UPF Clothing: Smart Sun Protection

A close up on a man wearing sunglasses and a hat and a Oasis Blue Open Air Caster shirt

Ever wonder how UPF (Ultraviolet Protection Factor) clothing works to deliver protection from the sun? Can it really be all that different from any other clothing? The answer is yes. And no. Clothing is your first line of defense in protecting your skin from the sun, and all clothing affords at least some protection. But some textiles do the job better than others, and clothing that bears a UPF rating in particular is up to the task. Read on for answers to common questions about intelligent clothing that can safeguard your sensitive skin from the sun.

A man wearing a hat and checked shirt casting a fly rod into the water

What is UPF Clothing?

Understanding a few basic but important terms is essential to understanding modern UPF clothing made from textiles steeped in science:

  • UPF stands for Ultraviolet Protection Factor and refers to the amount of the sun’s ultraviolet (UV) rays—invisible to us—that can penetrate fabric to reach the skin.
  • Ultraviolet (UV) Radiation is an invisible form of energy that comes from the sun; it passes through some materials. Small amounts of UV radiation are beneficial for people and essential for the production of vitamin D. Under a doctor’s supervision it can also help treat some diseases.
  • UVA radiation penetrates deeper into the skin than UVB and is thought to contribute to sunburn, skin cancers, and photoaging. UVA rays can also penetrate glass, for example, your car’s windows.
  • UVB radiation is the type of radiation chiefly associated with sunburn.
  • SPF stands for Sun Protection Factor and is a rating system for sunscreen, cosmetics, and other products that contain sunscreen. The SPF indicates how long you can stay in the sun before you can expect your skin to burn.
A family and their dog walking on the beach in the sun

Is UPF the Same as SPF?

The UPF rating is for clothing and the SPF rating is for lotion and other cosmetic products. The UPF rating is applied to textiles that protect your skin from the sun. And while the two are similar, the SPF rating used for cosmetics and sunscreens measures only how much UVB is blocked, but not UVA (unless it is labeled “broad spectrum”). UPF clothing blocks both types of radiation.

If your unprotected skin typically starts burning after 20 minutes, sunscreen with an SPF of 15 would give you 15 times that, or five additional hours. The UPF rating works differently; a garment with a UPF of 50 allows 1/50th of the sun’s ultraviolet radiation, or about two percent of it, to reach the skin through the fabric. By way of comparison, an ordinary white T-shirt has a UPF of 5, so it allows 1/5 (or 20 percent), of the sun’s UV radiation to reach the skin.

The UPF was standardized in Australia in 1996; in the USA the American Society for Testing and Materials (ASTM) sets standards for UPF labeling.

A woman wearing an orange shirt, hat, and sunglasses while near the water in the sun

Is UV Radiation Dangerous?

In a word, yes. But a better question is, How dangerous is UV radiation? UV radiation can damage your skin in as few as 15 minutes; prolonged exposure to it has dramatic health effects on the skin, the eyes, and the immune system:

  • The most immediately visible expression of these is sunburn (erythema), followed by premature aging (photoaging) with repeated exposure to the sun—damage that adds up over your lifetime.
  • The most serious consequence is skin cancer, with 66,000 deaths worldwide attributed annually to melanoma and other skin cancers.
  • Additionally, prolonged sun exposure has been linked to cataracts, the clouding of the lens of the eye that can lead to blindness.

Children are an especially vulnerable population: the Centers for Disease Control reports that a few serious sunburns obtained during childhood increase a child’s risk for developing skin cancer later in life.

A man wearing shorts out in the desert

How Does UPF Clothing Work?

UPF clothing either blocks or absorbs UV radiation to protect your skin. While “absorbing” UV rays may sound undesirable, it is actually transformative in a way that is helpful: when the “absorbent” textile encounters the UV, its energy is converted to heat, making it harmless.

Clothing that bears a UPF designation on its label has been tested and deemed to protect its wearer from UVA and UVB radiation, so long as it bears a rating of 15 or higher; in some cases, it may also have been treated with colorless dyes or chemical UV absorbers that block both UVA and UVB rays. The UPF rating is based on a fabric’s content, weight, color, and construction. But a fabric does not have to be labeled as such to provide UV protection.

Are You at Risk for Skin Cancer?

130,000 malignant melanomas occur globally each year. And while skin cancer is more common in fair-skinned people, it can occur in skin of any color.

