As the weather warms up, you may have noticed an increase in the debate between physical and chemical sunscreen. Most people know that sunscreen can offer protection from the dangers of prolonged UV radiation caused by the sun’s rays. But do you know how your sunscreen offers that protection?
History of Sunscreen in America
Many forms of sun protection have been used throughout history – from Ancient Egyptians’ mixture of jasmine and rice to Ancient Greeks’ use of olive oil. Skin safety under the sun has always been a concern.
In America, we had a variety of home remedies, but Benjamin Green’s greasy red substance called “red vet paint” is what revolutionized sunscreen and lead to the creation of Coppertone suntan cream. As more people began developing sunscreen, the FDA began regulating it for safety and effectiveness, including the adoption of the sun protection factor (SPF) rating. The SPF rating measures the fraction of sunburn-producing UV rays that reach the skin and can be determined by multiplying the SPF factor by the length of time it takes for you to burn without sunscreen.
Over the years, the FDA has continued to improve upon its original standards for sunscreen in America. Now, products must be clear on what form of protection they offer, including which UV rays they shield against and the ingredients they contain.
The latest debate around sunscreen is centred around the way it interacts with the skin.
Difference Between Chemical and Physical Sunscreen
The main difference is broken down into absorbent versus reflector. Chemical sunscreen absorbs UV rays into the skin and breaks down the radiation before expelling it whereas physical sunscreen acts as a mirror that reflects the UV rays off of the skin.
There are pros and cons to both types of sunscreen.
Chemical sunscreen is:
- Most commonly used and easier to find.
- More water-resistant.
- A quick absorbent.
- Ineffective until 20 minutes after application.
- Offers more UVA protection.
Physical sunscreen is:
- Less irritating for sensitive skin.
- A better moisturizer.
- More difficult to fully blend into the skin.
- Immediately effective upon application.
- More photostable and therefore lasts longer on skin.
What to Look for in Sunscreen
Many dermatologists agree that both types of sunscreen are successful in protecting the skin. The CDC believes that what really matters is making sure your sunscreen is:
- Broad-spectrum, which offers protection from both UVA and UVB rays.
- At least 15-30 SPF or higher.
- Using active ingredients like zinc oxide, titanium dioxide, avobenzone, ecamsule, oxybenzone, dioxybenzone, or sulisobenzone.
- Within the expiration date.
- Applied to all exposed areas and allowed to dry on the skin for 15-30 minutes.
- Reapplied no later than every two hours.
Other Protective Measures
To protect yourself from UV rays, it is recommended that you:
- Seek shaded areas – especially between 10 a.m. and 4 p.m.
- Look up your location’s Ultraviolet Index (UVI) before going outdoors.
- Add flat, tinted UV-protective film to your car’s side and rear windows.
- Use laundry additives that wash into regular fabrics to provide higher UV protection.
- Wear broad-brimmed hats and UV-blocking sunglasses.
- Avoid tanning booths and do not burn.
The key takeaway is that you should always use sunscreen – either chemical or physical – when participating in outdoor activities. The routine use of sunscreen can reduce the risk of melanoma and other forms of skin cancer.