Heres what the two have in common: theyre both injectable substances that minimize the appearance of fine lines and wrinkles. The difference is in how they work. Botox contains a purified form of a neuromodulator called botulinum that is injected directly into the facial muscles; this temporarily relaxes the specific muscles that cause wrinkles like crows feet to form. Botox is generally used for the top half of the face while fillers are generally used for the bottom half, although there are exceptions. Dermal fillers use ingredients such as hyaluronic acid to fill in and plump up wrinkles below the surface of the skin, and does not inhibit your ability to contract your facial muscles. Botox and dermal fillers can actually be used together in order to effectively reduce facial wrinkles. Often, these products are combined in what many call a liquid facelift.