Nail health after gel and acrylic: what the evidence actually says

Ask around a nail salon and three lines come up again and again. Gels wreck your nails. Biotin fixes them. Take a break every few sets. We went looking for the published research behind all three, and none of them is as settled as it sounds. The sturdiest research in this area is about allergy.

What a nail actually is

The nail plate you can see is a laminated sheet of keratin, already dead by the time it appears. It is made in the matrix under the skin at the base of the nail, rests on the nail bed, and is sealed at the tip by the onychodermal band and hyponychium (de Berker, 2013).

There is no living tissue in the visible plate. Surface damage from filing or heavy buffing grows out, and we found no research on anything applied on top that changes that. Onycholysis, the whitish lifting at the free edge, is a failure of the seal between plate and bed. That is a medical problem, so if you have lifting, pain, discolouration or a nail that will not settle, see a doctor.

Nails grow slowly, and more slowly with age

The classic longitudinal work found linear nail growth slows by roughly half across a lifespan (Orentreich et al, 1979). That study measured growth rate, not recovery, and we could not find published research on how long nails take to change once someone stops wearing gel or acrylic. So we will not give you a number of weeks. It varies with your growth rate, your age and what happened to the nail.

Measuring the plate after a hybrid manicure

One study took alginate casts of 20 thumbnails and scanned them in 3D before and after a hybrid manicure (Zdrada et al, 2022). The height of the plate changed by a similar amount across every section measured. The authors state that a change in nail height is not a desirable finding and that it indicates damage, attribute it to the products, the acetone and the filing together, and conclude that hybrid and gel manicure procedures cause significant change to the plate, with removal technique strongly influencing the result. That is 20 thumbnails in a study its own authors label preliminary, so treat it as a signal rather than a settled number.

That is 20 nails, no control group, and the authors call it preliminary themselves. In the papers we read, nobody had separated filing from acetone from the gel. The salon line "it is not the gel, it is the removal" is one reading of one small study, and it has not been established.

The problems that get reported

A systematic review of nail cosmetics sets out a different profile for each (Javaid et al, 2025). Allergic contact dermatitis, onycholysis and onychomycosis turn up under both. Gel adds paronychia, psoriasiform onychodystrophy and pterygium inversum unguis. Acrylic adds worn-down nail syndrome, pseudo-psoriatic nails and periungual eczema. The review names ultraviolet light, at-home manicures, acrylates and isocyanates among the risk factors.

A separate review of gel polish alone found 12 publications describing 88 patients, all of them women. Across those 88: 70.5 percent allergic contact dermatitis, 26.1 percent mechanical nail damage, and 3 cases, 3.4 percent, of ultraviolet-induced skin lesions. We should be specific about what those three were, because rounding them into a percentage hides it. All three were squamous cell carcinoma, a form of skin cancer, and the reported gap between ultraviolet exposure and diagnosis ran from 11 to 15 years. Three case reports in the world literature is a very small number and no rate of risk can be worked out from it, but the review authors say plainly that the literature is scant and that the answer is education rather than reassurance (Litaiem et al, 2022). If you would rather not put your hands under a lamp at all, say so when you book and we will talk through what else is possible.

Those percentages describe the mix of problems inside a small pile of case reports, not anyone's personal odds. We could not find a cohort study telling us what proportion of gel or acrylic clients run into onycholysis.

The allergy research is the sturdiest part of this topic

A seven-year retrospective study patch tested 2,005 consecutive patients for HEMA, methyl methacrylate and ethyl acrylate. Seventy-four of them, 3.7 percent, reacted to at least one. Of those, 86.5 percent were women, 70.3 percent had symptoms on the hands and 24.3 percent on the face, and nail product exposure was significantly more frequent in the younger patients (Jagodich et al, 2026).

About one in five of the acrylate-positive patients did not react to HEMA. Methyl methacrylate reactions predominantly appeared only at the day-seven reading. Patch testing and how it is read are a doctor's call, and that paper is worth mentioning to yours. The 3.7 percent came from people already referred with a suspected allergy, so it is not a rate for the general population.

A long run without trouble is not proof

In the gel polish review, allergic contact dermatitis appeared on average around 30 months after people started, with 2-hydroxypropyl methacrylate and 2-hydroxyethyl methacrylate the leading allergens (Litaiem et al, 2022). That average comes from 88 people in published case reports, so it is not a schedule anyone can apply to themselves. It does mean "I have had gels for years and been fine" carries less weight than it sounds.

