Mesotherapy, in its most common usage, refers to multiple injections of tiny amounts of a particular subtance (or combination of agents) within the skin to achieve a specific purpose. It is probably most commonly associated with the use of injectables to shrink unwanted fat deposits, such as those under the chin, love handle areas, sides of knees and around the bra straps.
At the present time, there are no commercial products available in the U.S, although two companies are in advanced phases of development of products for which FDA approval is anticipated down the road. One by Kythera contains desoxycholate, a natural fat dissolver, and the other, by Lithera, contains both a corticosteroid and and a beta-agonist (a combo used successfully in the treatment of asthma), which also promotes shrinkage of fat deposits. We eagerly look forward to the entrance of these products into the American aesthetic market.
In the meantime, preparations containing these or similar ingredients have been compounded by some pharmacies by physician prescription for specific patients for mesotherapy injection purposes and have yielded gratifying fat shrinkage in properly selected individuals, particularly for double chins. Injection mesotherapy typically requires a series of treatments (usually four or more treatments) spaced at six week intervals.
Web reference: http://youngerlookingwithoutsurgery.com