Did Howard Stark run Super Solider Serum experiments on Tony Stark? That's what a new Marvel Cinematic Universe fan would like us to believe and he even comes up with some evidence to back up his claim. However, some fans aren't buying it at all. One of the leading pieces of evidence points to the fact that Tony was able to wield his own version of the Infinity Gauntlet to snap Thanos out of existence during the events of Avengers: Endgame.

Humans should not be able to harness the power of all six Infinity Stones and Tony Stark paid the ultimate price at the conclusion of Endgame. A fan theory believes that Stark was able to do so because his father gave him some of the Super Soldier Serum at some point. The theory continues by stating Stark should have died in 2008's Iron Man after taking a bunch of shrapnel to his chest and that he should have died while taking punches from the Hulk in Age of Ultron. Additionally, the theory goes on to claim that he should not have survived having a moon thrown at him in Infinity War and that he should have died after taking Captain America's shield to the chest.

These are all interesting pieces of evidence to back up the Tony Stark and Super Soldier Serum theory, but a lot of fans aren't buying it, though it is fun to think about. However, there are some who believe if Stark was given some of the Super Soldier Serum, it was only a little bit, since Stark isn't that strong outside of his suit. We've seen plenty of evidence of how weak the character can be when not using his own technology.

Another fan weighed in and thought about a small dosage of Super Soldier Serum expanding Tony Stark's mind and intelligence. That sounds all well and good, but we all know Tony was influenced by the brilliance of his father and carried on the Stark tradition. The Super Soldier Serum theory is fun to think about, but it seems highly unlikely that the elder Stark ran experiments on his son or just gave it to him for some good luck.

Regardless of how outlandish the MCU fan theory about Tony Stark may sound, it has been picking up steam on social media, more than likely so fans can argue about it. It's pretty amazing to see how Marvel Studios has been able to achieve the success that it has and maintain it, with a passionate fan base discussing elements that may or may not have happened behind-the-scenes. Regardless, you can head over to Reddit and weigh in on the conversation as to whether or not Tony Stark was using performance enhancing Super Soldier Serum during his time in the Marvel Cinematic Universe.