The Efficacy of Sun Protection Factor (SPF) Against UV-B and UV-A of Cosmetic Products

Sunscreen is intended to protect the skin from sun burn but since the amount of protection needed varies among individuals, sunscreen manufactures offer consumers difference levels of protection. These different levels of protection are expressed as a numerical value called the sun protection factor or SPF. The SPF is the ratio between the minimal erythema dose (MED) of sunscreen product of the protected skin and the MED of the unprotected skin. The minimal erythema dose in human skin is defined as the lowest ultraviolet B (UV-B) dose produces the first perceptible unambigous erythema with defined border appearing over most of the field of UVB exposure 16 - 24 hours after UVB exposure.

The UVA protection factor is the ratio between the Minimal Persistent Pigmentation Darkening Dose (MPPDD) of sunscreen product of the protected skin and the MPPDD of the unprotected skin. The threshold response will be taken as an unequivocal pigment darkening with distinct border which persisted for at least 2 hours.

The test products are Day Gel-0120-C and Day Gel-0120-D with active ingredients ethylhexyl methoxycinnamate, Diethylamino hydroxybenzoyl hexyl benzoate