One Captain America theory posits The Winter Soldier may have teased the introduction of the Punisher in the MCU. The super soldier serum that gave Steve Rogers his powers may have been derived from Wakanda’s heart-shaped herb, according to another theory. Per another theory, Captain America may have changed his name to Braddock, aka Captain Britain, after Endgame, setting up a new storyline for the character.

As Captain America is one of the MCU‘s most important heroes, several interesting theories about the character have arisen that alter perceptions of the entire franchise. Since Captain America was the first hero introduced into the movie timeline of the MCU, he’s always been a central figure within the franchise. His importance as both an influential character and a leader for the MCU’s other heroes defined his first narrative arc, which followed Steve Rogers’ tenure with the shield. Avengers: Endgame saw Rogers pass the mantle to Sam Wilson, who is now the MCU’s new Captain America.

Concerning the two characters known as Captain America, many interesting MCU theories have been established that affect both the past and upcoming Marvel movies featuring the hero. Many are observations or speculation regarding the super soldier serum, while others concern the Captain America movies and potentially affect the entire franchise. As these theories are largely based on logic or direct evidence from the MCU, they are able to actively change the way the MCU as a whole is viewed. Here are 10 Captain America theories that completely change how you watch the MCU.


Captain America’s Complete MCU Timeline Explained

Captain America has been a staple of the Marvel Cinematic Universe since Phase 1, and here is his entire timeline from the beginning to the present.

10 The Punisher Appeared In The Winter Soldier

Phase 2 Could Have Subtly Introduced The Punisher

As the movies of the MCU are packed with Easter eggs and small connections between otherwise unrelated stories, one particular tease about a moment in Captain America: The Winter Soldier is responsible for an especially interesting theory. During a chase scene in the film, a yellow Penske truck crashes into a car driven by Hydra agents, helping Nick Fury. It later appears again and runs over Jasper Sitwell. Director Joe Russo hinted that the driver was a character with a “special set of skills,” prompting the theory that the moments are actually the Punisher’s first appearances in the MCU.

9 Steve Rogers Is Closely Connected To Black Panther

One Theory Links The Powers Of Two Important Avengers

One of the most important aspects of Steve Rogers’ origins involves the super soldier serum and the way in which he proves himself the perfect candidate for it. However, one theory disagrees, suggesting that it’s actually a connection to Black Panther that allowed the serum to work. The theory posits that the serum developed by Howard Stark was the only one to use Wakanda’s heart-shaped herb, which he obtained at the same time as the Vibranium for Cap’s shield. This explains the similarities between Cap and Black Panther’s powers, and why other attempts to replicate the formula failed, making it especially interesting.

8 Steve Rogers Changed His Name After Endgame

Endgame’s Ending Could Have Set Up The MCU’s Captain Britain

The Captain America movies of Phases 1-3 all followed Steve Rogers and his time as an Avenger in the MCU. However, one theory suggests that Endgame didn’t actually mark the end of his hero career, but that he instead changed his name after returning to the past. During the time heist, Steve hears Peggy mention Braddock – a reference to Captain Britain – and the theory believes that Braddock is actually Steve himself. Heading back in time and changing his name to operate as a different MCU hero would resolve a timeline issue, and be a great way to continue Rogers’ story.

7 Cap Briefly Overpowered Thanos Through Sheer Willpower

Steve Rogers May Have Unknowingly Used The Power Stone

Another interesting theory has huge implications not for the MCU, but rather for the character of Steve Rogers. During the climactic battle of Avengers: Infinity War, Captain America finds himself one-on-one with Thanos. Interestingly, Cap is able to hold off the Infinity Gauntlet-wielding Mad Titan alone for a considerable amount of time, and one theory believes it’s due to his character. As Cap was in contact with the Power Stone at the time, the theory suggests that he tapped into its power, and his own strength of will is what allowed him to hold off the much stronger antagonist.

