On Namek, the different explanations Vegeta gives to Freiza’s minions at different points contain different details in how exactly the zenkai boost works. Vegeta’s first explanation makes it sound more cultural than biological — Saiyans fight a lot and get experience that makes them strong, so they seek more fights for more experience. By the next time Vegeta is explaining the zenkai boost, it sounds like an inherent ability Saiyans have to naturally raise their own power levels to match a stronger opponent. The third time Vegeta explains it, he gives the best-known version of how the zenkai boost works: the Saiyans get stronger after experience near-death injuries, as Vegeta did fighting Goku on Earth.

Dragon Ball Super Explained Why Zenkai Boosts No Longer Happen

Chapter #20 of Dragon Ball Super gives some clarification at last. During Vegeta’s fight with Goku Black, Trunks and Mai watch as Vegeta fights at a disadvantage and rapidly lose ground. With Vegeta being repeatedly knocked down by Goku Black, Mai suggests repeatedly healing Vegeta with Senzu Beans to allow him to constantly heal and be empowered by the zenkai boost. It quickly becomes apparent that the plan doesn’t work, since Vegeta doesn’t seem to be getting any stronger as he recovers. Trunks suggests that Goku and Vegeta have “hit their limits”, either of their zenkai boost ability or of their physical growth, and no longer get stronger when they recover from injuries. This is the clearest explanation about the disappearance of zenkai boost provided in years.

While the idea of Saiyans become stronger after surviving intense battles fits the Saiyan culture, the zenkai boost has proven a difficult thing to write around, and the near-disappearance of this ability after the Namek Saga created one of Dragon Ball‘s biggest plot holes. Throughout the series, the exact rules have been changed to fit the demands of the plot, or the concept has been abandoned altogether to prevent it from completely breaking the plot and making the Saiyans too powerful. On Namek, to get strong enough to fight Frieza, Vegeta deliberately has Krillin almost kill him before being healed by Dende. This creates the lingering question of why more Saiyans don’t just deliberately heal and injury themselves, or why a zenkai boost did not happen in other situations, such as when Cell almost killed Vegeta.

Goku And Vegeta Have Hit The Limit Of Their Physical Growth

While it’s likely that Akira Toriyama simply decided to phase out this power from the series due to the potential abuse it could cause, it’s good that Dragon Ball Super decided to address the issue directly and in canon. It is also consistent with Vegeta’s recent declaration that he and Goku have long since reached the limit of their physical growth, and now have to get stronger by other means. Although ambiguities remain about the specific details of the zenkai boost ability, this explanation at least closes the most glaring plot hole about Saiyan powers. While the door remains open for other, weaker Saiyan characters to benefit from the zenkai boost, thanks to Dragon Ball Super there is now an explanation for why Goku and Vegeta no longer seem to get stronger despite the epic battles against awesomely powerful enemies they’ve survived.

Source: Screenrant.com