Hair Serums: Products, Reviews & Buying Guides

A hair serum is a finishing product used to smooth, add shine and tame frizz. It sits on top of the hair as a cosmetic step rather than a wash-out treatment, and a little usually goes a long way.

Many hair serums are silicone or oil-based, which helps coat the hair for a smoother look and softer feel. Different formulas lean towards high shine, lightweight finish or stronger frizz control, so the right one depends on your hair and the look you want, as well as how heavy your hair tends to feel by the end of the day.

Application depends on preference. Some people apply serum to damp hair before styling to help with smoothness and heat styling, while others use a small amount on dry hair to tame flyaways. Fine hair usually needs very little, while thick or coarse hair can take a bit more.

Use serum sparingly to avoid excess product buildup that can leave hair looking greasy or limp, and wash it out as part of your normal routine. Choose a formula suited to your hair type and finish. This is not a treatment for medical hair-loss conditions. The overviews below can help you compare options.