Pre Workout On Empty Stomach: Is It Good or Bad?

  • By Patrick Dougherty
  • 12 minute read
Taking Pre-Workout on an Empty Stomach: Good or Bad? A young athletic man is drinking pre-workout before exercising on the beach.

Thinking about taking pre-workout on an empty stomach? If you’re doing fasted training or simply don’t like to eat before training, you may have wondered if this practice is effective… or if it will send you running to the bathroom in the middle of your workout.

For those who prefer not to take pre-workout on an empty stomach, considering a pre workout meal might be beneficial.

The reality is, you can take pre-workout on an empty stomach and get some great results, as long as you choose the right ingredients and supplements.

In this article we explain how to take a pre-workout on an empty stomach for maximum performance without digestive issues, side effects or risks. Let’s get to it!

Key Takeaways

  • Taking pre workouts on an empty stomach may offer some advantages for athletes – but proceed with caution to avoid unpleasant side effects or even risks.

  • Avoid pre-workout formulas with megadose caffeine, artificial additives and sweeteners known to cause gastric distress, especially when taken on an empty stomach.

  • The best pre workout supplements for taking on an empty stomach may combine low-to-moderate dose caffeine, circulation-boosters and nootropics in ultraclean, high-quality formats.

  • If you choose to use a pre-workout supplement on an empty stomach, consult with your doctor, consider starting with a lower dose, monitor how you feel, and be sure to hydrate.

  • Pre Lab Pro® is the top pre workout formula to take on an empty stomach, as well as the best pre workout for early morning fasted training sessions.

  • Caffeine 2™ (caffeine pill) and MCT Energy Oil can also be taken as pre workout formulas; their clean design equates to excellent comfort and tolerability on an empty stomach.

  • Some athletes may prefer a pre workout meal instead of taking pre workout on an empty stomach.

Why Take a Pre Workout on Empty Stomach?

Why take a pre-workout on empty stomach? A woman is scooping pre-workout powder in preparation for her training session.

So can you take pre workout on an empty stomach?

Yes, if you take some precautions. In fact, taking pre workout supplements on an empty stomach can be a good strategy, depending on your lifestyle and fitness goals. Comparing this with having a pre workout meal, the choice depends on individual preferences and how your body responds to each approach.

Some potential benefits include:

  • Absorption: Active ingredients in pre-workout supplements are absorbed faster on an empty stomach, potentially leading to amplified effects that come on sooner.

  • Fat Burning: Exercising on an empty stomach, especially with moderate stimulation from a pre-workout plus MCT oil, may increase the body’s ability to burn fat as fuel.

  • Convenience: Some people just don’t like eating before a workout. But they still want the benefits of a pre-workout supplement, as long as it doesn’t give them any kind of gastric distress.

  • Fasted training enhancement: Fasted trainers can give their performance a boost with a pre-workout supplement. But they must take care to choose one that doesn’t break their fast.

Here’s the problem: If you take pre workout supplements on an empty stomach the wrong way, you will end up in the bathroom instead of on the treadmill. Let’s consider some concerns related to taking the wrong pre-workouts on an empty stomach:

  • Gastrointestinal Issues: Pre-workout supplements can cause stomach upset, nausea, diarrhea, and cramps, especially when taken without food to buffer their effects.

  • Risk of Hypoglycemia: Taking megadose stimulant-driven pre-workouts without eating can lower blood sugar levels, which may cause dizziness, shaking, fatigue, and poor performance.

  • Stim problems: Caffeine is way more intense on an empty stomach, with side effects like jitters, anxiety, heart palpitations, and high blood pressure. It may disrupt sleep too, which in turn impairs recovery and limits lean muscle mass growth.

The key to pre-workouts for fasted training is to take the right ingredients, appropriately dosed.

Let’s move on to some ingredients in pre-workouts that are safe, comfortable and effective when taken on an empty stomach.

Then we will talk about some pre-workout supplements that include them in good doses across the board.

Pre-Workout Ingredients to Take on an Empty Stomach

Not all pre-workout supplements and ingredients are great on an empty stomach, as many exercisers have found out the hard way.

The best pre-workout supplement ingredients for fitness enthusiasts who want to train on an empty stomach include the following:

Caffeine (Low-to-Moderate Dose)

Caffeine (low-to-moderate dose) can be taken on an empty stomach before training. Coffee beans are shown.

