EVERYTHING YOU NEED TO KNOW ABOUT SUNSCREEN (SPF FACTS)

The truth is we all need sun exposure. It’s our primary source of Vitamin D, which helps us absorb calcium for stronger, healthier bones. But an unprotected prolonged exposure to the suns ultraviolet rays can cause skin damage, eye damage, immune system suppression and even cancer.

Here are some facts that you must know about sunscreen.

How does the sun light affect the skin?

Natural sunlight contains of 3 types of harmful rays out of which UVA and UVB rays reaches the earth.

Ultraviolet radiation is broken into three types of wavelengths:

UV-A: This is the longest wavelength and is not absorbed by the ozone. It penetrates the skin deeper than UV-B.
UV-B: Responsible for sunburns. It is partially blocked by the ozone layer.
UV-C: This is totally absorbed by the earth’s atmosphere; we encounter it only from artificial radiation sources.

Excessive sun exposure often leads to skin damage and further aggravates acne.

The outer layer of skin cells contains the pigment melanin. Melanin protects sun from sun rays, which can cause skin damage over the time. An unprotected exposure to the sun’s UV rays could reduce its elasticity and cause a person to age prematurely. Sun tanning occurs because exposure to sunlight causes the skin to produce more melanin and to darken.

Some of the medication used for treating acne can make the skin more sensitive to harmful rays from sunlight. E.g. retinoid may increase photosensitivity, so people should be instructed to minimize sun exposure and to apply sunscreen on regular basis.

What is the role of sunscreen?

A sunscreen is a formulation aimed at reflecting or absorbing the sun’s harmful ultraviolet rays to minimize skin damage. Sunscreen works by combining organic and inorganic active ingredients. Inorganic ingredients like zinc oxide or titanium oxide reflect or scatter ultraviolet (UV) radiation. Organic ingredients like octyl methoxycinnamate (OMC) or oxybenzone absorb UV radiation, dissipating it as heat.

What features contribute to a good sunscreen?

A good sunscreen should protect the skin from broad spectrum ultra violet radiation. It should be a composition of two different sets of components comprising of a physical agent, that reflects the UV rays and a chemical agents that absorbs the UV rays. The components used in a good sunscreen should be safe, chemically inert, on irritating and non toxic. It should be retained on skin respite secretion of sweat; oils & water contact and be odorless. It should be non-staining to skin and clothing.

What is sun protection factor (SPF)?

All sunscreen are labeled with a sun protection factor (SPF) number. It is mainly a measure of UVB protection and ranges from 1 to 45 or above. An SPF 30 filters our 97% of the harmful UVB rays.

Another way of looking at it is:

SPF 15 (93% protection) allows 7 out of 100 photons through
SPF 30 (97% protection) allows 3 out of 100 photons through.

Are high SPF sunscreens better?

SPF at least 30 blocks 97% of the sun’s rays.SPF higher than 30 blocks slightly more of the sun’s rays, but no sunscreen can block 100% of sun’s rays. It is important to note that even if you are applying high-SPF sunscreen, it should be reapplied approximately every two hours when outdoors and after swimming or sweating.

When should one use sunscreen?

Everyone should use sunscreen every day. The sun emits UV rays year around. Even on cloudy days, harmful UV rays can penetrate your skin. Sunscreen is must for those who have had some dermatological procedures done to protect the skin which usually becomes sensitive after such processes.

How to apply sunscreen?

Apply sunscreen in a concentration of 2 mg/cm2
Apply generously and evenly over exposed surface of skin 15-20 minutes before sun exposure or as needed.
Reapply after every 3 hours or after swimming, perspiring pr towel drying.
For sensitive skin, test overnight on small area.

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