It is strange that when Indians travel abroad to a country experiencing high temperatures, we do not hesitate to buy a hat from the vendor at a tourist attraction–think Egypt, Morocco, even the ruins of Pompeii in Italy, in the midday sun.

But back at home in India, even when the temperatures reach the high 40s we would not even consider wearing a hat, let alone applying sunscreen.

Dr Bhavna Mangla, Delhi-based dermatologist, points out that being in the sun for long hours is not a good thing for anyone, anywhere, because the sun’s rays can damage the skin–which should be avoided and protected.

How does the sunlight damage the skin?

Getting down to the basics of understanding this, one should know that sunlight comprises three components: visible light, UV rays and infrared light. What damages your skin is the visible light and the UV rays which comprise UVB and UVA rays. It is the UVB rays which cause sunburn and tanning. UVB is biologically active, but cannot penetrate beyond the superficial skin layers. 

The UVA rays cause pigmentation, skin ageing, and wrinkles. As ascertained by the WHO: “The relatively long-wavelength UVA accounts for approximately 95 percent of the UV radiation reaching the Earth's surface. It can penetrate the deeper layers of the skin and is responsible for the immediate tanning effect. Furthermore, it also contributes to skin ageing and wrinkling. For a long time, it was thought that UVA could not cause any lasting damage. Recent studies strongly suggest that it may also enhance the development of skin cancers.”

Why do you need sunscreen indoors?

Since these rays can penetrate the skin, it is important to set up a barrier with sunscreen, even if one is indoors, shares Dr Mangla. Dr Mangla says visible light, also known as blue light or high energy light from laptops, computers, mobiles, TV and even LED lights, can also damage the skin.

How much sunscreen lotion should you apply?

According to international standards, the ideal quantity is a thickness of 2 mg/cm2, shares Dr Mangla. As a rule of thumb, she recommends you should apply one teaspoon of sunscreen over your entire face and neck. In case you are planning to step out, apply the sunscreen 30 minutes before leaving the house. You need to reapply the sunscreen after two or three hours to ensure your skin continues to be protected. According to the WHO, studies have shown that consumers apply much less than this—typically between 0.5 and 1.5 mg/cm2.

“Don’t forget to apply sunscreen on other exposed areas of the skin such as ears, hands and other body parts,” Dr Mangla cautions.

Which sunscreen is better–chemical or physical?

Chemical sunscreens can cause allergies, are unstable and systemically absorbed, shares Dr Mangla. Chemical sunscreens use organic materials like oxybenzone, avobenzone, homosalate, octinoxate, octocrylene, and octisalate to offer sun protection. They also need to be reapplied more frequently as they are not photostable and break down when exposed to UV light.

In her opinion physical or mineral sunscreens are better. Their two key ingredients, titanium and zinc oxide, act as physical barriers. They block a wide range of UV wavelengths and are photostable. Titanium and zinc oxide also cause less aggravation for even some sensitive skin types. Zinc oxide has played a pivotal role in preventing hyperpigmentation and is frequently recommended by dermatologists for melasma or dark spots. 

She also points out that sunscreen should not be used on kids who are less than two years old.

How do you choose a sunscreen according to your skin type?

If you have oily skin, Dr Mangla recommends you go for a gel-based, matte or emulsion-based sunscreen. Ideally, one should look for a sunscreen labelled as ‘non-comedogenic,’ which means that it has been shown not to block pores.

For dry skin, she suggests, one should opt for a cream-based sunscreen. Ideally, it should contain hydrating ingredients such as hyaluronic acid or ceramides. For sensitive skin, physical or tinted sunscreen is preferred, she says.

What is the ideal sunscreen?

There is no ideal sunscreen says Dr Mangla and no sunscreen can give you 100% protection. Avoiding the sun is the best bet for that. But the factors in your sunscreen to take into consideration are: the sun protection factor (SPF) should be over 30 or higher than that and it should be a broad-spectrum sunscreen coverage which can counter the effects of UVB rays which cause sunburn and UVA rays with their lasting damage. The SPF level is the measure of how much UVB light a sunscreen can filter out. It is why a higher level of SPF is recommended for the sunscreen you choose to use. Obviously, when the sun is really strong, ensure your sunscreen is doing its job even under the midday sun. That’s why it’s also important to reapply if you last applied it in the morning when leaving home.

Dr Mangla recommends one should always consult a dermatologist to know the best sunscreen for your skin type for greater efficacy.

The jury is out–Worldwide dermatologists recommend that using sunscreen every day, all year round, is your best bet to protect your skin from the damaging effects of the sun rays. Make it part of your daily routine to fight off everything from pigmentation, wrinkles, acne–and the more serious outcomes such as cancer.