If your hair seems to repel water on wash day, takes hours to air dry or always feels like your favourite treatments are sitting on top of your strands instead of sinking in, there’s a good chance you have low porosity hair. While concerns like product buildup can play a role, your hair’s porosity often determines how well it absorbs and retains moisture, oils and styling products.
Hair porosity refers to your hair’s ability to absorb and hold onto moisture. Knowing your hair’s porosity is just as important as understanding your hair type because it helps you choose products that actually work for your strands. The outermost layer of the hair shaft is made up of cuticles that control how easily moisture can pass through. In low porosity hair, these cuticles lie tightly packed together, making it more difficult for water and treatments to penetrate. As a result, products often remain on the surface instead of being absorbed effectively.
One of the easiest ways to determine your hair’s porosity is with the float test. Place a clean strand of hair into a bowl of room temperature water. If it sinks quickly, your hair is likely highly porous. If it stays suspended in the middle, you have medium porosity. If it floats on the surface, you most likely have low porosity hair.
When caring for low porosity hair, choosing the right formula is more important than layering on multiple products. Lightweight, water based serums enriched with humectants like aloe vera, glycerin and pectin help draw moisture into the hair without leaving behind a heavy or greasy finish. The best serums for low porosity hair focus on delivering hydration while allowing strands to absorb nourishment without creating buildup or weighing them down. Regular wash days can also remove product buildup, allowing treatments to absorb more effectively. For best results, apply your serum to damp hair, when the cuticle is slightly more receptive to moisture.
Finding a serum that hydrates without leaving behind buildup can be a challenge, but the right formula and ingredients can transform the way low porosity hair looks and feels. Below, we have rounded up the best lightweight serums for low porosity hair that deliver moisture, tame frizz and nourish strands without compromising on bounce or movement.
K18 Molecular Repair Hair Oil
If your low porosity hair tends to reject richer oils, this one strikes the right balance. The featherlight formula helps repair damage, tame frizz and boost shine without leaving strands coated or greasy. It’s also an excellent pick for colour treated hair, helping preserve vibrancy while protecting against heat styling.
