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Antti Latomäki: Examining the UV radiation of lash extension devices

Publication date 24.6.2024 12.18

In its monitoring project, the Radiation and Nuclear Safety Authority (STUK) examined the UV intensity of six devices used to attach lash extensions. The devices are used in beauty care to cure lash extension glue using UV radiation and have grown in popularity over the last couple of years.

For the purposes of conducting measurements, STUK purchased the devices from online stores. One of the devices was purchased from a Finnish online store, three from European operators and two from a Chinese e-commerce platform. This yielded a range of products from different price categories and with slightly differing technical details. As affordable devices are increasingly being imported for commercial use from outside the EU, STUK decided to include a couple of such devices as well. Of the equipment measured, the most affordable cost around EUR 40 and the most expensive over EUR 700.

The devices were examined for the following information:

  • Intensity of UV radiation emitted by the device
  • User instructions and markings concerning optical radiation
  • Other properties affecting radiation safety

On the basis of the above, it was assessed whether the properties of the device make it viable for use in cosmetic services. Instead of product monitoring, the aim of the project was to obtain information about this new type of device. Previously, STUK attempted to determine the characteristics of devices on the basis of their technical data, but the data proved to be either incomplete or implausible without exception.

Pay attention to eye safety when using the equipment

The measurements were taken at the operating distance specified in the instructions for the device and, additionally, at a distance of 20 cm according to the EN 62471:2008 standard. The standard classifies luminaire products in risk groups based on the risks of the radiation they produce. If you are considering purchasing a device, we recommend requesting a test report in accordance with the standard mentioned above.

Of the devices measured, three belonged to the highest risk classification RG3 and three to RG2. The classifications are based on the hazard of UV radiation to the unprotected eye. In the case of the most powerful device measured, the limit value would be exceeded in just 15 seconds at a viewing distance of 20 centimetres if the light was directed directly into the eyes. UV radiation can cause corneal inflammation and cataracts in the eye. However, when applying the lashes, the customer keeps their eyes closed, and the eyelid blocks at least 95% of the radiation to the eye. When performing treatments, it is therefore essential to ensure that the customer is not able to look at the light source when it is switched on.

What about skin? Many people correctly associate exposure to UV radiation with the risk of skin cancer. Lash extension devices do not emit UVB rays that damage the skin. Most devices have a wavelength at the borderline between UVA and blue light, and short curing times keep skin exposure low.

Of course, a lash technician should also take care of their own protection. For example, if their fingertips are repeatedly exposed to the device, the dose accumulated during the working day can be significant. Gloves and safety eyewear, for example, can be used to protect against UV radiation.

Follow the instructions

When using lash extension devices, it is important to consider how to use the device. The customer’s UV exposure increases significantly if the operating distance of the device is reduced. Exposure is also increased if the curing time of one lash is extended or if a large number of lashes is applied during the same appointment. Safer options include keeping the device as far away as possible during use and keeping the curing times short.

The user should, therefore, read the device instructions and especially observe the application distances and curing times specified therein. If there are no clear instructions for the device, it is worth considering whether the device is safe to use at all.

Sellers and importers of the devices should ensure that the devices come with instructions that help perform the treatments safely.

Differences in device properties and accessories

The devices measured by STUK were very similar in structure. The devices were intended to either stand on the floor or be mounted on a worktop and they were controlled with a foot switch. All devices used LED as the source of radiation with a wavelength of 365, 395, 400 or 405 nanometres.
However, there were significant differences in the intensity of the UV radiation emitted by the devices. The difference between the maximum and minimum measurements at a measuring distance of 20 centimetres was up to 20-fold.

One of the devices was equipped with separate alignment LEDs to help set the correct orientation and operating distance. As a safety feature on the same device, the curing time was technically limited to a maximum of three seconds, after which the radiation was automatically switched off. For other devices, the operator presses the footswitch to set the correct curing time.

There were significant differences in the instructions and markings of the devices. Some devices came with instructions and markings that were at least moderate in terms of content, whereas other devices had no instructions or markings. All of the instructions that were provided specified a certain distance of use and curing time. Two devices came with instructions that also included contraindications, in other words, obstacles to the safe performance of the treatment.

Both of the devices that were ordered from outside the EU were substandard in terms of instructions and markings. The devices did not come with instructions, and only one of them had a sticker attached to the power cable that contained a brief warning about UV radiation. The devices were also not labelled in a way that would indicate the manufacturer, model designation or other information that would allow identification of the products.

STUK has previously recommended buying beauty equipment only from trusted suppliers. The recommendation still applies, as devices can be purchased very cheaply from outside the EU, but it remains a mystery what they actually do or how they should be used.

The radiation operator is responsible for the safety of the service

STUK monitors the use of UV devices used to cure lash extension glue as part of the radiation control of cosmetic services. However, the responsibility for the safe use of radiation always lies with the cosmetic service provider.

When considering the purchase of a device, it is therefore always worthwhile to assess the risks associated with radiation for each specific device. In the case of the devices selected for the project, there do not seem to be any significant radiation risks associated with their use in beauty care, but it is always possible that unnecessarily powerful or otherwise dangerous devices may appear on the market.

It is important for the cosmetic service provider to ensure that the devices in use are safe and that they are used correctly. If you have any questions about the use of radiation, please contact STUK.

Like other adhesives containing acrylates, UV-cured adhesives are chemicals and are regulated by the Finnish Safety and Chemicals Agency (Tukes). During the current year, Tukes is also carrying out monitoring related to this topic. 


The author, inspector Antti Latomäki manages regulatory tasks, market surveillance and inspections in connection with the use of non-ionizing radiation in beauty care.





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