A basic white cotton T-shirt for men typically has a UV protection rating of 7 SPF when dry and drops to 3 SPF when wet. This doesn’t provide much protection from the effects of sun exposure. However, there are more expensive T-shirts that do offer SPF ratings of 70 or higher. A long-sleeve dark-colored T-shirt for men might offer the most protection from the sun, but applying sunscreen to the skin is still preferable.