When it comes to training time, you’ll generally find two groups of people: those that train fasted and those that train fed. While the groups may intermingle every so often, people tend to stick to what works for them.

And for those that fall into the former group, there’s nothing quite like getting your grind on at 6 am to start your day. It revs your metabolism, fires up your focus, and starts your day out on a high.

But with zero fuel in the tank, how are you supposed to power through a good training session?

For some people, it’s coffee. For others, it’s pre-workout.

Whatever side you fall on, is swapping out the morning breakfast or carb-loaded lunch that fuels your workout actually worth it?

Training fasted has its ups and downs, and for anyone wondering whether taking a pre-workout before fasted training is a good idea, we’re breaking it down for you.

We’re talking about everything you need to know regarding training in a fasted state and if taking your pre-workout on an empty stomach will actually give you the results you’re looking for.

Fasted Training: Yay Or Nay?

Training fasted has been a hot debate for ages. Some people stand by the fact that your body needs immediate fuel in the form of food to maximize your performance, whereas others suggest that your body has enough of what it needs in storage to fuel you through a food-less workout.

But does fasted training get you results?

For a lot of people, cardio is a staple when they’re in a fasted state. It’s believed that when you train in a caloric deficit, it helps your body tap into fat stores to provide fuel for your workout. But the validity of that may be debatable…

While there’s nothing wrong with training on an empty stomach in a fasted state, the research behind getting into the “fat-burning zone” isn’t exactly as straightforward as it may seem. Your body can store about 100g and 400g glycogen in the liver and the muscles, respectively 1.

And during exercise, the body preserves glucose at the expense of glycogen reservoirs, which means muscle and liver glycogen become depleted, while carbohydrate (CHO) oxidation increases by working muscles.

But what most people don’t realize is the duration of exercise it takes for glucose stores to become depleted and actually turn you into a fat-burning machine.

Studies find that after 2 hours of exercise, blood glucose still remains stable 1. Only after intense long-duration exercise does blood glucose fall to a point where hypoglycemia could kick in.

In order for your body to burn through those glucose stores and actually start burning fat, you’d have to exercise at a strenuous level for a decent amount of time.

However, if you’re doing a good cardio session at the end of a 12+ hour fast, getting into that zone may be slightly easier because your glycogen reserves have already been tapped into.

And if you’ve been fasting a full 24 hours, it’s likely pretty quick. Rodent studies find that a 24-hour fast alters both the metabolic response to exercise and time to exhaustion in endurance training, as well as preserving muscle glycogen content 2.

The “sparing” effect is likely due to more significant mobilization and utilization of fat, as evidenced by higher concentrations of plasma-free fatty acids (FFA). In turn, you see greater fat oxidation and better endurance performance 3.

With respect to muscle building, studies find it’s more about the cumulative intake of protein and carbohydrates to support muscle protein synthesis rather than the period right around training.

So, assuming you have enough amino acids in the pool to pull from to support MPS post-workout, you likely won’t compromise any existing muscle mass.

It’s also important to remember that even if you are training in a fasted state, you have to fuel up properly in the fed state.

Exercise puts a lot of stress on both your physical and metabolic systems, and if you want to support effective workouts and recovery, you need to be eating to support that throughout the day.

With all of that said, we get down to the point—can you take pre-workout on an empty stomach?

Is It Bad To Take Pre-Workout On An Empty Stomach?

As we’ve just shown, training in a fasted state has some potential benefits, but if you’re not into downing a cup of coffee before hitting the gym and need a bit of something extra to power you through, what do you do?

That’s the job of a good pre-workout.

For most pre-workout supplements, taking them in a fed or fasted state will produce similar results.

However, depending on your caffeine tolerance and the amount of caffeine in the formula, the effects may hit a bit harder with no food in your system.

And you also want to keep in mind what else is in your formula because some supplements can cause upset or adverse reactions when taken without food.

Be Mindful Of The Additives…

We know you’re aware that not all pre-workout supplements are created equal where efficacy and performance are concerned, but when it comes to taking a pre-workout on an empty stomach, what’s in your pre-workout can determine whether taking it on an empty stomach is going to put you in complete beast mode or in the bathroom…

That’s because a lot of the conventional pre-workouts you’ll find lining shelves are loaded with additives and synthetics that can irritate your gastrointestinal tract and lead to some pretty nasty symptoms, along with metabolic dysfunction and microbiome imbalances.