People at higher risk for damage from UV radiation:

  • Live in equatorial regions, or
  • Live at high elevations, or
  • Routinely spend time on reflective surfaces (e.g., snow)

The fairer your skin and the more intense the UV radiation where you are, the more preventive steps you should take to protect your skin and eyes.

A man wearing PRO Stretch Long-sleeved shirt and a woman on a boat fishing

Does UPF Clothing Really Work?

There is wide agreement among dermatologists that UPF clothing does work, and actually delivers more effective protection from the sun, and more reliably, than other means. But the amount of coverage is key, and the more skin you cover, the better protection you can expect: a long-sleeved shirt is better than a short-sleeved one, and pants are better than shorts.

Fair-skinned people stand to benefit the most from UPF clothing, but any skin type will benefit from it at least some. Ratings are scaled as follows:

  • 15 to 24—Good
  • 25 to 39—Very Good
  • 40 to 50—Excellent

It’s best to choose clothing with a UPF rating of 30 or higher; UPF 50 blocks 98 percent of UV radiation. And unlike sunscreen, UPF clothing works indefinitely—there is nothing to reapply for continued protection.

A woman wearing a PRO Sun Hoodie casting in a river

Does the Clothing in My Closet Protect Me from UV Rays?

All clothing protects your skin from harmful UV radiation to some extent, and clothing is generally the best means of protection. Beyond clothing that bears a specific UPF label, look for these benchmarks.

Material Synthetics top the list for protection from UV radiation. Nylon offers highly effective protection, and both wool and silk are moderately effective. Cotton, rayon, flax, and hemp are less effective unless they have been chemically treated. The most protective cotton is unbleached or naturally colored. But untreated denim can provide superior protection, with a UPF value of 1700, meaning only 1/1700th of the sun’s ultraviolet radiation penetrates it.

  • Colors that absorb UV radiation help reduce exposure to it. Dark colors are effective, but reds and other brights can absorb UV rays, too—the more vivid the color, the better it protects. Lighter colors can block UV radiation if the material’s weave is tight enough or it is chemically treated.
  • High concentrations of premium dyes are used in some UPF-labeled clothing; typically, the higher the concentration of the dyes, the darker the material. Also, look to pigment-dyed fabrics for UV protection—these are textiles colored with a process that chemically binds the color to the material’s fibers.
  • Tighter weaves are usually better UV blockers. You can get some idea of the effectiveness of a garment’s weave by holding it up to the light, but weave should not be the only yardstick to measure a textile’s UPF properties: the human eye can detect light, but it can’t see ultraviolet rays—even a tight weave can be breached by UV radiation.
  • Keep it dry: Wet fabric loses up to 50 percent of its UPF effectiveness for reasons not completely known. Faded fabrics are also less effective UV barriers. Choose quick-drying clothing for fun in the sun.

Choosing a garment with a UPF label ultimately takes the guesswork out of measuring whether it effectively blocks or absorbs UV rays, as its material will have been tested in a laboratory. And UPF-labeled garments now come in a wide range of colors and weights.

Quick Tips:

Wash natural fiber clothing several times to maximize shrinkage of the “holes” in the weave.

  • Weight—The heavier the better when it comes to UV protection. And while you may not consider this ideal if you are bound for the beach, ventilation holes are added to some UPF clothing for improved air circulation and comfort.
  • Elasticity—Stretchy clothing provides less protection than clothing without stretch because the weave expands when the material stretches. The correct fit is especially important in stretch clothing.

Wash your clothing with a UPF detergent additive or an optical brightening agent, which will enhance its natural UPF properties.

A woman with long brown hair outside wearing a hat and sunglasses

Beyond UPF

Smart Tips for Sun Protection

An active outdoor lifestyle demands a proactive approach to protection from the sun. A multi-pronged solution includes more than just the UPF label in your clothing:

  • A broad-brimmed hat gives you 360-degree protection in the sun.
  • UV-blocking sunglasses in a wraparound style protect your eyes better than a small lens style.
  • Be aware of reflected sunlight, which also carries UV radiation.
  • Apply a broad-spectrum sunscreen with an SPF of 15 to 30 to all exposed skin.
  • Play smart: seek the shade as often as possible when you’re outdoors.

Slow the sun’s harmful effects on your skin with these strategies, and include intelligent, modern UPF clothing in your wardrobe.