Does Creatine Have Caffeine? The Truth About Creatine, Caffeine, Energy, and Performance
Updated: Oct 8
Creatine is one of the most researched sports supplements in history. Caffeine is one of the most widely consumed performance-enhancing compounds in the world. Both are commonly used by athletes, military personnel, fitness enthusiasts, and everyday people looking to improve their workouts.
So it's no surprise that one of the most common questions I hear is:
Does creatine have caffeine?
The short answer is: No. Pure creatine monohydrate does not contain caffeine and is not considered a stimulant.
However, the confusion makes sense. People often notice improved workout performance after taking creatine, and they naturally assume it works similarly to caffeine. In reality, these supplements improve performance through completely different physiological mechanisms.
Caffeine primarily works on your central nervous system, increasing alertness and reducing the perception of fatigue. Creatine works primarily inside your muscles, helping regenerate ATP, the body's immediate source of energy for explosive movements. One helps you feel more energized. The other helps your muscles produce energy more efficiently during repeated high-intensity efforts.
Those are two very different things.
As a Human Performance expert, I've found that people often confuse "energy" with "stimulation." They're not the same. You don't need to feel jittery, wired, or buzzing to improve performance. In fact, some of the most effective performance strategies involve improving the body's ability to produce energy without relying on additional stimulants.
That's one reason creatine has remained one of the most recommended supplements by organizations like the International Society of Sports Nutrition (ISSN) and is supported by decades of peer-reviewed research.
In this guide, you'll learn:
Does creatine contain caffeine?
Is creatine a stimulant?
Does creatine make you feel energized?
Can you take creatine and caffeine together?
Does caffeine cancel out creatine?
Can creatine keep you awake?
How to identify supplements that contain both ingredients
When to use creatine versus caffeine
Quick Answer
Does Creatine Have Caffeine?
Pure creatine monohydrate does not contain caffeine. It is naturally caffeine-free and is not classified as a stimulant. Creatine supports high-intensity exercise by increasing phosphocreatine stores within muscle, allowing faster regeneration of ATP during repeated bouts of exercise. Caffeine, on the other hand, works primarily by blocking adenosine receptors in the brain, increasing alertness and decreasing the perception of fatigue.
Some pre-workout supplements combine creatine and caffeine into the same product. That does not mean creatine itself contains caffeine, it simply means the manufacturer chose to include both ingredients in one formula.
The International Society of Sports Nutrition Position Stand on Caffeine distinguishes these two supplements as separate ergogenic aids with different mechanisms of action rather than interchangeable ingredients.
⚡ Support Performance Without Guesswork
One thing I've learned over years of coaching is that performance doesn't have to depend on constantly increasing your caffeine intake.
Building consistent habits around:
Quality sleep
Proper hydration
Progressive training
Daily creatine intake
often has a greater long-term impact than relying on another highly caffeinated product.
That's one of the reasons I created HPSTIX. It was designed to simplify two evidence-based performance habits:
Creatine monohydrate
Electrolyte hydration
without confusing creatine's role with stimulant-based pre-workouts.
Always read the final Supplement Facts panel to verify whether any product contains caffeine.
Why People Think Creatine Contains Caffeine
The misunderstanding usually begins with one simple observation. Someone starts taking creatine. A few weeks later they notice:
Better workouts
Increased strength
More training volume
Improved recovery
Better performance
They assume, "It must work like caffeine." Not quite. Creatine doesn't stimulate your nervous system, it doesn't block fatigue receptors in your brain, it doesn't produce the classic feeling associated with drinking coffee or consuming an energy drink. Instead, creatine works much deeper, it helps your muscles regenerate ATP more efficiently during repeated high-intensity efforts. That's a completely different physiological process.
What Is Creatine?
Creatine is a naturally occurring compound synthesized from the amino acids:
Arginine
Glycine
Methionine
Your body produces creatine primarily in the:
Liver
Kidneys
Pancreas
It is then transported into skeletal muscle, where approximately 95% of your body's creatine is stored.
Inside muscle cells, creatine becomes phosphocreatine. During intense exercise, phosphocreatine helps rapidly regenerate ATP (adenosine triphosphate), which is the body's immediate energy currency for movements like:
Sprinting
Heavy lifting
Jumping
Throwing
Explosive sports
This is why creatine is especially effective for repeated bouts of high-intensity exercise. The NIH Office of Dietary Supplements identifies creatine as one of the most well-supported supplements for improving strength, power, and repeated maximal-effort exercise performance.