Two of the biggest culprits include:

  • Artificial sweeteners — Both synthetic and natural sweeteners may interfere with glucose tolerance and alter the composition of the gut microbiota 4. Excessive consumption of polyols may also cause GI disturbances in some people, such as gas, bloating, or diarrhea, similar to the reaction caused by excessive intake of high-fiber foods.
  • High-dose caffeine - On an empty stomach, caffeine is rapidly absorbed and can trigger nasty side effects like nausea, shakiness, and jitters, although the effects largely depend on your tolerance and caffeine metabolism.

So, if you want to avoid any nasty side effects that go along with taking pre-workout on an empty stomach, looking for a clean supplement that enhances performance but leaves all the downside behind is key.

In any case, training in a fasted state can have some major benefits, which means that knocking back your pre-workout on an empty stomach becomes a must.

Fasted training has been shown to significantly lower weight and fat mass, but also may increase endurance performance 5. However, when you’re trying to build muscle in a fasted state, it can be rather challenging because your body leans more towards a catabolic state than an anabolic one.

However, what makes pre-workouts so appealing to the fasted training crowd is that they may help to mitigate the damaging effects of training on an empty stomach. Simply put, they prevent muscle catabolism and allow you to get through your training session without compromising your existing gains.

After all, if you’re fasting and hitting the weight on an empty stomach, you want to make the most out of it.

The Best Pre-Workout For Fasted Training

If you’re looking for the pump and performance enhancement with none of the downsides that come along with the usual pre-workouts, there’s only one you should be eyeing—Pre Lab Pro®.

It’s a next-generation pre-workout formula that delivers bigger and better results. Whether you’re training fasted or not, Pre Lab Pro® is designed to help you push your body to its limits and extend beyond just strength and stamina.

With 2x muscle-pumping nitric oxide (NO) turbocharge, this pre-workout formula is designed to achieve optimal and peak performance.

And with moderate-dose smart caffeine, hydrating factors, and restorative essentials, you don’t need to worry about getting the pre-workout jitters or shakes if you’re training on an empty stomach.

It absorbs fast and gives you a fine-tuned, clean stimulation that helps you power you through the longest and most intense training sessions with ease and focus.

Key Features

  • RedNite® Beetroot Powder to improve neuromuscular performance, combat fatigue, enhance muscle energy, support healthy cardiovascular performance, and sharpen cognitive function
  • Setria® Performance Blend provides a powerful and sustained nitric oxide boost for better strength, power, speed, and endurance, and gives you a head start on muscle growth and recovery
  • Natural Caffeine supplies moderate-dose smart caffeine stacked with boosters and balancers for maximum benefits and minimal side effects
  • Ajipure® L-Tyrosine supports brain chemicals that drive athletic intensity and mental recovery, while sharpening focus under stress and replenishing neurotransmitters depleted by caffeine and intense training
  • Suntheanine® supports relaxed alertness, positive mood, and cognitive clarity, as well as enhancing the effects of caffeine to promote calmer, cleaner stimulation

All these ingredients combine to increase strength and stamina, drive intensity, boost power and speed, and accelerate recovery without breaking your fast.

And with only 80mg of caffeine per serving, you don’t need to worry about a heavy caffeine hit that will tank your workout. It’s optimized with boosters and balancers for the ultimate in clean stimulation.


  1. DH Four grams of glucose.Am J Physiol Endocrinol Metab. 2009;296(1):E11-E21.
  2. GL Dohm, EB Tapscott, HA Barakat, GJ Influence of fasting on glycogen depletion in rats during exercise.J Appl Physiol Respir Environ Exerc Physiol. 1983;55(3):830-833.
  3. GL Dohm, RT Beeker, RG Israel, EB Tapscott. Metabolic responses to exercise after fasting.J Appl Physiol (1985). 1986;61(4):1363-1368.
  4. FJ Ruiz-Ojeda, J Plaza-Díaz, MJ Sáez-Lara, A Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials [published correction appears in Adv Nutr. 2020 Mar 1;11(2):468]. Adv Nutr. 2019;10(suppl_1):S31-S48.
  5. H Zouhal, A Saeidi, A Salhi, et al. Exercise Training and Fasting: Current Insights. Open Access J Sports Med. 2020;11:1-28.