Nerve signals traveling from the brain to the muscle are blocked by this injectable (a safe-for-injecting form of botulism bacteria), temporarily preventing you from making certain wrinkle-causing expressions, particularly on the forehead. The botulinum toxin of choice used to be Botox, but now there's also Myobloc, which seems to work just as well and can be used on those immune to the effects of Botox.
Cost: from $400 per visit for either Myobloc and Botox.
Lasts: four to six months.
Possible side effects: bruising at the injection site and possible eyelid drooping when injected too close to the eyelids.
You can have two types of collagen (the fibrous protein that holds the skin together) injected: human (purified from cadavers) and bovine (purified from cows). It's best for lines around the lips, depressed acne scars and lip enlargement. While human collagen requires no allergy testing, bovine collagen does (two allergy tests are administered a month apart before the substance can be injected).
Cost: from $300 per treatment.
Lasts: about six months.
Possible side effects: temporary redness and swelling. While there has been concern about contracting mad-cow disease from bovine collagen, experts say this isn't likely. The concern that collagen injections can trigger autoimmune diseases like lupus is also unfounded, experts say.
Autologous (your own) fat
The procedure for this injectable is two-part: First, fat is removed from fatty areas of your body (such as the hips or stomach area) through a small needle connected to a syringe, and second, that fat is injected into wrinkles, lines between the mouth and nose and even on the backs of hands (where the skin thins with age).
Cost: about $500 plus the cost of the fat transfer (about $500).
Lasts: about 6 months.
Possible side effects: minimal redness, swelling and bruising. Also on the horizon is hyaluronic acid-the jellylike substance that fills in the space between collagen and elastin fibers and decreases with age, contributing to sagging skin. While it hasn't been OK'd yet for use as an injectable in the United States, experts anticipate that it will be approved by the Food and Drug Administration (at a cost of about $300 per visit).