7 Pre-workout Ingredients to Avoid And Why

Benedict Ang, CPT, PN1-NC
Published by Benedict Ang, CPT, PN1-NC | Staff Writer & Senior Coach
Last updated: January 11, 2024
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Being in the fitness industry for so long, I often get my hands on pre-workout formulas with highly questionable supplement-fact panels.

While it’s difficult to recommend the best pre-workout (since it depends on preferences), it’s not hard to tell what formulas to avoid, thanks to their shady ingredients list.

I collaborated with a nutritionist and a doctor to identify harmful ingredients commonly found in pre-workouts.

Quick Summary

  • Avoid pre-workout supplements with harmful ingredients such as yohimbe, DMAA, p-synephrine, and aminoisophetan to prevent potential health risks.
  • Choose pre-workouts with natural or tested artificial sweeteners and colors to minimize the risk of adverse effects.
  • A 2019 survey found that half of the top 100 pre-workout supplements contained proprietary blends, which can obscure the quantity and quality of their ingredients.
  • Personally, I believe that the best pre-workout is one with transparent labeling and scientifically backed ingredients that safely enhance performance.

What Pre-workout Ingredients Should You Avoid?

Close up shot of a scoop of pre-workout powder

Ingredients you should avoid in pre-workout are those with purported impressive and potent effects that, under the surface, carry a risk of unpredictable side effects due to the lack of scientific evidence and testing.

Those pre-workout ingredients primarily refer to yohimbe, DMAA, p-synephrine, and aminoisophetan. Let’s get into more detail.


I've seen yohimbe included in numerous pre-workout mixes, touted for its blood flow and fat loss benefits. From my own trial with a yohimbe supplement, I felt a noticeable uptick in energy. Still, I also experienced some jitters and a rapid heartbeat, which made me cautious about the dosage.

Yohimbe made its way to many formulas because some evidence suggests it may increase blood flow and aid in fat loss [1].

In traditional medicine, this ingredient extracted from African evergreen tree bark is used for erectile dysfunction treatment in recommended doses ranging from 5.4 to 10 milligrams three times daily [2].

In excess doses, yohimbe might induce side effects like anxiety, hypertension, and tachycardia - but it’s still part of proprietary blends where the exact ingredients or the amount is unknown [3].

Related: Does Yohimbe as a Pre-Workout Work?


DMAA is an FDA-banned substance known under the names of 1,3 - dimethylamylamine, methylhexanamine, or geranium extract, and it definitely earned its place among the pre-workout ingredients to avoid.

According to the FDA, ‘DMAA can raise blood pressure and lead to cardiovascular problems ranging from shortness of breath and tightening in your chest to heart attack’ [4].

Although it increases blood pressure and heart rate, several companies somehow still manage to make DMAA pre-workout because of its ability to boost performance and exercise capacity.


P-Synephrine graphic with a workout bottle and weights in the background

An ingredient called p-synephrine, also known as synephrine, bitter orange peel, or citrus aurantium, is used as a substitute for banned ephedrine due to its similarities with this banned substance.

Since it can affect muscle endurance, especially when combined with caffeine, you can see it on some pre-workout ingredient labels or even fat-burner formulas, as it may also impact fat oxidation [5]. Some potential side effects include migraines, nausea, dizziness, and hypertension.

According to the National Center for Complementary and Integrative Health, ‘there is currently little evidence that Bitter orange is safer to use than Ephedra’ [6].


Originally used as a drug for nasal congestion, DMHA (also known as dimethylhexylamine or octodrine) is nowadays used in pre-workouts as a central nervous system stimulant that boosts training performance enhances weight loss, and burns fat [7].

It’s often referred to as a legal upgraded substitute for DMAA since it provokes similar effects but suppresses appetite and improves cognitive functions.

However, it lacks evidence for safe use and may as well cause health implications similar to DMAA, like anxiety, rapid heartbeat, and high blood pressure [8].

