This nightly, leave-in treatment thickens and fortifies over time for thicker, stronger strands and fuller hair. For people with thin, fine or ultra-fine hair. Can be used nightly or twice-daily for the ultra-fine. To Use: Before bed, pump serum into palms 2 or 3 times, work into roots and through damp or dry hair. Longer hair types should pump again and be sure to smooth through ends.