Best Zero Calorie Pre-Workout

Boost your fasted training results with a zero-calorie pre-workout stack

What’s your favorite pre-workout supplement?

Is it Fanta orange soda? A lemon cookie?

A literal spoonful of sugar?

After all, processed sugars do offer a reliable, fast-acting source of brain and body energy.

And isn’t the whole point of taking a pre-workout supplement to quickly energize and enhance exercise performance?

This seems to be the strategy taken by many overcaffeinated, sugar-sweet pre-workout supplement stacks.

However, long-term health and fitness isn’t sustained by short-term bursts of calorie-spiking energy.

Even zero-calorie pre-workouts that swap the sugars with artificial sweeteners threaten to derail your health and fitness, due to the link between artificial additives and metabolic imbalance.

The most effective pre-workout supplement works without relying on the short-sighted crutches of synthetic stimulants and artificial sweeteners.

Because, despite being calorie-free, synthetic stimulants/artificial sweeteners disrupt many of the metabolic advantages of exercising - namely exercising on an empty stomach (a.k.a. fasted training).

In this article, we not only explain how to convert your calories into lean, mean muscle mass...

...but we also provide a full analysis of the Best Zero Calorie Pre-Workout you can take without disrupting your exercise results, whether fasting or not.

Let’s start here: What are calories?

Technically, a calorie is a unit for measuring heat (energy). One calorie equals the amount of heat (energy) required to raise the temperature of one gram of water up one degree Celsius.

However, when we say we’re “burning calories” at the gym, we don’t mean that we’re trying to boil the water in our bodies.

Typically, in the context of exercise, burning calories means “burning fat.”

This is because, in dietary terms, a calorie measures the amount of energy that food produces in the body.

And if we consume an excessive amount of food calories, our body stores those calories as fat that we quite literally have to burn through physical activity—i.e., energy expenditure.

When energy intake exceeds energy expenditure, there is an increase in body mass, of which 60-80% is typically comprised of body fat.

Conversely, when energy expenditure exceeds energy intake, we see a decrease in body mass that’s similarly comprised of body fat at 60-80%.

So, one of the most popular ways to “burn fat” is to simply reduce energy intake—i.e., eat less.

Except there’s one problem with this method: it’s not sustainable in the long run.

For one, food isn’t solely a source of caloric energy.

Food also sustains our health and fitness by supplying various essential nutrients, such as vitamins, minerals, amino acids, beneficial oils, antioxidants, and many more bio-active constituents required for a healthy metabolism.

We need more than caloric energy to sustain a healthy, active lifestyle. Yet, caloric excess may contribute towards metabolic dysregulation.

And so, with that in mind, keep reading to learn how to reorganize your calorie intake to serve your fitness and not your fatness.

The 3-Step Plan to Convert Calories into Lean Muscle Mass

When energy intake is lower than energy expenditure, fat mass decreases. This is the simple formula for cutting fat.

However, life isn’t always so simple, now is it? After all, if our energy intake is consistently lower than our energy expenditure, then, well, eventually we’ll run out of energy, won’t we?

And don’t we need energy to—oh, I don’t know— survive?!?

A more sustainable approach to achieving a more desirable body composition requires a more sophisticated plan. With that in mind, here is the three-step plan to burn more fat and build more muscle in less time without totally burning out:

1. Step One: Metabolic Energy Balance – The first step is all about quantity. To build a fitter physique, it’s more effective to establish a metabolic balance between energy intake and energy expenditure than it is to simply decrease energy intake.
2. Step Two: Intermittent Fasting – The second step is all about timing. By scheduling when to intake energy (feed) and when not to intake energy (fast), intermittent fasting can help encourage the body to use stored energy to fuel exercise and to convert food energy into fuel for anabolic muscle growth and repair.
3. Step Three: Take a Zero-Calorie Pre-Workout – To sustain heightened levels of exercise endurance and intensity while fasting, you’ll need a pre-workout supplement that boosts performance without breaking your fast.

In this context, we recommend Pre Lab Pro® as the ultimate zero-calorie pre-workout for fasted training, providing clean, jitter-free energy, nitric oxide boosting, and muscle endurance support.

Let’s take a closer look at each step.

Step One: Metabolic Energy Balance

The truth is the relationship between energy balance and body composition is much more complicated than the oversimplified prescription of “eat less to look sexy.”

While excessive energy intake (eating too much) is a common barrier to many peoples’ health and fitness goals, an effective, long-term strategy for maintaining a fit physique focuses less on simply “eating less” than it does on seeking metabolic energy balance.

