You should use 2-3 drops of serum on your medium-length hair and using too much serum can make your hair look greasy and oil rather than healthy. And if you want to style your hair, you can mix your serum and aloe vera gel and make a hair protectant spray to keep your hair naturally strong and healthy. Once you are done with styling the hair, use a teardrop and apply it over the hair using fingertips.