The current approach used to assess the protective efficiency of a sunscreen product is a worldwide method for the determination of its "SPF" which is based solely on ability to prevent erythema, i.e. UV-induced sunburn with visible redness.
SPF is the ratio of UV irradiation doses producing minimal erythema (MED) in sunscreen-protected skin vs. unprotected skin.
SPF does not refer to a sunscreen's potential to help prevent 90% of the visible signs of aging — an SPF 30 may not be more protective than an SPF 15.
The disadvantages of the existing method of assigning SPF to skin care products is being increasingly recognized because it does not take into account the damaging effects of UVA and due to misinformation has inclined users of sunscreens to stay longer under the sun in the belief that they are fully protected.
Despite the availability of reliable methods, no government endorsed consensus has been reached to measure the level of UVA protection and therefore to properly inform people about the actual capacity of sunscreens and other agents to protect from the whole range of UV radiation harmful to the skin.
Many studies pinpoint the physically and aesthetically damaging effects that may result from inadequate protection and emphasize the need to address this issue seriously.
Prescriptions:
Request/Refer:
Collaborative development of a sun protection factor test method: a proposed European standard. Int J Cosm Sci 1996; 18: 203-218.