Artificial Sweeteners and Colors

Pre-workouts often include these to enhance taste, but they may not contribute to the product's effectiveness. However, you should know that some sweeteners and artificial flavors may be harmful.

A 2012 study suggests that specific artificial sweeteners like acesulfame-potassium, aspartame, or sucralose can cause issues like weight gain, bowel disease, and even leukemia [9].

Unfortunately, similar issues surround artificial food dyes, as some studies show they can impact people with ADHD [10].

For all these reasons, you should choose dietary supplements that contain natural or more tested types of artificial sweeteners or colors.

High Caffeine Contents

Coffee beans with the chemical caffeine graphic

The Journal of the International Society of Sports Nutrition notes caffeine's benefits in pre-workouts, but warns against excessive amounts due to varied tolerance  [11].

How much caffeine in a pre-workout serving is too much depends on your caffeine metabolism and tolerance. The FDA recommends not exceeding 400 mg of caffeine daily, equal to 4-5 cups of coffee [12]. However, some supplements exceed this, risking health problems like anxiety, jitters, and high blood pressure [13].

To stay in a safe zone, opt for those that have doses within the range of daily recommendations or you can try caffeine-free pre-workouts.


Obscure brands often deceive by bulking up products with cheap, ineffective ingredients, creating a false impression of quality due to quantity.

Additives like maltodextrin, a nutritionally empty carb, can cause inflammation and digestive problems.

Increasing caffeine content serves a similar purpose; though it appears beneficial, excessive amounts are more harmful than helpful.

Other Things You Should Avoid

A woman mixing preworkout

Avoid pre-workouts with unknown or ineffective ingredient dosages.

Proprietary Blends

Proprietary blends in supplements mix all ingredients, obscuring individual dosages. A 2019 survey found half of the top pre-workouts use these blends [14], as companies hide under-dosed ingredients to reduce costs and increase profits.

Manufacturers aren't required to disclose each ingredient's dosage; the FDA only mandates listing the total blend weight and ingredients by descending weight order.

However, proprietary blends are often misleading, with potentially unsafe or ineffective ingredient doses.

Inadequate Ingredients Doses

In the era where online and clinical studies are accessible to everyone, it’s quite an easy task to choose a product that contains clinically effective dosages of ingredients, as anything else would be a waste of money.

Therefore, always opt for formulas that have scientifically-proven pre-workout ingredients in adequate amounts to get the most out of the product.

What Ingredients Should You Look For?

Close up shot of pre-workout powder

Ingredients you should look for in a pre-workout are:

  • Beta-alanine
  • Creatine Monohydrate
  • Caffeine
  • L-citrulline
  • BCAA (Branched-chain amino acids)

Pre-workout ingredients with proven benefits include beta-alanine, creatine monohydrate, caffeine, L-citrulline, staples in top brands. Beta-alanine, an amino acid, may enhance muscle endurance and lower fatigue in 2-5 grams daily doses [15].

Creatine monohydrate, safe and well-researched, is advised in 3-5 grams per day. Known for muscle mass gain, it also improves strength and performance in pre-workouts [16].

“With creatine, not only has it built a solid reputation among lifters and many other types of athletes, but the science backing it as a legit performance enhancer is robust and pretty consistent. With over 2,000 studies, it’s the most effective performance-boosting supplement out there.”

- Douglas Kalman, PhD., RD

Caffeine, a common pre-workout ingredient, boosts physical and cognitive performance by stimulating the central nervous system [17].

L-citrulline is an amino acid that can increase blood flow and widen blood vessels affecting the pump during the workout [18]. L-citrulline effective doses range from 3 to 10 grams [19].

BCAAs, three essential amino acids, regulate blood sugar and alleviate muscle soreness, making them popular in pre-workouts [20].

What Benefits do Pre-workouts Provide?

A person in the gym lifting weights

Pre-workouts offer several benefits, including increased energy, improved blood flow, and enhanced focus during workouts, making them valuable for challenging exercises.

Regular, moderate use lets ingredients like creatine accumulate, reducing fatigue over weeks.

