The Science Of Sunscreen

When it comes to sunscreens, it is easy to get overwhelmed by the surplus information, and the prospect of buying the right sunscreen becomes a daunting task. Therefore, we thought we'd give you a crash course on the science behind sunscreens and what you should be looking for when shopping for one.

So what is sunscreen? Sunscreens are typically a photo-protective topical product that helps resist harmful sunrays and shield the skin from sun damage.  In order to avoid skin damage that can result in skin cancer and ageing, sunscreens include active substances that shield the skin from UVA and UVB damage. Depending upon the SPF, sunscreens can help protect skin cells from the sun's ultraviolet radiation. To understand it better, UVB rays are the rays that cause burning while UVA rays cause skin ageing. Sunscreens shield skin against UV damage by including either chemical or physical active components (or a combination of the two).

The formulations of sunscreen products can range from creams, lotions, sprays, gels, sticks, mousses and powders. However, lotions and creams are the most commonly used and most effective formulations as they stay on the skin for longer for durable protection. 

Let's start with the most frequently asked question.

What’s In A Sunscreen & How Does It Work?

Sunscreens typically come in two types: chemical & physical. A chemical sunscreen uses ingredients such as oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate. These chemicals work by absorbing the UVA & UVB rays from the sun and releasing them in the form of heat, keeping the skin protected from the harmful effects of the rays.

A physical sunscreen, on the other hand, commonly known as a mineral sunscreen, uses titanium dioxide and zinc oxide, which physically blocks harmful UVA & UVB rays from penetrating the skin.

What Is SPF?

SPF measures how much solar energy (UV radiation) is needed to cause sunburn on skin that is shielded from the sun (i.e., while wearing sunscreen) compared to how much solar energy is required to cause sunburn on skin that is not protected from the sun.

A number like 15, 30, 40 usually follows SPF on sunscreens, etc. The higher the number, the better the protection against UVB rays. So a sunscreen with SPF 30 blocks 96.7 percent of UV radiation, allowing 3.3 percent to enter the skin, while SPF 50 blocks 98 percent, allowing just 2 percent to pass.

However, remember that the SPF number only refers to UVB protection, so it’s essential to go for sunscreens that say “broad spectrum” protection, which means they offer protection against UVA rays as well. UVA protection is commonly denoted with the PA+ symbol. 

What Is The Right Sunscreen For Me?

Between chemical and mineral sunscreens, the often-used one is the chemical sunscreen as it is more accessible. There are pros and cons to both types of protection.

The Pros of Chemical Sunscreens:

• It is fast absorbing, so it dries up on your skin very quickly, making it ideal for daily use.

• Its lightweight and stain-free formulation make it ideal for those with darker skin tones.

• Its quick drying properties make it perfect for those who lead a physically active lifestyle and those who tend to sweat a lot.

• It is great for beach time, and most chemical sunscreens are water resistant.

The Cons Of Chemical Sunscreens:

• Sensitive skin is more prone to irritation by chemical sunscreen ingredients.

• When the skin is exposed to UV radiation, some chemical sunscreens may result in photosensitivity, increased skin sensitivity, or an atypical skin response.

• The ingredients found in chemical sunscreens may not be environmentally friendly.

The Pros Of Mineral Sunscreens: 

• The active ingredients do not get absorbed into the skin, making them perfect for those with sensitive skin.

• The active ingredients found in mineral sunscreens are environmentally friendly.

• It provides excellent photo-stability, preventing minerals from deteriorating and losing their effectiveness when exposed to the energy from UV rays.

The Cons Of Mineral Sunscreens: 

• They usually leave a white residue on the skin.

• It might feel like a heavy application on the skin.

If you are susceptible to skin irritation, then look for a sunscreen that:

• Has broad spectrum protection

• Is SPF 30 or higher

• Is water resistant

• Is fragrance free, paraben free

• Is preferably non-comedogenic

While gels and sprays are productive, lotions and creams are most effective at delivering the active ingredients to your skin.

What are the side effects of Sunscreen?

Sunscreen are topical products with no side effects. However, depending upon the formulation and skin allergies one may have, sunscreens may have certain side effects like rashes or skin irritation. In case of the above, stop using the sunscreen immediately, wash off with cool water and check with your doctor.