Does Sunscreen Block Tan? Deep Dive into How Sunscreens Work

Does Sunscreen Block Tan? Deep Dive into How Sunscreens Work

When the sun is out, one of the instinctive things to do for many of us is reach for that bottle of sunscreen. After all, it is the backbone of protecting our skin against bad ultraviolet rays. But here is the important thing lots of people ask: Can sunscreen prevent tanning? We will have to delve deep into the inner mechanisms of sunscreen, the science behind tanning, and how best to protect your skin against the sun to understand the answer to this question.

How Does Sunscreen Work? What is Sunscreen?

Sunscreen is an over-the-counter topical product that one applies for absorbing, reflecting, or scattering solar rays; its purpose is to help protect the skin from further damage it may undergo due to ultraviolet radiation. The primary work of sunscreen, therefore, is to decrease the depth to which such dangerous rays penetrate into the skin and thus assist in preventing sunburn, premature aging, and lowering the chances of skin cancer.

There are two major types of UV rays one uses sunscreen to protect against. These include:

UVB Rays: These are the rays responsible for sunburn and one of the major culprits in skin cancer. UVB rays have shorter wavelengths, yet during the middle of the day, they are really strong.

UVA Rays: These are the rays that penetrate deeper into the skin and are believed to be the chief contributors to tanning, premature aging, and wrinkling. Unlike UVB rays, UVA rays are present with relatively equal intensity during all daylight hours.

 

How Does Sunscreen Work? Sunscreen works by containing active ingredients that act either as a physical or as a chemical blocker:

Physical Mineral Sunscreens: These contain the active ingredients zinc oxide or titanium dioxide, which work by physically sitting on top of the skin and reflecting UV radiation away from the skin. Chemical Sunscreens: These contain organic compounds-those with a carbon atom-based structure-like oxybenzone or avobenzone, which work by absorbing UV radiation and converting it to heat, which is liberated from the skin.

SPF is the measure of how much energy from the sun, or UVB, it takes to cause sunburn on skin that is protected by sunscreen, compared to unprotected skin. For reference, SPF 30 lets 3 percent of UVB rays reach the skin and blocks 97 percent of the rays. However, SPF does not tell the amount of protection against UVA radiation, which is the main cause of tanning. Tanning and Sunscreen: The Science Behind It
What causes tanning? It is your skin's natural reaction to UV radiation. Your skin produces a pigment called melanin when it is exposed to the sun; this melanin absorbs and scatters the UV radiation, which is a natural reaction of the body trying to protect the deeper layers of skin from damage.

Here's how:

UVB: This is the wavelength that reaches the skin, causes direct DNA damage to skin cells, and results in melanin production. This is also what causes sunburn if it becomes too strong or if the skin isn't protected well enough.
UVA Exposure: On the other hand, UVA rays penetrate deeper into the skin and contribute indirectly to DNA damage by generating free radicals. UVA exposure causes the oxidation of existing melanin in the skin, darkening the skin—a process we know as tanning.
Can Sunscreen Prevent Tanning? The short answer: Not completely. While sunscreen significantly cuts down on the amount of UV radiation that reaches the skin, it doesn't block all of it-particularly when it comes to UVA rays. That is why, even with regular application of sunscreen, you could still notice a gradual tan if you happen to spend a great deal of time outdoors.

SPF and Tanning: How It Works SPF is primarily a measure of protection against UVB rays, which cause sunburn rather than true tanning. In practice, the use of a high-SPF sunscreen reduces burning but does not completely block UVA rays, which can still initiate a tan. That's why it's so crucial to select a sunscreen that is "broad-spectrum," protecting against both UVA and UVB rays.

Large-spectrum sunscreens, however, still let through a small percent of UV rays to skin. These can eventually stimulate melanin production over time and cause tanning. The extent of this will, of course, depend on such factors as the SPF of your sunscreen, frequency of re-application, skin type, and intensity of sun exposure.

Tips to Minimize Tanning While Still Keeping Safe
If avoiding a tan is important to you, here are some strategies to improve your sun protection:

High SPF, Broad-Spectrum Sunscreens

Use a sunscreen with an SPF of at least 30 that also provides broad-spectrum protection. The higher the SPF rating, the more protection the sunscreen offers. However, no sunscreen protects completely. For example, SPF 50 filters out about 98% of UVB rays, while SPF 100 blocks about 99%.

 

 

Apply Generously and Reapply Often:
Most people don't use enough sunscreen, which reduces its effectiveness. Try to use one ounce-one shot glass full-for full-body coverage and put it on 15-30 minutes before heading outdoors. Reapply every two hours or more often after swimming, excessive sweating, or toweling dry.

Seek Shade During Peak Hours:
The sun's rays are strongest between 10 AM and 4 PM. Whenever possible, seek shade during this time, particularly if trying to prevent too much tanning.
Protective Clothing

Clothing can provide a physical barrier to the sun's UV rays. Check the UPF rating on clothing which indicates how much UV radiation actually reaches the skin from a specific fabric. Wide-brimmed hats, sunglasses that provide UV protection and long sleeved shirts can block your skin from these ultraviolet rays.

Apply Tanning Inhibitor:
Some products on the market claim to impede the tanning process, itself, by restricting a large amount of melanin from forming in the skin. These can be an added tool in your sun protection utility belt, but they should be used in addition to sunscreen application, not in place of it.

The Bottom Line: Embrace Healthy Sun Habits
Sunscreen is a powerful protector from skin damage, sunburn, and premature aging. However, one has to be in a frame of mind that by saving the skin from such damages, it decreases the possibility of tanning, but not entirely eliminating it. A small amount of UV still reaches your skin and initiates melanin production in your skin, which results in a tan.

Instead of trying to avoid tanning, your main priority should be to protect your skin from the sun. Remember that a tan means your skin has suffered from UV radiation, which can maybe cause long-term damage. High-SPF, broad-spectrum sunscreen will protect you well when applied often and in combination with other methods of protection.