Color Safe vs Chlorine Bleach: What is the Difference?

You likely know by now that you can’t use regular bleach on colored fabrics; rather, you have to use color-safe bleach. But why is that?
It all comes down to the active ingredient.
Regular bleach contains sodium hypochlorit. It is only safe to use on white and a few fabric types, as it can cause damage and discoloration. For example, the chemical reaction between bleach and wool will dissolve the wool fibers. Similarly, if you use bleach with dyed linen, you can expect the dyed fabric to become discolored, typically turning an off-white color.
Color-safe bleach, on the other hand, uses hydrogen peroxide as its active ingredient. This makes it safe for virtually all machine-washable fabrics, with some notable exceptions being leather, spandex, wool, silk, and mohair. On top of that, it can be used to remove stains and brighten colors on fabrics that can’t be washed with regular bleach.

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Typical household bleach is sodium hypochlorite, not sodium hydroxide. Sodium hydroxide is lye. There is usually a very small amount of sodium hydroxide added to household bleach to stop the sodium hypochlorite from degrading as quickly, but it's still mostly sodium hypochlorite.