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Gel manicures have turned into a tiny luxury that fits between lunch breaks and school runs. The ultraviolet or near‑ultraviolet lamps that harden glossy manicure coatings do the job in about four minutes, so the routine feels harmless.

The dryers bathe fingertips in swift pulses of light, but until recently few people asked what those pulses do to the skin that holds the nails. A new laboratory study brings unsettling answers.

The new work was led by photochemist Dr. María Laura Dántola at the Institute of Theoretical and Applied Physical‑Chemical Research (INIFTA), part of Argentina’s National Scientific and Technical Research Council (CONICET).

Studying manicure lamps

Serrano’s team placed common skin molecules, including tyrosinase, inside a chamber that mimicked a salon lamp and zapped them for the same four‑minute cycle used in most gel services.

All targets, from amino acids to lipids, emerged chemically altered and less able to perform their jobs.

“These devices are used without any controls or regulations requiring manufacturers to report on the potential risks of frequent exposure,” cautioned Dántola and colleagues.

One of the starkest changes hit tyrosinase, the enzyme that drives production of melanin, a pigment that shields DNA from solar radiation.

The researchers also measured how fast the altered molecules sparked oxidative stress reactions that can shred cell membranes. Reaction rates jumped within seconds, confirming that harm starts long before a hand is removed from the booth.

Why photosensitization matters

Photosensitization happens when a molecule absorbs light then transfers that energy to oxygen, creating reactive species. Those species slice through DNA, proteins, and lipids with no regard for cell repair cycles.

Because tyrosinase sits at the start of melanin synthesis, even small interruptions amplify downstream damage. Losing melanin’s natural sunscreen effect makes every future dose of sunlight or lamp light more hazardous.

Many over‑the‑counter skincare ingredients, including retinoids and some antibiotics, can enhance photosensitization.

People who use them may face higher risks because their skin already carries extra light‑reactive compounds.

Tyrosinase, melanin and lost defense

Tyrosinase flips the chemical switches that turn the amino acid tyrosine into melanin granules. When the lamp’s photons broke those switches, the team saw melanin output stall.

Without melanin the skin compensates poorly for incoming ultraviolet, so photo‑aging and cancer risk rise. The altered enzyme also disrupts color balance, explaining reports of blotchy pigmentation after frequent gel sessions.

Manicure lamps are very bright

Bench measurements showed the lamp delivered a dose of UVA radiation around 368–400 nanometers, the same band blamed for tanning and wrinkles.

A separate American study in 2023 reported that a 20‑minute session killed up to 70 percent of cultured human skin cells and stamped permanent mutations on the survivors.

Sensor data from the Argentine team indicate the lamp’s irradiance peaks at 7 milliwatts per square centimeter, nearly matching the noon sun in Buenos Aires during spring.

Weekly visits translate into roughly three and a half hours under that intensity each year, more than many people spend sunbathing.

A systematic review in 2024 concluded that while the absolute cancer risk appears low, the evidence remains weak and long‑term users should be told the data gaps.

Short bursts, long shadows

Gel clients often repeat the service every two to three weeks, layering dose upon dose across years. Cumulative exposure matters because photochemical injuries add rather than heal, especially when they trigger oxidative stress and DNA breaks.

A 2023 test on human keratinocytes showed sunscreen with SPF 50 cut cell death by more than one‑third during the same four‑minute irradiation used in salons.

Protective gloves that leave only the nail plate visible can block over 90 percent of the rays, yet they remain optional accessories.

“These are processes that, in one way or another, result in cell death,” added Dántola and colleagues after monitoring the altered enzyme profiles.

The comment echoes warnings from dermatology societies that link chronic UVA to premature aging and certain skin cancers.

Keeping nails and skin safe

Dermatologists at the American Academy of Dermatology urge customers to apply a broad‑spectrum SPF 30 or higher on their hands before every gel manicure and to choose LED lamps that cure polish faster and with lower UV output.

Salons can switch to newer hybrid lacquers that air‑dry or set under visible blue light, trimming exposure further. At home, limiting sessions and spacing them at least a month apart reduces cumulative dose.

For clients unwilling to give up the chip‑free finish, simple habits help: wear fingertip‑less UPF gloves, time the lamp cycles carefully, and keep moisturizer handy because dry skin amplifies light penetration.

Regulators have yet to issue binding standards for consumer nail lamps, so the burden falls on users and technicians.

Serrano’s group believes clear warning labels and pre‑packed barrier gloves would let people enjoy the beauty trend while understanding the trade‑offs.

Manicure lamps: Speed vs. safety

The beauty business around gel nails is sizable. Analysts estimate the global UV gel polish segment alone was worth almost six billion dollars in 2024 and could double within a decade.

