Why over-the-counter nail lacquer does not clear nail fungus

It is one of the most repeated stories at the clinic: “I have been using a lacquer for a year and the nail is exactly the same.” And there are almost always three reasons behind it, none of which is that the product is a scam.

They are worth understanding, because all three can be corrected.

A yellowish, thickened or lifting nail is not necessarily onychomycosis. It may be the consequence of an old knock —sometimes years earlier—, of continuous pressure from short footwear, of psoriasis, or of other nail conditions.

An antifungal applied to something that is not fungal does nothing, and months are lost while it is being used. That is why the first step is not to treat: it is to find out what it is.

The fungus lives within the thickness of the nail and underneath it, not on the surface. A thickened nail is a barrier: the lacquer stays on top and nothing changes below.

That is where the part you cannot do at home comes in: reducing the thickness of the nail and removing the damaged portion. It is not cosmetic, it is what gives a topical treatment any chance of reaching the problem.

A toenail takes months to renew completely. That means that even if the treatment works from day one, the already damaged part does NOT heal: it is replaced as new nail grows.

With that expectation, it is logical to conclude after two months that it is doing nothing. The way to know whether it is working is not to look at whether the discoloured patch fades, but whether the nail emerging from the base comes through healthy.

If the nail has changed in thickness or colour, if it bothers you when walking, or if you have spent months on a treatment without seeing healthy new nail coming through. And before that if you have diabetes or circulatory problems: in that case a thickened nail pressing on the skin is not simply a matter of appearance.