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Stim vs Non-Stim Pre-Workout (Which One Should You Take?)

Isaac Robertson
Published by Isaac Robertson
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: September 26, 2022

Many of my fitness clients swear by pre-workouts that contain caffeine and other stimulants, believing there is no other way to get the laser focus and energy necessary for their workouts.

Others are sensitive to stimulants and look for effective non-stim pre-workouts that will give them the equivalent energy and focus.

I feel this was an important topic to research for my clients, so after reading countless online articles and consulting our dietician, I have outlined the main differences between stimulant and non-stimulant pre-workout.

Quick Summary

  • Caffeine is the most common stimulant in pre-workouts, usually the equivalent of 1-3 cups of coffee.
  • Green tea extract paired with caffeine may be more effective at helping you lose fat than just one of the ingredients on its own.
  • Non-stimulant pre-workouts take a different route to boost energy, like improving blood flow.

Stimulant Versus Non-stimulant Pre-Workout

Top view of a stimulant powder

The main difference between stim and non-stim pre-workout is the stimulant content or the lack thereof, and there are many options on the market for both kinds.

Since the most common stimulant in these products is caffeine, non-stimulant pre-workout is usually aimed at those who metabolize caffeine slowly or are sensitive to it.

Caffeine is not the only stimulant to look for on the label, though.

Some other ingredients you may find on the label include guarana, theobromine, green tea extract, and Yohimbe.

Stimulants increase the levels of certain chemicals in the brain, which translates to increased alertness, attention, energy, and physical activity.

Stimulants also raise blood pressure and increase heart and breathing rates [1].

Whether you choose a non-stim pre-workout or one with stimulants often boils down to personal preference, time of day you work out, and sensitivity.

Let’s take a look at the benefits of each.

3 Benefits of Stimulant Pre-Workouts

A stimulang powder lying on the floor

As previously stated, caffeine is the most common stimulant in pre-workouts, and for a good reason.

1. Improves Energy and Focus

Caffeine enhances exercise aerobically and anaerobically by improving focus, energy, and endurance [2].

Stimulants like caffeine block the brain’s adenosine receptors, keeping the neurotransmitter adenosine levels low. High levels of adenosine are responsible for feeling sleepy, so blocking those receptors keeps you energized and alert.

Research shows that stimulants may improve reaction time and delay fatigue, which are necessary factors in enhancing exercise performance [3].

If stimulant intolerance does not play a role, these pre-workouts are great for boosting energy for workouts earlier in the day.

2. Helps Burn Fat

One meta-analysis shows caffeine intake for fat loss might promote weight, BMI, and body fat reduction [4].

Since stimulants give you an energy boost, they can also potentially allow for a high-intensity workout and increase the total caloric burn.

Green tea extract is often paired with caffeine in pre-workout supplements for its thermogenic properties and added fat-burning benefits [5].

3. Suppresses Appetite

A woman not in the mood to eat

Along with increasing energy, burning fat, and giving you laser focus, stimulants found in many pre-workout supplements may suppress your appetite.

Again, while working with caffeine, green tea extract plays a role in suppressing appetite, which, combined with exercise, aids weight loss [6].

Remember the formula for weight loss: calories burned need to be greater than calories taken in, so appetite suppression properties keep this formula optimized for weight loss.

“Green tea extract contains caffeine and catechins, which can boost metabolism, burn fat, and aid weight loss. Combining green tea extract with other ingredients may decrease appetite levels and reduce food intake.”

-Arlene Semeco, MS, RD.

4 Benefits of Stim-Free Pre-Workouts

A healthy person doing exercise outdoors

Non-stim pre-workouts are not worthless just because they lack a stimulant. These pre-workouts simply work differently to enhance exercise performance, like increasing blood flow.

1. No Jitters or Crashes

The massive kick of energy from caffeine or other stimulants is great until you crash hard, leading to headaches, decreased alertness, mood changes, and fatigue [7].

Using a non-stim pre-workout eliminates the crash and jitteriness many users experience, detracting from their workout efforts.

2. Enhancing Blood Flow

Many non-stimulant pre-workouts focus on enhancing nitric oxide production and promoting vasodilation which will increase blood flow, delivering necessary oxygen and nutrients to hard-working muscles.

Increasing blood flow during exercise leads to better pumps, more energy (without the stimulants), and reducing fatigue [8].

3. Contains Nootropics

Smart drugs in a container

Nootropics, also referred to as “cognitive enhancers” or “smart drugs,” can help improve focus and allow you to push through intense exercise [9].

Interestingly, creatine, known for increasing muscle growth, also has cognitive benefits [10].

Other nootropic supplements to look for are choline, alpha-GPC, and lion’s mane.

4. Promotes Working Out Any Time of Day

Let’s face it, not all of us thrive in the morning, including working out. Other times, our schedules may force us to work out later in the day.

With non-stim pre-workout, you don’t have to worry about what time of day you exercise and have trouble sleeping.

4 Best Stimulant Ingredients

A scoop of stimulant powder

Again, caffeine is the most common energy-boosting ingredient in stimulant pre-workouts. Let’s look closely at other stimulants you may find on the pre-workout label.

1. Guarana

Guarana comes from the seeds of a South American tree that researchers once thought the stimulant effects came from a chemical that was specific to that tree, but they learned that Guarana has a high concentration of caffeine, containing up to 3.6% to 5.8% caffeine by weight.

Coffee only has up to 2%.

2. Theobromine

Theobromine is a stimulant and bronchodilator found in chocolate.

