History KryptoniteFactor / Superman

[[folder: Comic Books]]

[[folder: Films]]

* The animated film ''WesternAnimation/SupermanDoomsday'' contains an almost amusing example in that even ''Superman'' needed Kryptonite to defeat his clone with identical powers. Admittedly, the real Superman isn't quite at full strength at this point.
--> '''Superman''': You have all my strengths... and weaknesses.

[[folder: Live-Action TV]]

* ''Series/LoisAndClark'', setting the tone for most [[Series/{{Smallville}} adaptations]] [[Series/Supergirl2015 after]] it, has red kryptonite affect him mentally instead of the comicverse rules of random one-off effects. Just how dark-side it makes a Kryptonian go depends on the tone of the adaptation, but one thing remains the same: under Red K, Kryptonians are dicks. However, this series also had Red K used to power devices that ''would'' affect him in different ways. You get dickishness out of merely putting a chunk of it near him, though.

[[folder: Western Animation]]

[[/folder]]

* In ''WesternAnimation/SupermanTheAnimatedSeries'', it was originally planned that ComicBook/{{Supergirl}}, being in this iteration not from Krypton, but rather the sister-planet of Argos, would not have a weakness to Kryptonite. This is demonstrated in the "Superman Adventures" comic based on the series. By the time of ''WesternAnimation/JusticeLeague Unlimited'', though, the weakness was firmly in place.

* ''Film/ManOfSteel'':
** Exposure to Krypton's native environmental conditions weakens and at first even incapacitates Superman.
** Zod's Kryptonians similarly initially lose control of their powers and pass out while trying to adapt to Earth's native atmosphere.

** Something often overlooked is that even ordinary humans are susceptible to Kryptonite radiation, just to a much lesser extent. Additionally, while Kryptonians' natural HealingFactor allows them to recover from radiation sickness almost as soon as they're out of the immediate vicinity of any Kryptonite, exposure in humans is cumulative, as with any radioactive substance. Lex Luthor, who always kept a piece of Kryptonite tucked close to his chest to ensure Superman could never come near him, ends up eventually contracting cancer from it and is forced to build a biomechanical suit to stop it from progressing.
* In Post-Crisis continuity, Gold Kryptonite part is "powerless for 30 seconds", mostly because [[LikeYouWouldReallyDoIt it couldn't credibly be used for much storytelling otherwise]].

* There are at least six colors of kryptonite, each with its own effects -- including pink Kryptonite in ''ComicBook/ManyHappyReturns'', which can change your sexual orientation.

