A composition for a thinning agent to reduce the viscosity of a traditional gel or gel polish includes at least one monomer and a photoinitiator. The thinner can reduce the viscosity of a gel polish that has thickened, and allow for easy application of the gel to the nails. Aspects of the thinner can cause a ultra-violet curable gel or gel polish, using a ultra-violet light, to cure using a ultra-violet light emitting diode light source, when the thinner is added to the gel. The thinner is versatile and can be added to any gel polish or traditional gel to extend the life of the gel.