What Is Caffeine?
Caffeine is completely different. Rather than working inside muscle cells, caffeine primarily affects the brain and central nervous system. Caffeine works by blocking adenosine receptors. Normally, adenosine accumulates throughout the day and contributes to feelings of tiredness. When caffeine blocks these receptors, many people experience:
Increased alertness
Reduced fatigue
Greater focus
Improved reaction time
Increased motivation to exercise
These effects happen relatively quickly, which is why many athletes consume caffeine approximately 30–60 minutes before training. Unlike creatine, caffeine's effects are temporary. Once it is metabolized, those effects gradually wear off.
Creatine vs. Caffeine
Although they're often mentioned together, these supplements serve very different purposes.
Feature | Creatine | Caffeine |
Contains caffeine? | No | Yes |
Stimulant | No | Yes |
Immediate energy feeling | No | Usually |
Primary mechanism | ATP regeneration | Adenosine receptor blockade |
Daily use recommended | Yes | Depends on goals |
Can affect sleep | Not directly | Yes |
Naturally found in | Meat and fish | Coffee, tea, cacao |
Primary benefit | High-intensity performance | Alertness and reduced fatigue |
Understanding this distinction helps explain why creatine doesn't produce the "buzz" many people associate with pre-workout supplements.
Does Creatine Give You Energy?
The answer depends on what you mean by "energy."
If you mean, "Will I feel wired like I drank coffee?"
No.
If you mean, "Will my muscles be better prepared to perform repeated high-intensity work?"
Yes.
One of the biggest misconceptions in fitness is that every performance supplement should make you feel something immediately. Creatine often doesn't.
Instead, it gradually increases muscle creatine stores over several days or weeks. As those stores increase, many people notice improvements in:
Strength
Power
Sprint performance
Training volume
Recovery between sets
Those improvements occur because the muscles can regenerate ATP more efficiently, not because your brain has been stimulated.
Does Creatine Make You Feel Jittery?
No. Pure creatine monohydrate should not produce classic stimulant symptoms such as:
Jitters
Shakiness
Racing heart
Nervousness
Restlessness
Anxiety caused by stimulants
If you experience those sensations after taking a creatine product, look beyond the word creatine.
Many products marketed as "creatine" are actually:
Pre-workouts
Multi-ingredient performance formulas
Energy drinks
Powder blends
These frequently contain:
Caffeine
Guarana
Green tea extract
Yohimbine
Other stimulants
The stimulant, not the creatine, is usually responsible for those effects. Always read the ingredient list carefully.
Does Creatine Keep You Awake?
Pure creatine monohydrate is not known to work like caffeine and should not directly stimulate the central nervous system.
Many people successfully take creatine:
In the morning
After workouts
During lunch
Before bed
without noticing changes in sleep.
However, several factors can create confusion.
For example:
Your creatine product may also contain caffeine.
You may be taking a pre-workout instead of plain creatine.
You exercised intensely late in the evening.
You consumed caffeine earlier in the day.
Those factors, not creatine itself, are often the real explanation.
If you'd like to learn more, read our Human Performance HQ article: Benefits of Taking Creatine Before Bed
Can Some Creatine Supplements Contain Caffeine?
Absolutely. This is where reading labels becomes essential. Creatine itself does not contain caffeine.
However, manufacturers often combine creatine with Caffeine, Beta-alanine, Citrulline, Taurine, Tyrosine, and Nitric oxide ingredients inside pre-workout supplements.
These products are designed to provide both:
Long-term creatine support
Immediate stimulant effects
That's why two products labeled "creatine" can feel completely different. Always check the Supplement Facts panel rather than assuming the front label tells the whole story.
The Ariel Hernandez Perspective
One thing I've learned as a Human Performance expert is that many people become overly dependent on stimulants.
Instead of asking, "How much caffeine do I need today?"
I encourage people to ask, "Why do I feel like I need so much caffeine?"
Sometimes the answer is:
Poor sleep
Chronic stress
Inadequate hydration
Poor nutrition
Excessive training
Recovery deficits
Caffeine can absolutely improve exercise performance. The research supporting moderate caffeine intake before exercise is quite strong. But caffeine should enhance a healthy lifestyle, not compensate for an unhealthy one.
