A fan favorite, Living Proof's Perfect Hair Day (PhD) Shampoo is a beautiful phthalate, paraben, silicone, sulfate and cruelty-free formula that helps you wash your hair less often, improves health and condition over time and makes locks feel cleaner for longer. A revolutionary formula, the shampoo is powered by the brand's patented 'Healthy Hair Molecule' (OFPMA), which does four things: smooths hair, polishes and protects strands, creates visibly healthier hair over time and helps repel dirt and oil to keep hair cleaner, longer. Prepare to become seriously obsessed.