Botox for Excessive Sweating (Hyperhidrosis) I have been using Botox for the treatment of facial wrinkles for many years now. Recently, I have been treating excessive underarm sweating (axillary hyperhidrosis) with Botox injections with great success. Although axillary hyperhidrosis is rarely a serious medical problem, it can be a serious social problem. Patients who have this problem are often very embarrassed. It can limit clothing selection and can ruin some types of fabrics. Antiperspirants can be helpful but in some patients, their effectiveness is limited. Botox injection is an effective treatment for axillary hyperhidrosis. It is thought that Botox paralyses the tiny muscles that play an important role in sweat excretion. Botox is injected just under the skin in the hair bearing area of the axilla (arm pit). It usually takes 2 to 3 days for maximum effect. The effect of the injection usually lasts 3 to 4 months. The effect wears off gradually and the injection needs to be repeated to maintain the effect. It has been my experience that each subsequent injection lasts longer with some patients obtaining up to 9 months of relief. The injection is moderately painful. There is burning and stinging during the injection. This usually passes within a few minutes. I use an entire vial of Botox (1/2 vial for each side). Possible complications include temporary bruising and swelling at the injection site. I have never had a patient who did not experience a marked decrease in sweating after the injection. Some patients are able to discontinue the use of antiperspirants. If you or someone you know of suffers from axillary hyperhidrosis, Botox can help. The treatment is costly but it can save a bundle in dry cleaning costs and in embarrassment.