One of the great things about Superman is how distinctive each member of his rogues’ gallery looks. From Bizarro to Mr. Mxyptlk to Doomsday, almost every single one of his villains has an unmistakable appearance that has remained largely consistent throughout their long history.  However, most fans would agree that the one Superman villain with the most recognizable look is Lex Luthor – the greatest bald-headed criminal mastermind of our time.

Only… he didn’t start out that way. Back in 1940, when Lex first debuted in Action Comics #23, he actually sported a full head of red hair and went only by his surname “Luthor.” Subsequent stories went on to establish that the evil genius didn’t even have a receding hairline, which begs the question – how did Lex Luthor become bald?

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As it turns out, the story behind Luthor’s hair loss has many versions. The “real world” explanation is that artist Leo Nowak, an artist on the Superman newspaper comic strip, accidentally drew Luthor as a bald man. Why Nowak did this is up for debate. Some believe he confused Lex Luthor with the Ultra-Humanite, a Superman villain who was originally depicted as a bald man by Joe Shuster in early Superman comics. Others and Nowak confused one of the bald henchmen Luthor employed with the actual Luthor, and gave Lex Luthor their bald head.

Regardless, Luthor’s new “bald look” took off and eventually became a well-known aspect of his character. Adventure Comics #271, actually provided an explanation for Luthor’s baldness as well as his hatred for Superman. As the story goes, Lex Luthor was once a brilliant young scientist (with a full head of brown hair) who recently moved to Smallville. When Superboy flew to meet the new resident, a Kryptonite meteor crashed in front of him and nearly killed the Boy of Steel with its radioactivity. Fortunately, Lex used the tractor he was riding to push the meteor into some quicksand, saving Superboy.

Turns out that Lex was a huge fan of Superboy and had an entire barn full of photos of Superboy as well as rocks that Superboy had punched and steel girders that he’d bent with his bare hands. Rather than being creeped out by Luthor’s stalker-tendencies, Superboy decided to build the young scientist a state-of-the-art laboratory out of some abandoned junk. He went on to fill Lex’s lab with rare, volatile chemicals that were so unknown even Superboy himself didn’t know what they would do. Deciding that the underage scientist he’d just met would be perfectly fine experimenting with such hazardous materials, Superboy bid his new pal goodbye and flew off.

Related: Why Smallville’s Michael Rosenbaum Is Still The Best Lex Luthor

Surprisingly, some of Lex’s early discoveries in the lab were complete successes. Lex’s first experiment resulted in a new form of protoplasmic life. Next, in gratitude to Superboy, Lex decided to create an antidote for Kryptonite – which he actually accomplished in just a few panels. In his excitement, however, he knocked over some of the rare, volatile chemicals and started a fire. Superboy arrived and extinguished the flames with his super breath – but the winds caused some acid to destroy the Kryptonite antidote and Luthor’s new protoplasm life form. Worse, the chemical fumes caused all of Luthor’s hair to fall out, giving him his famous bald look.

Stating he could never duplicate either experiment (because apparently, note taking wasn’t Luthor’s strong suit), Luthor claimed Superboy deliberately destroyed his work because the Boy of Steel was jealous of Luthor’s genius. Luthor went on to one-up Superboy by creating miracle inventions for Smallville, but when his inventions all went haywire, Superboy had to destroy them, further convincing Luthor that Superboy was his enemy. Later stories hint that the losing his hair drove Luthor criminally insane (since Luthor only developed a pathological hatred for Superboy after his hair fell out this actually seems likely). And since Superboy supplied Luthor with the unknown chemicals that caused his hair loss in the first place, Clark Kent is actually indirectly responsible for Luthor’s later criminal career!

For a long time, the laboratory fire was the accepted, canonical reason for Luthor’s baldness. When the DC Universe was rebooted in the aftermath of Crisis on Infinite Earths, however, the modern Luthor had a more… mundane reason for his baldness. Originally depicted as a middle-aged man with a receding hairline, Luthor eventually lost all of his hair due to male pattern baldness. While Luthor didn’t seem particularly ashamed of his bald head, when he got a chance to clone himself a new, younger body, he made sure to give it a full head of shoulder-length red hair and a thick beard, showing he had a huge complex about hair loss and tended to over-compensate when he had the chance.

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Outside of the comics, Luthor had other reasons for his baldness – mostly related to Superman. The Superboy live action television series revealed Luthor was caught in a laboratory fire much like his comic book counterpart that cost him his hair (he subsequently wore a wig to hide his bald head, much like Gene Hackman in the Superman movies). In the television series Lois & Clark: The New Adventures of Superman, Lex actually has a full head of hair for most of the series. However, when he nearly dies in one episode, the resurrection processes his scientists use to bring him back causes his hair to fall out.

Lex had an even weirder reason for his hair loss in the TV show Smallville. Here, the Kryptonite meteor shower that arrived on Earth along with Kal-El’s ship affected many humans with its radiation. One of these people was a nine-year-old, red-headed Lex Luthor who lost all of his hair after being irradiated by the meteors. On the plus side, the Kryptonite gave Lex a quasi-super power – a supercharged immune system and heightened healing that made it very hard for him to get sick (which actually helped explain how he survived so many near-death experiences in the show).

Other movies have a more mundane reason for Lex’s hair loss – Jesse Eisenberg’s red-headed Luthor gets his head shaved after being incarcerated (and decides to keep the look even after escaping). Gene Hackman and Kevin Spacy portrayed versions of Lex Luthor that seemed to have lost their hair naturally (a throwaway line in Superman Returns even hints Lex started going bald at a young age since his father made fun of his hair loss).

For a character who got his most distinctive feature thanks to an artist’s mistake, Lex Luthor has since become the first villain people think of when picturing a “bald headed mad scientist.” He may not care for his hairless look, but thanks to the way it’s come to symbolize his hatred of Superman, baldness and Lex Luthor are now completely inescapable from each other.

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