SPF 101: What Does the Number on Your Sunscreen Denote?
And what sorcery does +++ do?! Read on to get all your answers.
What does the number on the sunscreen tube denote? Do I really need to pay attention to that number?
Yes, you do! SPF stands for sun protection factor. SPF in a sunscreen is in relation to the UV-B rays, which are responsible for the darkening of the skin and can even lead to sunburn on long exposure to the sun. Contrary to popular belief; the Indian skin does not require a sunscreen with more than SPF-15. That is because the melanin is quite high in our skin and is in itself a strong protection against the UV-A and UV-B rays. Moreover, an SPF-30 does not mean double the protection from UV-B rays as compared to an SPF-15. While an SPF-15 sunscreen blocks around 93% of the UV-B radiation, a sunscreen with SPF-30 blocks around 96% of the UV-B radiation. Even an SPF-50 will give 97% protection from radiation, which is only marginally higher. However, the chemical percentage in the sunscreen becomes considerably higher with an increase in SPF, which is definitely not good for the skin.
Are there different types of sunscreens?
There are two general types of sunscreens, physical and chemical ones. The major difference lies in the UV filters they use—the active ingredients that protect you from the sun—and how they work on your skin. The major differences between physical and chemical sunscreens are listed in the table below and will help you in making an informed choice while picking your sunscreen.
| Physical Sunscreens | Chemical Sunscreens |
| Sits on top your skin and scatters the UV radiation and do not allow it to be absorbed into your skin at all | Work by absorbing UV rays |
Mainly rely on two minerals: Titanium dioxide (TiO2) and Zinc oxide (ZnO) | Rely on chemicals like Octylcrylene, Avobenzone, Octinoxate, Octisalate, OxyBenzone, and Homosalate and Helioplex to absorb the UV rays your skin is exposed to. There is growing concern that some of these chemical filters used can generate free radical damage and some are even thought to be endocrine disruptors, which means they are messing with your hormones.
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| Zinc oxide protects against the entire spectrum of UVB and UVA rays. Titanium dioxide protects against UVB rays, but not the full spectrum of UVA rays. | Chemical filters offer more coverage against UVA and UVB rays than physical sunscreens, but the range of protection will depend on the particular active and its stability. Avobenzone, for example, protects against the full spectrum UVA rays.
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| Starts protecting immediately upon application. | Must wait 20 minutes after application for effective sun protection.
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What does +++ indicate in SPF?
Our skin requires a two-fold protection from the Sun
first from UV-B rays, which darken the skin and can result in sunburn- and from UV-A rays, which penetrate deep down into the skin and are responsible for photo aging.
While the SPF number in a sunscreen refers to the protection against UV-B rays, +++ indicates that the sunscreen offers protection against UV-A rays as well.
The broad spectrum sunscreens are like killing two birds with one stone as it has ingredients that protects against UVA as well as UVB rays.
Inputs by Dr Neena Chopra, Director-Beauty & Technical, Just Herbs