UVA rays penetrate the deeper layers of skin. They stimulate the production of free radicals in the skin which cause oxidative stress and can lead to indirect DNA damage (where the free radicals modify cellular DNA over time). UVA rays are most commonly associated with photoageing (premature skin ageing caused by the sun). They can also trigger sun allergies such as Polymorphous Light Eruption (PLE). UVB rays can also provoke allergies, but to a lesser degree).

UVB rays provide the energy your skin needs to make Vitamin D and stimulate the production of melanin which is responsible for tanning. They don’t travel as deeply as UVA rays, penetrating only the outermost layers of skin, but they cause more immediate damage such as sunburn. UVB rays are directly absorbed by cellular DNA which can lead to skin diseases such as actinic keratosis and skin cancer.

Both types of UV can induce hyperpigmentation and may contribute to conditions such as sun spots (also known as age spots) and melasma.

The sunlight spectrum consists of UV, visible and infrared light. Visible sunlight can be detected by the human eye, while the others remain invisible. Part of this visible spectrum has a high energy level and is known as high-energy visible light. It is also referred to as HEVIS light, HEV Light, HEVL and sometimes ‘blue light’ or ‘blue violet light’

Like UVA rays, HEVIS light penetrates the deeper layers of skin (the dermis) and can generate free radicals. These free radicals are one of the main causes of photoageing (premature skin ageing caused by the sun). They interfere with skin cells and break down the collagen and elastin that gives our skin its plump, youthful appearance. HEVIS light has also been linked to uneven skin pigmentation and melasma.

Many modern sunscreens offer effective protection against UVA and UVB rays, but we recommend that you look out for products that also defend against the negative effects of HEVIS light. These products will give your skin reliable protection from photoageing and, in the long run, can also help to combat visible signs of skin ageing. 

The terms are defined by Cosmetics Europe and our products follow their guidelines. To be defined as water-resistant a product needs to retain half of its SPF after 2 x 20-minute sessions in the water. To qualify as extra water-resistant a product must retain half of its SPF after 4 x 20-minute sessions in the water.

To qualify as sweat-resistant a product needs to retain at least half its SPF under test conditions These involve measuring the SPF both before and after subjects are exposed to high temperature and humidity in a sauna to induce sweating. The sweat induction is stopped once drops of sweat are clearly visible on their backs and the after measure is taken once skin is completely dry.

Anti-sand means that sand is less likely to stick to your skin when using this product. In consumer research, 95% of respondents agreed that sand did not stick to their skin after application¹. This is because Eucerin Sun Gel-Cream Dry Touch Sensitive Protect SPF 50+ is an ultra-light formula which absorbs quickly and is non-sticky and non-greasy.

^{1 Beiersdorf AG, PiU, Spain, April-May 2019. Research was amongst 120 women aged 18 to 55 and all regular users of sun protection body products. Results were reported after two weeks of regular use.}