Creatine is different. Its purpose isn't to make you feel stimulated. Its purpose is to improve your body's ability to repeatedly produce energy during demanding physical activity.
Those are two separate tools. I personally think that's an important distinction because too many people judge supplements solely by whether they "feel" something immediately. Some of the most effective supplements, like creatine, work quietly in the background while your long-term performance steadily improves.
10 Facts About Creatine and Caffeine
Pure creatine monohydrate does not contain caffeine.
Creatine is not classified as a stimulant.
Creatine supports ATP regeneration rather than increasing nervous system stimulation.
Caffeine primarily works by blocking adenosine receptors in the brain.
Creatine usually doesn't produce jitters or a caffeine "buzz."
Some pre-workout supplements combine creatine and caffeine in the same formula.
Reading the Supplement Facts panel is the best way to identify added caffeine.
Creatine can improve performance without making you feel more alert.
Caffeine may improve focus and reduce perceived fatigue, but it isn't required for creatine to work.
Sleep, nutrition, hydration, and consistent training remain the true foundation of Human Performance.
The Human Performance HQ C.L.E.A.R. Supplement Protocol
One thing I have learned as a Human Performance expert is that most supplement confusion begins when people stop asking what an ingredient is supposed to do. They see creatine and caffeine in the same pre-workout formula and assume the two compounds are interchangeable.
They are not.
Creatine supports the phosphocreatine energy system and works best through consistent intake over time. Caffeine produces a more immediate stimulant effect by acting primarily on the central nervous system. Both may support performance, but they solve different problems. (SpringerLink)
That is why I recommend the Human Performance HQ C.L.E.A.R. Supplement Protocol.
C — Check the Entire Label
Never judge a product only by the largest word on the front of the container.
A product marketed as “creatine” may also contain:
Caffeine
Guarana
Green coffee extract
Green tea extract
Yerba mate
Beta-alanine
Yohimbine
Other stimulant blends
Likewise, a pre-workout may contain creatine, but not necessarily enough to provide a full evidence-based daily dose.
Review:
Serving size
Caffeine per serving
Creatine type
Creatine dose
Proprietary blends
Suggested number of scoops
Multi-ingredient pre-workouts vary widely in formula and dosage, so the finished product, not creatine itself, determines whether caffeine is present. (SpringerLink)
L — Learn the Purpose of Each Ingredient
Use creatine when your goal is to support:
Strength
Power
Repeated high-intensity efforts
Training volume
Muscle creatine saturation
Long-term resistance-training adaptations
Use caffeine strategically when your goal is to support:
Alertness
Focus
Reduced perceived effort
Endurance performance
Acute workout readiness
The NIH reports that caffeine may improve endurance, strength, power, and high-intensity team-sport performance at roughly 2–6 milligrams per kilogram of body weight. Higher doses are unlikely to produce additional benefits and may increase unwanted effects. (Office of Dietary Supplements)
Creatine does not require a pre-workout “feeling” to work. Caffeine often does produce a noticeable feeling.
E — Evaluate Your Timing
Creatine timing is relatively flexible. The important variable is consistently maintaining elevated muscle creatine stores.
You can take creatine:
With breakfast
Before training
After training
With lunch
In the evening
On rest days
Caffeine timing requires more intention because it can affect sleep, depending on:
Dose
Timing
Sensitivity
Habitual intake
Genetics
Other caffeine consumed that day
For creatine, think consistency. For caffeine, think timing and purpose.
A — Assess Your Personal Tolerance
Not everyone responds to caffeine the same way. One person may tolerate an afternoon coffee without any obvious sleep disruption.
Another may experience:
Anxiety
Restlessness
Racing heart
Gastrointestinal discomfort
Difficulty falling asleep
Lighter sleep
Frequent nighttime waking
The FDA notes substantial individual variation in caffeine sensitivity and elimination, even though up to 400 milligrams per day is not generally associated with negative effects for most healthy adults. That number is an upper reference, not a performance target everyone should chase. (U.S. Food and Drug Administration)
Creatine also varies in individual response, but it should not cause the classic stimulant sensations associated with caffeine.
