The Cosmetic Ingredient Review Expert Panel has adjusted its position on the safety of hydroquinone’s use in certain nail applications following debate as to whether consumers and professionals are likely to take appropriate measures to reduce their exposure to UV light in the curing process.

At its Sept. 9 meeting, panel members affirmed hydroquinone’s safety when used in nail adhesives and as a polymerization inhibitor in artificial nail coatings that are cured by LED light, but debated the safety when cured by UV or fluorescent light.

The panel issued the same assessment for related ingredient p-hydroxyanisole in similar applications.

The ingredient re-review was opened in 2013 due partly to the rise in popularity of gel manicures performed in professional settings, employing artificial nail systems that rely on hydroquinone to prevent polymerization until the nail polish is applied and cured. These have become available for use by consumers with home-use kits to achieve comparable effects as were achieved in salons. Panelists had concerns that in either scenario, the use of UV lamps in the curing process could subject consumers to possible additional cancer risks if precautions are not taken to minimize exposure.

Panelist Dr. Paul Snyder accepted that hydroquinone-containing UV-cured nail treatments are safe if users wear gloves or sunscreen, but maintained that a CIR safety determination should not “skirt the issue” that many professional salons use UV light without taking those measures.

At the panel’s December 2013 meeting, Dr. Donald Belsito, a professor of dermatology at Columbia University Medical Center, cited an article published in 2009 in the American Medical Association’s Archives of Dermatology, which drew a potential connection between exposure to UV nail lights and development of non-melanoma skin cancers on the hands of two healthy middle-aged women with no personal or family history of skin cancer.

Based on that report, among other emerging studies, Belsito suggested that “this is beginning to become a controversy in dermatology, whether the use of UV-cured nail acrylics increases the risk of cancer of the hands and periungual area.” He added: “That raises a whole, for me, ethical conundrum if that practice of doing UV-cured nail acrylics is not a good practice.”

He proposed tabling the re-review of hydroquinone and the safety of its use in such treatments until other panelists had digested the referenced literature.

In June 2014, the panel returned to the issue, turning out a tentative final amended report with the conclusion that hydroquinone is safe in nail adhesives and as a polymerization inhibitor in artificial nail coatings only when such products are applied in a professional setting and user hands are protected by sunscreens or photo-protective gloves in the nail-curing process when UV light is used. The panel was inclined to find the ingredient unsafe for home use when UV light is involved Also see "Viability Of Preservative MI Use Remains Unclear; CIR Tables Review" - HBW Insight, 24 March, 2014..

Discussion resumed at the CIR panel’s Sept. 9 meeting, focused again on expectations for UV light protection and the likelihood that salon professionals and consumers are observing, or will comply with, best practices to ensure safety.

Contrasting Views Inform Discussion

Initially, the team led by Belsito proposed that hydroquinone in nail adhesives and as a polymerization inhibitor should be restricted to professional use when UV light is used.

“Basically what we’re saying is that curing by UV light in the home setting is not a safe approach,” he said. “I don’t think we want to give the impression that just because UV light is available for home use, these products are safe.”

The vast majority of home use gel nail curing systems use LED lights, though some older lamps that use UV lights to cure are available online.

A second CIR team led by Dr. James Marks, chair of the dermatology department at Pennsylvania State University College of Medicine’s Milton S. Hershey Medical Center, argued that the panel’s conclusion should focus less on the setting in which hydroquinone-containing nail products are applied, and more on the safety of light-curing techniques available to both consumers and professional aestheticians.

“The idea is that when you use an LED light, it’s safe to use, and when you use another light, [it] is not,” he asserted, advising “zero UV lights even in professional settings.”

As debate continued, Dr. Paul Snyder, a professor of pathology at Perdue University’s School of Veterinary Medicine, recognized the irreconcilability of emerging positions within the panel. “Are we saying that professionals can use it safely and that there’s no safe use?”

He accepted that hydroquinone-containing UV-cured nail treatments are safe if users wear gloves or sunscreen. However, a CIR safety determination should not “skirt the issue” that many professional salons use UV light without taking those measures, he said, cautioning fellow panelists against sending a mixed message.

Belsito acknowledged that the panel’s goal “is not to make conclusions that do not have real-world relevance,” but “to make conclusions that provide a safe environment for consumers to use products.” At the same time, he maintained the feasibility of his proposal to issue a decision giving salons two choices – to cure nail gels with LED light or purchase gloves or sunscreen and cure with UV light.

“It takes less time to cure with LED. These people want to move customers in and out – they’ll probably switch,” Belsito speculated. “Safety-wise, if you want to keep using your old UV lamp, you should do it safely and in a professional setting and use provided gloves and sunscreen.”

Rachel Weintraub, a non-voting member of the panel representing the Consumer Federation of America, remained dubious. “There’s a huge disconnect with what you describe and what’s being used in most salons across the country,” she said.

Ultimately, the panel concluded that hydroquinone is safe for use in nail adhesives and as a polymerization inhibitor only in artificial nail coatings that are cured by LED light. Panelists agreed to elaborate in the report’s discussion portion on skin-cancer risks and the use of photo protection when it comes to UV lights.

Panelists also affirmed earlier conclusions regarding other applications of hydroquinone and p-hydoxyanisole, finding them safe at concentrations of ≤ 1% for cosmetic formulations designed for discontinuous, brief use followed by rinsing from the skin and hair, but unsafe in leave-on cosmetic products.

The panel again issued a tentative amended final report on the ingredient given its revised conclusions, which allows industry and other interested parties to weigh in on the assessment.

Also at the meeting, the panel issued a final amended assessment for preservative methylisothiazolinone, affirming its earlier tentative decision that the ingredient is safe for use in rinse-off products when limited to 100 ppm and safe in leave-on products when they are formulated to be non-sensitizing at concentration levels to be determined based on a quantitative risk assessment Also see "Final Word On Preservative MI Could Emerge From September CIR Meeting" - HBW Insight, 1 September, 2014..

CIR Panel Affirms Hydroquinone Safety, Questions Use Under UV Nail Lights

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