Social media trends and influencer tutorials push fans to redo manicures every week rather than once a month, increasing exposure well beyond the study’s four‑minute baseline. Convenience encourages at‑home kits, yet those kits often ship without detailed safety instructions.

Dántola stresses that the project sits in basic science, aimed at mapping chemical events rather than legislating behavior.

Still, sharing data allows dermatologists, engineers, and regulators to design larger trials that measure real skin after repeated consumer‑level doses.

Applied research may soon test glove fabrics, lamp filters, or polish formulas that polymerize under visible light. Until such options become standard, informed choice remains the safest tool on the manicure table.

The study is published in Chemical Research in Toxicology.

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Earth formed about 4.6 billion years ago, during the geological eon known as the Hadean. The name “Hadean” comes from the Greek god of the underworld, reflecting the extreme heat that likely characterized the planet at the time.

By 4.35 billion years ago, the Earth might have cooled down enough for the first crust to form and life to emerge.

However, very little is known about this early chapter in Earth’s history, as rocks and minerals from that time are extremely rare. This lack of preserved geological records makes it difficult to reconstruct what the Earth looked like during the Hadean Eon, leaving many questions about its earliest evolution unanswered.

We are part of a research team that has confirmed the oldest known rocks on Earth are located in northern Québec. Dating back more than four billion years, these rocks provide a rare and invaluable glimpse into the origins of our planet.

Remains from the Hadean Eon

The Hadean Eon is the first period in the geological timescale, spanning from Earth’s formation 4.6 billion years ago and ending around 4.03 billion years ago.

The oldest terrestrial materials ever dated by scientists are extremely rare zircon minerals that were discovered in western Australia. These zircons were formed as early as 4.4 billion years ago, and while their host rock eroded away, the durability of zircons allowed them to be preserved for a long time.

Studies of these zircon minerals has given us clues about the Hadean environment, and the formation and evolution of Earth’s oldest crust. The zircons’ chemistry suggests that they formed in magmas produced by the melting of sediments deposited at the bottom of an ancient ocean. This suggests that the zircons are evidence that the Hadean Eon cooled rapidly, and liquid water oceans were formed early on.

Other research on the Hadean zircons suggests that the Earth’s earliest crust was mafic (rich in magnesium and iron). Until recently, however, the existence of that crust remained to be confirmed.

In 2008, a study led by one of us — associate professor Jonathan O’Neil (then a McGill University doctoral student) — proposed that rocks of this ancient crust had been preserved in northern Québec and were the only known vestige of the Hadean.

Since then, the age of those rocks — found in the Nuvvuagittuq Greenstone Belt — has been controversial and the subject of ongoing scientific debate.

‘Big, old solid rock’

The Nuvvuagittuq Greenstone Belt is located in the northernmost region of Québec, in the Nunavik region above the 55th parallel. Most of the rocks there are metamorphosed volcanic rocks, rich in magnesium and iron. The most common rocks in the belt are called the Ujaraaluk rocks, meaning “big old solid rock” in Inuktitut.

The age of 4.3 billion years was proposed after variations in neodymium-142 were detected, an isotope produced exclusively during the Hadean through the radioactive decay of samarium-146. The relationship between samarium and neodymium isotope abundances had been previously used to date meteorites and lunar rocks, but before 2008 had never been applied to Earth rocks.

This interpretation, however, was challenged by several research groups, some of whom studied zircons within the belt and proposed a younger age of at most 3.78 billion years, placing the rocks in the Archean Eon instead.

Confirming the Hadean Age

In the summer of 2017, we returned to the Nuvvuagittuq belt to take a closer look at the ancient rocks. This time, we collected intrusive rocks — called metagabbros — that cut across the Ujaraaluk rock formation, hoping to obtain independent age constraints. The fact that these newly studied metagabbros are in intrusion in the Ujaraaluk rocks implies that the latter must be older.

The project was led by masters student Chris Sole at the University of Ottawa, who joined us in the field. Back in the laboratory, we collaborated with French geochronologist Jean-Louis Paquette. Additionally, two undergraduate students — David Benn (University of Ottawa) and Joeli Plakholm (Carleton University) participated to the project.

We combined our field observations with petrology, geochemistry, geochronology and applied two independent samarium-neodymium age dating methods, dating techniques used to assess the absolute ages of magmatic rocks, before they became metamorphic rocks. Both assessments yielded the same result: the intrusive rocks are 4.16 billion years old.

The oldest rocks

Since these metagabbros cut across the Ujaraaluk formation, the Ujaraaluk rocks must be even older, placing them firmly in the Hadean Eon.

Studying the Nuvvuagittuq rocks, the only preserved rocks from the Hadean, provides a unique opportunity to learn about the earliest history of our planet. They can help us understand how the first continents formed, and how and when Earth’s environment evolved to become habitable.