R — Respect the Fundamentals
Neither creatine nor caffeine can replace:
Sleep
Nutrition
Hydration
Progressive training
Recovery
Stress management
Caffeine can temporarily help you feel less tired. It cannot repay sleep debt. Creatine can support training capacity. It also cannot rescue an inconsistent program. Supplements work best when they support a well-built system rather than covering up weaknesses in that system.
Can You Take Creatine and Caffeine Together?
Yes.
Many athletes consume creatine and caffeine within the same day, and numerous commercial pre-workouts include both. The scientific question is not whether the compounds can physically coexist.
They can. The more complicated question is whether taking them at the exact same time changes their effectiveness. Research on simultaneous creatine and caffeine use is mixed, but current evidence does not support the blanket claim that caffeine universally cancels out creatine.
A review focused specifically on concurrent use concluded that the available studies are inconsistent, with gastrointestinal discomfort, study design, caffeine dose, and timing potentially explaining some conflicting findings. (PubMed)
A 2022 resistance-training study found that creatine alone produced a small improvement in knee-extensor muscle thickness, while adding caffeine did not provide a clear additional benefit across the other measured outcomes. That does not mean caffeine erased creatine’s effects; it means the combination was not clearly superior in that particular protocol. (PubMed)
A newer trial using creatine nitrate and caffeine reported some cognitive benefits from co-ingestion but no significant exercise-performance advantage from combining them. Again, the evidence suggests “different tools,” not a simple cancellation effect. (PubMed)
Does Caffeine Cancel Out Creatine?
The best evidence-based answer is:
Probably not, but taking them together does not always provide an additive benefit.
That distinction matters. “Not additive” means the combined effect may not be greater than using either supplement appropriately on its own. “Cancels out” would mean caffeine prevents creatine uptake or removes creatine’s established benefits. Current evidence does not consistently show that.
A 2022 timing review concluded that caffeine co-ingestion does not appear to change creatine uptake or creatine kinetics, although some evidence suggests that simultaneous use may blunt certain performance outcomes in specific situations. (PMC)
A practical solution is simple:
Take creatine daily.
Use caffeine only when it adds value.
Separate the doses if taking them together causes stomach discomfort.
Do not assume more ingredients produce better performance.
Why Did the “Caffeine Cancels Creatine” Myth Begin?
The concern largely originated from older studies in which participants took high doses of caffeine during creatine-loading protocols. Some reported less performance improvement or more gastrointestinal discomfort when the ingredients were combined.
Those findings were then simplified online into, “Never mix creatine and caffeine.” That conclusion goes beyond what the research can confidently support.
Potential explanations for mixed results include:
Large caffeine doses
Creatine-loading doses
Gastrointestinal distress
Different exercise tests
Short study duration
Habitual caffeine use
Small samples
Individual variation
The current literature calls for nuance, not prohibition.
Creatine and Coffee
You can mix creatine into coffee, but you do not have to.
Potential advantages include:
Convenience
Attaching creatine to an existing habit
Taking both before a morning workout
Potential disadvantages include:
Bitter or unpleasant taste
Stomach discomfort
Forgetting that coffee contributes to daily caffeine intake
Encouraging caffeine use when it is not actually needed
A controlled study comparing creatine loading alone with creatine plus coffee or caffeine found no clear improvements in strength or sprint performance from adding coffee or caffeine. Some gastrointestinal symptoms were also reported in the co-ingestion conditions. (PMC)
The practical takeaway: Mixing creatine with coffee is acceptable if you tolerate it, but it is not necessary for creatine absorption or performance. Consume the drink reasonably soon after mixing rather than leaving creatine sitting in a hot, acidic beverage for many hours.
Creatine vs. Pre-Workout
Creatine and pre-workout are not the same category.
Creatine
Creatine is a specific compound. Its primary purpose is to increase creatine and phosphocreatine availability within muscle over time.
Typical evidence-based use:
3–5 grams daily
Consistent intake
Training and rest days
Pre-Workout
Pre-workout is a broad product category. It may contain:
Caffeine
Citrulline
Beta-alanine
Creatine
Electrolytes
Nitrates
Amino acids
Flavoring and sweeteners
Some pre-workouts contain an effective dose of creatine. Others include only a small amount. A product listing “creatine” does not automatically mean it provides the full daily amount used in research. Likewise, the noticeable buzz from pre-workout usually comes from caffeine or another stimulant, not creatine.
Should You Use Creatine or Pre-Workout?
