Based on FDA regulations, determining the SPF assigned to a product requires clinical testing in which the product is applied at a concentration of 2mg/cm2 to the test subjects. This is dramatically more than the concentrations of cosmetics people apply in actual use. According to Leslie Baumann, MD, board-certified dermatologist and CEO of Baumann Cosmetic & Research Institute in Miami , FL, based on the concentration of sunscreen in foundation, you would have to wear SEVEN times as much liquid foundation as most people normally wear to get the SPF protection listed on the package. If you use powder, you’d have to use FOURTEEN times as much!
One would hope the FDA will either require that cosmetic companies remove those misleading SPF claims or require them to re-do the testing according to actual use. When tested according to actual use, Mukha foundations, the foundations in the pure mineral make-up line we carry at Timeless Laser & Skin Care, were found to provide an SPF of 30.
Another important fact to remember is that the SPF’s of each of the skin care products you wear at a given time are not cumulative; the maximum SPF you’ll get is the highest of the ones you apply. Just as importantly, mixing products can cause problems: if the two sunscreens use different active ingredients to protect you from the sun, they could end up compromsing one another. For instance, Octinoxate degrades Avobenzone, so these two sunscreens should never be layered.
The best plan to protect your skin from skin cancer risks of UVA and UVB rays as weel as the aging damage from UVA rays is to apply a broad spectrum sunscreen every single day as the first layer on your skin; never rely on your make-up to do the job.
We have several sunscreens and moisturizers with sunscreen for all skin types, an we are always glad to help you choose the one that’s right for you.