* ''ComicBook/{{Supergirl}}'' has the same weaknesses as her cousin Superman. Namely: kryptonite, red sunlight, and magic.
* In the ''ComicBook/NewKrypton'' storyline, ''ComicBook/{{Supergirl}}'' faced off against [[ArchEnemy Reactron]], an enemy powered by golden kryptonite which nullified her powers. It becomes a plot point in ''ComicBook/WhoIsSuperwoman'' when the titular villain no-sells Reactron's Kryptonite-fueled blasts, thus revealing she's not Kryptonian.
* In the ''ComicBook/RedDaughterOfKrypton'' arc, Silver Banshee managed to contain Supergirl for a short while when they fought because her sonic attacks are magic, and Kryptonians are vulnerable to magic. Later on, Kara was weakened when she fought [[spoiler:Worldkiller-1]] because Earth's atmosphere was poisoned with kryptonite.
* In the first ''ComicBook/SupergirlRebirth'' story, Red Kryptonite -which is non-lethal but does weird things to Kryptonians- turns a Kryptonian into a werewolf. Supergirl's foster mother Eliza Danvers uses a red solar grenade against Lar-On when she notices he speaks Kryptonian.
* Several times in ''ComicBook/ElseworldsFinestSupergirlAndBatgirl'', Supergirl feels weak and sick without knowing why… until Lex Luthor reveals what Kryptonite is and does to Kryptonians.
* In ''ComicBook/TheSupergirlFromKrypton2004'', Kara Zor-El's pod crash-lands on Earth after spending three decades and a half stuck inside a Kryptonite giant asteroid. Although she survived thanks to her pod's sunlight generators, [[ComicBook/Supergirl2005 she suffered from Kryptonite poisoning for over one year]].
* In ''ComicBook/Supergirl1982'' issue #21, both Super-cousins fight the Kryptonite Man. His power weakens them and hurts them.
-->'''Supergirl:''' Kryptonite... Cutting through me... like a knife.
* Kara is vulnerable to magic because it bypasses her natural invulnerability. In ''ComicBook/DemonSpawn'' Nightflame's attacks hurt her because that villain is a sorcerer.
* Notably PlayedWith regarding ComicBook/PowerGirl. As a Kryptonian from Earth 2 (and in fact, the alternate universe counterpart of Supergirl above), she's vulnerable to the same weaknesses...on Earth 2. Kryptonite from Earth 1, where she now resides, does nothing to her (and likely red sunlight too). Magic still affects her, but as above, its typically more a 'has no immunity to it' rather than something that makes her weaker.
* Notably, during a time where DC were insisting on keeping Superman as the ''only'' Kryptonian, Power Girl was retconned into an Atlantean who had incorrectly believed herself to be Kryptonian, and her powers were now magic in nature. During this time, she was given a weakness to "natural, unprocessed materials" (IE, rocks and trees). Its now explained that this was a result of reality trying to find a 'place' for her after her universe was destroyed, and was attempting to recreate her Kryptonite Factor. Nowadays this period is largely forgotten and ignored.
* Daxamites are descended from ancient Kryptonian colonists who intermingled with the native population of Daxam and have similar weaknesses save for Kryptonite itself, instead they're irrecoverably fatally allergic to lead:
* ''ComicBook/{{Superboy}} (1949)'' #89 story had Superboy meet [[ComicBook/{{Valor}} Mon-El]], an amnesiac with powers like his, who assumed due to this that he was Kryptonian. Near the end of the story, Clark gets suspicious and lobs lead boulders painted to look like Kryptonite at him. Mon-El collapses, and Superboy flies in to accuse him of fakery -- but the trauma has [[EasyAmnesia brought his memory back]]; he's a Daxamite, a member of a race similar to Kryptonians, but with a weakness to lead poisoning instead of Kryptonite. To keep him from dying, Superboy puts him in the PhantomZone, preserving him for a thousand years until the ComicBook/LegionOfSuperHeroes finds a cure. Later retellings have Clark and Mon-El seeing if Mon-El was a Kryptonian (whose memories were slowly coming back) and Mon-El getting sick after Clark takes out a lead box containing some Kryptonite.
* Bizarro and his race are vulnerable to ''blue'' Kryptonite. In ''ComicBook/{{Bizarrogirl}}'', Supergirl and Dr. Light discover they can block Bizarrogirl's powers with light of a K-class star.
-->'''Supergirl:''' Because I just had an interesting conversation with a brilliant scientist I know. Y'see, a yellow sun gives a Kryptonian powers and a red sun takes them away.\\
'''Bizarrogirl:''' Bah! Science am boring!\\
'''Supergirl:''' Ha. You are an imperfect Kryptonian clone, Bizarrogirl, super-powered by a blue sun. Dr. Light theorizes the light of a K-Class star will take your powers away.
* Originally, the blue kryptonite weakness was because Bizarro was a copy of Superman, imperfectly duplicated by a machine. Normal kryptonite had no effect, until Superman thought of using similarly imperfectly duplicated Kryptonite. Just as Bizarro himself has chalk-white skin and a skewed color scheme, the duplicated kryptonite was a different color than the regular stuff.
* ''ComicBook/LastDaughterOfKrypton'': Kara's attempt to retrieve her pod from Simon Tycho's base fails when she gets knocked out by the bits of Kryptonite stuck to the pod's hull.

* ''ComicBook/TheUntoldStoryOfArgoCity'': After being driven crazy by a Kandorian animal's venom, Edna Danvers uses a cache of Kryptonite rocks to attempt to murder Zor-El and Allura.
* Downplayed in ''ComicBook/SupergirlWomanOfTomorrow''. When she travels to Ruthye's homeworld, which revolves around a red star, Kara is weakened and can be hurt, but she is still inhumanly strong and tough. Arrows pierce her skin but they do not reach her muscles or vital organs.

