Botox is diluted from the deadliest natural substance ever recorded
The protein that smooths frown lines is the same one that causes botulism, and chemists rank it as the most lethal natural substance on record. Injected at a lethal dose, type A toxin would need only a few billionths of a gram per kilogram. Heavily diluted, it now treats migraines, spasticity and excessive sweating.
Botulinum toxin is made by the bacterium Clostridium botulinum and its relatives. It stops nerve endings releasing acetylcholine, the chemical messenger that tells muscles to contract, so the muscle goes slack. Seven main types are labelled A to G; A and B can sicken humans and are the ones used commercially. Estimates put the median lethal dose of type A at 1.3–2.1 ng/kg when injected, far lower than the amount needed by mouth. Soviet, American and Iraqi weapons programmes all developed it as a biological agent.
Medicine turned that paralysing effect into a tool for overactive muscles. It is used for spasticity after strokes or spinal injury, in cerebral palsy, for spasms of the eyelid, jaw and vocal cords, and to relax clenched muscles in the bladder or oesophagus. For misaligned eyes it can deliver a lasting fix: while one muscle is weakened, its opposite shortens and the relaxed one lengthens, so the new balance persists after the toxin wears off. The FDA approved it for preventing chronic migraine in 2010, though not for episodic migraine.
Cosmetically it is regarded as relatively safe and effective for wrinkles in the upper face. Relaxing the muscle beneath a crease lets the skin above flatten; results appear within three to five days, peak around a week, and for the vertical lines between the brows usually last two to four months. Newer versions such as daxibotulinumtoxinA, approved in the US in September 2022, joined established brands.
Risks come mainly from the toxin reaching the wrong muscles, whether by misplaced injection or spread over time, causing drooping eyelids, weakness or trouble swallowing. Therapeutic doses carry greater danger than cosmetic ones, and in 2008 the FDA warned that the toxin could travel far from the injection site, especially in children treated for spasticity.
Source: Botulinum toxin
