Pre-workout mixes, powders, or drinks are a great way to increase energy levels, gain motivation and begin your routine.

Because of the caffeine and other ingredients on some brands, though, you may experience pre-workout side effects. 

From moderate to severe, these side effects can be debilitating and even prevent you from working out properly.

So what are the side effects of pre-workout products, and how can you limit or get rid of them? That is exactly what we will uncover in the guide below.  

Pre-workout supplements, energy boosters, and performance boosters can have many side effects. These will vary between individuals, and you may experience one or none of them.

If you notice anything different about yourself after taking a supplement, the below guide may be able to help. 

1. Insomnia 

Most supplements designed for pre-workout ingestion contain a lot of caffeine. The equivalent of up to four cups of coffee per scoop is not uncommon (and some have more!)

Those of you that wake up early to work out before getting ready for the rest of the day may not notice any effects. 

However, for those that find the time to work out late at night, after a full day at work and getting the kids to bed, you may have a harder time falling asleep.

This form of insomnia is known as caffeine induced insomnia. It can be mild or severe, depending on your existing sleeping habits.[1]

Caffeine will stay in your system, giving you energy boosts for up to 8 hours (though this is cut in half with a rigorous workout).

If you take a pre-workout at 9 pm and plan to be in bed by 11 pm or midnight, will pre-workout keep you awake? Yes, you may lay awake for a few hours instead of sleeping. 

How To Prevent:

There are two methods to use a supplement and get a full night's sleep.

If insomnia is a side effect you observe, you can read labels carefully and stay away from any pre-workout powders that use caffeine. 

Or, you can take the supplement much earlier in the day, even if you still work out later.

pre-workout side effects

2. Diarrhea 

Whether or not we want to admit it, many of us have a sensitive stomach. If this is the case, a lot of supplement ingredients can send you running to the bathroom shortly after drinking.

Caffeine and creatine are the two most prominent ingredients that have a laxative effect. However, you need to understand your body and the full list of ingredients on your product labels. 

For example, Yohimbe, arginine, and sodium bicarbonate are also laxative-like when consumed in large doses. That isn't all, though; more sensitive stomachs can also develop the sudden urge to go with magnesium and taurine, too. It can be quite difficult to find a pre-workout without any or all of these ingredients, though. 

How To Prevent:

If pre-workout makes you poop, the best defense here is to dilute your pre-workout even more. Adding more water will help disperse the ingredients and slow their reaction time down in the body.

Drinking water during the workout and even throughout the day will all but eliminate this side effect completely.

3. Dehydration 

Muscle support and recovery are big aspects of workout supplements, including pre-workout options.

Many of the ingredients are designed to absorb water for various reasons. If your pre-workout has a weight loss claim, that is typically water weight. Creatine, though, is the largest water absorbent of any of the ingredients.

Its main job is to take water from body parts not in use and carry it to the muscles being worked out for better hydration and faster recovery. 

By doing this, though, you can experience some level of dehydration. The good news is that this typically only affects you when you first start taking the supplement.

After a few doses, your body adjusts and handles the water movement much better. In rare cases, though, it can get severe or last much longer than expected. 

How To Prevent:

To combat this, you can either cut back on the amount of pre-workout you use, find a brand that doesn't use creatine.

But, the best option is to drink plenty of water throughout the day.  

4. Headaches 

In direct relation to dehydration, headaches are another side effect of water leaving the body.

When you become dehydrated, the water layer around your brain becomes thinner, and your brain can come into physical contact with your skull resulting in a headache. 

However, this isn’t the only cause. Some ingredients in pre-workouts will act as vasodilators. Vasodilation is a wanted effect by some workout enthusiasts.

It causes the blood vessels to expand all over your body, even the brain. When this happens, it can give you a headache. 

How To Prevent:

To combat this side effect, you can drink more water throughout the day or find pre-workouts that do not contain arginine, citrulline (malate), or beta-alanine.

Another option is to cut back on the amount of pre-workout you use until you are adjusted to the ingredients. 

