UVA radiation creates serious cumulative changes in skin. Research has shown that unprotected exposure to UVA rays can, within one week, create distinct injury. Research also indicates UVA exposure is even more damaging than we once knew: it seems that when UVA radiation hits skin, it not only penetrates to skin’s lower layers but the damage “bounces back” like light reflecting from a mirror, giving every layer of your skin a double-whammy of damage. UVA radiation prompts tanning, yes, but the tan you see is direct evidence of your skin responding, as best it can, to the onslaught of damage it just endured.