The basic components of energy balance include energy intake, energy expenditure, and energy storage. When energy intake equals energy expenditure, the body is in energy balance and body energy (typically measured as body weight) is stable.

In general, it’s better to achieve metabolic energy balance by increasing energy expenditure (exercise) than by reducing energy intake (food restrictions).

A fit, healthy physique isn’t maintained solely by food restrictions.

For one, by itself, decreasing calorie intake only has a limited, short-term influence on body composition, which explains the frustrating “yo-yo” effect of dieting that sees a harmfully cyclical loss and gain of weight over time.

Again, we need energy—not to mention nutrients. And if we fail to meet our bodies’ energy and nutrient demands, eventually we’ll exhaust ourselves and our cravings for energy-rich fats and sugars will bounce back with a vengeance, while our overall health gradually diminishes.

Instead, here’s what you should do: expend more energy through exercise to establish a healthier balance between energy expenditure and energy intake. Think in terms of “energy balance” rather than “calorie restrictions.”

As a result, your body’s metabolism will convert food energy more towards anabolic muscle growth and recovery than towards fat storage.

Step Two: Intermittent Fasting

Establishing a consistent circadian rhythm around a consistent schedule of sleeping, exercising, and eating may go a long way in optimizing your metabolism.

Sleeping at irregular bedtimes, exercising at inconsistent daytimes, eating at an unpredictable pace—this is fundamentally what it means to live in chaos.

And chaos is an impossible foundation upon which to build a healthy, active lifestyle.

One of the best ways to put your life (and, thus, your health) back in order is to adopt an intermittent fasting routine, which essentially involves prolonging the fasting intervals between scheduled mealtimes.

The emphasis on fasting is different from dieting in that you can consume as many calories and food types as you desire, so long as you do it within a specified time frame.

The point of intermittent fasting isn’t necessarily to limit daily calorie intake but rather to set limits on when to consume your daily calories.

Healthy metabolic regulation is strongly linked to a healthy circadian rhythm, which organizes our energy usage and storage around predictable, consistent sleeping, exercising, and eating schedules.

In a natural environment, food sources aren’t as widespread and easily accessible as they are in our fast food-lined streets. Intermittent fasting mimics the natural eating patterns of the natural world.

However, when combined with exercise, intermittent fasting is exceptionally conducive to fat burning, as the fasting body turns to stored fat for energy fuel (ketogenesis) in the absence of food fuel. Making intermittent fasting (or, specifically, fasted training) an effective tool for sculpting a desirable body composition.

Related Post: Best Nighttime Supplement for Muscle Growth

Is it Safe to Exercise on an Empty Stomach?

For the most part, yes—so long as you’re still meeting your heightened energy demands with adequate caloric intake ideally immediately after exercising. Because the body risks muscle catabolism (breakdown) and cognitive impairment while in a fasted state, it’s best to work out in the morning, and then to follow that workout up with a muscle-nourishing breakfast and protein shake.

Research suggests that fasted training in the morning may not only increase fat oxidation (fat burning) but also decrease energy intake throughout the day, as early-morning exercise encourages the body to rely more on stored fat for daytime energy fuel.

Step Three: Take a Zero-Calorie Pre-Workout

The last step is the easiest: take a zero-calorie pre-workout supplement such as Pre Lab Pro®.

Pre Lab Pro® is designed to enhance exercise performance without breaking your fast, providing clean energy, nitric oxide boost, and focus support.

While there are significant metabolic advantages to fasted training, there are also a couple compromises:

• Compromise #1: whereas fasted training encourages the mobilization of stored fat for energy fuel, eating before exercise may bolster exercise endurance.
• Compromise #2: despite the notable increases in anabolic growth factors that occur during the fasting period of intermittent fasting, fasting may exacerbate the usual protein breakdown that occurs while exercising.

Pre Lab Pro® supports endurance while protecting muscle tissue against the deleterious effects of fasting by priming muscle tissue with all-natural, clean performance enhancers that work without breaking your fast.

Shop Pre Lab Pro®

Top Zero-Calorie Pre-Workout Ingredients

1) L-Citrulline

Featured in Pre Lab Pro® as part of the Setria® Performance Blend, L-Citrulline is an effective pre-workout compound that converts to L-arginine, boosting nitric oxide (N.O.) for enhanced muscle circulation and power.