That depends on your goal. Choose plain creatine when you want:
Long-term strength support
Improved repeated high-intensity performance
A stimulant-free option
Flexible timing
Simpler ingredient control
Consider a caffeinated pre-workout when you want:
Immediate alertness
Increased motivation
Reduced perceived fatigue
An acute performance aid
You may also use both strategically.
For example:
Creatine every day
Caffeine only before selected workouts
No caffeine before evening training
Lower caffeine during periods of high stress or poor sleep
This helps prevent caffeine from becoming the foundation of your energy strategy.
Does Creatine Work Without Caffeine?
Absolutely.
Creatine does not need caffeine to:
Increase muscle creatine stores
Support phosphocreatine availability
Improve repeated high-intensity capacity
Complement resistance training
Support strength development
Research supporting creatine spans many studies in which creatine was used independently of caffeine. Reviews continue to describe 3–5 grams per day as a commonly effective and well-tolerated approach. (SpringerLink)
A caffeine-free creatine product can be fully effective.
Can You Take Creatine Before Bed?
Yes. Pure creatine is not a stimulant, so taking it before bed should not produce the same alerting effect as caffeine.
The practical concerns are more likely to involve:
Whether the product contains hidden stimulants
Whether you consume a large amount of fluid immediately before sleep
Whether evening training has raised your alertness
Whether you also consumed caffeine
Creatine’s exact timing matters less than daily consistency.
For a deeper explanation, read:
Caffeine and Sleep
Unlike creatine, caffeine can interfere with sleep. Potential effects include:
Delayed sleep onset
Reduced total sleep time
Lighter sleep
Increased awakenings
Reduced perceived recovery
The exact response varies considerably between individuals.
Caffeine has a multi-hour half-life, meaning a meaningful portion may remain in your system long after consumption. For someone sensitive to caffeine, a late-afternoon pre-workout may still affect sleep that evening.
This creates a performance tradeoff. Caffeine may improve today's workout, and poor sleep may reduce tomorrow's recovery. As a Human Performance expert, I view sleep as the higher priority when those goals conflict.
Is More Caffeine Better?
No. More caffeine does not reliably create more benefit.
The NIH notes that roughly 2–6 mg/kg may improve exercise performance, but larger amounts do not appear to enhance performance further and increase the chance of side effects. (Office of Dietary Supplements)
High doses may increase:
Anxiety
Gastrointestinal distress
Shakiness
Rapid heart rate
Sleep disruption
Dependence
Tolerance
Start with the lowest effective dose. Some people perform perfectly well with no caffeine at all.
Should You Cycle Caffeine?
Caffeine tolerance can develop with regular use, meaning the same dose may feel less noticeable over time. That does not necessarily mean caffeine has stopped producing all physiological effects, but increasing the dose repeatedly is rarely the best solution.
A better strategy may include:
Using caffeine only for important workouts
Reducing intake on recovery days
Avoiding automatic afternoon consumption
Taking periodic lower-caffeine phases
Prioritizing sleep when fatigue rises
Creatine generally does not require this type of cycling.
A Practical Creatine and Caffeine Routine
Here is a simple example.
Morning Workout
Creatine: Take your daily dose before or after training.
Caffeine: Optional, based on tolerance and need.
Hydration: Begin before the workout.
Afternoon Workout
Creatine: Take whenever convenient.
Caffeine: Consider a lower dose, especially when sleep is sensitive.
Hydration: Adjust for environment and sweat loss.
Evening Workout
Creatine: Fine to take.
Caffeine: Often best reduced or avoided.
Recovery: Prioritize nutrition, hydration, and sleep.
Rest Day
Creatine: Continue your daily dose.
Caffeine: Use based on daily needs rather than because creatine requires it.
Creatine is a consistency tool. Caffeine is a situational tool.
FAQs
Does creatine have caffeine?
No. Pure creatine monohydrate does not contain caffeine and is not classified as a stimulant. Creatine works primarily by increasing muscle phosphocreatine availability and supporting ATP regeneration during high-intensity exercise. Some pre-workouts combine creatine and caffeine, so always verify the finished product’s Supplement Facts label.
Is creatine a stimulant?
No. Creatine does not primarily stimulate the central nervous system or block adenosine receptors like caffeine. It generally does not produce an immediate buzz, heightened alertness, or stimulant crash. Its performance benefits develop as muscle creatine stores increase through consistent supplementation.
