No, you should not leave hair serum overnight as the ingredients may leave a residue that can damage your hair.
A good rule of thumb is to apply a serum up to 30 minutes before you wash your hair.
Hair serums are designed primarily to protect and nourish the scalp and add shine and smoothness to the hair’s surface. They can also help tame frizz, prevent dryness, reduce split ends, stimulate growth, provide color protection and even protect against heat damage. However, they should not be left in overnight as this can have an adverse effect on your hair health over time.
The main issue with leaving serum in overnight is that it can leave behind a waxy residue which will build up gradually each night until eventually it becomes difficult for shampoo or conditioner to penetrate through this layer of waxiness. This means that no matter how often you wash your hair, dirt and grime will become trapped underneath the coating of product leading to dull looking strands with little body or movement – plus increased risk of breakage due to lack of moisture from regular washing!
This problem is compounded if you use styling products such as hairspray or mousse after applying the serum; these usually contain alcohols which strip away any protective oils present in the scalp so when they come into contact with those same oils again (from using too much serum) it creates an uneven distribution across your head resulting in greasy patches along with clumps forming at certain sections where hairsprays/mousses have been applied most heavily. This further contributes towards dulling down locks making them look lifeless instead vibrant! So make sure never go overboard when applying both types of products together – use sparingly only whats necessary for desired results without compromising on their overall quality afterwards!
Hair serums can help tame frizz, prevent dryness and reduce split ends.
Leaving serum in overnight can leave behind a waxy residue that builds up over time.
Using styling products after applying the serum can cause uneven distribution of oils leading to greasy patches and dull hair.