SUPPLEMENTS ARE EVERYWHERE these days, and some promise to help boost your libido and enable you to get stronger erections that last longer. If you’re dealing with erectile dysfunction, it’s no surprise that you’d want to take them.

But do they actually help? And, better yet, are they safe?

Nathan Starke, M.D., a urologist and director of the Men’s Health Clinic at Houston Methodist, says his patients ask him about supplements “all the time.” And while supplements are usually safe for most people, he urges caution when taking them.

“My usual mantra when guys ask me about all these supplements is, ‘take it, and if you think it helps you, then really, it’s probably helping the mental side of things,’” Dr. Starke says, adding that supplements won’t address the root cause of erectile dysfunction.

Some of these products are actually dubious. There are significant dangers when it comes to “herbal Viagra,” explains Jamin Brahmbhatt, M.D., a urologist at Orlando Health. This term is used to describe the natural supplements advertised to boost your erection.

If you go to a convenience store and see something behind the counter with a name like “Boner Blaster 5,000,” it’s a surefire way to know a supplement is not legit. “Even if you buy them at a big retailer, and they seem to be made of ‘natural’ ingredients, be cautious,” Dr. Brahmbhatt says. “No one is regulating this stuff.”

That’s concerning. It’s not clear what you could be putting in your body, and there’s always the chance it could harm your overall health—including your sexual health. Here’s what you should know about supplements claiming to enhance your sex life.

The Best Supplements for Sex

SOME SUPPLEMENTS MAY help your overall health, which could, in turn, benefit your sexual health. But some might have little effect. Here’s what experts say.

Omega-3s

OMEGA-3 FATTY ACIDS are a maybe when it comes to protecting your heart and your erections. The research goes back and forth about whether fish oil supplements are really helpful for the heart. If the scales tip toward them being helpful to your heart, then your erections may benefit as well, explains Dr. Brahmbhatt. That’s because heart-healthy changes are geared toward improving blood flow and increasing the size of blood vessels, he says.

Your penis has some of the smallest blood vessels in your body, meaning they more easily get clogged up. Impeded blood flow is bad for erections, so anything that improves blood flow is good.

That’s why, at first, it might not make sense that many blood pressure medications list erectile dysfunction as a side effect, he adds. The reason is they modulate the way that blood vessels open and close, which can reduce flow overall, especially in the penis.

By contrast, omega-3 fatty acids can have the opposite effect because they lower inflammation that might be affecting blood vessels, while also reducing blood clotting. That can help boost your blood flow. While you can get your omegas from supplements, getting them from foods such as fatty fish is your best bet.

L-Arginine

L-ARGININE IS AN essential amino acid that can be good for both heart health and erectile issues, Dr. Brahmbhatt says.

In fact, a study in the journal Andrology found that patients with severe or complete erectile dysfunction had L-arginine levels that were significantly lower than that of men with milder forms of ED. L-arginine is broken down by the body into nitric oxide, a smooth muscle relaxer that allows for more blood flow to the penis, which is important for erections. (Drugs including Cialis and Viagra block the breakdown of nitric oxide in the body, so there are higher circulating levels to help with erections.)

L-arginine is found in most protein-rich foods such as red meat, poultry, beans, and dairy products, according to the Mayo Clinic, which has marked it as generally safe but cautions people who take blood pressure meds to talk to a doctor first.

This is good advice for any supplements if you’re on blood pressure medications, Dr. Brahmbhatt says. That’s because a product like L-arginine can reduce your blood pressure—which is great if it’s a bit too high, but not if you’re already bringing it down with meds. In that case, you may see a sudden and dramatic drop in pressure that could cause you to faint, or in extreme cases, have a stroke.

If you’re not on those meds and want to try the amino acid, Dr. Brahmbhatt suggests starting at a dose of about six grams a day to see how you tolerate it. In some people, the supplement can cause side effects, including nausea, abdominal pain, diarrhea, and bloating.

L-Citrulline

IN ADDITION TO L-arginine, L-citrulline may help with stronger erections. This is because L-citrulline is converted in the body to L-arginine, explains Peter Tsambarlis, M.D., a urologist at Northwestern Medicine.

L-citrulline can also aid in the production of nitric oxide (NO). “Nitric oxide is involved in vasodilation (widening and opening up of blood vessels), which can begin and maintain the erectile response,” says Michael Eisenberg, M.D., a urologist at Stanford Medicine.

A 2001 study published in Expert Opinion Pharmacotherapy states that “NO is the principal agent responsible for the relaxation of penile smooth muscle.” (FYI, penile erection is a vascular phenomenon that directly results from smooth muscle relaxation along with arterial dilation and venous restriction.)

Vitamin D

SOME STUDIES SUGGEST that men with vitamin D deficiencies are more likely to have erectile dysfunction, says Dr. Brahmbhatt. That may be because low levels of the vitamin are associated with diseases like hypertension, coronary artery disease, and peripheral vascular disease. Basically, blood flow issues that affect your system can also raise your risk of ED.

Although you can get some vitamin D from foods including salmon and eggs, along with sunshine, most people in the U.S. lack the vitamin, especially if you live in the northern part of the country, says registered dietitian Brianna Elliott, R.D.

She adds that the longer you maintain low levels, the more effects you might see, including potential ED. But how much you should take is a moving target. The National Institutes of Health recommends 600 IU, while the Endocrine Society suggests much higher levels of up to 2,000 IU daily.

“This would be a good topic for your next doctor visit,” Elliott says, noting that it’s easy to test for vitamin D levels, and from there, you can get a recommendation about dosage amounts based on that information.

Folic Acid (B9)

ANOTHER SUPPLEMENT THAT is good for overall health and wellness, including erectile health, is folic acid or B9. Some research has linked improvement in sexual performance with folic acid supplementation, which lowered levels of the amino acid homocysteine, explains Dr. Tsambarlis. “Homocysteine levels were previously found to be higher in men with ED than their counterparts who were not suffering from ED.”

More Effective ED Remedies

IN GENERAL, HERE’S the best possible “supplement” you can take for your sex life: lifestyle changes. A healthy diet, regular exercise, good sleep habits, and lower stress levels all go a long way toward improving your health, as you’ve heard a million times, Dr. Starke says.

“Overall health and sexual health are closely related,” explains Dr. Eisenberg. “Thus, anything that benefits heart health can also benefit sexual health. A good diet, exercise, and maintaining a good body weight can all help [as well].”

“Diet and exercise have consistently outperformed supplements and have a significant and reliable impact on sexual performance,” says Dr. Tsambarlis.

The Bottom Line on ED Supplements

KEEP IN MIND that supplements are not held to the standards of pharmaceuticals. Always choose supplements with a third-party verification, like NSF or USP. Any supplement can also have side effects. Pharmaceutical testing reveals those for approved drugs, but supplements don’t undergo review in this way.

“I always attempt to temper expectations when utilizing supplements for sexual performance,” says Dr. Tsambarlis.

And be sure to talk to your doctor before taking them if you have heart problems, kidney disease, high blood pressure, or other health conditions, Dr. Starke says.

No supplement is going to come close to helping your libido and erectile function as much as getting regular exercise, eating a balanced diet, handling stress, getting plenty of sleep, and managing any health conditions that you have, Dr. Starke says.

“There is definitely not any single supplement that I would say if your erections are suffering and you think you’re doing everything else right, take X because that is going to make all the difference,” he adds.