* ''ComicBook/TheHuntForReactron'', the eponymous villain tries to use Golden Kryptonite to depower his Kryptonian enemies in order to destroy them easily, but he is rendered helpless when Flamebird crushes his chunk of rock.
* ''ComicBook/TheGirlWithTheXRayMind'': After giving Lex Luthor powers, the Phantom Zone criminals intend to trick him into retrieving a sample of Golden Kryptonite to remove Superman and Supergirl's powers, as well as Luthor's.
* Subverted in ''ComicBook/TheStrangeRevengeOfLenaLuthor''. Supergirl wakes up in a chamber which supposedly uses high-gravity generators and fluorescent panels which emit red sunlight to nullify her powers by duplicating Krypton's environment. She soon realizes, though, that her kidnappers are gaslighting her and those red lamps have no effect on her.

* Nonetheless, Kryptonite is ''not'' a harmless substance. It's more-or-less a radioactive isotope, and can cause harm to anyone if exposed to it for long periods without the proper protection. In some continuities, Lex Luthor develops cancer or goes crazy thanks to repeated exposure. In ''ComicBook/TheCondemnedLegionnaires'', the female Legionnaires get sick because of involuntary exposure to Red Kryptonite.
* ''ComicBook/WayOfTheWorld'' features Krallian aliens, who are depowered by a substance called Selenite.

* In ''ComicBook/TheSupergirlBatgirlPlot'', Superman believes he cannot be harmed by a meteor thrown by Supergirl until his XRayVision tells him there's Kryptonite inside the rocky outside. The fat that "Supergirl" was not harmed by the Green-K clues him in that he is not fighting his cousin but an impersonator.

* In ''ComicBook/Supergirl1984'', there is not Kryptonite to found anywhere in the story, and magic takes its place as the tool used by the villain to hurt the Kryptonian hero.

* ''ComicBook/TheCondemnedLegionnaires'': Subverted. Supergirl reasons Satan Girl's must be Kryptonian given her powerset, so Kara borrows a box of Kryptonite powder to weaken her; though, Satan Girl shrugs it off completely, and later it is her who dumps a heap of Kryptonite rocks on Supergirl to get rid of her.

* "ComicBook/TheSuperSteedOfSteel": Subverted. Villain Vostar uses a chunk of Kryptonite to murder Supergirl and Comet, unaware that Comet is not from Krypton. Hence, he is downright shocked when Comet remains completely unaffected and flies Supergirl away.

** Something often overlooked is that even ordinary humans are susceptible to Kryptonite radiation, just to a much lesser extent. Additionally, while Kryptonians' natural HealingFactor allows them to recover from radiation sickness almost as soon as they're out of the immediate vicinity of any Kryptonite, exposure in humans is cumulative. Lex Luthor, who always kept a piece of Kryptonite tucked close to his chest to ensure Superman could never come near him, ends up eventually contracting cancer from it and is forced to build a biomechanical suit to stop it from progressing.

* ''Franchise/{{Supergirl}}'' has the same weaknesses as her cousin Superman. Namely: kryptonite, red sunlight, and magic.

!!Comic Books
* ''ComicBook/{{Superman}}'' is the {{Trope Namer|s}}, with his weakness to Kryptonite (radioactive GreenRocks from his home planet) established back in the 40's. Since then, he's gained a few other vulnerabilities: he has no particular resistance to magic (DependingOnTheWriter, it may either be a bona fide weakness or that he's just as vulnerable to magic as anyone else, meaning it's a relative weakness for someone immune to almost anything else), red sun radiation can temporarily rob him of his powers, and there's a whole spectrum of colored Kryptonite with varying effects (from Red Kryptonite that causes a random change for 48 hours, to Gold Kryptonite that robs him of his powers ''permanently''). He can still be killed by a huge amount of brute force from a similarly powered being such as Doomsday.

* In ''ComicBook/KryptoniteNevermore'', all Kryptonite on Earth is turned into iron. Comicbook/JimmyOlsen notes magic is still a problem, though.

