Not quite feeling the gym today? Wish that you could take the day off and just veg out on the couch instead? Everybody has days where they just aren't feeling it. That's one reason why supplements were created! 

Sports nutrition products can help you build muscle, gain endurance, and add strength. They can also just give you the energy you need to close the chip bag, get on your gear, and hit the Smith machine. 

So, if it's an energy boost you're after, look for these ingredients. 


Topping the list is the ingredient most people are very familiar with: caffeine. Caffeine acts on your central nervous system to give you both physical energy and mental focus, which can translate into better concentration and drive in the gym. 


It can also help you burn more fat by releasing more fatty acids from fat cells, leading to weight loss. And, studies have shown that caffeine improves total exercise endurance levels and increases the total level of energy burned from fat fuel sources.[1]

Of course, consuming too much caffeine can over stimulate your central nervous system and actually make you tired. And, over time, your body can adapt to caffeine, meaning it will take more to produce the same energy boost. 


Next up is citrulline, sometimes in the form of citrulline malate. Found in the juicy red center of watermelon, citrulline acts as a vasodilator by increasing levels of nitric oxide in your system. Arginine is generally considered as the main nitric oxide prerequisite, but much of the arginine you ingest doesn't make it into your bloodstream due to digestive enzymes known as arginases. Citrulline, however, makes it to the bloodstream with great bioavailability where it is then converted into arginine so it can cause that great pump that we all love!

If it's endurance you're after, this just might be the ingredient for you. In one study, people who took 8 grams of citrulline supplement were able to complete 53 percent more repetitions on the test exercises than when they took a placebo. Those who took the citrulline also noticed a 40-percent decrease in muscle soreness both 24 and 48 hours after the training session.[2]


Looking for an energy booster designed to help kick-start your workout? Try synephrine. This adrenergic amine can increase your energy and, like caffeine, increase your body's ability to break down and burn fat. 


Also like caffeine, synephrine stimulates the central nervous system—but it doesn't increase heart rate or raise blood pressure as much as caffeine does. If you're caffeine-sensitive but like the buzz, synephrine might be the one for you. 

Also sold as "bitter orange," this ingredient works by stimulating beta-3 receptors in your body, which then speed up the breakdown of stored body fat. Many people also notice that their appetite is blunted when they use synephrine, further helping with fat loss. 

Some people take it a step further and use synephrine with caffeine for an extra kick. Be forewarned, though: Two things stimulating your central nervous system at once can lead to anxiety, insomnia, and poor digestion.

Green Tea Extract 

If you like the benefits of caffeine but want a little more out of your energy booster, try green tea extract. Green tea (as well as the extract) naturally contains caffeine and plant compounds called catechin polyphenols. Both of these substances help burn fat. 

Green Tea

In a study published in the American Society for Clinical Nutrition, three groups of people were given either a green tea extract (containing 50 mg caffeine and 90 mg of catechin polyphenols), or just 50 mg of caffeine, or just a placebo. The group that used green tea extract expended 4 percent more energy over a 24-hour period than the other groups. This group also had higher levels of the hormone norepinephrine, which helps the body burn fat.[3]


Rounding out the list of potential energy boosters is yohimbe. Yohimbe comes from the bark of a tree, and gets converted into yohimbine inside your body. 

This ingredient works as an Alpha-2 receptor antagonist. While the biochemistry can get a little messy, this means that it increases the amount of norepinephrine in the system through the restriction of a mechanism that would normally inhibit its release. This, among other stimulatory actions, causes systemic increases in blood pressure through vasoconstriction. 

Studies have confirmed that yohimbe may also increase the amount of energy you burn when exercising, as well as your overall metabolic rate—both of which improve your ability to lose weight.

  1. Costill, D. L., Dalsky, G. P., & Fink, W. J. (1977). Effects of caffeine ingestion on metabolism and exercise performance. Medicine and Science in Sports, 10(3), 155-158. 
  2. Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. The Journal of Strength & Conditioning Research, 24(5), 1215-1222. 
  3. Dulloo, A. G., Duret, C., Rohrer, D., Girardier, L., Mensi, N., Fathi, M., ... & Vandermander, J. (1999). Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. The American Journal of Clinical Nutrition, 70(6), 1040-1045.

About the Author

Shannon Clark

Shannon Clark

Shannon Clark is a freelance health and fitness writer located in Edmonton, Alberta, Canada.

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