5. High Blood Pressure 

High blood pressure is one of the health conditions that you may not even know about. This is part of what makes it so dangerous.

If you are already suffering from high blood pressure or have an underlying condition, a pre-workout with a stimulant added (like caffeine) can trigger a high blood pressure episode. 

How To Prevent:

If you are unsure, or if high blood pressure runs in your family, it is always advised to see a doctor before you begin a workout or pre-workout supplement regimen.

That aside, you can avoid those that contain stimulants like caffeine until you know for sure. 

how to get rid of pre-workout side effects

6. Tingles Or Prickle Sensation 

One of the most common side effects of a pre-workout supplement is a tingly sensation. This can occur on your neck, face, back, hands, or feet (or all of them).

This is a side effect of niacin (vitamin B3), but beta-alanine also has some impact. This itchy, tingly feeling is caused by a condition known as a niacin flush. It causes small blood vessel dilation, or skin flushing.

This can cause redness, patchy skin, and the tingly pins and needles feeling in your extremities. The good news is that this is a central nervous system reaction to new ingredients.

The biggest reason it is used is because it triggers at about the same time the rest of the ingredients are absorbed, so you know "it is working." 

Without the niacin, you may wonder if you are feeling the effects of the supplement or not. This reaction, though, is harmless and will subside in a few minutes. After several doses, you won't get the feeling anymore.

How To Prevent:

While it isn't painful, it can be bothersome for many gym-goers. If this is you, you will want to find a supplement that doesn't contain vitamin B3 and doesn't have pre-workout tingles.

Drinking more water to dilute the niacin is also helpful.

Keep in mind that for almost all users, the effect is made noticeable with 500mg of niacin or more, so you can also avoid higher doses of niacin and still get the benefits. 

Related Article - Why Does Pre-Workout Make Me Itchy?

7. Anxiety & Jittery Feelings 

The old culprit, caffeine, is back at it again. With large doses of caffeine come a lot of side effects.

However, this varies based on a lot of factors. Your own personal level of consumption, underlying conditions, and even age, height, and weight come into play. 

One of the lesser felt side effects of caffeine is anxiety. You can get anxious or nervous when consuming too much caffeine, which can take hours to dissipate.

If you take a pre-workout with high levels of caffeine and don't consume caffeine regularly, you may have increased heart rate, sweating, and anxious feelings from pre-workout. 

How To Prevent:

This will pass, but to help, it is advised to drink more water, lessen the amount of pre-workout you take, or find a caffeine-free option. 

Likewise, caffeine can also make you jittery. From a feeling of unrest to full-on leg bouncing, nervous hands and twitching, pre-workout jitters can make you uncomfortable. 

Again, this is primarily due to the dosage levels, and lowering the intake quantity can help reduce these symptoms. 

8. Nausea 

As covered before with diarrhea, those same components can cause digestive upset that doesn’t result in the rush to a nearby restroom.

Instead, you can get stomach pangs, tightness in your belly, and feelings of nausea. 

Caffeine and creatine are the major offenders once again, but you should also check the label for magnesium and sodium bicarbonate.

Both act as laxatives but, in smaller doses, can cause stomach upset and the feeling that you will vomit. 

How To Prevent:

While most pre-workouts have stopped using sodium bicarbonate for this reason, it is still around. The best defense is not to use pre-workouts with these ingredients. However, that can be hard to avoid. 

Second best is to drink more water throughout the day and mix your powder with more water. The dilution will help eliminate the nauseous feelings. 

Related Article - Best Pre-Workout Substitutes

side effects of pre-workout

What Are The Long Term Effects Of Taking Pre Workouts?

Long term effects are still being debated, and studies are constantly changing. The majority of findings, though, is that pre-workout supplements have no significant, long-lasting side effects on healthy, active individuals.[2]

Those of a very young age, the elderly, and women who are pregnant or nursing, though, may have more severe short-term side effects (as outlined above).

