A quick and simple guide to sunscreen

All about sunscreen: This quick and simple guide covers the basics of sunscreen application, the importance of sunscreen and other important tips regarding sunscreens.


We all know how important it is to apply sunscreen before going out under the sun but it is equally important to apply it even when you are indoors. Dermatologists suggest that a good sunscreen is a must-have in our daily skincare routine.

Sunscreen, also known as sun creamsunblock or suntan lotion, is a lotion, spray, gel, foam, stick or other topical product that absorbs or reflects some of the sun‘s ultraviolet (UV) radiation and thus helps protect against sunburn

Importance of sunscreen

Protects against the harmful ultraviolet rays

Depletion of the ozone layer has led to an increase in UV rays. UV rays have many harmful effects on the skin and are the cause of some major skin disorders. It has been observed that sunscreens increase skin’s tolerability to UV rays. Sunscreens protect the skin against sunburn, thus providing a protective shield against UV rays.

Reduces premature ageing of the skin

Continuous exposure to harmful UV rays can cause wrinkles and sagging of the skin. Sunscreen provides a protective layer and protects the skin against premature aging.

Maintains the overall health of the skin

Apart from the above-mentioned benefits, sunscreen also helps in maintaining the overall health of the skin. It helps maintain an even skin tone and it also keeps the skin smooth and damage-free.

Types of sunscreen

Sunscreens can be classified into:

Physical sunscreens: Physical blockers reflect ultraviolet rays from the sun. They contain one of the two active ingredients: Zinc oxide or titanium dioxide. It leaves behind a white cast and creates a barrier on your skin’s surface that reflects UV rays off the skin.

Chemical sunscreens: Chemical blockers contain chemicals like aminobenzoic acid, avobenzone, octisalate, octocrylene, and oxybenzone. It absorbs into the skin like lotion and absorbs UV radiation before it can damage your skin cells.

The sun produces two types of ultraviolet (UV) radiation: UVA and UVB. 

UVA – UVA radiation causes skin damage, premature aging and skin reactions to medications, soaps, cosmetics, and other chemicals. These radiations can affect the skin beneath the surface even when you can’t feel the burning.

UVB – UVB radiation causes sunburn.

Some ingredients of sunscreen can cause the skin to become more sensitive. If a sunscreen causes redness or irritation, wash it off and stop using it. 

What is SPF and what does it tell us?

importance of sunscreen

SPF is the abbreviation of Sun Protection Factor. The term SPF is usually followed by a number. This number indicates how well the sunscreen protects the skin against sunburn. SPF is one of the major factors in evaluating the efficacy of sunscreen. 

The SPF value reflects only how well a product will protect from UVB rays, the main cause of sunburn. It does not reflect the product’s ability to protect the skin from UVA (which causes skin damage), yet protection from UVA is important.

SPF and labelling

The SPF can be measured by applying sunscreen to the skin of a volunteer and measuring how long it takes before sunburn occurs when exposed to an artificial sunlight source.   

“SPF 15” means that 115 of the burning radiation will reach the skin; assuming sunscreen is applied evenly at a thick dosage of 2 milligrams per square centimetre. 

If a person develops sunburn in 10 minutes when not wearing sunscreen, the same person in the same intensity of sunlight will take 150 minutes to develop sunburn of the same severity if wearing sunscreen with an SPF of 15.

It is important to note that sunscreens with a higher SPF do not last or remain effective on the skin any longer than lower SPF and must be continually reapplied as directed, usually every two hours. 

SPF 30 blocks nearly 97% of UVB radiation, SPF 50 blocks about 98%, and SPF 100 blocks about 99%.

How can I choose the right sunscreen for my skin type?

Choose broad-spectrum: Broad-spectrum sunscreen means the product protects from both UVA and UVB rays.

 Go for SPF of at least 30 and look for active ingredients. Avoid wearing very high SPF (over 50).

Choose sunscreen according to the skin type: 

Dry Moisturizer or cream-based sunscreens are ideal.
Oily Gel / Water-based sunscreens are ideal.
Acne-Prone Avoid cream-based as they are greasy and heavy and can clog pores.
Sensitive Physical sunscreens are ideal. Make sure the product is free of alcohol and fragrance.
Darker Chemical Sunscreens are ideal. If looking for physical creams, look for one that’s marked ‘sheer’.

Apply sunscreen to get maximum benefits of protection. The face and neck need about ½ a teaspoon of sunscreen. Make sure you apply sunscreen on the face, neck and hands.

How often should I apply sunscreen?


Sunscreen should be applied daily, no matter whether you stay indoors or outdoors. Even on cloudy days, you should apply sunscreen. Around 80% of sunlight can pass through clouds, thereby affecting the exposed area of the skin.

Reapply sunscreen every two to three hours, especially when outdoors and directly after being exposed to water. 

Therefore, make sunscreen a part of your daily lifestyle. 

Note: Some ingredients of sunscreen can cause the skin to become more sensitive. If a sunscreen causes redness or irritation, wash it off and stop using it. 

About the author: Asmita Shah (INFS Faculty)

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