Shellac and similar gel-polish systems can damage your nails, though the harm comes less from the polish itself sitting on the nail and more from everything surrounding its use: the removal process, the UV lamp that cures it, and the chemical ingredients that some people’s skin reacts to. None of these risks are guaranteed to cause problems for every person every time, but they are well-documented enough that anyone who regularly gets gel manicures should understand what they are signing up for and how to reduce the downsides.
What “Shellac” Actually Refers To
In everyday conversation, “Shellac” has become a catch-all term for any long-wear gel-polish manicure, much the way “Band-Aid” stands in for adhesive bandages. Strictly speaking, CND Shellac is a specific brand that markets itself as a hybrid between traditional nail polish and a full hard-gel system. It is thinner than most gel polishes and is designed to soak off more easily. But the risks discussed here apply broadly to UV- or LED-cured gel polishes regardless of brand, because they share the same basic chemistry: liquid monomers (usually acrylates or methacrylates) that harden into a solid polymer film when exposed to UV or LED light. The curing process, the adhesion promoters that bond the polish to your nail plate, and the photoinitiators that kick off the chemical reaction are all common across the category.1Europe PMC. The Chemistry of Behind the UV-Curable Nail Polishes
How Gel Polish Thins Your Nails
The most common complaint people have after removing Shellac or gel polish is that their nails feel thin, brittle, and peeling. Research backs this up. In one study using ultrasound and confocal microscopy to measure nail thickness before and after a gel-polish application-and-removal cycle, the nail plate thinned measurably, dropping from about 0.063 cm to 0.050 cm in one measurement and from 0.059 cm to 0.030 cm in another.2PubMed. Nail damage from gel polish manicure That second reading represents roughly a halving of the nail’s thickness, which is significant when you consider the nail plate is already thin to begin with.
The culprit is primarily the removal process rather than the polish itself. To get gel polish off, a nail technician typically files the top coat to break its seal, then wraps each fingertip in acetone-soaked cotton for ten to twenty minutes. The acetone dissolves the polymer, but it also strips moisture and natural oils from the nail plate and surrounding skin. When the softened gel doesn’t lift cleanly, technicians or clients often scrape or peel it, which can physically remove layers of nail along with the polish. This mechanical scraping is where most of the thinning happens. The nail plate is made of tightly packed layers of dead keratin cells, and forcing off a well-bonded polish tears those layers apart.
Nails grow slowly, roughly three to four millimeters per month for fingernails, so the damaged portion stays visible for months. If you re-apply gel polish immediately to hide the damage, you start the cycle over without giving the nail a chance to grow out healthy tissue. This is how people end up in a loop where their nails seem permanently weak and they feel they “need” gel polish to protect them.
The UV Lamp Question
Every gel-polish system requires a UV or LED lamp to cure (harden) the polish, and those lamps emit ultraviolet radiation, which naturally raises concerns about skin cancer. A scoping review that pulled together multiple studies on nail lamp emissions found that the exposure picture is more complicated than a simple yes-or-no risk assessment. At the recommended distances for consumer use, measured UV doses were generally below acute-damage safety thresholds. However, within the 355-to-385-nanometer range, the lamp’s output was up to 4.2 times higher than the sun at a UV index of 6. A ten-minute exposure to a UV nail lamp was found to be equivalent to the entire recommended daylight exposure limit for outdoor workers.3PubMed Central. Assessing the Health Implications of UV / LED Nail Lamp Radiation Exposure During Manicure and Pedicure Procedures: A Scoping Review
What does that mean in practice? The same review noted that one researcher estimated you would need to monitor tens of thousands or even hundreds of thousands of women using nail lamps weekly, over many years, to detect just one additional UV-induced squamous cell carcinoma. On a population level, the absolute risk from occasional salon visits appears very small. But in vitro experiments on human and mouse cell cultures have confirmed that UV nail lamp emissions do cause DNA damage, including cytotoxicity, mutagenesis, and oxidative stress.3PubMed Central. Assessing the Health Implications of UV / LED Nail Lamp Radiation Exposure During Manicure and Pedicure Procedures: A Scoping Review The cells in a petri dish are not the same as skin protected by the body’s repair mechanisms, but the finding does demonstrate a biological pathway for harm. The prudent approach, recommended by dermatologists, is to apply a broad-spectrum sunscreen with SPF greater than 30 to your hands before curing, or to wear UV-protective fingerless gloves that expose only the nail.4PubMed Central. Exposome Impact on Nail Health: The Effect of the Different Exposomal Factors on Nail Health
LED lamps, which have largely replaced older UV-only units in many salons, emit a narrower spectrum of light and cure faster, typically in 30 to 60 seconds per coat rather than two to three minutes. They still emit UV-range wavelengths, so the same sunscreen and glove advice applies, but the shorter exposure time does reduce total dose per session.
