Creatine side effects: hair loss, kidneys, bloating and water weight

Every week someone asks whether creatine will make their hair fall out or wreck their kidneys. These fears have specific origins, and the research has caught up with most of them.

Hair loss

The hair worry comes from one 2009 study of college rugby players. During a week of loading and two weeks of maintenance, their DHT (a hormone linked to male-pattern hair loss) rose, while testosterone did not. The study had 20 players, did not measure hair at all, and was never repeated.

In 2025 a 12-week randomized, placebo-controlled trial finally measured hair directly. Young men took 5 g of creatine monohydrate a day or a placebo. Dermatologists measured hair density, follicle counts and thickness. There were no meaningful differences in DHT, testosterone, or any hair measure.

One trial is not the last word, and people with a strong family history of hair loss sometimes choose to avoid creatine anyway. But the evidence no longer supports the rumor.

Kidneys

Creatine breaks down into creatinine, which the kidneys clear. Doctors use blood creatinine to estimate kidney function (eGFR). If you take creatine, your creatinine can read a little high, and your eGFR can look lower than it is, without your kidneys being harmed.

Studies in healthy adults, including some lasting years, have not found kidney damage from normal doses. What that means in practice:

• Tell your doctor you take creatine before blood work, so a high creatinine is interpreted correctly.
• If you have kidney disease, reduced kidney function, or diabetes with kidney involvement, ask your doctor before taking it.

Bloating, cramps and stomach upset

These are real, and they are mostly about dose. Taking 20 g a day during a loading phase, or 10 g at once, is when most people report them. Fixes:

1. Skip loading and take 3–5 g a day. See do you need to load creatine?.
2. Split larger doses.
3. Dissolve the powder fully in warm liquid.
4. Take it with food.

Water weight

Creatine pulls water into muscle cells. Many people gain about 1–2 kg in the first weeks, especially when loading. That is water inside the muscle, not fat, and it is not the same as puffy water retention under the skin. Weight-class athletes time it around weigh-ins for this reason.

Other claims

• Dehydration and cramps: Studies have not shown creatine causes either; some found fewer cramps.
• Liver damage: Not seen in studies of healthy people at normal doses.
• Teens: Some sports-medicine groups advise caution under 18 because of limited data, though studies so far have not found harm.

Most of the real-world risk is not the molecule. It is a poor-quality or mislabeled product. See does creatine brand matter?.

Frequently asked questions

Does creatine cause hair loss?

A 2025 randomized trial of 5 g a day for 12 weeks found no change in DHT or in hair density, follicle count, or thickness. The rumor came from a single 2009 study that measured DHT, not hair.

Is creatine bad for your kidneys?

In healthy adults, studies have not shown kidney harm at normal doses. Creatine can raise blood creatinine and make kidney tests look worse than they are, so tell your doctor you take it. People with kidney disease should ask a doctor first.

Why do I feel bloated on creatine?

Usually because of a high dose at once, such as a loading phase, or undissolved powder. Taking 3–5 g a day dissolved in liquid, with food, usually fixes it.

Does creatine make you gain fat?

No. Early weight gain is water stored in muscle.

Sources

• Does creatine cause hair loss? A 12-week randomized controlled trial (JISSN, 2025)
• Three weeks of creatine monohydrate supplementation affects dihydrotestosterone (van der Merwe et al., 2009)
• Common questions and misconceptions about creatine supplementation (Antonio et al., 2021)
• ISSN position stand: creatine supplementation (Kreider et al., 2017)