Why SPF & PA Must Be Your New BFF
May 29, 2024Sunscreens have become a non-negotiable step in our morning skincare routine. They are our first line of defence against harmful UV radiation from the sun that causes sunburns and photodamage. But finding the right sunscreen formulation for your skin isn’t an easy task.
Because not all sunscreen formulations are made equal. There are several factors to consider while buying sunscreen, like your skin type, chemical vs mineral UV filters, and most importantly, the amount of UV protection you will get.
Sunlight contains two types of UV radiation-UVA and UVB rays.
UVA rays are long-wavelength radiation that can penetrate deeply into the skin, leading to premature wrinkles, sagging skin, fine lines, and dark spots..
UVB are short-wavelength sun rays that can damage the outermost layer of skin leading to sunburns.
The amount of protection a sunscreen can offer is measured through SPF and PA ratings. So understanding what these numbers mean, and how they are calculated will help you choose the best sunscreen for your needs by identifying the level of UV protection it offers.
What Is SPF?
According to the FDA, the SPF (Sun Protection Factor) rating measures how much UV radiation is required to produce sunburn after applying sunscreen compared to the amount of UV radiation required to produce sunburn on unprotected skin. Since UVB rays are primarily responsible for causing sunburns, the SPF rating indicates the amount of UVB rays absorbed by the sunscreen.
To decide the SPF of a sunscreen, laboratory tests are carried out where the sunscreen is applied liberally to the skin and then exposed to UV lamps. A simple formula is then used to calculate the SPF rating.
The time it takes for a patch of skin to slightly redden when covered in sunscreen is divided by the time it takes to slightly redden with no sunscreen. Say it took 600 seconds for the skin to burn with sunscreen, and 20 seconds to burn without it. 600 is divided by 20, and the SPF rating is 30.
Is a Higher SPF better?
Yes, a sunscreen with a higher SPF value will give you more sun protection but this protection is not directly proportional and increases only marginally. For eg. A sunscreen with SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97%, and SPF 50 blocks 98%. So SPF 100 sunscreen will not provide 2x protection compared to SPF 50.
There is a popular misconception that the SPF rating of a sunscreen determines how long you can stay in the sun. For instance, some think that if they usually get sunburnt in 20 minutes, using SPF 15 sunscreen means they can stay out 15 times longer.
However, SPF actually measures the amount of UV radiation, not time. The intensity of UV radiation changes throughout the day, and the amount of UV exposure between 9 and 10 a.m. equals just 15 minutes of the afternoon sun.
In addition to this, your skin colour can also determine how long it takes for your skin to develop a sunburn. The skin's outer layer contains a brown pigment called melanin, which acts as a natural defence against UV rays.
The more melanin is in your skin, the darker will be your skin tone—and the better natural protection you will have against sunburns. So people with pale skin tones absorb more UV light and thus tend to burn faster.
What Is PA Rating?
Compared to UVB rays, UVA rays penetrate deeper into the skin and accelerate the formation of wrinkles, fine lines, and age spots. So your sunscreen should also protect your skin against UVA rays to maintain healthy, youthful-looking skin over time.
PA rating on the sunscreen label stands for "Protection Grade of UVA" and it's a system developed to measure the level of protection a sunscreen offers against UVA rays which are primarily responsible for causing skin ageing.
When you see a sunscreen labelled with a PA rating, like PA++ or PA+++, it indicates how well the product protects against UVA rays. The ratings range from PA+ to PA++++, with higher numbers of ‘+’ indicating better protection against UVA rays. So PA++++ offers the strongest protection while PA+ is the weakest.
How Much SPF and PA Do You Really Need?
The ideal amount of SPF you need depends on factors like your sun exposure level, skin tone, and the time you will spend under direct sunlight. For Indian skin, dermatologists usually recommend using a broad-spectrum sunscreen with an SPF rating of 30 or higher.
If you have fair or sensitive skin, you may reach for sunscreens with the highest SPF to prevent sunburn and reduce the risk of skin damage. However, according to the Skin Cancer Foundation, products with very high SPFs(like SPF 100) tend to create a false sense of security.
People who use them tend to stay out in the sun much longer and even skip reapplication leading to more UV damage. So sunscreen with SPF 30-50 is a good choice for your daily routine.
And just like with SPF, choosing the right PA rating also depends on factors like your skin type, the intensity of sun exposure, and outdoor activities. If you're planning to be out in the sun for several hours, especially around mid-day, pick a sunscreen with the highest PA rating (i.e. PA++++).
Try Juicy Chemistry Moisturizing Mineral Sunscreen
Our Moisturizing Mineral Sunscreen has titanium dioxide and phytonutrients to protect your skin from UV rays all year around. The broad spectrum formula with SPF 40 PA++++ rating has been clinically tested to protect your skin from UVA/UVB rays.
The no-white cast, the non-greasy formula gets absorbed easily without pilling on the skin due to its lightweight consistency. It also has emollients like squalane and aloe vera juice to keep your skin hydrated and moisturised while you are out in the skin.
Suitable for all skin types and ages(2+ years), including sensitive and acne-prone skin, our mineral sunscreen is a perfect choice to keep your entire family protected from harsh sun rays.
Shop our SPF 40 mineral sunscreen here.
FAQs
How long is SPF effective?
The protection from your sunscreen wears off within a few hours due to sweating, rubbing your face, or being in contact with water during swimming or rain. So you need to reapply it throughout the day.
How many times should SPF be reapplied?
You should reapply sunscreen every 2-3 hours, or more frequently if you are swimming or sweating profusely to ensure your skin is protected throughout the day.
Are makeup with SPF effective?
Makeup products are often not applied in sufficient amounts to get the SPF level printed on the label. So it's best not to rely on them for sun protection. Always wear sunscreen under your makeup for proper UV protection.
