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There are two types of gel, hard gel and soft gel.
Hard gel gets its name because, once cured, it is tough enough to be made into a nail extension. Nail extensions are artificial nails created by using a nail product to extend the nail past the edge of the natural nail.
Soft gel refers to the gel products that are too soft to create a nail extension. This includes gel polishes and thicker gels meant for gel-overlay services. Gel polishes are used for the increasingly popular gel polish manicures. These manicures are gentle to the natural nail and the polish stays intact on the nail for at least a couple of weeks with high shine and no cracking, peeling or chipping.
The product used to create nail extensions using gel or gel nails is gel, not to be confused with acrylic nails, which are created using liquid monomer and polymer powder. All gel services are performed using some form of gel, which usually comes in pots of gel or bottles of gel polish. Gel also comes in a variety of colors. All forms of gel require curing, or hardening, under a UV (ultraviolet) light, which can be either a conventional bulb or LED lamp.
UV curing refers to the chemical process that occurs when photoinitiators within the gel itself are exposed to the UV or blue light. The energy from the light causes certain bonds in the initiator molecules to break, forming free radicals. The radicals begin attacking double bonds in the gel's component molecules, beginning a polymerization reaction which eventually encompasses all the molecules of the gel. Gels usually contain a mixture of acrylic monomers and oligomers, which combine to form long, interlocking chains during the polymerization, a process known as cross-linking. These long, bonded chains make the gel hard and chemically resistant. Usually, once the nail extension and/or gel manicure has been finished, there is a residual tacky layer, referred to as the "inhibition layer," that is removed by wiping with a preferably lint-free wipe soaked in high concentrate alcohol.
The process typically ends with an application of cuticle oil on all fingers, to bring back nourishment into the cuticle after harsh alcohol application.
Gel nails vs other artificial nails
Acrylic nails are a more common form of artificial nails and may also be referred to as "liquid and powder nails". They have been around for decades[when?] whereas gel nail products are still a very recent addition to the nail industry first being introduced in the 1980s. The most popular acrylic nail service is the pink and white which refers to the use of pink colored acrylic and a white acrylic powder to create a long-lasting French manicure look. Just as with gel nails, acrylic nail extensions can be created using forms to create sculpted nails or tips. Forms are special stickers that are placed at the end of each finger, under the finger nail, and secured in place so that wet acrylic can be sculpted into a nail extension at the fingernail's edge. Thus, each nail extension is sculpted and why this procedure is referred to as "sculpts" or "sculpted nails." Tips are simply mass-produced plastic nail tips that are adhered to the fingernail's edge using nail resin. Each tip is clipped and filed into shape before applying the wet acrylic and the nail extension is made.
Fiberglass and silk wraps
Fiberglass and silk wraps are overlay services. This means that a product is laid on top of or "overlaid" onto the existing natural nail. In this scenario, the manicurist will cut pieces of fiberglass or silk and then adhere to the nail with a type of resin. This service is often used in cases of broken nails or to strengthen the natural nail.
Pros of gel nails
- Gel nails can allow those allergic to acrylic or nail resin to enjoy an extension service
- Healthier option for your nails
- Dries faster than regular polish
- Different from the dip powder
- Lasts longer than normal polish
- Many gel nail clients report that gel nails feel more natural and less rigid than acrylic nail extensions
- Soft gel nails (gel polish) are easily removed with acetone when soaked or wrapped for about 8–15 minutes and do little to no damage to the natural nail
- Gel polish manicures can last up to 3 weeks with no chipping, peeling or cracking
- Leaves a glossier finish
- Gel nails do not produce any odor
- The curing time is very fast when using an L.E.D. light. This can be as low as 5–10 seconds with a 36 watt LED lamp. More powerful lamps are appearing all the time with 60 watts being available at the time of writing.
- Gel polish nails mean nails are dry immediately upon completion of the service so salon-goers do not need to worry about smudging or ruining their manicure
- Holds shine and does not fade like regular nail polish
- Acrylic is much harder. We want our nails to bend when whacked against something hard. Gel provides that flexibility. Gel takes the brunt of the force and cracks, but usually the nail won’t break.
Cons of gel nails
- They can be too complicated for people to perform on themselves.
- The nails can increase risk for infection if not done in a professional salon.
- They are more expensive than traditional manicures.
- They are more difficult to remove. They often need to be removed by a professional for an additional fee.
- The improper removal of gel nail polish can weaken your nail beds and cuticles. 
- The UV light used for gel manicures can damage DNA and collagen. 
- Roy, Sree. "The Science of Gels". www.nailsmag.com. NAILS Magazine. Retrieved 18 May 2017.
- "Pros and cons of gel nail polish for manicures". Phagans Portland Beauty Schools.[self-published source?]
- "Gel Nails or Acrylic? Which is Better? | Nail Care HQ".
- "Gel manicures: The good, the bad and the UV | American Academy of Dermatology". www.aad.org. Retrieved 2019-09-10.