Allergic Reactions to Acrylates
This is the risk that tends to surprise people the most. The monomers used in gel polishes, particularly acrylates and methacrylates, are potent contact allergens. You can use gel polish for years without any issue, then suddenly develop an allergy that makes your fingertips red, itchy, swollen, or blistered. The sensitization is cumulative and, once established, often permanent.
In an eight-year retrospective study of people referred for suspected contact allergy to nail cosmetics, 97% of subjects tested positive for a reaction to 2-hydroxyethyl methacrylate, commonly known as HEMA, which is one of the most widely used monomers in gel polish formulations.5PubMed. Contact allergy to acrylate-containing nail cosmetics: A retrospective 8-year study That 97% figure reflects the population who already suspected they had a problem and sought patch testing, not the general population, but it tells you which ingredient is overwhelmingly responsible when things go wrong.
The allergy doesn’t always stay confined to your fingertips. Because you touch your face, neck, and eyelids throughout the day, acrylate contact dermatitis can show up anywhere your fingers land. Some people develop reactions on their eyelids without ever connecting it to their nails. And because acrylate monomers are also used in dental fillings, medical adhesives, and certain orthopedic cements, a person who develops acrylate sensitization from nail products may react to those medical materials too. That cross-reactivity is a genuine clinical concern, not a hypothetical one.
Some brands have responded by marketing “HEMA-free” gel polishes, which substitute other methacrylate monomers for HEMA. These can reduce the risk for people specifically sensitized to HEMA, but they still contain acrylate-family chemicals that can trigger their own allergic responses. HEMA-free is a meaningful step in the right direction for many people, but it is not a guarantee of safety for anyone who is already broadly sensitized to acrylates.
Why DIY Gel Kits Carry Extra Risk
Home gel-polish kits have exploded in popularity, and while they offer convenience and cost savings, they also increase certain risks. Allergic contact dermatitis from gel polish has been reported more frequently in people who use at-home kits compared to salon clients.6PubMed Central. Adverse Effects of Do-It-Yourself Nail Cosmetics: A Literature Review The reasons make intuitive sense: at home, people tend to apply gel coats too thickly, don’t cure them for long enough under the lamp, and may use lamps that are underpowered for the specific polish formula they bought. All of these lead to incomplete curing, which leaves uncured monomers sitting on or near the skin instead of locked into the hardened polymer. Those free monomers are the molecules that trigger sensitization.
In a salon, a trained technician generally knows how to apply thin, even coats and cure them fully. They also know to keep gel polish off the surrounding skin and cuticle, which reduces monomer contact with living tissue. At home, it is much harder to apply polish to your dominant hand without getting it on the skin, and most people don’t realize how critical complete curing is to safety. If you do use a home kit, matching the lamp to the polish brand (so the wavelength and power are compatible with the photoinitiator system in that polish) is one of the most important things you can do.
Infections Under the Polish
A long-wear manicure creates a sealed environment between the polish and the nail plate. If moisture gets trapped under the gel, either during application or through a small lift at the edge over the following weeks, it creates conditions where bacteria and fungi can thrive. The most recognizable result is green nail syndrome, where the nail develops a green or greenish-black discoloration caused by Pseudomonas aeruginosa, a common environmental bacterium that produces pigmented compounds. A case report documented a woman who developed green nail syndrome involving a co-infection with both Pseudomonas and the Burkholderia cepacia complex, linked to her history of manicures and frequent hand exposure to water and detergents.7PubMed Central. Pseudomonas aeruginosa and Burkholderia cepacia complex co-infection in green nail syndrome: a case report
Green nail syndrome is treatable, and it is not dangerous in the way a systemic infection would be. But it does require removing the polish, keeping the nail dry, and sometimes using topical antibiotics for weeks. During that time, you cannot wear gel polish. Fungal nail infections that develop under gel polish are harder to treat and can take months to resolve. The key prevention step is making sure there is no lifting or peeling at the edges of your gel manicure, because that gap is how moisture and microorganisms get in. If you notice even a slight lift, removing the polish promptly rather than waiting for your next appointment reduces your infection risk considerably.
Occupational Hazards for Nail Technicians
Clients are exposed to gel-polish chemicals during a single appointment every few weeks. Nail technicians are exposed all day, every working day, and their risk profile is fundamentally different. Research on dust collected from nail salons found photoinitiator concentrations that vastly exceeded those in control environments, with total concentrations in salon dust ranging from 610 to over 10 million nanograms per gram, compared to a geometric mean of roughly 1,430 nanograms per gram in non-salon settings.8PubMed. Nail salon dust reveals alarmingly high photoinitiator levels: Assessing occupational risks That same study estimated that nail salon workers’ occupational exposure to photoinitiators through dust ingestion alone was about 4.86 nanograms per kilogram of body weight per day, and simulated digestion tests suggested that 10% to 42% of ingested photoinitiators could become biologically available to the body.