Many pre-workout supplements will supply caffeine. And with good reason: Researchers believe that as an ergogenic, caffeine can help sharpen alertness, delay fatigue, improve endurance, boost workout power and more in the gym.(1)

Consuming caffeine on an empty stomach before working out is generally okay for most people. It absorbs fast this way -- so you can a quick boost to your energy levels as soon as you hit the gym.

However, some people might experience stomach upset, acid reflux, or jitters when they consume caffeine without food. Caffeine intake also has a mild diuretic effect; more so on an empty stomach.

Tip: Go with "smart caffeine" formulas: low-to-moderate dose caffeine with helper nutrients that keep your workout energy balanced and calm. And be sure to stay well-hydrated throughout your session!

Learn more about smart caffeine pills for pre-workout use


L-theanine, found in the green tea pictured here, can mitigate caffeine side effects and sharpen gym clarity. It’s an ideal empty stomach pre-workout.

If you're taking caffeinated pre-workout on an empty stomach, you should consider taking L-theanine too.

This amino acid found in green tea can help to enhance caffeine benefits while taking the edge off caffeine jitters, which may be more pronounced if it is taken on an empty stomach.(2)

L-Theanine also helps improve focus and mental clarity while reducing stress -- an ideal cognitive combination for crushing it at the gym.

L-theanine does not typically cause side effects, even when taken on an empty stomach. It’s non-sedative, too -- it calms the nervous system but won’t make you sleepy during your workout.

L-Citrulline + L-Glutathione (as Setria)

L-Citrulline + L-Glutathione (as Setria) is a pre-workout for circulation. Watermelon, a natural source of citrulline, is shown.

L-Citrulline + L-Glutathione combination is so popular among athletes, bodybuilders, and exercisers because it increases production of nitric oxide (NO).(3)

By promoting synthesis of NO, a signaling compound that relaxes blood vessels and boosts blood flow, L-citrulline unleashes the prized "muscle pump" that helps enhance performance, including muscle strength and power.

Setria Performance Blend is a patented blend of these two pre-workouts. It's a good pre-workout for an empty stomach because it has been well-researched in clinical trials and widely used, demonstrating muscle-building, performance-enhancing benefits without side effects.


L-Tyrosine powder.

Tyrosine is a dual-powered nootropic/ergogenic amino acid that helps make neurotransmitters like dopamine, norepinephrine, and epinephrine that regulate cognition, mood, and stress responses. It is found in pre workouts, as well as in performance-driven brain supplements.

Benefits associated with L-Tyrosine include intensified physical performance and mental sharpness under stress (like high-intensity exercise). Research suggests it may enhance exercise under adverse conditions, such as cold or heat.(4)

L-Tyrosine is actually absorbed faster and more efficiently on an empty stomach, making it a great nutrient for enhancing workouts and ultimate lean muscle growth.

Learn more about how L-Tyrosine works


Cross sections of beetroot slices. Beetroot can be taken pre-workout on an empty stomach.

Beetroot nitrates convert into nitric oxide: a compound that helps widen blood vessels and increase blood flow.(5)

Enhanced circulation allows more oxygen and nutrients to reach the muscles during training sessions, potentially improving stamina and performance.

Studies have also shown that nitrates enhance the efficiency of mitochondria, the energy-producing powerhouses of cells. This means that muscles can produce more energy with the same amount of oxygen, which is great for endurance sports.

When consumed on an empty stomach, the nitrates in beetroot juice can be absorbed more quickly into the bloodstream, making it an efficient pre-workout boost for exercise performance. It's also clean, safe, natural and easy to digest. It even tastes pretty good!

MCT Oil (Medium-Chain Triglycerides) with C8+C10 MCTs

MCT Oil (Medium-Chain Triglycerides) with C8+C10 MCTs can boost workout energy. Split coconuts are shown.

If you're into intermittent fasting, fasted training, keto dieting, or general fat loss, MCT oil is a must-have supplement.

MCT (medium-chain triglyceride) oil is a fast-acting energy fuel source. Researchers have suggested it enhances exercise endurance by boosting cells' mitochondria powerplants.(6)

Plus, MCT oil doesn't disrupt body fat burning and may help with weight loss by encouraging breakdown of stored fat (instead of catabolizing lean mass) during exercise.

But even though they provide a clean energy boost, you have to be extra careful when taking MCT supplements on an empty stomach -- especially before working out.

