Protecting the skin
text size

Protecting the skin

Know your defence against UVA & UVB radiation


There might be a rainy and almost wintery season here in Thailand but virtually the all year-round bright and sunny weather requires us to be well protected against UV radiation. The higher the SPF (Sun Protection Factor), even though claimed over 100, however doesn't mean that your sunscreen will keep skin safe from UV damage.

L’Oreal scientist, Dr Dominique Moyal specialises in research on UV rays and sunscreen efficacy.

The SPF number only indicates protection against UVB rays but equally important is to know the level of UVA defence, which is now marked by La Roche-Posay new labelling of its sunscreen products showing "UVB + UVA", with the word UVA encircled.

"Most people are aware of the risks associated with UVB exposure, and so they look for sunscreen products with high SPF. UVB rays mainly cause burning whereas UVA rays are responsible for photoageing, which is what Europeans are more likely to be worried about," said L'Oreal Research Center scientist, Dr Dominique Moyal, who specialises in the field of evaluation of sunscreen product efficacy.

Up to 80% of skin ageing can be attributed to UVA rays, which penetrate deeper into the dermis or base layer, resulting in a loss of elasticity leading to wrinkle, sagging and overall premature ageing of the skin. UVB primarily affects the outer epidermis level, with a large dose of the radiation causing redness, blistering and sunburn.

UVA rays however keeps on haunting us throughout the day and the damage doesn't immediately show like in the case of UVB exposure.

From sunrise to sunset, there are small fluctuations of UVA rays during the day, whereas UVB rays reach a sharp peak between noon and 4pm. UVA rays are also active on cloudy days and in even wintertime, and moreover, they can pass through windows and glass, making the indoors or sitting near windows dangerous for your skin.

"The intensity of UVA in Asia is much higher than in Europe, and during April to October, there is four times more dosage of UVA here in Bangkok than in Paris," the French scientist noted the higher risk of UVA damage in this part of the world.

Since up to 95% of UV rays that reach the skin are UVA rays, it's important to shield the skin from this penetrative radiation. Currently there is no international standard for gauging UVA protection, and so it can be measured by the PA (Protection Grade of UVA) system used in Japan and PPD (Persistent Pigment Darkening) method recommended in Europe.

Activating melanin production, UVA causes a pigmentation effect and PPD is the ratio of the dose required to produce a minimally perceptible pigment response on sunscreen-treated skin to the dose for unprotected skin.

The PA system grades UV protection by the number of plus sign, with PA+++ referring to PPD 8 or higher. As the PPD classification is more quantifying, La Roche-Posay uses this to rate its sunscreen products, which offer from PPD 19 to 42 while providing SPF 30 or over 50.

In the EU, the labelling of SPF is maximum at 50+ because using sunscreen producers with a higher number may mislead people to stay in the sun.

Dr Moyal emphasised that consumers have to consider both SPF and PPD, and also look at the proportionality of UVB to UVA protection. The latest recommendation in the EU is that the SPF divided by PPD should be below 3 in order to acquire a better balance of protection against both types of radiation.

"The new labelling will help consumers choose efficient sunscreen products for daily use or outdoor activities," she said. "However it's not good enough to have efficacy in a bottle. They really need to apply sunscreen effectively, and product texture is important to encourage enough application for optimal sun protection."

Under the L'Oreal Group, La Roche-Posay is a brand recommended by dermatologists and its products are retailed at pharmacies. The sunscreen line-up include Anthelios gel, fluid, lotion, melt-in cream, and spray formulated for different skin types and people's lifestyles.


Kids in Thailand love summertime because it coincides with their annual break from school during which they indulge in all sorts of outdoor activities including swimming. But this outdoor fun comes with higher risk of damage from the intense rays of the sun.

Doctors actually advise total sun avoidance for children below the age of three while kids above that age should also be well protected from the sun because the skin is still in development and too fragile for exposure to harmful UV rays.

Protection includes educating the kids how the sun can cause immediate damage which can accumulate over the years. Sun protection should be part of their daily routine involving avoiding peak sunlight and encouraging activities in the shade; wearing protective clothing and hat; and applying sunscreen formulated especially for children.

Their thinner skin also makes it more sensitive to chemical substances, thus the need for gentle formulas specifically developed for children's sensitive skin. In addition, sunscreen products with a pleasant texture will get kids applying them regularly.

La Roche-Posay's sunscreens for kids over three are said to contain no fragrance, paraben and less chemical filter while Mexoplex, a new-generation filter system, provides sun protection especially against UVA.

This summer, the French skincare brand is donating Anthelios Dermo-Pediatrics Lotion SPF50+/PPD 39 to the Pediatric Dermatological Society of Thailand, who will pass on the sunscreen lotion to kids with SLE (systemic lupus erythematosus), which increases the skin's vulnerability to sunlight.

Till the end of this month, sales of every 10 La Roche-Posay Anthelios sunscreen products means that an SLE patient will have a tube of sunscreen to protect sensitive skin.

Do you like the content of this article?