Although it may be a source of endless exasperation for Vegeta, Dragon Ball has made it clear that Goku is always going to stay one step ahead of his fellow Saiyan when it comes to power. As it turns out, there's a fairly simple and logical explanation for why that's the case, but the answer lies only in an Akira Toriyama interview.

Since the moment Goku attained Super Saiyan for the first time, he catapulted ahead of Vegeta in of strength and has been in front of him more or less ever since. That's not to look down on Vegeta's power in any way--he's inarguably a powerful warrior, but much to his frustration, Goku is the one breaking new barriers constantly, proving what levels of strength are truly possible. It's a core element of the duo's rivalry, and one of Vegeta's top driving motivators to train himself harder.

According to Toriyama, however, it may not be possible for Vegeta to sur Goku, and it's due to something not mentioned directly in the series: S-Cells.

Toriyama's Theory of S-Cells Proves Why Goku Always Beats Vegeta

In a January 2018 interview from Saikyo Jump and translated by Kanzenshuu, Toriyama spoke about the process of going Super Saiyan and what exactly that entails. Toriyama says, "In order to become a Super Saiyan, one’s body must contain something called 'S-Cells.' Once these S-Cells reach a certain amount, a trigger such as anger will explosively increase the S-Cells and cause a change in the body; that’s Super Saiyan." Toriyama goes on to say that not every Saiyan has S-Cells, especially not at the quantity needed to turn into a Super Saiyan.

What's more interesting is Toriyama's explanation of how one goes about cultivating S-Cells. Toriyama states that a gentle spirit can cause S-Cells to proliferate, but a gentle spirit alone isn't enough; it also requires a certain level of battle power and experience. Since most Saiyans have rowdy, violent attitudes like Vegeta, S-Cells became incredibly rare, leading to the Super Saiyan fading into myth and legend. Goku, however, is a rare example of a gentle-spirited Saiyan who also possesses great battle experience, giving him the perfect combination of factors to trigger Super Saiyan for the first time in centuries.

Thus, according to Toriyama himself, Goku will always have an easier time unlocking new levels of Super Saiyan because his body and temperament are perfectly aligned with the conditions needed to succeed. Vegeta, on the other hand, lacks that gentle spirit; while he's grown more calm and caring over the years, he still struggles with keeping his attitude in check, and so long as that's the case, he'll never fully be able to catch up with Goku. In that sense, befriending Goku and living (largely) peacefully on Earth is without a doubt one of the best moves Vegeta has ever made in of increasing his power.

Goku and Vegeta may be eternal rivals, constantly pushing one another to ever greater heights, but it seems that no matter what he does, Vegeta will always remain just behind Goku due largely to his personality. No doubt this would be extremely frustrating for Vegeta to hear, but even the power he currently wields is really a sign of what a good influence Goku has been on him. Goku may stay one step ahead of Vegeta, but Vegeta would never have reached the levels of power he currently enjoys without Dragon Ball's greatest rivalry.

This Explanation Applies to More than Just Goku and Vegeta

When one looks at the totality of Dragon Ball, this explanation actually makes a lot more sense than almost any other for explaining the proliferation of Super Saiyan. Gohan is an especially sensitive and gentle spirit, to the point where opted out of training to focus on an ordinary life on Earth, and he was the first to obtain Super Saiyan 2 as a result. Goten and Trunks, while a bit more rambunctious, are also far more gentle than your average Saiyan, and similarly had a relatively easy time attaining Super Saiyan.

One can even look to Universe 6's Saiyans as further proof that this S-Cell theory is valid. The Universe 6 Saiyans, such as Cabba and Caulifla, come from a more peaceful Saiyan race, one that never lost their homeworld. Cabba is clearly a very gentle boy in his fight with Vegeta, but he also had enough battle experience to be selected by Champa for the tournament between Universes 6 and 7. Like Goku, he has the perfect mix of traits that made it possible for him to attain Super Saiyan, especially when his rage was triggered by Vegeta's villain act.

This even applies to the Legendary Super Saiyans, such as Broly and Kale. Kale is quite meek and gentle, allowing for S-Cells to build up in her body, but her combat experience is limited. As soon as she starts to gain fighting experience, she gains the ability to become Super Saiyan quite rapidly. Broly, whose new characterization in Super can easily be classified as a "gentle giant," is very unlikely to fight in his base state, and while he had to fight for survival to some extent, he also had a fairly peaceful life with his father on Vampa.

It's a bit ironic that Frieza feared the Super Saiyan so much, as his ruthless rule and the evil deeds he had Saiyans commit on his behalf were actually the perfect recipe to prevent any Saiyan from ever obtaining the Super Saiyan state. By ensuring their culture is militaristic and devoid of love, no Saiyan would have the gentle nature needed to cultivate S Cells, and thus their battle experience would be ultimately irrelevant, rendering Super Saiyan impossible. He didn't need to destroy Planet Vegeta at all, as he'd already thoroughly subverted the conditions necessary.

Why Akira Toriyama's S-Cells Explanation Avoids The Classic "Midi-chlorians Problem"

S-Cells Aren't a Retcon like Midi-chlorians

It's tempting to automatically compare S-Cells to the Star Wars prequels' infamous Midi-chlorians, as both are microscopic indicators of power. However, while Midi-chlorians explained away the Force in a way that wasn't consistent with how Star Wars had presented it previously, S-Cells actually reinforce what was known about how Super Saiyan was obtained. Goku certainly had the gentle overall nature required, and his battle experience was fairly extensive even then. All he needed was the right trigger, and boom, instant Super Saiyan.

Midi-chlorians were a retcon, changing the mystical nature of the Force into something that could be measured and tested, and perhaps even modified. Fans were outraged because they felt the very concept invalidated what had come before, and the new explanation didn't really offer anything compelling to the story. S-Cells have never been directly mentioned in Dragon Ball, only in this interview, so at least for now, fans are free to accept or disregard this information as they see fit.

S-Cells are merely a formalization of what was already known about Super Saiyan and how the transformation works. The system works the same way whether one embraces the idea of S-Cells or not, unlike Midi-chlorians. Midi-chlorians were also considered intelligent, with a will of their own, which S-Cells don't possess. S-Cells also don't seem to be inherited, but must be developed by each individual through their own life and choices, ensuring that Super Saiyan is still something that must be worked for to be attained.

While the idea of S-Cells may seem like a simple after-the-fact explanation for how Super Saiyan works, the answer is shockingly consistent with how obtaining Super Saiyan has actually worked out throughout the series. Life on Earth, and on the peaceful Universe 6 Saiyan homeworld of Sadala, provides an environment that encourages a gentle spirit even among Saiyans, giving these Saiyans a surplus of S-Cells. All it takes from that point is some combat experience, and some kind of trigger like intense anger, and that's the perfect recipe for creating a Super Saiyan.

As an explanation for why only some Saiyans can go Super, S-Cells are surprisingly effective, and perfectly fit Dragon Ball's Saiyan situation.