Acrylate sensitization is also a recognized occupational hazard for nail technicians, driven by the cumulative skin contact that comes with handling uncured product day after day.9Journal of Education, Health and Sport. Emerging Trends in Gel Nail Allergies: Prevalence, Symptoms, and Occupational Hazards Associated with Acrylate Sensitization For technicians, wearing nitrile gloves during application (not latex, which can degrade on contact with acrylates), using local exhaust ventilation at the workstation, and replacing gloves immediately if gel product gets on them are not optional extras. They are the difference between a sustainable career and one cut short by occupational dermatitis. Clients don’t typically think about the technician’s exposure, but it’s worth choosing salons with visible ventilation systems and staff wearing gloves, because those are markers of a shop that takes chemical safety seriously.
Practical Harm Reduction If You Keep Using Gel Polish
If you enjoy Shellac or gel manicures and don’t want to give them up entirely, you can meaningfully reduce each of the risks discussed above with a few habits:
- Soak, don’t scrape: Insist on a full acetone soak for removal, and never let a technician peel or force off gel that hasn’t fully loosened. If you’re removing at home, re-wrap and wait longer rather than picking at stubborn spots.
- Protect your skin from UV: Apply broad-spectrum SPF 30+ sunscreen to the backs of your hands and fingers before your appointment, or wear UV-blocking fingerless gloves during curing.
- Take breaks: Giving your nails a few weeks between gel applications lets you assess the nail plate’s condition and allows regrowth. A continuous cycle of application and removal without breaks compounds thinning.
- Watch for early allergy signs: Itching, redness, or small blisters on your fingertips, cuticle area, or even your face and eyelids after a gel manicure may signal the beginning of acrylate sensitization. Don’t push through it. See a dermatologist for patch testing before getting another gel manicure.
- Check for lifting: If the gel starts to peel away from the nail edge, have it removed rather than gluing it down or ignoring it. That gap invites infection.
Alternatives Worth Considering
The market for long-wear nail products has expanded well beyond traditional gel polish, and each alternative has its own trade-off profile.
Regular nail polish is the lowest-risk option. It requires no UV lamp, involves no acrylate monomers, and comes off with a simple acetone or non-acetone remover without scraping. The downside is durability: you’ll get a few days to a week of chip-free wear at best, compared to two to three weeks with gel. For people who have developed acrylate sensitization, traditional polish is the safest retreat.
Dip powder systems (sometimes called SNS nails, after one popular brand) use a resin and finely ground acrylic powder instead of UV-cured gel. Because there is no lamp involved, you eliminate the UV exposure issue entirely. However, dip powders still rely on acrylate-based adhesives, so they are not safe for someone with an established acrylate allergy. They also bond firmly to the nail and need acetone soaking for removal, meaning the mechanical thinning risk is comparable to gel polish if removal isn’t done carefully. A sanitation concern specific to dip powders is cross-contamination: if you dip your finger directly into a shared jar of powder at a salon, bacteria from one client’s hands can transfer to the next. Reputable salons pour the powder over each client’s nail from a separate container rather than dipping.
Press-on nails have come a long way from the cheap drugstore versions of the 1990s. Modern press-ons use adhesive tabs or gentle nail glue, last several days to over a week depending on the brand, and pop off without acetone or scraping. They sidestep UV exposure, minimize chemical contact, and leave the nail plate largely intact. For someone who wants the look of a salon manicure without cumulative damage, they are worth a serious look. The trade-off is fit: because they are not custom-molded, they can feel bulky or lift at the edges if the sizing isn’t right.
Nail wraps and stickers, made from thin films of regular or gel polish, offer another middle ground. Some are cured with a lamp after application; others simply adhere with heat or pressure. Lamp-cured wraps involve the same UV and acrylate considerations as liquid gel polish, so they don’t solve those problems. Non-cured wraps avoid both issues but tend to peel faster, especially on nails that get wet frequently.
When Nail Changes Are Not About Polish at All
One misconception worth addressing is the assumption that every nail problem someone notices after removing gel polish was caused by the gel polish. Nails can develop ridges, white spots, brittleness, and discoloration for many reasons that have nothing to do with manicures: nutritional deficiencies, thyroid conditions, psoriasis, fungal infections acquired independently, and simple aging all change how nails look and feel. Because gel polish hides the nail plate for weeks at a time, conditions that develop gradually go unnoticed until removal day, when they seem to appear suddenly and get blamed on the polish.
If your nails look abnormal after removing gel polish and the changes don’t improve over a few months of polish-free growth, seeing a dermatologist is worthwhile. Persistent thickening, yellow or brown discoloration, pitting, or nails that separate from the nail bed can be signs of conditions that deserve their own treatment, unrelated to your manicure history. On the other hand, if the main issue is thinning and peeling that gradually improves as new nail grows in from the base, that pattern is consistent with removal damage, and time and gentle care are the fix.