Pre-workout supplements have become increasingly popular.

Advocates claim that they can improve your fitness and give you the energy you need to power through challenging workouts.

However, many experts say that they’re potentially dangerous and wholly unnecessary.

This article tells you everything you need to know about pre-workout supplements, including whether they’re good or bad for your health.

Pre-workout supplements — sometimes referred to as “pre-workouts” — are multi-ingredient dietary formulas designed to boost energy and athletic performance.

They’re typically a powdered substance that you mix in water and drink before exercise.

While countless formulas exist, there’s little consistency in terms of ingredients. Amino acids, B vitamins, caffeine, creatine, and artificial sweeteners are often included, but quantities can vary widely depending on the brand.


Pre-workout supplements, which are powdered and mixed with water, are advertised to improve athletic performance and energy prior to exercise. However, there’s no set list of ingredients.

Research on the effectiveness of pre-workout supplements is very limited. Nonetheless, some studies suggest that certain ingredients may benefit athletic performance (1).

Nitric oxide precursors

Nitric oxide is a compound your body naturally produces to relax blood vessels and improve blood flow.

Some of the common compounds that your body uses to make nitric oxide are included in pre-workout supplements. These include L-arginine, L-citrulline, and sources of dietary nitrates, such as beetroot juice (2).

A few small studies suggest that supplementing with these compounds boosts oxygen and nutrient transport to your muscles, potentially enhancing athletic performance (2).

Yet, as most of the available research on nitric oxide focuses on young men, it remains unclear whether these results apply to other groups. More research is needed.


Caffeine is frequently used in pre-workout supplements to increase energy and focus.

One of the most popular stimulants, caffeine may improve mental alertness, memory, exercise performance, and fat burning (3, 4).


Creatine is a chemical compound naturally produced in your body. It’s primarily stored in skeletal muscle, where it plays a role in energy production and muscular strength (5).

It’s often included in pre-workout formulas but also sold as a standalone supplement. It’s particularly popular among weightlifters, bodybuilders, and other power athletes.

Research suggests that supplementing with creatine can increase your body’s stored supply of this compound, thus helping improve recovery time, muscle mass, strength, and exercise performance (5).


Certain ingredients in pre-workout supplements, such as creatine, caffeine, and nitric oxide precursors, have been shown to support athletic performance.

Although pre-workout supplements are generally safe, they aren’t completely risk-free (1).

If you’re thinking about adding them to your workout regimen, be sure to consider their potential downsides first.

Artificial sweeteners and sugar alcohols

Pre-workout supplements frequently contain artificial sweeteners or sugar alcohols.

While they enhance flavor without adding calories, some sweeteners may cause intestinal distress and discomfort in some people.

In particular, high intake of sugar alcohols may trigger uncomfortable symptoms, such as gas, bloating, and diarrhea — all of which can disrupt your workout (6).

Some people report a similar digestive response from eating certain artificial sweeteners like sucralose. However, such symptoms haven’t been scientifically proven (7).

You may want to avoid pre-workout formulas that contain large quantities of these sweeteners. Otherwise, try a small amount first to see how you tolerate it.

Excess caffeine

The major energy-boosting element of most pre-workout supplements is caffeine.

Excessive intake of this stimulant can lead to negative side effects, such as increased blood pressure, impaired sleep, and anxiety (8).

Most pre-workout formulas contain about as much caffeine as you’d get in 1–2 cups (240–475 ml) of coffee, but if you’re also getting this compound from other sources throughout the day, it might be easy to accidentally consume too much.

Supplement quality and safety

In some countries, including the United States, dietary supplements are not closely regulated. Therefore, product labels can be inaccurate or misleading.

If supplement safety and quality are compromised, you may inadvertently consume banned substances or dangerous amounts of certain compounds (1).

To ensure safety, only buy supplements that have been tested by a third party, such as NSF International or USP.


Certain ingredients in pre-workout supplements may lead to negative side effects. Always check the ingredient label before purchasing and opt for products tested by a third party.

Pre-workout formulas aren’t for everyone.

If you frequently lack energy or have difficulty making it through your workout, you shouldn’t automatically resort to supplements.

Adequate hydration, sleep, and diet are essential for any exercise routine to optimize your energy levels and help repair your muscles.

Moreover, the variability in ingredients of pre-workout supplements makes it difficult to determine their effectiveness.

They can also be expensive — and research hasn’t proven them to be more effective than whole foods that provide the same nutrients. For example, a banana and a mug of coffee is a suitable, cheap, and accessible alternative to a pre-workout supplement.

That said, if you find that pre-workout formulas work for you, there’s no reason to stop. Just be mindful of their ingredients and your total intake.


Studies do not reliably show pre-workout supplements to be effective. Notably, they cannot replace a balanced diet, quality sleep, and adequate hydration. If you prefer to use one anyway, be conscientious about its ingredients and your total intake.

Pre-workout supplements are primarily used to enhance physical performance and energy, but research doesn’t back many of their supposed benefits.

Although certain ingredients may boost your results, there’s no standardized formula and several potential downsides.

To fuel your workout, choose nutritious, energy-boosting foods like bananas and coffee instead.

However, if you prefer taking a pre-workout formula, it’s best to check its ingredients and opt for supplements certified by a third party.

Above all, make sure you’re getting a balanced diet, plenty of water, and sufficient sleep.