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If you’re using creatine to help improve your workout in the gym or build muscle mass, you may want to look a little closer at how creatine and caffeine interact.

Caffeine and creatine are some of the top ergogenic aids in the fitness industry. An ergogenic aid is one that aims to improve performance, endurance, or recovery.

Yet, despite their widespread use, there’s confusion as to whether caffeine and creatine are safe to take together.

Though older research suggested caffeine cancels out any of creatine’s purported benefits, many experts argue that there is little modern research that supports this beyond mild digestive discomfort.

Keep reading to find out what the research says, along with the pros and cons and best practices for using creatine and caffeine together.

Caffeine is a natural stimulant found mostly in coffee and tea. It’s also found synthetically in energy drinks, preworkout supplements, and soda.

It’s considered a stimulant because it acts on the central nervous system to induce a sense of alertness (1).

Creatine is an amino acid derivative that can support muscle and strength development. It’s one of the most widely studied ergogenic aids and is well-regarded for its benefits in strength training (2, 3, 4).

Though they have separately been shown to be effective in sports performance, you might be wondering how they work when taken together.

It was once thought that caffeine blunted the performance-enhancing benefits of creatine. However, most modern research disproves this.

A 2017 study that took place over 5 days split 54 males into four groups (5):

  • anhydrous caffeine (300 mg) with creatine (20 grams)
  • instant coffee (300 mg caffeine) with creatine (20 grams)
  • creatine only (20 grams)
  • a placebo group

Results showed no significant differences in power and sprinting performance among all groups. Participants taking caffeine and creatine reported greater digestive discomfort, though (5).

A 2015 review of research found no pharmacokinetic interactions — in other words, how the body affects a drug — between caffeine and creatine. Moreover, they found that multi-ingredient supplements containing both creatine and caffeine may support strength and power performance (6).

Due to conflicting reports of combined caffeine and creatine on athletic performance, more research is needed.

Though research on the effectiveness of the two ingredients combined is scarce, their individual benefits in sports and athletic performance are widely accepted (3, 7, 8, 9).

It’s been suggested that the real culprit behind caffeine’s purported effect on creatine may have more to do with their opposing effects on muscle relaxation time as well as gastrointestinal side effects than with specific interactions between the two. Keep in mind that this is largely speculation (6, 10).

Caffeine may act as a diuretic — a food or beverage that promotes urination — in individuals who consume little to no caffeine on a regular basis. However, people who usually drink caffeine are less susceptible to its diuretic effects (6).

On the other hand, creatine can lead to water retention, though this water retention is intracellular and occurs as a short-term effect. Studies suggest creatine doesn’t increase total body water over longer periods of time (6, 11).

Considering their opposing effects on hydration, this may negatively affect performance. Either way, if you’re not drinking enough water during a workout, you can quickly lose too much body fluid and become dehydrated.

Summary

Together, caffeine and creatine appear to have no negative effects on athletic performance and may even enhance power and strength. However, they may also increase the likelihood of digestive discomfort and risk for dehydration.

Here are some of the pros and cons you may want to keep in mind for combining creatine and caffeine.

Pros

Caffeine and creatine are both regarded as safe and effective performance enhancers. Some of their benefits include (3, 7, 8, 9):

  • Increased power and strength. Creatine ensures that you have plenty of energy when you’re exercising. It does this by increasing a substance called phosphocreatine in your muscles. This helps your cells quickly produce more energy (ATP) in working muscles, allowing for greater explosive power and strength.
  • Increased muscle mass. Both creatine and caffeine are linked to greater strength gains and muscle mass. In particular, they may help you lift more weight or perform more reps, which encourages muscle hypertrophy (muscle building).
  • Increased alertness and energy. Caffeine stimulates the central nervous system by stopping a chemical called adenosine from binding to receptors in your brain that make you sleepy. This can provide you with an additional sense of energy to support your workout.
  • Proven ergogenic benefits. Numerous studies have supported both creatine and caffeine as safe and effective performance enhancers. In particular, they have been shown to improve muscle building, strength, and performance in power, sprinting, and high intensity sports.

Cons

Despite the many benefits of caffeine and creatine, it’s important to consider some of their downsides (6, 12, 13):

  • Digestive discomfort. Caffeine may increase peristalsis — the movement of digested food through the intestines. This may lead to stomach discomfort and more frequent bowel movements. Sensitivity to caffeine is highly individual, though.
  • Possibly worsened sleep. Due to its stimulating effects, drinking caffeine too close to bedtime may lead to difficulty sleeping. Since lack of sleep can hinder athletic performance, it’s best to stop consuming caffeine at least 6 hours before bedtime.
Summary

Caffeine and creatine are both independently regarded as safe and effective sports performance aids. However, the combination may lead to worsened sleep, increased risk of dehydration, and digestive discomfort in some people.

Here are some best practices for taking creatine and caffeine:

  • Stay hydrated. Be sure to drink plenty of water throughout the day, especially when exercising. For most people, a good indication of hydration is a pale yellow urine color.
  • Limit your caffeine intake. Caffeine sensitivity is highly individual, meaning some people can tolerate more or less caffeine before experiencing unwanted side effects. However, most people can safely tolerate up to 400 mg of caffeine per day (14).
  • Stop consuming caffeine at least 6 hours before bed. The closer to bedtime you consume caffeine, the more likely it’ll keep you awake at night. Keep your caffeine intake (and, if possible, your workouts) to the morning or early afternoon (15).
  • Switch to decaf. Decaffeinated coffee has about a tenth or less caffeine as a regular cup of coffee. This means it’s less likely to dehydrate you or keep you up at night if you have it later in the day.
Summary

Each person will tolerate caffeine and creatine differently. That’s why it’s important to listen to your body to determine what works best for you.

If you choose to take creatine and caffeine — either together or separately — there are best practices for sports and athletic performance. However, always consult a healthcare professional before taking new supplements or changing doses.

Caffeine

A 2021 position statement by the International Society of Sports Nutrition (ISSN) recommends taking 0.9–2.7 mg of caffeine per pound (2–6 mg/kg) when used as an ergogenic aid. For most people, around 3–4 cups of coffee per day is sufficient (8).

Once consumed, caffeine reaches its peak in around 60 minutes. So, try having a cup of coffee or preworkout about an hour before exercising (8).

Creatine

A 2017 position statement by ISSN recommends starting with a “loading dose” of 0.3 grams per kilogram (0.14 grams per pound) per day for 5–7 days, then adjusting your daily dose to 3–5 grams per day on an ongoing basis (3).

For example, 200 pound (90.1 kg) person would take 27 grams per day for the first week, then lower their dose to 3–5 grams per day.

It’s likely best to take creatine shortly before a workout, though more research is needed to determine the exact time frame (15).

In moderate amounts, creatine and caffeine taken together shouldn’t have a negative influence on your workouts. In fact, the two may enhance your performance.

Both creatine and caffeine have been widely studied for their ergogenic benefits. In particular, they may support muscle growth, strength, and power. That said, common side effects include stomach upset. Also caffeine and creatine have opposite effects on muscle relaxation and water retention.

It’s best to speak with a healthcare professional before adding creatine or caffeine to your diet or making a drastic change in dosage. This is especially true if you’re adding both at the same time or changing your workout or physical activity in general.

If you’re looking for a performance boost, creatine and caffeine are both great options.