Creatine — Research Profile

No. Loading (20 g/day for 5-7 days) saturates muscle creatine stores faster, but 3-5 g/day reaches the same saturation level after about 3-4 weeks. Loading is optional — it just speeds up the timeline. Many people skip loading to avoid potential GI discomfort.

This concern comes from a single 2009 study that showed creatine increased DHT levels. However, the study had significant limitations, no follow-up studies have replicated this finding, and multiple large-scale studies have found no association between creatine and hair loss. The ISSN position stand does not list hair loss as a side effect.

Yes. Creatine raises creatinine levels (a kidney function marker), which can cause false positives on kidney tests, but this does not indicate kidney damage. Multiple studies lasting up to 5 years have found no adverse kidney effects in healthy individuals. People with pre-existing kidney disease should consult their doctor.

Creatine monohydrate. It is by far the most researched form, and the ISSN concludes that claims other forms (HCl, buffered/Kre-Alkalyn, ethyl ester) are degraded less or absorbed better in the body are currently unfounded. Monohydrate is also the cheapest, making it the default evidence-based choice.

The strongest evidence is for high-intensity, repetitive exercise capacity and for greater gains in muscular strength and lean body mass when combined with resistance training: pooled reviews show creatine adds roughly 8% more strength than training alone and about 1.1 kg more lean body mass. A separate meta-analysis found a small overall memory benefit that was meaningful mainly in older adults (aged 66-76) rather than younger people. For pure aerobic endurance in trained athletes, a meta-analysis found no meaningful benefit.

A common protocol is a loading phase of 5 g (about 0.3 g/kg body weight) four times daily for 5-7 days, followed by 3-5 g/day to maintain elevated stores. Loading is optional: taking 3 g/day from the start saturates muscle over about 28 days with the same end result, just more slowly.

No specific time of day is required, because the benefit comes from keeping muscle stores saturated over time rather than from an acute pre-workout effect. The ISSN gives no clear advantage to before- versus after-training dosing; what does help retention is taking it with a carbohydrate or carbohydrate-plus-protein meal. Pick a daily time you will stick to.

The only side effect consistently reported in the literature is weight gain, largely from increased intramuscular water and lean mass. Controlled studies have not found the commonly claimed increases in muscle cramping, dehydration, or gastrointestinal upset, although large single doses can cause temporary stomach discomfort. Splitting the dose and taking it with fluid minimizes that.

Creatine has no well-documented pharmacokinetic drug interactions, but caution is warranted with drugs that stress the kidneys, such as NSAIDs, diuretics, and cyclosporine, particularly in anyone with impaired renal function. Interaction references also advise against combining creatine with stimulants like caffeine or ephedra, a pairing linked to warnings about serious cardiovascular events. If you take prescription medication or have kidney disease, clear creatine with your prescriber first.

It is most useful for people doing resistance training or high-intensity, repeated-effort sports who want greater strength and lean-mass gains. Older adults may benefit for preserving muscle mass and function, and vegetarians and vegans often respond more strongly because their baseline muscle creatine is lower from a meat-free diet. It offers little to those seeking pure endurance or who do no anaerobic training.

With a loading phase of about 5 g four times daily (roughly 0.3 g/kg) for 5-7 days, muscle creatine stores saturate within a week and high-intensity, repetitive exercise performance rises by roughly 10-20%. Skipping the load and taking 3 g/day still saturates stores, but takes about 28 days. Visible strength and lean-mass gains build over several weeks of resistance training, not from creatine alone.

The ISSN position stand concludes that creatine use at intakes up to 30 g/day for as long as 5 years is safe and well tolerated in healthy people from infants to the elderly. A 2025 systematic review and meta-analysis of kidney function found only a small rise in serum creatinine (a marker naturally inflated by creatine's own metabolism) and no significant change in glomerular filtration rate, indicating preserved kidney function. People with pre-existing kidney disease are the exception and should be monitored by their clinician.

No formal upper limit is set, but there is little reason to exceed a 3-5 g/day maintenance dose since muscle stores saturate and surplus creatine is simply excreted in urine. Intakes as high as 30 g/day have been tolerated in trials without evidence of toxicity. The main consequence of higher intakes is water/lean-mass weight gain, and large single doses can cause transient stomach upset.

Yes. Taking creatine alongside carbohydrate, or carbohydrate plus protein, has been reported to more consistently improve creatine retention in muscle. It is commonly stacked into post-workout shakes or with protein powder, and no adverse interaction with common training supplements has been established.

Choose plain creatine monohydrate, which is the most-studied and effective form; branded Creapure is a common high-purity option. Claims that HCl, buffered, or other forms are better absorbed are not supported by evidence, so they rarely justify a premium. Third-party certification (NSF Certified for Sport or Informed Sport) confirms label accuracy and screens for banned contaminants.