Dragon Ball Z

Saiyans become Super Saiyans, and their hair color is generally golden. Although black appeared in Dragon Ball GT, blue appeared in Dragon Ball Super. But as long as it is a Saiyan, the tail can be turned into a super four without being cut off, or it can be turned into a super blue with the guidance of an angel. However, there is such a color, no matter who gets the guidance, or the Saiyan with high talent, if there is no blood of the ancient Saiyan, it will not be able to become an ultra-green form in this life.
There are only three Saiyans with ancient blood in the current Dragon Ball. They are Broly, Kyle of the Sixth Universe, and Amos, the ancestor of the Saiyan clan. It can be seen that the Saiyans with ancient blood have a different color of Chaosai hair. But friends who have watched Broly's theatrical version discovered that when Vegeta turned into a super game, the color of her hair once turned green. What caused this?
In fact, this situation occurred because Vegeta's blood began to return to his ancestors. Everyone knows that the blood of the Saiyans can be divided into three stages. Such as Wukong belongs to the ordinary blood, Vegeta belongs to the royal blood, and Broly belongs to the ancient blood. There is an obvious distinction between the bloodlines of these three levels, that is, the situation after becoming a gorilla is different. Saiyans of ordinary blood become gorillas and lose all their sanity at the beginning, but they can regain their sanity through acquired practice.
But even after regaining his sanity, he couldn't speak. In contrast, the Saiyan of the royal blood became a gorilla. Not only could he retain all his sanity, he could also speak in the state of a gorilla. Finally, the Saiyans of ancient blood can play the effect of becoming a gorilla without directly becoming a gorilla. In addition, Vegeta is the elite of the elite fighters, surpassing his father at a very young age. It shows that bloodlines of the same level also have strengths and weaknesses.
Otherwise, the king Vegeta had lived for so long, and his fighting power would only be in his early ten thousand years. There is also the Kel of the Sixth Universe, although he also has ancient blood. But after turning into an ultra-green form, they teamed up with Kalifula to fight against Wukong, which was actually not an opponent of Ultrablue Wukong. On the other hand, after Broly became super green, his strength can easily beat two super blues. In this way, you know why Vegeta's hair turned green.
Because Vegeta's royal bloodline has reached the top level, and it is only a thin line away from the ancient bloodline. Coupled with the continuous improvement of Vegeta's strength, her own blood will naturally increase accordingly. When Vegeta was just super-strength, she saw Broly turn super green and her bloodline was suppressed, so she didn't have the heart to resist. But when Dragon Ball Super Vegeta reached the super-blue combat power, there was a trace of ancient blood in the royal bloodline. When he encountered the Avia that Broly broke out again, Vegeta was no longer timid.
And friends who have seen Dragon Ball GT know that changing from Super 3 to Super 4 requires becoming a gorilla. The appearance of Super Four is more in line with the image of Saiyan. Afterwards, Super Five in Dragon Ball AF also had the same image setting as Super Four. Not only did the hair change, but also brown hair appeared on the body. According to this evolutionary route, it is not difficult to see that the more Saiyans go to the back, the more they become super-races, the closer they are to the appearance of gorillas. This phenomenon is called the return of blood in the novel.  Dragon Ball Trainers UK
It's just that because Dragon Ball Super took the path of the realm of gods, it didn't highlight the characteristics of Saiyan's return to ancestors. But the sudden appearance of Vegeta's green hair may be a foreshadowing arranged by the author. Because Broly is no longer limited to the theater version, in the new theater version in 2022, Broly's figure reappears. Perhaps Vegeta's next form is the awakening of the ancient bloodline and turning into super green.