Also, if you compare pre-workouts vs energy drinks, these formulas have specific ingredients designed to get you through your training and usually don’t contain empty calories.

However, consult a doctor before using stimulants if you have health conditions or take medication.


What Is The Most Effective Ingredient in a Pre-workout?

The most effective ingredient in a pre-workout is caffeine. Proper caffeine intake can improve your overall performance, keep you focused, and give you energy - the essential benefits a formula should provide. Usually, formulas contain caffeine doses ranging from 150-300 mg per serving, equal to three cups of coffee.

What Ingredients in Pre-workout Make You Crash?

An ingredient in pre-workout that makes you crash is caffeine. High doses of caffeine cause profound inhibition of adenosine (a substance responsible for energy transfer inside the body), leading to improved energy, performance, and focus.

However, when caffeine starts to fade, previously inhibited adenosine starts overflowing and causes sudden tiredness, irritability, and inability to concentrate.

What Does Taurine Do in Pre-workout?

In pre-workout, taurine may enhance focus, reduce oxidative stress, improve muscle contractions, aid in hydration, and promote blood flow. Its effectiveness varies among individuals and supplements, so consulting a healthcare professional before use is advisable.

What Does L-theanine Do in Pre-workout?

In pre-workout, L-theanine can help promote focus, reduce caffeine-related jitters, and improve mood, creating a balanced workout experience.

Can You Take Vitamin C as a Pre-workout?

Although you can take Vitamin C before a workout, is not a typical pre-workout supplement because it does not directly enhance exercise performance. Pre-workout supplements are specifically formulated for energy, focus, and muscle support. Vitamin C is important for overall health but not as a pre-workout booster.

Can You Take Turmeric Before Workout?

Yes, you can take turmeric before a workout. Turmeric contains an active compound called curcumin, which has anti-inflammatory and antioxidant properties. Some people take turmeric or curcumin supplements before exercise to potentially reduce exercise-induced inflammation and muscle soreness.

Is Maca Pre-workout Effective?

Yes, maca pre-workout is effective. As an adaptogen, maca may help the body better manage stress, potentially improving workout resilience and recovery. It also contains vitamins, minerals, and amino acids, which can support overall health and may aid in physical performance.


  1. https://www.sciencedirect.com/science/article/abs/pii/S0306987701914598
  2. https://www.sciencedirect.com/science/article/abs/pii/S0163725801001565
  3. https://www.nccih.nih.gov/health/yohimbe
  4. https://www.fda.gov/food/dietary-supplement-ingredient-directory/dmaa-products-marketed-dietary-supplements
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573476/
  6. https://www.sciencedirect.com/science/article/abs/pii/S0278691508002226
  7. https://www.mdpi.com/2076-3425/8/2/34
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5836053/
  9. https://pubmed.ncbi.nlm.nih.gov/23097267/
  10. https://pubmed.ncbi.nlm.nih.gov/21729092/
  11. https://jissn.biomedcentral.com/articles/10.1186/s12970-016-0138-7
  12. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
  13. https://pubmed.ncbi.nlm.nih.gov/2321541/
  14. https://pubmed.ncbi.nlm.nih.gov/30678328/
  15. https://pubmed.ncbi.nlm.nih.gov/18992136/
  16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5469049/
  17. https://pubmed.ncbi.nlm.nih.gov/31618910/
  18. https://pubmed.ncbi.nlm.nih.gov/27749691/
  19. https://pubmed.ncbi.nlm.nih.gov/26023227/
  20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7126259/
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About The Author

Benedict Ang, CPT, PN1-NC
Staff Writer & Senior Coach
Benedict Ang, CPT, PN1-NC is an ex-National Soccer player turned MMA and Kickboxing champion, with ACE CPT and PN1-NC certifications. His advice is rooted in education and experience, ensuring that readers receive scientific and battle-tested insights. His mission is to empower his clients and readers to realize their potential and become the best versions of themselves.
Learn more about our editorial policy
Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
Learn more about our editorial policy

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