6 The Super Soldier Serum Has An Unfortunate Side Effect

One Gross Theory Repaints Cap’s Transformation In A Negative Light

Perhaps the most hilarious Captain America theory is also the most disgusting, but it’s based solely on evidence offered by the movies of the MCU. Cap explains that his metabolism is four times faster than the average human, preventing him from getting drunk. However, the theory explains that this would also affect other bodily functions, meaning he’d need to use the bathroom four times more than most people. The idea that the super soldier serum results in super soldier bathroom breaks adds a touch of bizarre hilarity to Cap’s otherwise serious character.

5 Steve Rogers’ Soul World Theory Fixes Plot Holes

Cap’s Happy Ending Might Actually Have Been A Little Tragic

The rules regarding the Soul Stone are only loosely established within the MCU, allowing room for an intriguing but tragic theory. When obtaining the Soul Stone, other characters were obliged to do so with the sacrifice of a soul, and the theory believes that returning it might have required something similar. The theory is that Steve doesn’t return to the past at all, but rather, his reunion with Peggy was in the Soul World after returning the Infinity Stone to Vormir. The theory clears up potential timeline issues of Steve’s return to the past, but it does make his ending much less happy – and doesn’t explain how he’d be able to return to the present to give Sam Wilson the shield.

4 Penicillin Played A Big Role In Steve Rogers’ Transformation

A Throwaway Line Could Explain The Differences Between Cap and Red Skull

In the MCU, Steve Rogers is the most successful recipient of the super soldier serum, and one theory attributes this to simple penicillin. Before his transformation, Steve is given a shot of penicillin, which is played off as a joke. However, the theory suggests that Johann Schmidt wasn’t given the same, and as the serum enhances everything in the body, it also enhanced latent bacteria. The theory believes penicillin was the ingredient that allowed Steve’s perfect transformation, and that the Red Skull’s own appearance stemmed from enhanced bacteria.

3 Sam Wilson May Have Unknowingly Been Given Super Soldier Serum

A Theory About SHIELD Makes Better Sense Of Sam Wilson’s Captain America

The ending of The Falcon and the Winter Soldier sees Sam Wilson embrace his role as the MCU’s new Captain America, but one theory better explains some of his abilities. Throughout his time in the franchise, Wilson has been depicted as a non-superpowered Avenger, but the theory believes he may have been given a watered-down version of the super soldier serum. This would explain how he’s able to withstand attacks that should kill him, and how he’s later able to train enough to reach similar physical capabilities to Steve Rogers.

The Resulting Timeline Could Have Seen Rogers Brainwashed By Hydra

One particularly clever theory regarding the aftermath of Endgame’s time heist has troubling implications for the MCU’s Multiverse. When Captain America is forced to fight himself in 2012, he’s narrowly able to overpower his past self using Loki’s scepter, rendering the hero unconscious. However, as the building was filled with Hydra sleeper agents and the scepter places people in highly susceptible states, the theory believes that timeline’s version of Cap would have then been brainwashed into a loyal Hydra soldier. It repaints the time heist as an especially irresponsible piece of meddling, with potential fallout to face in the MCU’s future.

1 Steve Rogers’ Enhanced Intelligence Was Focused Solely On Combat & Leadership

The MCU’s Cap Might Have Wasted His Potential

As the super soldier serum is said to enhance every aspect of a person, one logical theory suggests that Steve Rogers also must have some level of genius. The theory believes that the time of his transformation forced him to focus his intellect solely on combat and leadership in order to help win the war, which is why he isn’t as scientifically gifted as some of his fellow Avengers. The theory makes a surprising amount of sense, making it perhaps one of the most compelling Captain America theories about the MCU.

Key Release Dates

Deadpool 3

Captain America: Brave New World

Marvel’s Fantastic Four

Marvel’s Thunderbolts

Blade (2025)

Avengers: The Kang Dynasty

Avengers: Secret Wars

 Some theories make major changes to Cap’s story.  Read More