Botulinum Neurotoxin (BoNT) is a naturally occurring protein produced by the bacterium Clostridium botulinum.

BoNT is typically injected into a muscle or gland during treatment. Once injected, nerve endings absorb the toxin, which disrupts the communication between the nerve and the muscle or gland. This results in muscle weakness or a reduction in functions such as saliva production or sweating.

After an injection, it typically takes between two and seven days for the effects to begin, with the full results appearing around two weeks. The effects are temporary, lasting approximately three to six months, after which further injections may be needed. To avoid the body rejecting the treatment, injections are usually spaced no more than three months apart.

Dystonia: Involuntary muscle spasms causing abnormal postures or movements, including:

• Cervical dystonia (torticollis): abnormal head turning or tilting due to neck muscle contractions.
• Blepharospasm: excessive blinking or eye spasms.
• Oromandibular dystonia: abnormal movements in the jaw and lower face.
• Laryngeal dystonia (spasmodic dysphonia): affects the vocal cords.
• Writer's cramp or dystonia affecting the hands or arms.
• Hemifacial spasm: Twitching muscles on one side of the face or around one eye.
• Spasticity: Increased muscle tone and spasms caused by conditions such as cerebral palsy, stroke, spinal cord injuries, or multiple sclerosis.
• Hyperhidrosis: Excessive sweating, especially in areas like the palms or armpits, which can be reduced with BoNT injections.

Other conditions that may improve with BoNT injections:

• Tremors in the head, hands, or voice.
• Tics.
• Excessive drooling (sialorrhea), particularly in patients with Parkinson's disease or ALS.
• Overactive bladder.
• Chronic migraine headaches.

Although BoNT is a potent toxin, when administered in the correct dosage and at the right site, it is considered both safe and effective. The most common side effect is localized muscle weakness at the injection site. For example, this can result in eyelid drooping or double vision if injected around the eyes.

Other potential side effects include pain, bruising, or bleeding at the injection site. To minimize risks, BoNT injections should only be given by experienced healthcare professionals.

BoNT treatments are highly effective, with many patients experiencing a 50–90% improvement in symptoms for two to three months.