Certain groups should have higher or lower SPFs depending on age and other factors:
Babies and young children should be well covered with clothing, sunglasses, and hats as the first line of defense against sunburn.
Sunscreens should not be used on babies younger than six months without consulting a physician.
Sunscreens should be used only if necessary in older children, since the long-term effects of the chemicals used in sunscreens are still unknown.
For example, in two 2000 studies, one found greater numbers of moles and the other fewer numbers in children who used sunscreens.
Studies suggest that having numerous, normal moles may significantly increase the risk for melanoma.
Well-conducted studies on specific sunscreens are necessary to determine their safety in children.
Older children and adults (even those with darker skin) benefit from using SPFs of 15 and over. Some experts recommend that most people should use SPF 30 on the face and 15 on the body.
Adults who burn easily instead of tanning and anyone with risk factors for skin cancer should use at least SPF 30.