Can creatine and caffeine be taken together?
Yes. Many people use both ingredients, and current evidence does not show that the combination is inherently unsafe for healthy adults using appropriate doses. Research on whether simultaneous ingestion adds further performance benefits is mixed, and some users may experience gastrointestinal discomfort. Separating the doses is a reasonable option when tolerance is a concern.
Does caffeine cancel out creatine?
Current evidence does not support the claim that caffeine universally cancels out creatine or prevents muscle creatine uptake. Some studies have found no added benefit when the ingredients are taken together, while others suggest certain performance effects could be blunted under specific protocols. That is different from showing that caffeine completely neutralizes creatine.
Does creatine keep you awake?
Pure creatine is not a stimulant and is not expected to keep you awake in the same way caffeine can. If a creatine product disrupts your sleep, check whether it also contains caffeine, guarana, tea extract, or another stimulant. Large amounts of fluid immediately before bed may also interrupt sleep through nighttime bathroom trips.
Can you mix creatine with coffee?
Yes, provided you tolerate the combination. Mixing creatine into coffee does not appear necessary for effectiveness, and research has not shown a clear performance advantage from combining them. Take the drink soon after mixing and monitor gastrointestinal comfort and total caffeine intake.
Is caffeine-free creatine effective?
Yes. Pure creatine monohydrate works independently of caffeine and has extensive research supporting its use for strength, power, repeated high-intensity performance, and resistance-training adaptations. Caffeine-free creatine may be especially useful for evening exercisers, caffeine-sensitive individuals, and people trying to protect sleep.
Key Takeaways
Pure creatine does not contain caffeine.
Creatine is not a stimulant.
Creatine supports ATP regeneration, while caffeine primarily increases alertness by blocking adenosine receptors.
They can be used within the same routine, but the combination is not always superior.
Current evidence does not show that caffeine universally cancels out creatine.
Creatine can be taken before bed, while late caffeine may disrupt sleep.
Creatine should generally be used consistently; caffeine should be used deliberately.
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RESEARCH BACKED CITATIONS
Guest NS, VanDusseldorp TA, Nelson MT, et al. International Society of Sports Nutrition Position Stand: Caffeine and Exercise Performance. This position stand reviews caffeine dosing, mechanisms, performance effects, timing, individual response, and concurrent use with other supplements. (SpringerLink)
NIH Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance. The NIH summarizes evidence supporting caffeine and creatine, including their different mechanisms, common doses, benefits, and potential adverse effects. (Office of Dietary Supplements)
Antonio J, Candow DG, Forbes SC, et al. Common Questions and Misconceptions About Creatine Supplementation. This peer-reviewed review addresses creatine dosing, safety, effectiveness, water retention, and common misinformation. (SpringerLink)
Trexler ET, Smith-Ryan AE, Roelofs EJ, Hirsch KR, Mock MG. Creatine and Caffeine: Considerations for Concurrent Supplementation. This review evaluates mixed findings concerning simultaneous creatine and caffeine use and discusses potential gastrointestinal and performance considerations. (PubMed)
Pakulak A, Candow DG, Totosy de Zepetnek J, et al. Effects of Creatine and Caffeine Supplementation During Resistance Training. The study found limited differences between groups, with a small muscle-thickness improvement in the creatine-only group and no evidence that caffeine universally neutralized creatine. (PubMed)
Trexler ET, Smith-Ryan AE, Roelofs EJ, Hirsch KR, Mock MG. Effects of Coffee and Caffeine During Creatine Loading. This controlled trial examined creatine alone versus creatine combined with coffee or caffeine and reported no clear additional performance benefit from co-ingestion. (PMC)
Mabrey G, et al. The Effect of Creatine Nitrate and Caffeine Individually or Combined on Exercise Performance and Cognitive Function. The trial reported some cognitive findings but no significant exercise-performance advantage from the combined condition. (PubMed)
Harty PS, Zabriskie HA, Erickson JL, et al. Multi-Ingredient Pre-Workout Supplements: Safety Implications and Performance Outcomes. This review explains the complexity and variability of multi-ingredient pre-workout products that may combine caffeine, creatine, and other compounds. (SpringerLink)
U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? The FDA cites 400 milligrams per day as an amount not generally associated with negative effects for most adults, while emphasizing substantial individual variability. (U.S. Food and Drug Administration)
