Can sunscreen prevent tanning?

Why sunscreen cannot prevent every tan

UVA rays cause tanning, while UVB rays cause sunburn. SPF measures UVB protection, not UVA, so the number alone does not tell you how much protection you have from tanning rays. Broad spectrum sunscreen covers both UVA and UVB, a surprisingly unpoetic name for a useful pair of jobs. SPF 30 blocks about 97 percent of UVB rays, and higher SPFs block slightly more. UVA reaches deeper skin and contributes to premature aging; UVB affects the surface. UVA can also pass through untreated, untinted window glass.12345

Can you still tan while wearing sunscreen?

Yes. Even careful use leaves some UV exposure because sunscreen cannot block every ray. Applying too little, missing a patch, or failing to reapply lowers protection further. Water, sweat, and towel drying can remove sunscreen, while sand, water, and snow reflect UV onto exposed skin. A tan can still happen, which means sunscreen reduced exposure rather than erased it. Do not use sunscreen as a reason to stay outside longer.356

Does SPF 50 prevent tanning?

No. SPF 50 offers stronger UVB protection than a lower SPF, but SPF measures UVB, not UVA, and UVA rays cause tanning. Choose a broad spectrum SPF 50 to cover both kinds of rays. A higher broad spectrum SPF provides more UVA and UVB protection than a lower one, but it still cannot block every ray or guarantee that you will not tan. Keep to the same reapplication schedule rather than treating a higher number as extra time in the sun.15

How can I protect my skin from tanning in the sun?

1. 1Choose a broad spectrum sunscreen with SPF 30 or higher. Pick a water resistant formula if you expect to swim or sweat heavily.
2. 2Apply it generously and evenly to dry, exposed skin 15 minutes before going outdoors. For an adult body, about 1 ounce covers skin not covered by clothing; use at least 1 teaspoon for your face. Cover your ears, neck, tops of feet, and exposed scalp.
3. 3Reapply about every two hours outdoors, and after swimming, sweating, or towel drying, even if the sunscreen is water resistant. Reapply sooner if it rubs or wipes off.
4. 4Limit direct sun around midday and check the local UV index. Seek shade when it is 3 or higher, but do not rely on shade alone. Tightly woven clothing, a wide brim hat, and sunglasses add coverage. Be extra careful near reflective sand, snow, and water.

If you mean dark marks rather than an overall tan, visible light can also darken skin, particularly in darker skin tones. Hyperpigmentation means darkened patches of skin. A tinted broad spectrum sunscreen containing iron oxides can add protection against visible light as well as UVA and UVB.57

If your aim is a tanned look instead, sunless tanning products give temporary artificial color, and "artificial" is unusually honest wording for beauty marketing. Most do not contain sunscreen, so they do not replace sun protection.4