What bacterium is used to produce botulinum toxin for cosmetic injections?

The bacterium used to produce botulinum toxin for cosmetic injections is Clostridium botulinum. The purified toxin, commonly known through brand names such as Botox, is administered in extremely small, controlled doses to temporarily relax selected muscles and soften the appearance of dynamic wrinkles.

C. botulinum is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium. In oxygen-poor conditions, it can produce botulinum neurotoxins, which block the release of acetylcholine at neuromuscular junctions. That prevents targeted muscles from contracting normally. The same biological action that makes the toxin dangerous in botulism is useful therapeutically when the dose and injection site are carefully controlled.

The bacterium was identified in connection with a food-poisoning outbreak in Belgium in 1895. Cosmetic use is only one application: botulinum toxin is also used for conditions involving abnormal muscle contractions, excessive sweating, migraine, and bladder disorders. The answer is conventionally C. botulinum, although related Clostridium species can produce some botulinum toxin types too; that broader scientific detail does not change the standard quiz answer.