The primary benefit of theobromine is its bronchodilator properties, which will increase lung capacity, making breathing easier during exercise [11].

3. Green Tea Extract

Green tea extract on a small plate

Green tea extract offers the same benefits as caffeine, like suppressing appetite, increasing workout intensity, and reducing stress [12].

Because green tea extract as a pre-workout contains caffeine. When reading the label, you should take note of all the caffeine content in a serving; it adds up quickly.

4. Yohimbe

Yohimbe is the chemical found in the bark of the Yohimbe tree, an evergreen native to Africa. Yohimbe as a pre-workout is best known for its aphrodisiac properties [13].

Using Yohimbe for fat loss stimulates the body’s “fight or flight” system, which releases adrenaline (epinephrine) and noradrenaline (norepinephrine).

The release of these chemicals makes you more alert, raises body temperature, and increases blood pressure, leading to increased fat burning [14].

Keep in mind, in addition to stimulants, many of the best non-stim ingredients we talk about next can and should be found in stimulant pre-workouts for their benefits to muscle pump, recovery, muscular endurance, and blood flow.

6 Best Non-Stim Ingredients

Pouring a Non Stimulant powder inside water

Without the benefits of stimulants, you should look for the following ingredients in non-stimulant pre-workout formulas.

1. Creatine

Creatine offers a lot of value as a pre-workout ingredient.

Though there has long been a question about its safety, research shows it is not only safe but effective and popular as a pre-workout supplement.

Research shows creatine may [15]:

  • Help muscle cells produce more energy.
  • Promote muscle mass
  • Improve high-intensity exercise performance
  • Improve brain function
  • Reduce fatigue

“Supplementing with creatine provides additional ATP energy, which improves high-intensity exercise performance.” -Rudy Mawer, MSc, CISSN.

2. Citrulline

Citrulline enhances nitric oxide production.  Nitric oxide is a vasodilator, allowing more oxygen and nutrients to get to the muscles.

More oxygen means better muscle pumps, lower blood pressure, and reduced muscle soreness, which boosts exercise performance [16].

3. Glycerol

Glycerol, like citrulline, can also promote muscle pumps but does so by flooding your muscles with water and is found to benefit both aerobic and anaerobic exercise [17].

4. BCAAs

Two BCAA inside a small scoop

The three branched-chain amino acids are leucine, isoleucine, and valine.

BCAAs for pre-workout is essential for muscle growth and recovery, reduce fatigue and prevent muscle breakdown [18].

5. Betaine

Betaine derived from beets is a popular pre-workout supplement addition because research shows it improves body composition and increases muscles, work capacity, and power [19].

6. Beta-alanine

Beta-alanine may promote the production of carnosine in the muscles.

Higher carnosine levels may boost athletic performance by increasing muscular stamina and delaying fatigue [20].

Does Stim-Free Pre-Workout Work?

Yes, stimulant-free pre-workout can work to enhance athletic performance because they may still improve focus and boost energy; they just take a different avenue to do so than caffeine.

A formula of ingredients that will potentially increase energy levels, improve blood flow, and allow you to push longer without stimulating your central nervous system can work for many people who prefer not to consume stimulants or are sensitive to stimulants.

Learn More: 5 Ways to Boost Energy Before Workout (Based on Science)

FAQs

Should I Cycle Off Stimulant-Free Pre-Workout?

You should cycle off stimulant-free pre-workouts, which holds true for any supplement because, over time, your body adapts to the ingredients, and the pre-workout may lose effectiveness.

How Long Does Non-Stimulant Pre-Workout Last?

How long non-stimulant pre-workout lasts depends on the ingredients, but most effects last two or three hours after consumption.

Which One Is for You?

Only you can decide between stimulant pre-workouts or non-stimulant pre-workouts based on your personal preference, fitness goals, and tolerance.

If you work out late, have a sensitivity to stimulants, or simply prefer not to consume them, check out our guide on stim-free pre-workouts that proved to be effective workout boosters as well.

However, most people can tolerate stimulants fine, having no adverse effects from the massive energy boost. We’ve also tried and tested some great stim pre-workouts for pump, so check them out to find the one that is tailored to your needs.


References:

  1. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/central-nervous-system-stimulant
  2. https://jissn.biomedcentral.com/articles/10.1186/s12970-020-00383-4
  3. https://www.sciencedaily.com/releases/2021/12/211201085155.htm
  4. https://pubmed.ncbi.nlm.nih.gov/30335479/
  5. https://pubmed.ncbi.nlm.nih.gov/10584049/
  6. https://www.healthline.com/nutrition/10-natural-appetite-suppressants
  7. https://www.healthline.com/nutrition/caffeine-crash
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666933/
  9. https://www.webmd.com/vitamins-and-supplements/features/nootropics-smart-drugs-overview
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093191/
  11. https://www.sciencedirect.com/topics/medicine-and-dentistry/theobromine
  12. https://www.livestrong.com/article/401200-will-green-tea-before-a-workout-burn-more-fat/
  13. https://www.webmd.com/vitamins/ai/ingredientmono-759/yohimbe
  14. https://pubmed.ncbi.nlm.nih.gov/17214405/
  15. https://www.healthline.com/nutrition/10-benefits-of-creatine
  16. https://www.healthline.com/nutrition/nitric-oxide-supplements
  17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3590833/
  18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212987/
  19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3844502/
  20. https://www.webmd.com/vitamins-and-supplements/beta-alanine-uses-and-risks

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