Unprotected UV exposure is the major contributors in aging. Actually, there are two types of suncreams: the physical and chemical suncream.
Physical sunscreen provides a protective layer on the skin that block the UV light from penetrating the dermis. Chemical suncream works with your skin to produce chemical substance that stop UV light exposure.
Remember the smell or packeting do not have any relationship with the effectiveness of the suncream. Tanning both is also fatal to your skin.