The PA index is one of the indexes that shows the level of UV protection of sunscreen. Choosing a suitable sunscreen helps protect the skin from the harmful effects of UV rays.
1. What is the PA index?
The PA index stands for Protection Grade of UVA, which is an index that measures the body's ability to protect against UVA rays of sunscreens announced by the Japan Cosmetics Association.
PA is converted from PFA, which stands for Protection Factor of UVA. PFA is calculated based on the minimum UVA dose to cause melasma within 2-4 hours after sun exposure. Currently, sunscreens provide a fairly long UVA filtering index on the skin, about 4-8 hours for PA++, 8-12 hours for PA+++, or 16 hours for PA++++.
Harmful effects of UVA rays on the body:
- This is the type of ray with the largest amount of rays reaching the earth, accounting for 95% of the UV rays reaching the earth. They cause sunstroke.
- Can penetrate deeply into the skin, causing changes. Causing skin cancer and skin aging.
- Permeates the cornea affecting the lens and retina.
UV rays also have benefits for the body if the amount of rays is moderate, helping the body synthesize vitamin D to prevent rickets, treat some skin diseases, and stimulate body activities.
2. How many levels of PA index are there in sunscreen?
Usually, on sunscreen packaging, the PA index is shown with the “+” sign and it is divided into 4 levels
- PA+
- PA++
- PA+++
- PA++++
However, for some types of sunscreens, the PA index symbol may not be seen, but instead there are abbreviations such as UVA-UVB, UVA/UVB or UVA1, UVA2. Or there may be unique symbols from certain brands or countries.
For example, SPF 60-12 means SPF 60 and PA+++.
In addition, if you often use sunscreen products from countries such as the UK, the US or some European countries, you will often not see brands providing the PA index. Instead, you will the words “Broad Spectrum” or “Full Spectrum” which means that these sunscreen products have been recognized to have the effect of limiting the harmful effects of both UVA and UVB rays.
3. Meaning of the PA index
PA+ has the ability to resist UVA rays at a level of 40-50%
PA++ has better UVA resistance, at a level of 60-70% and the filtering time is about 4-6 hours.
PA+++: Good UVA resistance, up to 90%, filtering time is about 8-12 hours
PA++++: Has very good UVA resistance, up to over 95%. Filtering time is up to 16 hours.
4. How to choose a sunscreen with a good PA index?
PA is an index against UVA rays, so products containing higher levels of addition have better sun protection and skin protection against the harmful effects of UVA rays.
Therefore, when going outdoors, you should choose sunscreens with PA+++ or PA++ to provide better protection and longer-lasting coverage.
Hopefully, this article will help readers understand the PA index on sunscreen, the levels and the meaning of this index. It will help you choose a suitable sunscreen to help protect your skin from the harmful effects of UV ray.
Please dial HOTLINE for more information or register for an appointment HERE. Download MyVinmec app to make appointments faster and to manage your bookings easily.
