ssj4 makes goku an adult, but makes vegeta younger?

In Dragon Ball GT, achieving Super Saiyan 4 forces Goku’s body to mature into its prime adult form. Unlike other transformations, SSJ4 taps into the Saiyan’s primal essence—combining the Great Ape’s raw power with controlled fury. The process reverses his child-like state (from GT’s start), proving SSJ4 isn’t just about strength, but mastering the Saiyan’s true nature. A rare fusion of instinct and discipline