The pokemon using Synthesis will regain a fixed amount of their maximum HP. The amount ranges from 1/8th (by integer division) to the amount of the using pokemon's maximum HP. The amount is determined by several factors:
1. If used in a link battle or in Stadium 2, the base recovery amount will be 1/2.
2. If used in a standard game battle, the amount varies based on the time of day in the game. During the Day hours (not including Morning), the base recovery amount will be 1/2. At any other time of day, the base recovery amount will be 1/4th.
3. If the move Sunny Day is in effect, the base recovery amount will be twice of what it normally is. If Rain Dance is in effect, the base amount will be 1/2 of what it normally is.
Synthesis will automatically fail if the using pokemon's current HP is equivalent to their maximum HP.
