Does creatine cause you to become a bit thicker? Unpacking the science of water retention and muscle gain

October 18, 2025 •

4 min read

According to the International Society of Sport Nutrition (ISSN), creatine loading can cause muscles to temporarily retain up to a liter of water, leading to a noticeable increase in body weight. This initial change is a key reason for the question, does creatine cause you to become a bit thicker?, but it's important to differentiate it from actual fat gain, which creatine does not cause.

Quick Summary

Creatine can make a person appear thicker due to two factors: intracellular water retention, which provides a temporary fuller look, and an increase in lean muscle mass over time by enhancing exercise performance. It does not increase fat mass, and its effects on physique depend heavily on training and nutrition.

Key Points

Not Fat Gain: Creatine is calorie-free and does not cause an increase in body fat.
Initial Water Retention: Early weight gain on creatine is mostly temporary water drawn into muscle cells, making them look fuller.
Long-Term Muscle Growth: By boosting energy stores for intense exercise, creatine promotes greater workload and, over time, increases lean muscle mass.
Manage Bloating: Skipping the loading phase or ensuring high water intake can minimize temporary bloating caused by water retention.
Enhances Training: The primary benefit is improved performance in high-intensity exercise, which indirectly leads to superior body composition changes.
Individual Response Varies: The extent of water retention and muscle gain differs between individuals based on genetics, dosage, and training regimen.

Understanding the 'Thicker' Appearance from Creatine

When people observe a change in their physique after starting creatine, often described as becoming a "bit thicker," it's a common and well-documented effect. However, the reasons for this change are often misunderstood. The increase in perceived size is primarily the result of two distinct, but related, physiological processes: temporary intracellular water retention and long-term muscle hypertrophy. It is crucial to understand that creatine does not cause an increase in body fat. The supplement is calorie-free and has no impact on fat metabolism.

The science behind the 'thicker' appearance

At the cellular level, creatine functions as an osmotically active substance. When supplemented, creatine increases the concentration of phosphocreatine within muscle cells. This, in turn, draws water into the cells to maintain osmotic balance. This process is known as cellular volumization. This increased water content makes the muscles look fuller and more voluminous, contributing to the initial feeling or appearance of being "thicker" or "bigger". This effect is particularly noticeable during the initial loading phase of creatine supplementation, where higher doses are used to rapidly saturate muscle stores. The resulting weight gain, typically 2 to 4 pounds in the first week, is mostly water weight and not a permanent change in body fat.

Water retention vs. muscle hypertrophy

While initial weight gain is attributed to water, the long-term changes in body composition are far more significant. By boosting the body's stores of adenosine triphosphate (ATP), creatine enables more powerful and sustained high-intensity exercise. This allows individuals to push harder during workouts, leading to greater training volume and higher intensity over time. The result is a more pronounced stimulus for muscle protein synthesis and growth (hypertrophy).


Feature	Water Retention (Initial Effect)	Muscle Hypertrophy (Long-Term Effect)
Cause	Osmotic effect of creatine pulling water into muscle cells.	Increased training performance leading to greater muscle growth stimulation.
Duration	Temporary; subsides after the loading phase or as the body adjusts.	Permanent, provided consistent training and nutrition are maintained.
Appearance	Muscles look fuller, more voluminous, or "pumped".	Increased overall muscle size and definition.
Weight Gain	Rapid increase (2-4 lbs) in the first week, primarily from water.	Gradual increase in weight over weeks or months, mostly from lean mass.
Physical Feel	Can sometimes lead to a feeling of puffiness or bloating.	Greater strength, power, and overall size.
Body Fat	No effect on body fat.	Can help reduce body fat percentage indirectly by increasing lean mass.

Debunking the fat gain myth

A common misconception is that the weight gain from creatine is fat. However, this is scientifically unfounded. Creatine is a nitrogenous organic acid derived from amino acids and contains zero calories. Fat gain can only occur when there is a consistent calorie surplus over an extended period, meaning you consume more calories than your body expends. Any increase in scale weight while taking creatine is overwhelmingly a result of increased muscle hydration and eventual lean muscle tissue growth. In fact, some studies show that when combined with resistance training, creatine can lead to a slight reduction in body fat percentage, likely due to increased metabolism from the gained muscle mass.

Optimizing your diet and supplementation for physique

To maximize the benefits of creatine and manage potential side effects like bloating, a strategic approach to nutrition and supplementation is key.

Stay Well-Hydrated: Since creatine pulls water into the muscles, it's essential to increase your overall fluid intake to prevent dehydration and to help manage any uncomfortable bloating. Aim for plenty of water throughout the day.
Consistent Intake: For long-term muscle gains and to avoid the rapid water retention of a loading phase, many people opt for a consistent daily maintenance dose of 3–5 grams. This method is just as effective over time and minimizes the initial side effects.
Pair with Carbs and Protein: Taking creatine with carbohydrates or a protein-based meal can enhance absorption into the muscles. This also provides a great post-workout anabolic signal for muscle repair and growth.
Prioritize Whole Foods: Remember that creatine is a supplement, not a replacement for a balanced diet. A diet rich in lean protein, healthy fats, and complex carbohydrates will provide the foundation for optimal body composition changes.

Conclusion: The Final Verdict on Creatine and 'Thickening'

Creatine does not cause you to become thicker by adding body fat. The perception of increased thickness comes from a combination of temporary, intracellular water retention during initial supplementation and a more significant, lasting gain in lean muscle mass over time. By enhancing your training performance, creatine helps build muscle more effectively, and it is this muscle gain that alters your body composition. Any potential bloating from water retention is typically mild and short-lived, especially if you skip the initial loading phase. Ultimately, a thicker, more muscular physique from creatine is a sign of hard-earned progress in the gym, not an unwanted side effect of fat storage.

Learn more about creatine and exercise from Healthline: https://www.healthline.com/nutrition/what-is-creatine

Frequently Asked Questions

No, creatine does not cause fat gain. Any perception of looking 'bigger' is due to temporary water retention inside muscle cells during the initial phase of supplementation or, over time, from increased lean muscle mass. This is different from the less desirable 'puffy' look caused by subcutaneous (under the skin) water retention, which creatine does not cause.

The water weight gain, particularly during a loading phase, is temporary. It typically resolves within a few weeks as your body adjusts to the elevated creatine levels. Consistent daily maintenance dosing without a loading phase can also minimize this effect from the start.

The initial water retention that makes muscles appear fuller is temporary. However, the increase in muscle mass that occurs from improved training performance while taking creatine is permanent, as long as you continue to train and eat appropriately.

Yes, you can. Creatine does not add fat and by helping you maintain performance during a calorie deficit, it can help preserve lean muscle mass while you lose fat. It allows you to train harder, increasing calorie expenditure.

Many people choose to skip the loading phase (20-25g daily for 5-7 days) and go straight to a maintenance dose (3-5g daily) to avoid the associated water retention and potential stomach discomfort. The muscles will still become saturated, just over a longer period (3-4 weeks).

Creatine works by increasing your muscles' phosphocreatine stores, which helps produce more ATP—the primary energy source for high-intensity exercise. This extra energy allows you to complete more reps and sets, leading to a greater stimulus for muscle repair and growth over time.

While both men and women gain lean body mass from creatine supplementation combined with resistance training, men tend to see larger gains on average. Some research suggests this may be due to women having higher baseline creatine levels, but it is effective for both sexes.

No, taking creatine alone without an exercise regimen will not cause you to gain muscle mass. While you may experience some water weight gain, its primary function is to enhance performance, which then facilitates muscle growth when paired with resistance training.