In many parts of India we have two seasons: hot and hotter. The sun mercilessly beats down upon us, not just making us sweat but also damaging our skin. Nothing can stop the former, but sunscreen is the proper defense against the latter.

Don’t be fooled into thinking that summer is the only time of year you need to pull out that tube of SPF. Whether it’s the height of summer, the midst of monsoon showers, or the fleeting winter months, our skin needs protection from the sun’s rays every single day.

What does sunscreen do?

Sunscreen protects your skin from ultraviolet (UV) radiation. The sun’s rays contain two types of UV radiation that enter the Earth’s atmosphere: UVA and UVB rays, both of which are harmful for the human body and can lead to a host of problems. UVA rays are responsible for premature aging of the skin and can cause wrinkles; UVB rays are what cause sunburn. Both types of rays can damage your cells’ DNA, potentially causing skin cancer, and both weaken your immune system over time.

How does sunscreen work?

Some sunscreens contain chemical ingredients that absorb UV radiation, thereby reducing the UV rays that penetrate your skin. Other sunscreens – popularly, though not officially, known as ‘sunblocks’ – contain chemical ingredients that rest on top of the skin, preventing (or ‘blocking’) UV rays from ever reaching your skin. Though zinc oxide, a very visible sunblock, is unsightly, it provides extensive protection against both UVA and UVB rays.

How safe are sunscreen ingredients?

Sunscreen is safe to use by anyone older than six months. Babies younger than six months have very sensitive skin; they should not be exposed to the sun at all, especially because their skin is too sensitive for sunscreen.

Why and how often should I use sunscreen?

Adults should use sunscreen with an SPF of at least 15 daily, to reduce the risk of getting skin cancer, minimise the chance of sunburn, and delay the appearance of aging.  You should apply SPF 30 or higher to children’s delicate skin any time they’ll be exposed to sun.

What is SPF and how do I use it to pick a sunscreen?

SPF stands for Sun Protection Factor, and it indicates the strength of your sunscreen. However, this doesn’t mean that SPF 30 is twice as effective as SPF 15 in protecting your skin. According to the United States Environmental Protection Agency, SPF 15 provides 93% protection against UVB rays, while SPF 30 provides 97% protection.

What else should I look for in a sunscreen?

More important than the SPF is whether the sunscreen protects against both UVA and UVB rays. The SPF ratings apply only to UVB rays, so look for a sunscreen that uses the words “broad spectrum.” This means that the sunscreen will protect against both UVB and UVA rays.

My make-up says it has an SPF level. Isn’t that good enough?

Many moisturizers and foundations today contain some of the ingredients found in sunscreens; these products are easily identified by the SPF level on their packaging. While these products are certainly better than using no sunscreen at all, don’t skip the sunscreen if you’re going to be outdoors for a long period of time. (Pro tip: apply it first, under your makeup or moisturizer).

Are there any other considerations before I buy sunscreen?

If you have sensitive skin, you should avoid sunscreens that contain alcohol and fragrances (often listed as perfume or parfum in the ingredients) as these can aggravate your skin.

Additionally, the chemical ingredients that protect your skin by absorbing UV rays can cause allergic reactions such as itching, redness, stinging, rash, or acne. When you’re trying a new brand of sunscreen, always do a spot test to make sure that your skin won’t react adversely to the chemicals.

How do I get the most benefit from my sunscreen?

In order to be effective, sunscreen must be applied directly onto any skin directly exposed to the sun. On a regular day, this means applying sunscreen on your face, ears, neck, hands, and potentially arms and legs (depending on the coverage your clothes provide).

You should apply sunscreen at least 15 to 20 minutes before going outdoors, to allow your skin time to absorb it. If you’ll be spending a significant amount of time outdoors, you’ll likely need to re-apply the sunscreen every two hours. It’s also very, very important that you re-apply sunscreen after swimming or sweating — even if the packaging says “water resistant.”

I only need sunscreen outdoors on sunny days, right?

You may think that a window or other kind of glass barrier between you and the sun will protect you, but that isn’t the case. UV rays penetrate even tinted glass, so you need to apply sunscreen if you’re going to be travelling by car or seated indoors by a window for a long time.  Also, UV rays travel through clouds, so don’t assume you don’t need sun protection on cloudy days.

I have sunscreen left over from last summer—can I use it?

Remember that sunscreen, just like cosmetics and medicines, has an expiration date. Keep an eye on that date and stop using it once the sunscreen has expired.