Does creatine cause erectile dysfunction?

Does creatine cause erection problems? No study has found that it does. Creatine is not among the causes of erectile dysfunction named by healthdirect, Healthy Male or Australian Prescriber, and the trials that measured men's hormones on creatine found no change in testosterone. No trial has tested erections or sex drive directly, so the honest answer is no evidence of harm — and no evidence that it helps either.

Does creatine lower testosterone or sex drive?

Not in the trials that measured it. In a 12-week randomised trial, 38 resistance-trained men aged 18 to 40 took 5 g of creatine or a placebo powder a day; creatine made no difference to total testosterone, free testosterone or dihydrotestosterone (DHT) (Lak et al., J Int Soc Sports Nutr 2025). An earlier crossover study in 20 rugby players also found testosterone unchanged, but DHT was 56% higher after a week of loading on 25 g a day and still 40% higher after two weeks on 5 g a day (van der Merwe et al., Clin J Sport Med 2009). Neither study asked about erections or libido.

Low testosterone does matter: hypogonadism, where the testicles cannot make enough testosterone, is on healthdirect's list of causes, and a doctor assessing erection problems may refer you for blood tests (healthdirect). If a hormone problem is the cause, Healthy Male says the doctor will usually treat that first.

Is creatine a steroid?

No. Creatine is a nutrient: the body makes about 1 g a day, a diet with meat and fish supplies about another 1 g, and a supplement tops up the stores in muscle (AIS Sports Supplement Framework — creatine). Anabolic steroids are synthetic medicines similar to testosterone. Their short-term side effects include "changes in sex drive", and in men shrunken testicles, lower sperm production and infertility; in Australia they are legal only when a doctor prescribes them for a medical reason (healthdirect — Anabolic steroids). The two get confused because both are used by people building muscle. If you use steroids and ED medicines, read can you take Viagra while on steroids?

What side effects does creatine have?

Mostly a little weight gain. The Australian Institute of Sport puts creatine monohydrate in Group A — strong evidence for use in specific situations in sport — and finds "no evidence of systematic serious adverse effects". What it does list is a gain of up to 1 or 2 kg of body water while muscle creatine stays high, and occasional mild stomach upset, which skipping the loading phase and taking 3–5 g a day with meals helps avoid (AIS).

Creatine also nudges up creatinine, a blood marker of kidney function. A 2025 meta-analysis found a small rise in creatinine but no significant change in the kidneys' filtration rate, and put it down to creatine's turnover rather than kidney damage (Naeini et al., BMC Nephrol 2025). If you have a kidney blood test, tell your GP you take it.

Is the bigger risk what else is in the tub?

Often, yes. The TGA warns that counterfeit supplements can contain ingredients not on the label, including illegal prescription medicines, substances banned in sport and toxic substances (TGA — Sports supplements in Australia). The AIS points athletes to Sport Integrity Australia's list of batch-tested products and adds that even those carry the lowest risk, not a guarantee. Nearly all the safety and efficacy data are on plain creatine monohydrate powder; the AIS calls the newer blends and "better absorption" forms a marketing edge rather than evidence-based (AIS). Products that promise hormone or sexual effects are a different matter: why some "herbal" sex pills contain hidden medicines. The same question for protein powders is answered in can whey protein cause erectile dysfunction?

Can you take creatine with Viagra or Cialis?

Neither Australian leaflet names creatine among the medicines that interact (Viagra CMI; Cialis CMI). Both ask you to tell your doctor or pharmacist about "any medicines, vitamins or supplements that you buy without a prescription from your pharmacy, supermarket or health food shop". The rules that do apply are the tablets' own: never with nitrates for chest pain, and no more than one tablet in 24 hours (healthdirect — Sildenafil).

What does cause erection problems, then?

Usually something physical: reduced blood flow from clogged arteries, diabetes, high blood pressure, nerve problems, hormone problems, some medicines, alcohol and smoking — and sometimes stress, anxiety or relationship problems (healthdirect). healthdirect's prevention list is short: stop smoking, exercise more, lose weight and eat healthy food. Training is on the right side of that list — can exercise improve ED? — though men who train very hard ask the opposite question: can overtraining lead to ED? Riders ask whether the saddle affects erectile function, and dieters about the keto diet.

The short answer

Creatine has not been shown to cause erection problems or to lower testosterone, and at the usual 3–5 g a day its main side effect is a kilo or two of water weight. If erections change, look at the usual causes with your GP, and choose plain creatine monohydrate over blends that promise more. Other supplement and diet questions, from vitamin B12 to caffeine, are in our guide to lifestyle and erectile dysfunction.