Serum vs Oil
I bet you didn’t think there was a difference between serum and oil. True, they both add shine, softness, they both look and feel similar. The reality is that they perform differently, giving them different jobs. Serum sits on the outside of the strand while oil is absorbed.
Being that this often thick goop circles around the hair strands it tames frizz, guards hair from pollutants, protects against styling tools and sun damage.
Because oil penetrates the hair it deposits fatty acids which act as a glue to split ends and prevents more breakage from happening. While moisture is infused into hair with the oil, it also fixes a tangled mess.
In a nutshell, serum is used for styling (applied to wet hair) and oil is for treatment. Oil can be thrown into a mix with a hair mask or applied to wet or dried hair.