* ''ComicBook/{{Superman}}'' is the {{Trope Namer|s}}, with his weakness to Kryptonite (radioactive GreenRocks from his home planet) established back in the 40's. Since then, he's gained a few other vulnerabilities: he has no particular resistance to magic (DependingOnTheWriter, it may either be a bona fide weakness or that he's just as vulnerable to magic as anyone else, meaning it's a relative weakness for someone immune to almost anything else), red sun radiation can temporarily rob him of his powers, and there's a whole spectrum of coloured Kryptonite with varying effects (from Red Kryptonite that causes a random change for 48 hours, to Gold Kryptonite that robs him of his powers ''permanently''). He can still be killed by a huge amount of brute force from a similarly powered being such as Doomsday.

* Interestingly, in ''WesternAnimation/SupermanTheAnimatedSeries'', it was originally planned that ComicBook/{{Supergirl}}, being in this iteration not from Krypton, but rather the sister-planet of Argos, would not have a weakness to Kryptonite. This is demonstrated in the "Superman Adventures" comic based on the series. By the time of ''WesternAnimation/JusticeLeague Unlimited'', though, the weakness was firmly in place.

* ''ComicBook/{{Supergirl}}'' has the same weaknesses as her cousin Superman. Namely: kryptonite, red sunlight, and magic.
* In the ''ComicBook/NewKrypton'' storyline, Supergirl faced off against [[ArchEnemy Reactron]], an enemy powered by golden kryptonite which nullified her powers. It becomes a plot point in ''ComicBook/WhoIsSuperwoman'' when the titular villain no-sells Reactron's Kryptonite-fueled blasts, thus revealing she's not Kryptonian.

!!Films
* ''Film/ManOfSteel'':
** Exposure to Krypton's native environmental conditions weakens and at first even incapacitates Superman.
** Zod's Kryptonians similarly initially lose control of their powers and pass out while trying to adapt to Earth's native atmosphere.

* Subverted again in ''ComicBook/KingdomCome''. Spending two decades soaking up rays in rural Kansas and not using his powers has supercharged the Big Blue Boyscout to the point where Lex Luthor believes that a kryptonite-doped nuke wouldn't even be able to muss his hair, much less kill him. The only vulnerability he is shown to have is magic, and he gets a shallow cut from Wonder Woman's sword, which was forged by Haphaestus and is, according to her, sharp enough to carve the electrons off an atom.

* Though there is a caveat we should mention: Kryptonite is ''not'' a harmless substance. It's more-or-less a radioactive isotope, and can cause harm to anyone if exposed to it for long periods without the proper protection. In some continuities, Lex Luthor develops cancer or goes crazy thanks to repeated exposure.

* There are at least six colors of kryptonite, each with its own effects -- [[ComicBook/ManyHappyReturns including Pink Kryptonite, which can change your sexual orientation]].

* Kara is vulnerable to magic because it bypasses her natural invulnerability. In ''Comicbook/DemonSpawn'' Nightflame's attacks hurt her because that villain is a sorcerer.

--->'''Supergirl:''' Kryptonite... Cutting through me... like a knife.

--->'''Supergirl:''' Because I just had an interesting conversation with a brilliant scientist I know. Y'see, a yellow sun gives a Kryptonian powers and a red sun takes them away.\\

* Though there is a caveat we should mention: Kryptonite is ''not'' a harmless substance. It's more-or-less a radioactive isotope, and can cause harm to anyone if exposed to it for long periods without the proper protection. In some continualities Lex Luthor develops cancer, or goes crazy, thanks to repeated exposure.

* ''[[Series/WonderWoman1975 Wonder Woman]]'':
** Initially, Wonder Woman would lose her superhuman strength if her magic belt was removed from her uniform. Similarly, she possessed no resistance to chloroform, which conveniently made its way into a number of Season 1 episodes. When the show was moved to the 1970s, the former weakness was addressed only once (and only then when she willingly removed her belt, lasso, and bracelets to assure an enemy that she did not wish to fight him), and the chloroform was used far less often.
** There's another, less obvious weakness - Diana Prince needs enough freedom of movement to spin to turn into Wonder Woman. No villains ''deliberately'' exploited this (since very few knew about her secret identity in the first place), but several accidentally used it when they handcuffed Diana to a support beam or something similar.