UVB rays are most likely to cause sunburn while UVA rays are more likely to cause wrinkles. Sunscreen can protect the skin from both UVA and UVB rays.
There are some common myths and misconceptions surrounding sunscreens that people should be aware of before buying their next bottle.
Understanding the truth about sunscreen can help people use sunscreen correctly.
UVA vs. UVB light
Understanding sunscreen myths requires a basic understanding of UVA and UVB light. They are both forms of ultraviolet (UV) light that can affect the skin after exposure.
UVA light has a longer wave that penetrates into the thickest layer of skin, called the dermis. Unprotected exposure to UVA rays can lead to skin aging, wrinkles, and a suppressed immune system.
UVB rays have a shorter wave and are most responsible for sunburn, which is the burning of the top layer of skin. UVB rays can play a key role in developing skin cancer, and frequent sunburns may cause permanent damage over time.
Twelve myths about sunscreen
We look at 12 common misconceptions about sunscreen.
1. Sunscreen is not always necessary
Many people believe that sunscreen is only necessary when their entire body is exposed to sunlight, such as when at the pool or swimming in the ocean. Ultraviolet light is still harmful to exposed skin, no matter how much of it is exposed.
Some people also believe that sunscreen is not necessary on cloudy days because the sun does not feel as strong as usual. The truth is that anytime the body is exposed to light from the sun, it is exposed to UV rays, even if it is an overcast day.
The lower arms and face are common areas to leave exposed throughout the day, which may increase their risk of sun damage. It is best to cover the exposed skin with sunscreen and consider other protective methods, such as wearing a hat.
2. Sunscreen will prevent the body from absorbing vitamin D
Vitamin D is a vital nutrient for human health, and the body makes it easily through exposure to UV rays. Sunscreen, however, blocks UV rays. So, in theory, using sunscreen 100 percent of the time would prevent a person from getting the proper levels of vitamin D.
However, sunlight can penetrate clothing, sunscreens lose their effectiveness over time, and it is likely a person will forget to put sunscreen on every time they see the sun.
Many scientists and dermatologists suggest that just 5 to 30 minutes of sun exposure per day can create the proper amount of vitamin D in the body.
3. Sunscreen causes health problems
This myth comes from an older study done on oxybenzone, one of the active ingredients in many sunscreens. Rats exposed to oxybenzone experienced serious negative side effects.
However, as a research letter posted to Archives of Dermatology points out, the levels of exposure this study reached to produce health problems in the rats were extremely high.
Their calculations demonstrated that these results were unattainable in humans, even those who use sunscreen regularly and liberally.
The researchers noted that after 40 years of oxybenzone being an ingredient in sunscreens, there are no published studies that demonstrate toxic effects in humans caused by absorbed oxybenzone.
4. People with dark skin do not need sunscreen
People with dark skin are still at risk of sunburn and skin damage. Taking precautions, such as wearing sunscreen, is always recommended regardless of skin color.
Some people believe that those with more melanin in their skin do not need to use sunscreen. This is because melanin acts to diffuse UVB rays and may protect against sunburns, to some extent.
While people with darker skin are more protected from the sun, they should still use a full spectrum sunscreen. UVA damage is not blocked by melanin in the same way and can lead to premature skin aging and wrinkles.
Melanin will also not protect the skin from extreme sun exposure, such as spending long hours in the sun unprotected. People with darker skin are also not protected against skin cancer.
One study noted that skin cancer survival rates were lowest in people with darker skin, including African-Americans, Asian-Americans, Native Americans, and Pacific Islanders. These results indicated a need for better screening and awareness of the risk of skin cancer.
5. Tanning beds provide a protective base tan
Some people believe that they should use tanning beds to get a quick tan before summer comes, or before exposing themselves to a lot of sun, such as when on vacation.
Tanning beds use high concentrations of UVA light to darken the skin quickly, whereas the sun includes both UVA and UVB light.
Exposing the body to high levels of UVA light from a tanning bed creates a temporary tan that will do very little to protect the skin from sun exposure and sunburns caused by UVB light.
6. Makeup is enough to protect the face
While it is true that makeup may provide a little protection from the sun, it is not much and is not a replacement for a good sunscreen.
Makeup should be seen as an additional layer of protection, not the only layer of protection.
7. Sunscreen works better than covering up
It can be tempting to think that a layer of sunscreen makes the body invincible to the sun. Many people who wear sunscreen believe this allows them to stay protected throughout the day, even if much of the skin is exposed.
The truth is, covering up the skin is much better protection than sunscreen. A long-brimmed hat and clothing will protect the skin better than any sunscreen.
8. You cannot tan while wearing sunscreen
Sunscreen will protect the skin from most light rays, but some will still reach the skin. This means it is still possible to get a tan while wearing sunscreen.
Sunscreen helps protect against UVA and UVB rays, but it may not protect the body completely. It is still possible to get a tan while using sunscreen, even when someone applies it multiple times throughout the day.
A tan is the body's natural protective response to UV exposure. To avoid a tan, it is best to apply sunscreen and cover up with a hat and long clothing.
9. All sunscreen is the same
There is a common misconception that all sunscreen is roughly the same and will do the same job. There are a variety of ingredients in sunscreens, however, and they may protect against different levels of sun exposure.
Active ingredients such as titanium dioxide, zinc oxide, and ecamsule are often used to filter out UVA and UVB rays. There are also chemical blockers, such as avobenzone. These ingredients all block the sun in different ways.
Using a full spectrum sunscreen is important because it will protect the skin against the largest range of UV light.
The other important consideration is the sun protection factor (SPF). The United States Food & Drug Administration (FDA) recommend regularly applying a sunscreen with an SPF of 15 or higher, even on cloudy days.
10. One application of sunscreen lasts all day
Many people think that sunscreen will last all day after just one application. In reality, sunscreen breaks down in the light and loses its effectiveness over a short period of time.
People should apply sunscreen every 2 to 4 hours, at least.
11. Sunscreen is waterproof
Sunscreen labeled as water-resistant or sweat-resistant, or marketed as sunscreen for sports, may appear to be waterproof. Unfortunately, this is an overstatement of what sunscreen can do.
No sunscreen product can be 100 percent waterproof. People must always reapply water-resistant sunscreens after water exposure. Allow sunscreen to settle on the skin for at least 10 to 15 minutes before going in the water.
12. Sunscreen never expires
Contrary to common belief, sunscreen naturally expires. The active ingredients can break down over time, and using expired sunblock may leave the skin unprotected.
Understanding the truth about these myths can help people use sunscreen effectively.
Instructions for each sunscreen can vary, and people should follow the instructions on the packaging for maximum protection. Proper use of sunscreen can help guard against skin damage and sunburn.