Botox is a protein produced by the bacterium Clostridium botulinum. When used to treat severe underarm sweating, known medically as "primary axillary hyperhidrosis," small doses of an injectable form of the botulinum toxin stop the release of the chemical messenger acetylcholine, temporarily blocking the nerves in the underarm that stimulate sweating.
Botox: Not Just for Wrinkles
Botox was first approved in December 1989 to treat two eye muscle disorders -- blepharospasm (contraction of the eye muscles, which causes severe involuntary blinking) and strabismus (when the eyes don't line up together, known commonly as cross-eyed). Since then it has been approved to treat cervical dystonia, a neurological movement disorder causing severe neck and shoulder muscle contractions.
Most recently, in 2002, it was approved as Botox Cosmetic to temporarily improve the appearance of moderate to severe frown lines between the eyebrows.
Botox Dries Up Sweat
In two multicenter, controlled clinical trials involving more than 600 adults, those who received Botox had significantly reduced underarm sweating as compared with the placebo group. In one study, four weeks after being injected, the percentage of people showing a 50% reduction in sweating was 91% in the Botox group compared with 36% in the placebo group. In another study, the average duration of response following the first treatment was 170 days.
The most common side effects following treatment (occurring in 3% to 10% of patients) included injection site pain and bleeding, sweating in other parts of the body, flu-like symptoms, headache, fever, itching, and anxiety.
Before being treated for severe underarm sweating, patients should be evaluated for other potential causes of the problem, such as an overactive thyroid, to avoid treatment with Botox without addressing a potentially serious underlying disease that requires other forms of treatment.
The safety and effectiveness of Botox for severe sweating in body areas other than the armpits has not been established.
Because Botox is a prescription drug, it must be used carefully under medical supervision for all the product's approved indications.