Here's the rub: MCTs are usually sourced from coconuts. Because it contains all four MCTs (C6 Caproic Acid, C8 Caprylic Acid, C10 Capric Acid, C12 Lauric Acid) including the C6 and C12 that will often cause diarrhea and digestive system irritation if taken on an empty stomach before your training session.

If you want to take MCT pre-workout for fasted training, be sure to take it as C8 (caprylic acid) and C10 (capric acid) sourced from organic coconuts to minimize digestive side effects.

Learn more about MCT oil supplements

Pre-Workout Ingredients to Avoid on an Empty Stomach

Many pre-workout supplements are best avoided on an empty stomach.

Why? Primarily because they can create gastric distress that interferes with gym performance.

Some empty stomach pre-workout ingredients to avoid include:

  • Creatine: A top sports nutrient, but it can cause cramps or bloating on an empty stomach -- especially during the high-dose loading phase. Post- workout creatine is considered superior, especially combined with a protein shake.

  • Baking soda (in large doses): Effective for buffering lactic acid, but too much on an empty stomach can lead to stomach cramps, nausea, and diarrhea. Not good side effects for working out!

  • Arginine: One of the amino acids, it boosts nitric oxide levels, it can disrupt the gut when taken in high doses on an empty stomach. We prefer Setria Performance and beetroot for nitric oxide enhancement.

  • High amounts of Caffeine: High doses of caffeine (like in most pre-workout supplements!) on an empty stomach can lead to jitters, heart palpitations, and upset stomach.

  • High-Glycemic Carbs: Some pre-workouts have sugars. On an empty stomach, they can rapidly spike blood sugar (and energy) followed by a crash that kills your workout.

All of these pre-workout ingredients are decent choices... just not on an empty stomach.

Consuming a small snack or ensuring you're hydrated can sometimes help to reduce any adverse effects.

Top Pre-Workout Supplements to Take on an Empty Stomach

Now that we've covered some ingredients that are safe, comfortable and effective to take without food, let's check out some top sports supplements that supply them.

Best Pre Workout to Take on Empty Stomach: Pre Lab Pro®

Best Pre Workout to Take on Empty Stomach: Pre Lab Pro. Tub is shown surrounded by a splash of delicious red berry flavored drink.

Pre Lab Pro® is a nootropics-enhanced pre-workout formula that is safe and comfortable to take on an empty stomach -- perfect for fasted training. It's also the best pre-workout for early morning training sessions.

The “world’s smartest pre-workout nutrition”, it is designed for sharp cognitive function and better strength, power, endurance, energy and more. Ingredients:

  • Red Beetroot Powder, 1500 mg

  • Setria® Performance Blend, 2200 mg

  • Natural Caffeine, 80 mg

  • L-Theanine, 160 mg

  • L-Tyrosine, 400 mg

  • NutriGenesis® vitamins & minerals

    • Vitamin D3, 500 iu

    • Potassium, 49.5 mg

    • Iron, 2.5 mg

    • Riboflavin ( Vitamin B2) 500 mcg

    • Vitamin B6, 750 MCG

    • Folate (Vitamin B9), 167 mcg DFE

    • Vitamin B12, 2 MCG

  • Himalayan Pink Salt, 500 mg

Pre Lab® Pro key features:

  • Great for aerobic or resistance training or aerobic; endurance, strength, power, and speed

  • Perfect pre-workout for morning workouts: clean, natural, convenient and easy to absorb

  • Promotes focus, concentration, intensity and calmness during workouts

  • Clean energy: 80 mg caffeine + 100 mg theanine = no jitters or crashes

  • Supplies natural electrolytes to help with hydration, energy and mental clarity

  • Stress support to help you stay balanced before, during and after your workout

  • No artificial sweeteners, colors or flavors. Natural berry flavor.

How to take: To take your pre workout, add a single scoop to ¾ of a pint (300 ml) of water. Mix in a shaker bottle into a delicious berry flavored drink (no artificial flavors). No blender necessary. Drink 15-30 minutes before workout, on an empty stomach if desired.


Performance Lab® MCT Energy Oil

Performance Lab MCT Energy Oil. Bottle shown amidst split coconut pieces.

Performance Lab® MCT Energy Oil is fast brain fuel. Its C8/C10 medium-chain triglycerides (MCT) are rapidly absorbed and broken down into ketones, which fuel production of cell energy.

