How to have thicker hair
“If you are looking to add volume to your hair, start with a volumizing shampoo as the foundation,” says Augsten. “Volumizing shampoos are going to help fatten and swell the hair cuticle to create a more airy feel and look of the hair.”
Volumizing shampoos and thickening shampoos can both help to make hair look fuller overall, however, the two products work in different ways and produce slightly different results. The biggest difference to note is that thickening shampoos focus on individual strands of hair, while volumizing shampoos focus more on the roots. Thickening shampoos work by infusing the hair with proteins, vitamins, polymers, and/or moisture that plump up each strand making each piece appear thicker. This is ideal for boosting thickness in fine hair types.
Volumizing shampoos focus more on adding lift to the roots. They do this by helping to break down build-up around the scalp and infusing the hair with invigorating ingredients like caffeine, biotin, and meadowfoam seed oil.
Volumizing and thickening shampoos can be a great solution for both fine and thin hair, but just know that each will produce a slightly different result.