Another study conducted by Andrew Jagim et al. found that of those that regularly consume pre-workout supplements, about 54% reported some form of side effect.[3For long-term concerns, though, the results seem to be fairly low. There are two ingredients to be wary of, though, when it comes to long-term use.

Caffeine ingestion can play a role in heart-related diseases and issues, though most reports come from those with underlying or unknown conditions. 

Another is for niacin and beta-alanine. These are the ingredients that cause the skin flushing and tingly feelings when consumed (more than 500gm per day). While the short-term effects subside on their own in about an hour, there may be long-term complications.[4]

Because the effects are the result of a central nervous system and neurological condition, it is under scrutiny for long-term effects. Currently, nothing significant has been reported, but only time will tell. 

pre-workout side effects long term

Popular Pre-Workout Brands And Their Side Effects

Almost all pre-workout brands will have some side effects.

This is because you are introducing a concentrated amount of stimulants, vitamins, additives, and rest of the ingredients into your system at one time. This will not go unnoticed by your body. 

In most cases, the side effects are mild, temporary, and expected. However, some brands have a higher risk than others.

Some of the best pre-workout brands (based on sales and popularity) are the C4 series from Cellucor and the Six Star brand for its affordable pricing. Both of these, however, have very low levels of caffeine and other notable ingredients, so they're both ineffective and basically side effect-free.

On the other hand, brands like Psychotic, Lit AF, Woke AF, and I AM God, give you plenty of energy to take on your workout. Unfortunately, they also contain a lot of caffeine, magnesium, and beta-alanine, which can cause anxiety, digestive issues, and headaches. 

The Total War brand, as well as BAMF, are also considered as some of the brands that have the most side effects.

Now, disregarding the above-mentioned ineffective ones, pre-workouts bound to cause you the least amount of problems are clean, well-dosed formulas, like the ones from Transparent Labs. Whether you go for their Stim-Free or regular pre-workout, you're likely to experience a nice, gradual influx of energy, followed by minimal adverse effects.

Finally, with proprietary blends, you never know exactly how much of an ingredient is included, other than the fact that the ingredient listed first is the most abundant one.

With brands like these - you're best to look the other way. Nine times out of ten, the results aren't there, but we can't say the same for side effects.

Common Pre-Workout Side Effects Questions

Is pre-workout bad for your liver? 

Yes, there is a risk of liver damage if pre-workouts are taken in high doses or daily. With the barrage of ingredients taken all at once, the liver can have a hard time breaking them down and filtering them properly. This will result in creating higher liver enzymes, which can lead to further complications and eventual liver disease. 

Can pre-workouts cause loss of appetite? 

Yes, some pre-workouts have shown instances of reduced appetite due to the BCAAs included. While these are critical building blocks for muscles, they also help your brain regulate food intake levels and give you the "feeling of being full." While this is a temporary condition until the BCAAA levels are normalized, it can cause hunger-related issues for several days while your body adjusts. 

Can pre-workouts give you a fever? 

With niacin and beta-alanine rushes and skin flushing, you can develop fever-like symptoms from pre-workout. While you won't have an actual fever and your core temperature will remain steady, the flushed feeling and skin rush can make you feel hotter to the touch. 

What is a good replacement for pre-workouts? 

The best replacement for pre-workout is a solid diet. Eating the right food, in the right amounts, at the right times will give you all the benefits of a pre-workout on a daily basis, without the need for extra consumption or shots of post-mix powders. 


There is a lot of concern, especially with new users, about the side effects of pre-workout supplements. The powder mixes and drinks can contain a lot of ingredients that might affect you in certain ways. 

While almost all of the symptoms can be minimized or eliminated with cautious use, time to adjust, or drinking more water, there is still cause for concern.

If you plan to start using pre-workouts for your routine, it is important to know the possible side effects as outlined in this guide so you can better prepare for them. 



Miloš Lepotic

Miloš Lepotic

Meet Miloš, a certified sports nutritionist and self-taught supplement expert whose pharmacological background and nearly a decade of gym experience make him the perfect guide for optimizing your health and athletic performance through supplement reviews and practical advice rooted in factual, science-backed information.