Q. Do the new paint-on products for toenail fungus work?

A. Maybe. But some simpler, safer, less expensive options may be a better choice.

Some 35 million people in the U.S. suffer from onychomycosis, or nail fungus, a hardy, microscopic organism that can cause thick, grayish, greenish toenails. While unpleasant to look at, the infections usually only require medical treatment when they strike people who have diabetes, and for those with compromised immune systems. Most people treat toenail fungus for cosmetic reasons.  

But before you try a paint-on prescription medication, make sure that you truly have toenail fungus, says Marvin M. Lipman, M.D., Consumer Reports chief medical adviser. In some cases, what looks like toenail fungus is actually a nail injury.

If your doctor confirms a nail-fungus infection, the new drugs may help, but not usually. In studies of up to 54 weeks, the two newer nail lacquers, tavaborole (Kerydin) and efinaconazole (Jublia), cleared up fungal infections for 6.5 to 17.8 percent of users. In addition, the drugs have to be applied every day for 11 months—and cost about $600 per bottle. The older paint-on drug ciclopirox (Penlac nail lacquer and generic) clears up nail fungus infection in 5.5 to 8.5 ­percent of infected people.

Oral prescription anti-fungals such as terbinafine (Lamisil and generic) are more effective (they cure 66 percent of fungal infections after 12 weeks) but pose risks, including digestive discomfort, headache, rash, loss of sense of smell, and in rare cases, liver problems. There have also been reports of people developing lupus while taking terbinafine. So your doctor should closely monitor you and you should report any problems you have. Finally, it can’t be taken by women who are pregnant or breastfeeding due to risks it poses to the baby.

In addition, there are now fungus-zapping lasers that are being pushed with Groupons and other discounts. But there’s no solid evidence those help—one small study found no benefit after 3 months. And a course of treatment can run hundreds or thousands of dollars that isn’t covered by insurance.

The good news is that an inexpensive remedy might already be in most people's medicine cabinets. Small studies suggest that the medicated chest rub, such as Vaporub, might knock out the fungus in up to 38% of people. Larger studies are needed to confirm it helps, but it’s not expected to have any serious side effects. And if you go with a generic option, the cost could be pennies per day, so it could be worth a shot. But it could take several months of daily application before you notice a difference.