None of the research we read tested application technique as an intervention. So we cannot tell you that any way of applying or removing gel, ours included, lowers anyone's chance of a reaction, and we will not imply it.

Biotin and the famous 25 percent

The claim that biotin makes nails 25 percent thicker traces back to a 1990 electron microscopy study, where that figure came from eight patients. A second, looser group of 14 gained about 7 percent. There was no placebo, no randomisation and no blinding (Colombo et al, 1990). A later review concluded that larger controlled trials are still needed to establish whether biotin does anything for nails and at what dose (Lipner and Scher, 2018). None of the biotin work we read involved gel or acrylic damage; it was done in people with brittle nails and onychoschizia.

The one randomised trial

Fifty people with brittle nail syndrome were randomised, with blinded assessors, to a hydroxypropyl chitosan nail lacquer on its own or the same lacquer plus oral biotin for four months (Chiavetta et al, 2019). Onychodystrophy scores fell 57 percent with the lacquer alone and 62 percent with lacquer plus biotin. For the proportion reaching at least a halving of their score, 53 percent against 80 percent, p = 0.05.

That sits exactly on the conventional cutoff, in a trial of 50 people. It did not detect a clear difference between the two arms, and a trial this small also cannot show that adding biotin does nothing. The question is open.

Both arms received the lacquer, so there was no untreated group and the trial cannot say what the lacquer did on its own. Baseline severity scores differed, 8.4 and 11.8. The average age was 64, and the condition was brittle nail syndrome, not manicure damage in a 28-year-old. That lacquer sits inside medical care, not on a salon or retailer shelf, and we are not suggesting anyone go looking for it.

Hydration, oils and rest periods

An international panel of nail specialists reports that brittle nails affect up to 20 percent of people, more often women over 50, lists altered nail hydration among the contributing factors, and recommends topical moisturisers and restructuring lacquers alongside treating the underlying cause (Chessa et al, 2020). That is expert consensus and not trial data. Oils and creams are formulated to soften and condition the surface, not to fix anything underneath.

Rest periods are the awkward one. We could not find published research on breaks or polish-free intervals between manicures. So whatever rule you have heard, two weeks off after three sets or some variant, is convention. It has not been tested in anything we read, and we will not tell you it works or that it does not.

Where the research runs out

We could not find a head-to-head trial of gel against acrylic against traditional polish, or a comparison of acetone soaking, e-filing and peeling, or anything measuring how nails recover once someone stops. The published harm literature is almost entirely women, and none of these papers explains why.

So the problems are described but poorly counted, and the popular fixes have less behind them than the confidence they are sold with. If your nails or the skin around them are sore, lifting, discoloured or reacting, that goes to a doctor.

References

1. de Berker et al. (2013). Nail anatomy. Clinics in Dermatology. PMID: 24079579
2. Orentreich et al. (1979). The effect of aging on the rate of linear nail growth. The Journal of Investigative Dermatology. PMID: 448171
3. Zdrada et al. (2022). Application of a three-dimensional scanner to the quantitative assessment of the nail plate condition after a hybrid manicure procedure. Preliminary study. Skin Research and Technology. PMID: 35253948
4. Javaid et al. (2025). Dermatologic conditions associated with various types of popular nail cosmetics: a systematic review of existing literature and future recommendations. Journal of Cosmetic Dermatology. PMID: 41118424
5. Litaiem et al. (2022). Side effects of gel nail polish: a systematic review. Clinics in Dermatology. PMID: 35907576
6. Jagodich et al. (2026). 2-hydroxyethyl methacrylate, methyl methacrylate and ethyl acrylate sensitisation: a 7-year retrospective study. Contact Dermatitis. PMID: 41255027
7. Chessa et al. (2020). Pathogenesis, clinical signs and treatment recommendations in brittle nails: a review. Dermatology and Therapy. PMID: 31749091
8. Lipner et al. (2018). Biotin for the treatment of nail disease: what is the evidence? The Journal of Dermatological Treatment. PMID: 29057689
9. Colombo et al. (1990). Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy. Journal of the American Academy of Dermatology. PMID: 2273113
10. Chiavetta et al. (2019). Treatment of brittle nail with a hydroxypropyl chitosan-based lacquer, alone or in combination with oral biotin: a randomized, assessor-blinded trial. Dermatologic Therapy. PMID: 31344296