Ingredients: Purified C8+C10 MCTs (medium-chain triglycerides) from 100% organic non-GMO coconuts. Per tablespoon: 8.6 g C8 MCT (Caprylic Acid); 4.2 g C10 MCT (Capric Acid).

Performance Lab® MCT Energy Oil is a high-quality brand: super clean, made from 100% organic coconuts and sport-tuned with high-performance C8/C10 MCTs, only.

This is an important advantage. Other MCT oils may use C6 and C12 MCTs, too... even though they are more associated with gastric distress that can interrupt your workout and limit your performance.

You can add MCT to coffee, soups, salads, shakes and smoothies, or simply take it straight. Take it to get a clean boost of mind-body vitality you can feel fast while you are working out.


Performance Lab® Caffeine 2™

Performance Lab® Caffeine 2. Bottle is shown on its side with capsules spilling out.

Coffee may not be the best pre-workout caffeine source because it can sometimes cause digestive issues in the gym. That's where a good caffeine pill enters the picture.

Caffeine 2 presents an ultramodern new take on the typical “caffeine pill." It delivers greater mental (and athletic!) performance benefits in a clean format that is healthy and comfortable for daily use, even when taken on an empty stomach.

Ingredients: Natural Caffeine (from Coffea robusta seeds), L-Theanine, L-Tyrosine, NutriGenesis® Caffeine Balance B-Complex.

What gym goers get with this formula is sport-tuned stimulation: Surging energy levels, mental clarity, extended workout time and greater intensity without agitation, indigestion, crashes and overstimulation.

It's also customizable with precision-dose caffeine. Need extra energy? Pop another cap and get an addition 50 mg. Keep adjusting until you find your performance peak.



Can you take pre-workout on an empty stomach? In short, yes. Taking pre-workout supplements on an empty stomach can provide benefits such as faster absorption and more pronounced benefits for exercise performance.

These effects can potentially help you enhance exercise performance, build muscle mass, protect muscle from protein breakdown and optimize body composition.

However, if you choose to take pre-workout on an empty stomach first thing in the morning (or any other time of day, really), you should be aware of possible risks.

The practice may lead to gastric distress, increased sensitivity to stimulants, and other side effects like hypoglycemia during prolonged or intense workouts. Especially if you’re using inferior pre-workout formulas.

To minimize potential negative effects, it’s advisable to start pre workouts with a lower dose to test tolerance. If you upset your stomach taking pre workout fasted, stop immediately and talk to your doctor. Even better, consult a healthcare provider before getting started.

Ultimately, personal experimentation and awareness of one’s own body responses are key in determining the best approach to pre-workout supplementation. Some individuals may prefer a pre workout meal to avoid potential side effects of taking pre workout on an empty stomach.

  1. Giráldez-Costas V, Del Coso J, Mañas A, Salinero JJ. The Long Way to Establish the Ergogenic Effect of Caffeine on Strength Performance: An Overview Review. Nutrients. 2023 Feb 27;15(5):1178. doi: 10.3390/nu15051178. PMID: 36904177; PMCID: PMC10005568.

  2. Dodd, F. L. et al. “ A Double-Blind, Placebo-Controlled Study Evaluating the Effects of Caffeine and L-Theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood.” Psychopharmacology 232.14 (2015): 2563–2576. PMC. Web. 1 Oct. 2016.

  3. McKinley-Barnard S et al. Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis. J Int Soc Sports Nutr. 2015; 12: 27.

  4. Tumilty L, Davison G, Beckmann M, Thatcher R. Oral tyrosine supplementation improves exercise capacity in the heat. Eur J Appl Physiol. 2011 Dec;111(12):2941-50. doi: 10.1007/s00421-011-1921-4. Epub 2011 Mar 25. PMID: 21437603.

  5. Domínguez R, Cuenca E, Maté-Muñoz JL, García-Fernández P, Serra-Paya N, Estevan MC, Herreros PV, Garnacho-Castaño MV. Effects of Beetroot Juice Supplementation on Cardiorespiratory Endurance in Athletes. A Systematic Review. Nutrients. 2017 Jan 6;9(1):43.

  6. Wang Y, Liu Z, Han Y, Xu J, Huang W, Li Z. Medium Chain Triglycerides enhances exercise endurance through the increased mitochondrial biogenesis and metabolism. PLoS One. 2018 Feb 8;13(2):e0191182. doi: 10.1371/journal.pone.0191182. PMID: 29420554; PMCID: PMC5805166.