Why does gel polish feel hot in the UV/LED lamp?

Gel releases heat while it hardens. This is called an exothermic reaction. A fast-curing gel or a thick layer releases all the heat at once, which causes a sudden spike. A burning feeling is not a sign that the gel works better. Take your hand out of the lamp, wait a few seconds, and put it back.

Have you ever put your hand in a UV or LED lamp and felt a sudden, sharp wave of heat? A common myth says that if it burns, the gel is working better. It isn't true. A strong burning feeling is not normal, and you should never just tough it out. This is what I took from Douglas Schoon's Nail Structure and Product Chemistry and his article on heat spikes.

Why gel heats up

Under UV light, liquid gel polish or builder gel turns into a solid. This process is called polymerization. Chemical bonds form very quickly between the molecules, and as they form, they give off energy as heat. In chemistry this is called an exothermic reaction.

Every UV-curing product does this. How much heat you feel depends on how fast the reaction goes. A fast-curing gel, or a layer that is too thick, releases all its heat at once, and that is the sudden spike you feel. Gel is also more likely to feel hot on nails that have been filed too thin.

Milady's textbook also lists nail enhancement products curing (polymerizing) as an example of an exothermic reaction.

Why a burn matters for your nails

The skin under the nail plate is the nail bed. It is very sensitive and full of blood vessels and nerve endings. If the heat is too strong:

• it can burn the delicate tissue under the nail
• it can make the nail plate separate from the nail bed, a condition called onycholysis
• the gap can trap moisture, and bacteria can grow there

What I do to keep you comfortable

• I use a professional lamp with a low-heat mode that raises the power gradually, so the reaction is slower.
• I apply builder gel in thin, controlled layers instead of one heavy layer, so the heat is released slowly.
• I choose good quality gels that give off less heat as they cure.

A simple rule

If you feel heat in the lamp, take your hand out right away. Wait a few seconds until the warmth goes away, then put it back in. Please never suffer through it. Just tell me and we'll adjust.

If you have a burn, pain or the nail is lifting from the nail bed, please stop and see a doctor.

By Volha Zhybuliova

Sources: Douglas D. Schoon, Nail Structure and Product Chemistry (Milady); Doug Schoon, Heat Spikes (Nail Knowledge); Milady Standard Nail Technology, 7th ed. (Cengage Learning), Ch. 10, The Basics of Chemistry