|
|
 |
|
 |
|
In vivo Sunscreen Testing
In vivo sunscreen testing involves photo-testing human subjects after application of the sunscreen at an internationally agreed thickness of 2 mg/cm2 body surface. A “water-resistant” claim can be made for a sunscreen if the SPF is maintained after two 20-minute water immersions. The protection offered by a “water-resistant” sunscreen is indicated by the SPF, which is assessed after photo-testing in vivo. Remember, this SPF rating refers only to protection against UV-B radiation. Sunscreens that do not meet the above criteria following water immersion are not considered “water-resistant”.
Several studies indicate that under in real-world conditions application thickness more likely approximates 0.5-1.0 mg/cm2, lowering the effective SPF of the product. When in vivo SPF testing is conducted outdoors, the efficacy of products is found to be lower than in the laboratory.
Previous page
Sunlight & UV rays
SPF Rating
Sunscreen Testing
Critical Wavelength
Sunscreen Ingredients
Photostability
Skin Sensitivity
|
|
|
