As a cosmetics testing lab, AMA Laboratories, Inc. offers a range of services to businesses seeking FDA approval. One of the tests that AMA Laboratories, Inc. administers is for products containing SPF, mainly through in vivo testing.
In general, SPF quality is determined through in vivo and in vitro testing. The ability for SPF to effectively work is based on a few factors. The first factor is related to the product’s ingredients and the SPF formula used. Other factors include the users’ skin type, the way they apply the product, and the amount of UV ray exposure.
In vivo testing requires that the number of subjects is at least ten participants. Clinicians apply a certain amount of sunscreen on the volunteers’ back, allowing the product to dry for 15 minutes. After the product is dried, researchers will administer doses of UV radiation to the area. The clinicians will also apply a series of doses to areas that are not protected by the SPF product.
Anywhere between 16 and 24 hours later, clinicians will return to see how the product fared. This trial varies with some labs placing the product on various parts of the body. The clinicians determine SPF by looking at the lowest dose of UV that causes mild sunburn with the product divided by the lowest dose of UV that caused mild sunburn without the product.
In vitro testing, conversely, involves using artificial substrates that mimic human skin types. These substrates, in conjunction with computer mathematical models, predict effectiveness based on the absorption of active ingredients. Currently, there is no standard for measuring SPF levels using this method.
AMA Laboratories Inc 