By Barb Nefer
According to the United States Food and Drug Administration (FDA), sunscreen must last for a period of three years. During that time, it must provide the level of protection stated on the label. Manufacturers typically base their expiration dates on this requirement. After three years, the sunscreen's ingredients can break down, and the sunscreen can lose its effectiveness. The expiration...
By Ysabel Doran
Eyelash growth interests us for obvious cosmetic reasons, but eyelashes perform important practical functions, too. Eyelashes protect the eyes from small foreign debris like dust, and they keep perspiration from running into the eyes. Also, eyelashes are connected to sensitive nerves in the eyelid that trigger the blinking reflex when objects get too close to the eye. The upper eyelids each have ...
By Bambi Turner
Flat irons, often called "hair irons" or "straighteners," are electrical devices used to temporarily straighten curly or wavy hair. They consist of two metal plates that are hinged in the middle. Users clamp the plates around sections of hair and pull the device along the length of the hair to straighten it. Flat irons operate by producing high levels of heat. These high...