A bonder uses UV light-activated ingredients to bond with the natural keratin in the nail, while also remaining partially exposed to bond with a gel product.

Bonders come in many different forms, explains Peter DeSantis of DeEnterprises, and the primary function of a bonder is to maximize the adhesion of artificial nail enhancements. Bonders can be primers, base coats for UV light activated products, solvent-based solutions to remove natural oils from the natural nail, or products that raise the PH on the natural nail. Most bonders are formulated to bond with the natural keratin on the nail plate to increase adhesion and to prevent lifting.