Unlike L-arginine, L-Citrulline is more bioavailable, bypassing the liver to convert to L-arginine in the kidneys, ultimately promoting N.O. production. This enhances blood flow, delivers oxygen and nutrients to muscles, and leads to that satisfying "muscle pump" effect.

In a clinical study on the combined effects of L-Citrulline and L-Glutathione (both present in Pre Lab Pro®), researchers observed increased lean mass and muscle strength after resistance training.(1) This makes Kyowa Quality® L-Citrulline an ideal N.O.-boosting ingredient for both aerobic and anaerobic performance, whether fasting or not.

2) L-Glutathione

Also featured in Pre Lab Pro® as part of the Setria® Performance Blend, L-Glutathione is a powerful antioxidant enzyme that bolsters stress resistance against oxidative stress and strengthens immunity against exercise-related pathogens.

Exercise, especially intense workouts, can lead to oxidative stress and muscle soreness, and L-Glutathione helps mitigate these effects. By supporting the body's natural antioxidant defenses, L-Glutathione reduces muscle fatigue and promotes recovery, meaning you’ll be ready to tackle your next workout.

Combined with L-Citrulline, L-Glutathione enhances nitric oxide production, leading to greater muscle pumps and increased exercise intensity, while also providing a protective antioxidant safety net for muscle tissue.

3) L-Theanine + Caffeine Blend

This blend combines the focus-enhancing effects of L-Theanine with the natural stimulation of caffeine.

L-Theanine, an amino acid found in green tea, helps smooth out the stimulating effects of caffeine, creating a balanced, jitter-free energy boost.

This combination improves alertness, reaction time, and overall cognitive performance, which means you can stay sharp and focused without the unwanted crashes or jitters often associated with caffeine alone.

The blend is designed for stamina. Helping you to push through challenging workouts while maintaining mental clarity and calm.

Don’t Forget Your Electrolytes!

One of the major disadvantages of fasted training is electrolyte-deficiency and dehydration.

While fasting, you can drink water without breaking your fast. In fact, it’s recommended to get adequate H2O intake, whether fasting or not, prior to exercise. However, the problem is that you need more than water to stay hydrated.

You also need electrolytes, namely the four basic electrolytes:

1. Magnesium
2. Potassium
3. Calcium
4. Sodium

Fortunately, these essential trace minerals come at zero caloric cost, and, thus, may be supplemented without breaking a fast.

And one of the best electrolyte sources you can take to improve your workout hydration levels is Himalayan pink salt, a natural, unprocessed salt chunk that brings the electrolytes along with the good vibes.

Pre Lab Pro® includes Himalayan pink salt along with potassium. Supplying key electrolytes to help maintain hydration and muscle function, even while training in a fasted state.

Best Zero-Calorie Pre-Workout: Performance Lab® Pre Lab Pro®

Pre Lab Pro® is an all-natural, calorie-free formulation that supports nitric oxide activity, boosts energy levels, and enhances endurance and focus—all without breaking your fast.

Pre Lab Pro® can help you maximize your workout results by:

• Elevated nitric oxide (NO) activity to support circulation and delivery of oxygen and nutrients to muscles.
• Buildable caffeine dosage for controlled stimulation and jitter-free energy.
• Vegan, non-GMO, and no artificial additives for a clean, healthy workout boost.

Without breaking your fast or loading you up with empty calories, Pre Lab Pro® helps maximize your strength and muscle load for a powerful boost on clean, healthy, athletic performance.

Shop Pre Lab Pro®

What’s in Pre Lab Pro®?

• Vitamin D3 (from Algae), 12.5 mcg
• NutriGenesis® Riboflavin, 0.5 mg
• NutriGenesis® Vitamin B6, 0.75 mg
• NutriGenesis® Folate, 167 mcg DFE
• NutriGenesis® Vitamin B12, 2 mcg
• NutriGenesis® Potassium, 49.5 mg
• NutriGenesis® Iron, 2.5 mg
• Sodium (from Himalayan Pink Salt), 200 mg
• Natural Caffeine (from Coffea robusta seeds), 80 mg
• L-Theanine (from Green Tea), 160 mg
• L-Tyrosine, 400 mg
• Setria® Performance Blend, 2,200 mg
• L-Citrulline (Kyowa Quality®)
• L-Glutathione (Setria®)
• Red Beet Powder (Beta Vulgaris L - root), 1,500 mg
• Himalayan Pink Salt, 500 mg

Pre Lab Pro®’s all-natural formula supercharges the body’s natural energy and endurance levels without relying on harmful stimulants or synthetics.

