S-Cells (S細胞 Esu Saibō) are microscopic cells found in most Saiyans. The amount of S-Cells depends on the spirit of the Saiyan in question: the more gentle the spirit, the greater the amount of S-Cells; alternatively, when a Saiyan increases their battle power, it can also increase the amount of S-Cells in their body. S-Cells are essential to becoming a Super Saiyan, and when a Saiyan has gained enough they can transform by feeling intense levels of anger or sadness; alternatively (as demonstrated by Caulifla), by focusing their power into a tingling sensation in their upper-back (directly below their neck) the Saiyan in question can trigger the transformation into a Super Saiyan without the need for emotional stress. S-Cells can be passed down through genetics, making it easier for even partial Saiyans, such as Goku Jr. and Vegeta Jr., to become Super Saiyans.
- Presumably, artificial Saiyan hybrids such as Cell, Cell Jr., Mira, Fu, and Bio-Broly also possess S-Cells. If so, it can be assumed that Mira, Fu, and Bio-Broly require them for their Super Saiyan forms, though it is unknown how they function for Cell, though presumably they have some influence in the form of Cell's Super Saiyan state.
- Gentle Saiyans having more S-Cells may explain why Super Saiyans were rare for a long time in Universe 7 as the Saiyans there were violent and lived in a society that valued aggression and ruthlessness.