Does Drinking Pre-Workout Count Towards Water Intake? The Definitive Guide

October 16, 2025 •

4 min read

Studies from Johns Hopkins Medicine show that for every hour of intense activity, people can lose up to two quarts of fluid. The question is, does drinking pre-workout count towards water intake to replenish these losses, or does it complicate your hydration needs? This question is more complex than it appears, with the answer depending heavily on the supplement's ingredients.

Quick Summary

While pre-workout contains water, its components can complicate your body's fluid balance. Key ingredients like caffeine and creatine may increase water loss or redistribution, meaning it should not be considered a direct substitute for plain water.

Key Points

Depends on Ingredients: Pre-workout contains water, but its impact on hydration is complicated by additives like caffeine and creatine.
Caffeine is a Diuretic: High caffeine content in pre-workout can increase urination, potentially counteracting the hydrating fluid you consume.
Creatine Needs More Water: Creatine draws water into your muscle cells, meaning you need more plain water intake to maintain overall body hydration.
Plain Water is King: Pre-workout should supplement, not replace, your intake of plain water, which is essential for proper fluid balance.
Watch for Dehydration: Relying solely on pre-workout for hydration can lead to dehydration symptoms like headaches and muscle cramps.
Timing Matters: Hydrate consistently throughout the day with plain water, consuming your pre-workout and extra water strategically around exercise.

The Simple Answer vs. The Nuanced Truth

At a fundamental level, any liquid consumed contributes to your total fluid intake. If you mix a scoop of pre-workout powder with 12 ounces of water, your body has received 12 ounces of fluid. However, this simple fact is misleading because it doesn't account for how the other ingredients in the supplement interact with your body's hydration mechanisms. The effect is not the same as drinking pure, plain water. For optimal hydration, especially around intense exercise, you must understand the distinction between basic fluid consumption and effective cellular hydration.

Key Ingredients That Influence Hydration

Pre-workout formulas are complex blends, and several common ingredients play significant roles in how your body manages fluid. Understanding these components is crucial to managing your hydration correctly.

The Diuretic Effect of Caffeine

Caffeine is a powerful stimulant and a staple in most pre-workout formulas. While it provides an energy boost and enhances focus, it is also a mild diuretic. A diuretic increases the production of urine, which can lead to greater fluid loss during and after your workout. For someone with a low caffeine tolerance or for those consuming large doses, this effect is more pronounced. The net result is that the water you consume with your caffeinated pre-workout may be flushed from your system more quickly than if you had consumed plain water. This is why many people report feeling dehydrated, experiencing dry mouth, or needing to urinate more frequently after taking pre-workout.

The Water-Pulling Effect of Creatine

Creatine is another popular pre-workout ingredient, renowned for its ability to enhance strength and power output. Creatine works by drawing water from the bloodstream into your muscle cells. This process is beneficial for muscle function but means that while you are consuming fluids, the water is being partitioned differently within your body. If you don't increase your overall water intake to compensate for this shift, other parts of your body, including your brain, can become relatively dehydrated. This can lead to headaches, another common side effect associated with pre-workout use. Proper hydration is therefore essential for creatine to work effectively and for your body to function optimally.

Pre-Workout vs. Plain Water: A Comparison

To highlight the differences, consider this comparison table. It illustrates why a glass of pre-workout is not a one-to-one replacement for plain water.


Feature	Plain Water	Pre-Workout Drink
Primary Function	Hydration, metabolic support, temperature regulation.	Energy, focus, strength, muscle pumps.
Fluid Balance Impact	Neutral; supports total body fluid balance without complicating factors.	Disruptive due to diuretic and cellular water-pulling ingredients.
Electrolyte Content	Typically low or none (unless mineral water).	Can be included, but composition varies; may not adequately replace sweat loss.
Digestive Impact	Gentle on the stomach; can aid digestion.	Can cause stomach upset, bloating, or diarrhea due to stimulants, artificial sweeteners, or high doses of certain ingredients.
Best Used For	Continuous, daily hydration and replenishing fluid losses.	Targeted performance boost before exercise, not daily fluid needs.

