Side Effects of Pre-Workout Supplements [How to Avoid Them]

Updated on  February 26, 2023
William Toro

Published By:  William Toro

Fact Checked by: Bridget MacDonald, RDN

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Pre-workout supplements have become an integral part of athletic lifestyles.

This is due to the ability to either increase performance, improve strength, or achieve the desired level of muscle mass.

Nevertheless, these stimulant-based pre-workouts can carry serious side effects that should be duly considered before implementation.

So, let's take a closer look at pre-workout side effects.

Pre-Workout Side Effects



Pre-workout supplements often contain stimulants such as caffeine. It can cause anxiety or insomnia in some individuals. [1]

If you are taking pre-workouts and experiencing insomnia then it is best to stop using them. The stimulants are likely the culprits. Try switching to pre-workout supplements that do not contain caffeine or any other stimulants.

If you stop taking pre-workouts but still can't sleep, you should speak to your doctor. The doctor may perform a medical diagnosis to determine the cause of insomnia and prescribe medications as needed.


Anxiety and nervousness

Some people may also experience a feeling of nervousness and increased heart rate when ingesting pre-workouts. Although not all individuals will experience this side effect, it may be induced by consuming too much caffeine in the supplement. [2]

If you find that you’ve had an adverse reaction to a pre-workout supplement such as feeling jittery or experiencing anxiety then consult your physician immediately to rule out serious medical conditions such as high blood pressure or heart disease.



The ingredients in many supplements are known to cause dehydration, which can lead to weight gain due to increased water retention.

The natural compound ingredient creatine may also lead to increased water retention. Studies show that creatine may cause water retention, which can contribute to weight gain. [3]

To avoid the side effects of these compounds and keep your body hydrated and healthy, try drinking more water throughout the day.


Itching sensations

You might experience some tingling or itching sensations in the skin, face, throat, ears, or lips. These are often caused by the beta-alanine found in the pre-workout supplements.

For detailed explanation you can have a look at Why does pre workout itches?

Beta-alanine helps to temporarily relieve muscle soreness. However, some people experience itching or tingling when they take beta-alanine. [4]

Allergic reactions to beta-alanine are rare, but they may occur. If you find this issue, then you can try to take the pre-workouts without beta-alanine.


Digestive upset

This is a sign of a condition known as “heat injury” which can be caused by some common ingredients found in these supplements including high caffeine content, sodium bicarbonate, and magnesium. [56]

If you’ve been taking a pre-workout supplement and have experienced stomach pain or diarrhea, then you should stop taking it immediately.

You should also consult your doctor if you experience any new symptoms after starting the supplement.



Headaches are one of the most common side effects of pre-workout supplements. The cause of the headache isn't necessarily the pre-workout supplement you're taking, but rather, it's usually because you're not getting enough water in your diet and your body.

Pre-workout supplements require a lot more water than 30 minutes before their use to get appropriate levels within your body. This is because the body needs water to "flush" out the creatine or other ingredients that are used in most pre-workout supplements.

If you're feeling a headache that you believe is from a pre-workout supplement, try drinking more water.

If it doesn't help, leave the product out of your diet for a week and see how you feel. You might notice that your headache disappears or lessens if you do not take the pre-workout supplement any longer.


High Blood Pressure

High blood pressure is a long-term issue that can cause serious health problems, the most common of which is heart disease.

Although many factors contribute to high blood pressure, one contributing factor involves certain pre-workout supplements.

If you have high blood pressure and are considering taking a pre-workout supplement, please weigh the possible risks against the potential benefits before doing so. Talk to your doctor about what might be best for you. They will also be able to provide ongoing care if necessary.

How to Avoid Pre-Workout Side Effects?

The most important thing to remember when taking any pre-workout supplement is to follow the recommended serving. If you are given a specific dose per two scoops or scoop, always adhere to the suggested amount.

Taking more than the suggested amount will increase your risk of experiencing side effects. Furthermore, it may be wise to start with a smaller dose of caffeine when using pre-workout supplements in general to gauge your tolerance.

If you experience adverse reactions on the first few days of using a pre-workout supplement, then you should discontinue use altogether.

