The short answerIn the US, approved ED pills such as Viagra and Cialis need a prescription, and supplements marketed for erections are a risky bet. The FDA warns that many products sold for sexual enhancement are "likely to be contaminated with dangerous hidden ingredients," often undeclared prescription drugs. A licensed online prescription is now quick and inexpensive enough that the supplement aisle rarely makes sense.
The FDA's sexual enhancement notifications page is blunt. Products that claim to help with sexual enhancement or treat sexual dysfunction, including "male enhancement supplements, erectile dysfunction treatments, male energy pills and stamina pills," are likely to be contaminated with dangerous hidden ingredients. They're "sometimes falsely advertised as dietary supplements, food and/or all-natural treatments," often have many positive reviews, are sold online and in stores, and "pose a serious health risk and are not guaranteed to work." The page, updated as recently as October 15, 2026, lists new products almost every month, and the FDA says the list "covers only a small fraction" of contaminated products. Source: FDA, sexual enhancement and energy product notifications.
Why hidden ingredients are dangerous
One example from May 29, 2026 shows the problem. FDA laboratory analysis of Erectus Plus, a male enhancement product sold on websites including eBay, found sildenafil, tadalafil and testosterone propionate that weren't on the label. The FDA warned that these undeclared ingredients "may interact with nitrates found in some prescription drugs, such as nitroglycerin, and may lower blood pressure to dangerous levels." The same notice reminds readers that FDA approval of Viagra and Cialis "is restricted to use under the supervision of a licensed health care professional." Source: FDA, Erectus Plus notification, May 29, 2026. For a man who takes nitrates for his heart, an "herbal" product secretly containing a prescription drug is exactly the combination the warnings exist to prevent. That's the real risk of OTC ED products: not that they don't work, but that you can't know what's in them.
What about the UK?
Readers outside the US may have seen that sildenafil can be bought from a pharmacy without a GP prescription in the UK. The NHS confirms you can get sildenafil "on prescription or you can buy it from a pharmacy," but you need a prescription for the other PDE5 inhibitors, and it urges care buying online "as many websites sell fake medicines."
Natural approaches that do have evidence
The natural approaches with real evidence behind them aren't capsules; they're lifestyle change and pelvic floor training, covered next. The NIDDK asks men to talk with a health care professional before using dietary supplements or alternative medicines for ED, because they can affect how other medicines work. Source: NIDDK, treatment. Our guides to over-the-counter ED treatment and natural ED remedies look at individual products and claims.