Recommendations for Optimal Hydration

Effective hydration requires a strategy that complements your pre-workout, not one that treats it as a substitute for water. Here are key recommendations:

General Daily Hydration

Prioritize Plain Water: Your daily fluid intake should primarily come from plain water. A good rule of thumb is to drink half your body weight in ounces per day as a baseline. For example, a 180lb person would aim for 90 ounces.
Monitor Urine Color: A simple and effective way to gauge hydration is by observing the color of your urine. It should be a pale yellow. Dark yellow urine indicates dehydration, while completely clear urine might signal over-hydration, also known as hyponatremia in extreme cases.

Timing Your Hydration with Pre-Workout

Before Your Workout: Drink 17-20 ounces of plain water two to three hours before exercise. This ensures you start your workout in a euhydrated state (properly hydrated). Drink your pre-workout 30-60 minutes before you start, following the manufacturer's directions for mixing with water.
During Your Workout: Continue to sip plain water throughout your training session. For every 15-20 minutes of exercise, aim for 7-10 ounces of fluid. For longer, more intense workouts (over an hour), consider an electrolyte beverage to replace minerals lost through sweat.
After Your Workout: Rehydrate to aid recovery. Weighing yourself before and after your workout can help determine fluid loss. For every pound of weight lost, consume 16-24 ounces of water.

Tips for Managing Pre-Workout's Hydration Impact

Start Small: Begin with a smaller dose than recommended to assess your body's sensitivity to stimulants and other ingredients.
Read Labels: Pay close attention to ingredients. Formulas high in caffeine or certain sweeteners may require extra hydration. Look for supplements that include electrolytes.
Consume with Food: Taking your pre-workout on an empty stomach can exacerbate stomach upset and dehydration. Having a small, carbohydrate-based snack beforehand can help.

Conclusion: Supplement, Don't Substitute

In conclusion, while the liquid in your pre-workout drink does technically count toward your total fluid intake, it is not a direct substitute for plain water. The active ingredients, particularly caffeine and creatine, affect your body's fluid balance in complex ways that require additional hydration, not less. Relying on pre-workout alone for your hydration needs can lead to dehydration, reduced performance, and unpleasant side effects like headaches and cramps. For optimal performance, energy, and overall health, you should continue to prioritize plain water as your primary source of hydration and use pre-workout as a targeted, performance-enhancing supplement, not a daily fluid replacement. For more information on maintaining proper fluid balance, see this resource from the NIH.

Frequently Asked Questions

No, you should not substitute plain water with pre-workout. While it contains fluid, the active ingredients like caffeine and creatine alter your body's fluid balance. Plain water is essential for daily hydration and metabolic function.

Pre-workout can cause dehydration due to its high caffeine content, which is a mild diuretic that increases urination. Additionally, heavy breathing during intense exercise and ingredients like creatine, which pulls water into muscle cells, can contribute to the feeling of dehydration.

Yes. Creatine works by drawing water into your muscle cells. This means that while your muscles are hydrated, other parts of your body can become dehydrated if you do not increase your overall water intake to compensate for this fluid shift.

You should mix your pre-workout with the amount of water specified on the label, typically 8-12 ounces. However, you should also consume additional plain water before, during, and after your workout to properly hydrate and counteract any dehydrating effects.

For basic hydration, plain water is the best choice. For longer or more intense workouts, or if you are a heavy sweater, an electrolyte drink can help replenish lost minerals like sodium and potassium.

Yes, pre-workouts can cause headaches. This can be due to dehydration caused by stimulants like caffeine, which thins the fluid surrounding your brain. It can also be caused by ingredients that promote vasodilation, increasing blood flow to the brain and causing pressure.

Yes, you should be mindful of electrolytes. Intense exercise causes sweat loss, which includes important electrolytes like sodium and potassium. If your pre-workout doesn't contain electrolytes, or if your workout is particularly long or intense, you may need a separate electrolyte source to prevent an imbalance.