Pros and Cons of Mixing Creatine and Caffeine

If you’re using creatine to boost your gym performance or grow muscle mass, you might want to consider how creatine and caffeine interact.

Caffeine and creatine rank among the most popular ergogenic aids in fitness. An ergogenic aid is any substance or practice intended to enhance performance, endurance, or recovery.

Despite how commonly they’re used, there remains uncertainty about whether caffeine and creatine are safe or effective when combined.

Older studies hinted that caffeine might negate creatine’s benefits, but many specialists point out there’s little contemporary evidence supporting that view beyond occasional digestive upset.

Read on to learn what current studies report, plus the benefits, drawbacks, and recommended practices for using creatine and caffeine together.

What the research shows

Caffeine is a naturally occurring stimulant found mainly in coffee and tea, and also added to energy drinks, preworkout blends, and sodas.

It’s classed as a stimulant because it influences the central nervous system and promotes wakefulness (1).

Creatine is a derivative of amino acids that supports muscle and strength gains. It’s one of the most extensively studied performance supplements and is widely accepted for its benefits in resistance training (2, 3, 4).

While each has proven benefits on its own, many people wonder how they interact when consumed together.

No meaningful effect on performance

There was a time when researchers believed caffeine could diminish creatine’s performance-enhancing effects. Yet most recent studies do not support that conclusion.

A 2017 trial over five days divided 54 men 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)
• placebo

Findings revealed no notable differences in power or sprint performance between groups. Those taking both caffeine and creatine did report increased gastrointestinal discomfort (5).

A 2015 review found no pharmacokinetic interactions — meaning no significant way the body’s handling of one affects the other — between caffeine and creatine, and suggested multi-ingredient products containing both may support strength and power (6).

Because studies have reported mixed results, additional research is warranted.

Although joint-effect data are limited, the individual advantages of each ingredient for athletic performance are well established (3, 7, 8, 9).

Possible side effects

Some suggest the apparent interaction between caffeine and creatine may be due more to their opposite effects on muscle relaxation timing and to gastrointestinal issues rather than a direct biochemical interaction; however, this remains largely speculative (6, 10).

Caffeine can act as a mild diuretic in those who rarely consume it, though habitual caffeine users tend to be less affected (6).

Creatine can cause short-term water retention, but this is intracellular and evidence suggests it doesn’t raise total body water over extended periods (6, 11).

Because they can push hydration in different directions, combining them might negatively influence performance if you’re not adequately hydrated. Inadequate fluid intake during exercise can quickly lead to significant fluid loss and dehydration.

Summary: Taken together, caffeine and creatine appear unlikely to impair athletic performance and may even aid strength and power. Still, they can raise the chance of stomach upset and may increase dehydration risk.

Pros and cons of using creatine with caffeine

Below are some advantages and drawbacks to weigh when mixing creatine and caffeine.

Pros

Both caffeine and creatine are considered safe and effective ergogenic aids. Potential benefits include (3, 7, 8, 9):

• Greater power and strength. Creatine increases intramuscular phosphocreatine, enabling faster ATP resynthesis during intense effort, which supports explosive power and force production.
• Enhanced muscle growth. Both substances are tied to increased strength gains and muscle mass, in part because they allow you to lift heavier or perform more repetitions, promoting hypertrophy.
• Boosted alertness and vigor. Caffeine blocks adenosine receptors, reducing sleepiness and providing extra perceived energy to fuel a workout. If you’re curious about timing your caffeine, see tips on coffee before workout.
• Documented ergogenic effects. Numerous studies support both compounds as effective for enhancing muscle growth, strength, and performance in power, sprint, and high-intensity activities.

Cons

Despite the positives, consider some potential negatives (6, 12, 13):

• Gastrointestinal upset. Caffeine can speed intestinal motility, which may cause stomach discomfort or more frequent bowel movements. Individual sensitivity varies.
• Potential sleep disruption. Because it stimulates the nervous system, consuming caffeine too close to bedtime can make falling asleep harder. Poor sleep can undermine athletic progress, so avoid caffeine within about 6 hours of bedtime.

Summary: Caffeine and creatine are both established, generally safe performance enhancers. Yet combining them could worsen sleep, raise dehydration risk, and cause digestive issues in some people.

Best practices when combining creatine and caffeine

Consider these recommendations if you plan to use creatine and caffeine together:

• Keep hydrated. Drink plenty of fluids throughout the day, particularly around workouts. Pale yellow urine is a practical indicator of adequate hydration.
• Limit total caffeine. Sensitivity varies, but most adults can safely consume up to 400 mg of caffeine daily (14).
• Avoid caffeine within ~6 hours of sleep. The closer caffeine is to bedtime, the more likely it will disrupt sleep. If possible, schedule caffeine intake and intensive exercise in the morning or early afternoon (15).
• Try decaf later in the day. Decaffeinated coffee contains roughly a tenth (or less) of the caffeine of a regular cup, making it less likely to cause dehydration or disturb sleep when consumed later.

Summary: Individuals tolerate caffeine and creatine differently, so pay attention to how your body responds and adjust accordingly.

Dosage and timing

If you opt to use creatine and caffeine — together or separately — follow evidence-based dosing guidelines and consult a healthcare professional before starting or changing supplement routines.

Caffeine

The International Society of Sports Nutrition (ISSN) suggests 2–6 mg/kg (0.9–2.7 mg per pound) of caffeine when used as a performance aid. For many people, that equates to about 3–4 cups of coffee per day (8).

Caffeine typically peaks around 60 minutes after ingestion, so having coffee or a preworkout roughly an hour before training may be most effective (8).

Creatine

ISSN guidance from 2017 recommends a loading phase of ~0.3 g/kg (0.14 g/lb) daily for 5–7 days, followed by a maintenance dose of 3–5 grams daily (3).

For instance, a 200 lb (90.1 kg) person might take roughly 27 grams daily during the loading week, then reduce to 3–5 grams per day thereafter.

Taking creatine shortly before exercise is commonly advised, although more research is required to pinpoint the optimal timing (15).

Bottom line

When used in moderation, creatine and caffeine together are unlikely to harm your workouts and may even improve performance.

Both supplements are well-studied for their ergogenic effects, including support for muscle growth, strength, and power. Common adverse effects include stomach upset; additionally, caffeine and creatine can have contrasting effects on muscle relaxation and fluid balance.

Consult a healthcare professional before beginning creatine or caffeine supplementation or making significant changes to dosages—especially if you plan to add both or alter your activity level substantially.

If you want a boost in performance, creatine and caffeine are both viable options.