Does garlic help erectile dysfunction? No study has tested garlic on its own as a treatment for ED in men. The evidence is a study in rats, one 35-man pilot trial of garlic added to tadalafil, and garlic's small effect on blood pressure and cholesterol, two conditions linked with erection problems. Garlic is good food; it is not a proven treatment.
What has actually been tested?
Three studies come close, and none shows that eating garlic treats ED.
| Study | Who | What was given | Result |
|---|---|---|---|
| Yang et al., 2013 | Rats with diabetes | S-allyl cysteine, a garlic compound, for 4 weeks | Erections restored in the rats; never tested in men |
| Bhat and Shastry, 2024 — randomised pilot trial | 35 men whose ED had not responded well to tadalafil 5 mg | Garlic 5 g twice a day or placebo, both with nightly tadalafil, for 4 weeks | Erection scores improved more with garlic added |
| Nishimatsu et al., 2014 — open-label trial | 49 men with symptoms of ageing | A Japanese product of six ingredients (aged garlic extract, ginseng, velvet antler, epimedium and two others) or a traditional herbal medicine | Erection scores rose on the six-ingredient product; garlic's own share cannot be told apart |
The pilot trial is the only one in men with ED, and it tested garlic as an add-on to a prescription medicine, in men without other illnesses, for a month. It needs repeating in a larger trial before it means much.
Why do people think garlic helps erections?
Because of blood vessels. Garlic supplements "may reduce levels of total cholesterol and low-density lipoprotein (LDL) cholesterol to a small extent in people who have high blood cholesterol levels", and limited evidence suggests they "may reduce blood pressure to a small extent in people who have high blood pressure" (NCCIH — Garlic). In a meta-analysis of trials in people with high blood pressure, systolic pressure fell by about 8.7 mmHg and diastolic by 6.1 mmHg (Ried, J Nutr 2016). Erection problems can be an early sign of high blood pressure or high cholesterol (healthdirect) — see can high blood pressure cause ED? and can high cholesterol cause ED? No trial has checked whether garlic's effect on either one improves erections, and its long-term effect on heart disease is unknown: "Future long-term trials are needed" (Ried).
Does garlic improve sperm or testosterone?
The studies disagree. A review found that some reported garlic helping male sexual function and testicular function, while others found that it "impairs testicular functions (such as inhibition of testosterone production)" and harms sperm (Hammami and El May, 2013). On that evidence, garlic is not a fertility treatment.
How much garlic, and is it safe?
No amount of garlic has been shown to help erections; the pilot trial used 5 g twice a day for four weeks. Taken by mouth, garlic has been used safely in studies lasting up to seven years. Its side effects include "breath and body odor, abdominal pain, flatulence, and nausea", and some people are allergic to it. Supplements are different: "Taking garlic supplements may increase the risk of bleeding", which matters before surgery and if you take anticoagulants or aspirin (NCCIH). Blood thinners and ED medicines are covered in Viagra with blood thinners or warfarin.
Can you take garlic with Viagra or Cialis?
Neither the Australian Viagra nor the Cialis leaflet names garlic, and in the pilot trial men took garlic with daily tadalafil. Both leaflets ask you to tell your doctor about "any medicines, vitamins or supplements that you buy without a prescription from your pharmacy, supermarket or health food shop" (Viagra CMI; Cialis CMI). Be wary of "herbal" sex capsules that list garlic among their ingredients: some products sold as natural formulas have been found to contain undeclared sildenafil or tadalafil — see the TGA's hidden-drug warnings.
What has better evidence than garlic?
Changes to how you live. Losing weight, exercising more, stopping smoking and pelvic-floor training have each helped men with ED in trials — see natural remedies for erectile dysfunction. Among supplements, L-arginine has the most consistent trials, with a modest effect; what to eat is in foods and erectile dysfunction.
The short answer
Garlic has not been shown to treat erectile dysfunction. It may lower blood pressure and cholesterol a little in people whose levels are high, one small trial found it helped when added to tadalafil, and supplements can raise the risk of bleeding. Erection problems can be the first sign of heart disease or diabetes, so they are worth a GP visit (healthdirect). Every natural option is ranked by its evidence in natural alternatives to Viagra.
