Saiyan
This is the normal state of a Saiyan. It is characterized by having black hair and eyes, and being born with a tail. The only true surviving Saiyans where Goku, Vegeta, Napa, Radditz, Turles, Brolly, and Paraguas.
Oozaru
This is not really a stage to a Saiyan but is a part of them. This stage only occurs if a saiyan sees a fulll moon. To become this stage a Saiyan must have a tail. Once they see the full moon they transform into a giant weremonkey with destructive power. Over time this form can be controlled though.
Super Saiyan
This form is very hard to reach. To be in this form you must first have to have a certain level of power. There are physical changes to this stage, you have blond hair and green eyes. To become this stage the Saiyan usually has to build up some kind of rage.
Ultra Super Saiyan
This stage is generally between Super Saiyan and Super Saiyan 2. It has his disadvantages though. It sacrifices speed for strength. In a physical change, the muscles become more bulky.
Super Saiyan 2
This stage has great advantages. It increases the person's speed, strength, and agility. It also has a physical change, the hair is slightly pushed back more.
Super Saiyan 3
This stage requires a lot of strength, and energy from the heart. The hair in this stage seems to grow down to the knees while the muscles get a bit bigger. This stage enhances the Saiyan's power a lot!
Golden Oozaru
This stage is way more powerful than the regular Ooozaru. This stage occurs when a saiyan with a tail, looks at the "Full Earth". It is distinguished from the regular Oozaru, apart from the increase in power, in the hair color, that now is gold. This stage is often referred to as the "Super Saiyan" of Oozaru.
Saiyan Level 4
Saiyan Level 4, you ask? This stage is acquired by a Golden Oozaru who can be controlled. Since this level isn't really a "Super Saiyan" the hair stays black and the Saiyan gets a red coat of fur.