Additionally, if you are already taking medication for high blood pressure or heart disease it may be wise to discuss the use of pre-workout supplements with your physician in advance. If you are taking other medications then consult with your physician before taking a pre-workout supplement to determine whether it's safe for you to use.

What Is In Pre-Workout Supplements?

Pre-workout supplementation is a big industry, with many people using them to enhance their workouts. But what are the side effects of these supplements? And how do they work? Let's take a quick look at some popular ingredients in pre-workout supplements.


Caffeine is the most common stimulant used by humans. It stimulates brain activity and increases alertness and energy levels, making it useful for both exercising and studying. However, too much caffeine can cause jitters. Also, caffeine can cause headaches or nausea when you work out or study hard. [7]


Beta-alanine reduces feelings of fatigue during exercise, giving you more efficiency and endurance for your workout. Beta-alanine has a major side effect: tingling on the skin, and itching in the first 30 minutes after ingestion. This is because beta-alanine causes your body to produce more carnosine, which is a substance that makes your muscles contract harder. This substance also gives your sweat and urine a decidedly unpleasant odor. [8]


Athletes use supplements with creatine to increase muscle mass and strength. Creatine improves muscle strength and endurance by helping your muscles produce more ATP, which encourages optimal muscle function. The body converts creatine to creatine phosphate, which is stored in the muscles as energy to improve exercise performance. [9]

Related post: Best Pre-Workouts With Creatine

Citrulline Malate

Citrulline malate is an amino acid that's found in citrulline, a substance produced by your body during exercise. Citrulline increases the flow of amino acids into your muscles to build new proteins, which could improve muscle endurance. Citrulline also encourages your body to release lactic acid at a faster rate during exercise so that lactic acid levels decrease faster after exercise. [10]

Beta-Phenylethylamine HCL

Like other stimulants, beta-phenylethylamine increases alertness and energy levels. Unlike most stimulants, it can calm your nerves and relieve anxiety. It's not currently approved by the FDA to treat any conditions. [11]

Pyridoxal phosphate

Pyridoxal phosphate also works as a muscle relaxant. It's used to treat muscle diseases such as muscular dystrophy and is approved by the FDA to treat high blood pressure. [12]

Other ingredients in pre-workout supplements that increase alertness or energy levels include Niacin, L-tyrosine, Bacopa Monnier, Yohimbe, caffeine anhydrous, picamilon, and synephrine.


Some people take supplements before a workout to increase energy or build muscle, but they could have undesired effects.

The side effects of pre-workout supplements include increased heart rate, anxiety, and muscle cramps. In some cases, the supplements can also cause nausea, appetite loss, and digestive issues.

There are also risks that certain ingredients in pre-workout supplementation could trigger a heart attack or stroke if not used correctly. These pre-workout side effects can be avoided through proper use of these substances to gauge whether they may be beneficial to a person's physical well-being.

William Toro

William Toro ‧ CPT & Nutritionist

William is a certified personal trainer from NASM, he has also been a rehab physiologist for sports persons. He has more than 15 years of experience training people. And has featured in multiple publications like FoxNews, CNBC, Bustle, and other. 


1. Danielle Pacheco, Dr. Nilong Vyas, Caffeine and Sleep, retrieved from
2. Diogo R. Lara, Caffeine, mental health, and psychiatric disorders, retrieved from
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4. Qin Liu, Parul Sikand, Chao Ma, Zongxiang Tang, Liang Han, Zhe Li, Shuohao Sun, Robert H. LaMotte, Xinzhong Dong, Mechanisms of Itch Evoked by β-Alanine, retrieved from
5. Mayo Clinic, Sodium Bicarbonate (Oral Route, Intravenous Route, Subcutaneous Route), retrieved from
6. Katherine Zeratsky, R.D., L.D., I've heard that magnesium supplements have health benefits. Should I take one?, retrieved from
7. WebMD, Caffeine, retrieved from
8. WebMD, Beta-Alanine, retrieved from
9. WebMD, Creatine, retrieved from
10. WebMD, L-citruline, retrieved from
11. WebMD, Phenethylamine (Pea), retrieved from
12. WebMD, Melatonin 2.5 Mg-Pyridoxal Phosphate(Vit B6) 338 Mcg Sublingual Tablet Hypnotics, retrieved from

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