Question: What is the deadliest substance on earth?

Keith Siew answered on 17 Jun 2013:

Well this is something that I learnt when studying neuropharmacology… and I found it quite surprising and a little scary too…

I’m sure you’ve heard of a thing called Botox… that stuff people get injected into their face to stop wrinkles on their foreheads… well that stuff is called botulinum toxin and is derived from a bacteria commonly found in the soil.

This is actually the most toxic substance to humans we know of! It acts by blocking the nerve cells ability to release their little chemical messengers, effectively causing paralysis and shutting down the body.

To give you an idea of how toxic this stuff is… the LD50 (the lethal dose of substance required to kill 50% of people it is given to) is only 1 nanogram (1 billionth of a gram) per kilogram bodyweight…

So to put that into perspective let’s do the math!

If we assume that there are currently 7 billion people on the planet… and the average weight of a person is roughly 70kg…. then it would only take just 490g (half a bag of sugar) of botulinum toxin to kill half the population of the world!!! That’s 3.5 billion people!!! Scary stuff and people willing inject the stuff into their face to get rid of wrinkle?!?! I think they’re crazy!