Performing it twice in a short time brought him to his knees and expended all of his remaining energy.

Goku acknowledged that he had little experience with the transformation, with his fight with Kid Buu being the first time he used it in a full fight with a living body. Satan distracted Kid Buu, he was unable to do so, draining his power completely and leaving him in a weakened, normal state where he could not even control the Spirit Bomb.

Likewise, when the now fully living Super Saiyan 3 Goku attempted to regain energy while Vegeta and Mr. Goku as a Super Saiyan 3 watches Vegeta fight Kid Buu When the then-deceased Goku showed Babidi and Majin Buu the form, he cut his remaining temporal revival energy in half, and in the anime when he shows his power to the excited Trunks and Goten, his energy was completely dissipated, forcing him to return to Other World. However, with the enormous power, there are some very serious setbacks stemming from the rapid use of ki energy. In addition, this power could be sensed even as far as the distance between Earth and Supreme Kai's planet, something that not only shocked Supreme Kai, Kibito, and Gohan, but worried them as well. During subsequent transformations, Goku seemingly controlled it enough to prevent such dangerous side-effects. The first time that Goku used this form on Earth, its power caused massive tidal waves and hurricanes and nearly shook the planet apart. The difference between Super Saiyan 3 and Super Saiyan 2, its predecessor, is immediately noticeable as speed, strength and endurance are all pushed far beyond the normal limits. If the user has died and is not encumbered by a living body, this strain is reduced somewhat, and additional energy depletion is minimized (such as in Goku's case during his first fight with Majin Buu). This notably leads to extended levels of fatigue, even long after powering down. Where the third stage of Super Saiyan's purpose was 100% utilization of physical stamina, the purpose of the Super Saiyan 3 transformation is to increase the utilization of ki, and as a result, the transformation rapidly consumes the energy of the user.

Db raging blast 2 majin vegeta