With reference to Why aren't there more supersoldiers?

After the formula to the serum used on Steve was lost, many tried to replicate it over the decades without success. In the accepted answer to that question, it was mentioned that the serum used on Bucky was the closest attempt made: it granted the same qualities Steve has to Bucky but without transforming his physical appearance.

Strictly speaking, nobody is looking for Erskine's exact formula. They are looking to recreate its effect of transforming ordinary people into the perfect human and supersoldier. It stands to reason that all attempts have failed because the test subjects after their corresponding experiments did not achieve the desired perfection observed in Steve.

The serum used on Bucky, once again, is considered the closest attempt to success but is ultimately still a failure. That probably means, in Hydra's eyes, that Bucky is not as perfect a soldier as Steve. It can't be because of his mental brainwashing—Hydra did that, wanted that, and it works as intended - nor his lost arm - humans never possessed the ability to regenerate limbs in the first place—which aren't caused by the serum used on him.

If Bucky is considered to have the same qualities as Steve, then exactly how is the effects of the serum used on Bucky different such that Hydra rejected it?

The only answer I've right now is that Bucky's physical appearance wasn't transformed like Steve, although their physical abilities are supposedly the same. Is that what Hydra wanted? I would imagine not standing out with an extraordinarily perfect body build is preferred for a soldier-assassin.

  • How do we know that Bucky has the same qualities as Steve?
    – Adamant
    Commented Jun 3, 2016 at 5:28
  • The answer in that referenced question said Bucky is functionally the same as Steve if you don't count the metal arm. I don't have an original source to back that up though. And Bucky isn't psychotic. He's perfectly fine when he wasn't brainwashed, which was induced in him by Hydra for their purposes. Commented Jun 3, 2016 at 5:47
  • @HarryJohnston: we certainly see some tetchy enhanced individuals in The Winter Soldier, although they probably weren’t based on Bucky’s serum. Commented Jun 3, 2016 at 8:53
  • @HarryJohnston December 16, 1991 is decades after the Winter Soldier's first appearances in the Cold War though, so that's incorrect. Commented Jun 4, 2016 at 7:12
  • D'oh. Yes, my suggestion would have had him using his enhanced powers to steal the serum that gave him enhanced powers. Not exactly a well-thought-through idea. Commented Jun 4, 2016 at 22:36

1 Answer 1


Who says Hydra rejected the serum used on Bucky?

First of all, it's worth noting that we have no idea what the formula actually contains, so it's impossible to know if the version Dr Zola used on James Buchanan "Bucky" Barnes was different to the one that Dr Erskine used on Steve Rogers.

However, we can be pretty sure of at least one difference in the overall process of created super soldiers - Dr Zola didn't seem to be aware of the need for Vita Radiation, which was an important part of Project Rebirth and the main reason that Howard Stark was involved.

That being said, it's clear to us that the formula Zola used on Bucky worked at least somewhat thanks to his ability to go toe-to-toe with Steve in Captain America: The Winter Soldier, so there must be another reason why that formula wasn't used on more people.

The main one seems to be that Zola may have actually lost the formula that worked on Bucky. As we see in Captain America: The First Avenger, Zola had only recently experimented on Bucky before the base Hydra were working from came under attack by Steve Rogers, meaning not only did Zola not know if his experiment had worked until much later on (when Bucky was delivered to him after the Second World War), he may have lost the secret to his formula in the mean time, most likely when the base self-destructed.

Additionally, it's worth noting that even the version of the formula used on Bucky seems to have been inconsistent. Some of the prisoners of war that Steve rescues during his assault on the aforementioned Hydra base hint as much - when asked where he might be able to find Bucky, they reply;

"There's an isolation ward in the factory. No one's ever come back from it."

Being as we later learn that Bucky was being experimented on in the isolation ward, it seems safe to assume that those who never came back from it had also been experimented on, unsuccessfully.

So in short, the formula invented by Dr Arnim Zola was at least somewhat different to the one used on Steve Rogers, inconsistent at best, and may have been lost in the destruction of a Hydra base anyway.

  • The one fault I find in your argument is that Bucky is still a normal imperfect human when he was first rescued by the Cap. He was only turned into the Winter Soldier after WWII as you said so yourself. The formula can't be lost in that base as a result, and since Hydra has gone undercover in Shield, we can assume there's no similar attack that can cause a loss of the formula until Winter Soldier. Commented Jun 3, 2016 at 11:30
  • 1
    If we agree the Winter Soldier worked, then we need to question why Hydra needed Howard's serums to make more. The only explanation I can see is that the Winter Soldier isn't good enough, and they want better. That's how I conclude Bucky's serum was rejected. Without a good enough reason to believe it was lost, I can only believe Hydra for some reason deliberately not want to use it again. I'd still accept the possibility of yet another lost formula, but the justification for that in your answer isn't sound enough imo Commented Jun 3, 2016 at 11:34
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    @thegreatjedi He was only given the metal arm after World War II, but he was experimented on with the serum while captured by Hydra, which allowed him to survive the fall from the train. For all we know, Zola's formula takes a long time to work, which might explain why he wasn't immediately powered up in the same way as Steve - maybe that's why the Vita Rays were important to Project Rebirth? Commented Jun 3, 2016 at 11:41
  • @thegreatjedi As for Howard's serum - by that point, Zola is dead and Hydra is ran by other people. There are a whole host of reasons why they might be looking to create more super soldiers, including the simple fact that they know Howard Stark has been working on a formula that they have the opportunity to steal. Commented Jun 3, 2016 at 11:43
  • WWII is 1939-45 (6 years). There's many 6 years between 1945 and the 21st century when Steve was melted out. If they wanted more Buckies, they could - with Shield as their front they've no problem with sourcing for resources unless they can't find enough on Earth. If they didn't want to, I find it hard to believe they wouldn't archive that formula if they believed it worked. They couldn't have forgotten about it if they manage to remember that Bucky exists. When they changed their minds and decided to get more, after Howard's serum failed, why wasn't the formula taken out of storage? Commented Jun 3, 2016 at 12:14

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