vitamins, choline aids in nerve signaling, detoxification, and fat and cholesterol metabolism. (x) (x)

Choline and betaine for athletic performance

Choline is a precursor of betaine, which itself is a precursor of carnitine–and if you’ve been reading this list (of course you have), you know by now that carnitine gives you an energy boost in the gym. (x) Because it’s linked to betaine and carnitine, choline’s benefits are similar: it stimulates fat burning, may lead to improved body composition, and could improve your athletic endurance and performance.


If you’ve been weight training, you’ve most likely heard of creatine. As one of the most widely-studied nutritional supplements, it has plenty of research to back up its numerous training benefits. Here’s the lowdown on a bodybuilder’s best friend.

What is it?

Creatine is a substance found naturally in muscle cells that is similar to amino acids (the amino acids glycine and arginine can produce it). Its primary role is to give muscles energy during workouts by increasing the amount of ATP in the body.

Improve athletic performance

Creatine is most effective at maximizing high-intensity exercise capacity because it boosts ATP levels. Here’s how it works: explosive workout movements like jumping and sprinting deplete ATP after only about 10 seconds, leaving you fatigued and unable to push yourself further. (x)

But taking creatine increases its concentration in your muscles by 15-32%, meaning improved ATP availability and energy levels for better endurance and performance. One study found that creatine improved athletic performance by 10-15%, and strength by up to 15%. (x) In another study, 19 resistance-trained men were given either creatine or a placebo over the course of a 12-week workout program. At the end of the 12 weeks, those who supplemented with creatine increased their bench press weight by 24% and their squat weight by 32%, while the placebo group increased weight by 16% and 24% respectively. (x) Another study found that taking creatine before working out increased bench press volume by up to 43%. (x)

Build muscle and lean body mass

Creatine’s muscle-building powers come from its ability to reduce myostatin, a protein that can inhibit muscle growth. (x) When taken before exercise, it may increase muscle by up to 35% and lean body mass by 6%. (x) Participants taking creatine in one study gained almost twice the amount of lean body mass over a 4-12 week period than those who took a placebo. (x)

Dream team

Research suggests that taking creatine and beta-alanine together may enhance their benefits. Read more about creatine and beta-alanine supplementation here.

Note: Avoid taking creatine with caffeine, as it may cause unwanted side effects like anxiety, stomach upset, and dehydration. Some studies suggest that caffeine and creatine may counteract each other when taken together, so save coffee for breakfast and creatine for your workout.


Found in foods like watermelon, cucumbers, garlic, and legumes, citrulline is a nonessential amino acid (the body produces it on its own). It’s a precursor to arginine. (x)

Improved endurance

Citrulline removes ammonia and lactic acid buildup in the body, both of which cause fatigue and burnout during exercise.  In doing so, citrulline may increase the length of time athletes are able to exercise until exhaustion. (x) A study of 18 men who took citrulline for 15 days found that the supplement had improved their aerobic energy during exercise. (x)

Taking citrulline two hours before working out may also improve the body’s use of amino acids–ideal for building and maintaining muscle. (x)


There are two types of citrulline supplements: pure citrulline and citrulline malate, which includes an added compound called malic acid.

Malic acid is found in many fruits and vegetables. It may increase energy during exercise and benefit athletic performance.

Participants taking citrulline malate in one study increased the number of their bench press reps by more than 50%. The benefits didn’t stop in the gym: supplementation also decreased post-workout muscle soreness by 40%. (x)

So which form of citrulline should you take? It’s your call–some people prefer plain citrulline, while others like the added energy boost of citrulline malate. Experiment with all of these supplements to find out which one works best for your body, and always consult with your doctor before starting any supplement routine.

Stay tuned for Part 3, and read Part 1 here.

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Casey Eade

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