Well, the basic idea behind it is that it is material from his home planet... and on his own planet, he *isn't* a superhero... he's just normal. So, being around material similar to himself can take away his special powers. Now, of course there is a lot more to it through different Superman storylines, but that is the closest I can get to "why." ...
Because that is what the author wanted it to be.
Kryptonite
No, kryptonite is a fictional material. However, in 2007, scientists in Siberia discovered a mineral with almost the same chemical composition as the fictional kryptonite.
His weakness is famously kryptonite, and his strengths include super strength, super ,speed, super durability, and super senses.
super kriponite aouto maticcly kills him
Green kryptonite causes weakness while red kryptonite has different side effects with every exposure.
Kryptonite is Superman's weakness.
yes they do have a kid together. supermans son is superboy and he has no weakness to kryptonite because superman conceived with a human
Kryptonite
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Kryptonite
His weakness to Kryptonite .
No, kryptonite is a fictional material. However, in 2007, scientists in Siberia discovered a mineral with almost the same chemical composition as the fictional kryptonite.
His weakness is famously kryptonite, and his strengths include super strength, super ,speed, super durability, and super senses.
super kriponite aouto maticcly kills him
Clark Kent's weakness in Smallville is Kryptonite