Know Your Sunscreen – What is SPF and PA

I discussed about the UVA and UVB rays in sunlight in my post yesterday (read here) and today I thought of adding mu thoughts (and knowledge) about the sunscreens that you can use to protect your skin from sun damage.

There are two types of sunscreens available in the market – chemical creams and actual shield screams. I have never used a chemical sunscreen but I have read about it and know that they are strong and not meant for sensitive skin. Chemical sunscreens absorb ingredients of the UVA and UVB rays. They also do not leave a white residue like SPF sunscreens. This is all I know about chemical sunscreens.

Onto the more common sunscreens meant for all ages and skin types available in the market. The sunscreens contain two main indicators of their potency against UVA and UVB rays – SPF and PA. The sunscreens that contain only SPF, protect only against UVB rays while the sunscreens containing PA offer protection against UVA rays.

It is just common-sense to know that we need protection against both UVA and UVB rays and hence we need sunscreens that contain both SPF and PA. Such sunscreens are regarded as broad spectrum sunscreens.

What is SPF?

SPF (which stands for Sun Protection Factor) is an indicator of the strength of the cream to act as a shield against UVB rays. If you read my last post, you know that UVB rays cause tanning and sunburn. So you need SPF in your sunscreen to prevent sun tanning and burn. The number written beside SPF is directly proportional to number of minutes a sunscreen can protect you against UVB rays. SPF can go from 5 to 90.

Common SPF and their protection time range-  
SPF 15 ~ 150 minutes ( 2 1/2 hours)
SPF 30 ~ 300 minutes (5 hours)
SPF 50 ~ 500 minutes (6 hours)

Most sunscreens have an SPF of 30 or 50, tinted moisturizers offer SPF 15.

What is PA in a sunscreen?

PA which signifies “The Protection Grade of UVA” protects against the damaging effects of UVA rays. In my last post I discussed the perils of skin exposure to UVA rays – wrinkles, skin ageing and danger of skin cancer. UVA can penetrate the skin, clouds, windows and curtains so we need to apply sunscreens on a cloudy day, in winter months and even if we are indoor sitting close to window receiving sunshine.

PA ranking:
PA+      – Least protection against UVA rays
PA++    – Medium Protection
PA+++  – Highest protection

If you go outdoors between the late morning to afternoon (11 am – 3 pm) time frame, make sure you use a broad spectrum sunscreen with SPF 30 or more and PA+++.

The main (first in the list) ingredients in the sunscreen should be Titanium Oxide or Zinc Oxide.

There are a few more things that you need to keep in mind while selecting a sunscreen.

– If you are going to be swimming or playing in the water, you need to find a water-resistant (oil-based) sunscreen so that it does not wash off.
– Wear sunglasses with UV protection to protect your eyes.
Reapply the sunscreen during long exposure duration. So if you are re-applying a sunscreen with an SPF of 50 (it will last 6 hours), you can get maximum benefit if you re-apply the sunscreen after 3 hours of first application.
– Sunscreens need to be applied a little thickly (build up a layer)
– Apply sunscreen 15-20 minutes before stepping out for maximum protection.
– Snow, Ice or Water bodies can deflect sunrays increasing the exposure amount of the rays so WEAR A SUNSREEN even in winter!

My sun protection routine –

  • I always wear good quality sunglasses whenever I am out in the sun.
  • I always carry an umbrella with me (and walk under it 😉 ) if I go out during the day.
  • I carry a sunscreen with me especially if I am travelling.
  • I apply sunscreen to my feet, arms, hands, face and neck before going out.
  • I wear a thin full-sleeved cotton jacket while outdoors (even if I am sweating!) to protect my arms. I hate getting tanned (which most Asians like me do!)

I hope you found this information about sunscreens helpful and I hope this post will help you make an informed decision about buying and using sunscreens. Experiment with various sunscreens in the market to suit your skin type and always try to carry a sunscreens with you during the day. It is better to take care of your skin before it gets damaged and then finding remedies!

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