If you’ve ever had a chemical peel at the spa, you are familiar with Trichloroacetic acid, or TCA. It is a common agent used to smooth out fine lines, dull acne scars and soften wrinkles. It showed some promise as a tattoo removal—or more specifically tattoo fading—treatment in tests conducted in the early 1990s. The limited efficacy has spawned a cottage industry of products containing TCA and marketed as tattoo removal creams, but before you look to one of those as a panacea, there are a few things you should know.

TCA is best used as a supplemental treatment prior to undergoing the much more successful, but much more expensive, laser removal. TCA will fade most tattoos, and so using it according to the product instructions can possibly save you some money and some pain by decreasing the number of laser treatments you will need.

Sellers of TCA products insist that TCA does not cause scarring, though between 10 and 20 percent of patients have adverse skin reactions, according to the Tattoo Health Organization. Symptoms range from mild irritation to severe blistering and discoloration. They recommend testing a small area of the skin first before spreading the product over the entire tattoo. Even without a reaction to TCA, there may still be visible scarring when the tattoo fades, but that is generally from the application of the tattoo itself, not the TCA.

A quality tattoo applied by an artist with professional equipment has real staying power. Even laser treatments can’t completely remove a deep, dark tattoo. TCA works best on homemade tattoos or amateur tattoos that don’t penetrate as deeply into the dermis.

TCA is not recommended for people with darker skin tones. A condition called hypopigmentation may result with TCA treatments, leaving behind a lighter patch of skin where the tattoo was. Coupled with an incomplete removal, this effect can be less desirable than the tattoo itself.

TCA works best on brightly colored tattoos, and you will probably notice that the colored areas fade first from a tattoo with both black outline and colored areas. You should see results in two to three applications spanning several months. After six applications, you have probably gone as far as you can go using TCA alone. Laser treatment may make a good result even better.