Many pre-workouts boast of having an excellent selection of performance enhancers, yet they too often sell themselves short by caking their formulas in performance-disruptive artificial additives and a heart-racing amount of caffeine.

Pre Lab Pro® contains a moderate dose of natural caffeine that’s calibrated to support focus and intensity, without crashes, jitters or sleepless nights.

Artificial sweeteners do taste sweet without ramping up the calorie count, and, yes, stimulants do supply a reliable source of cognitive energy.

However, the combined downsides of both may significantly disrupt your metabolism.

Pre Lab Pro® uses natural flavors and sweeteners such as stevia, monk fruit extract and xylitol. Stevia is a sweetener made from the stevia plant leaf which is 300 times sweeter than sucrose and has anti-inflammatory and antioxidant effects.(2)

By eschewing stimulants and synthetics, Pre Lab Pro® not only acutely promotes exercise performance but long-term health and fitness as well.

Many inferior pre-workout stacks sweeten their formulas with GI-disruptive chemicals to mask their cheaply manufactured ingredients. It’s a double negative whammy: harmful artificial sweeteners disguise the poor taste of harmful, unnatural ingredients.

Billed as “zero calorie” formulas, these artificially sweetened pre-workouts unfortunately have warped our worldview meaning we see something like “Arctic Blue Razz” as a legitimate, desirable flavor to throw in our bodies. It’s not!

Fortunately, Pre Lab Pro® is setting the record straight by showing that zero-calorie ergogenics that are clean, healthy, and all-natural do exist.

Conclusion

Best Zero Calorie Pre-Workout: Pre Lab Pro®

While fasted training is an effective strategy for burning fat and building lean muscle mass, a clean pre-workout supplement like Pre Lab Pro® is essential for maximizing exercise capacity without disrupting metabolic advantages.

By supplying only clean, potent, all-natural pre-workout ingredients, Pre Lab Pro® helps you reach your fitness goals without the negative effects of synthetic chemicals or artificial sweeteners.

Whether your training is fasted or non-fasted, Pre Lab Pro® delivers a powerful boost for exercise performance.

Ultimate Zero-Calorie Workout Stack

If you’re looking to take your workouts to the next level, Pre Lab Pro® is just the start. For a truly powerful stack, we’ve got some superstar supplements that pair perfectly with Pre Lab Pro® to help you get the most out of every training session.

Here’s how you can build the ultimate zero-calorie workout stack:

NutriGenesis® Multi

Think of this as your all-in-one nutritional insurance. A foundational multivitamin providing essential vitamins and minerals produced using NutriGenesis® technology for enhanced bioavailability.

NutriGenesis® Multi offers a complete blend of micronutrients, including Vitamins A, C, D, E, and a range of B vitamins, magnesium, zinc, selenium, and more.

Whether you’re pushing hard at the gym or just getting through a busy day, NutriGenesis® Multi keeps your body nourished and your immune system strong—especially important during intense training phases.

Shop Performance Lab® NutriGenesis®

Performance Lab® Flex

Formulated to support joint health and reduce inflammation, Flex is packed with joint-friendly ingredients like glucosamine, chondroitin, and CurcuWIN® turmeric extract.

It’s formulated to maintain joint mobility and comfort. Flex soothes, protects, nourishes and lubricates achy joints and is easy on the stomach for fasted training.

Shop Performance Lab® Flex

Performance Lab® MCT Energy Oil

For an energy boost that’s clean and efficient, Performance Lab® MCT is a blend of C8 and C10 medium-chain triglycerides sourced from organic coconuts. These MCTs provide rapid, clean energy for both the brain and body, making it perfect for fueling ketogenic or intermittent fasting protocols.

MCTs bypass normal fat digestion and quickly convert into ketones, which can enhance endurance and cognitive performance during workouts.

Shop Performance Lab® MCT Oil

Performance Lab® Energy

Performance Lab® Energy is a stim-free, crash-free supplement designed to support mind-body vitality.

It features MicroActive® CoQ10, BioPQQ®, and Acetyl L-Carnitine to optimize mitochondrial function and cellular energy production without the use of stimulants like caffeine.

This means you can boost your energy and endurance in a sustainable, jitter-free manner, enhancing both mental and physical performance.

Shop Performance Lab® Energy

With Pre Lab Pro® as your foundation, these supplements combine to create a stack that’s more than just the sum of its parts. They complement each other beautifully, covering everything from joint health and daily nutrition to clean energy and optimized recovery—helping you perform at your peak, every single day.