Booster serum is an advanced, lightweight treatment serum that helps protect the skin with antioxidants that fight free radical attack. It contains ceremides to help reduce skin's natural moisture loss and hyaluronic acid to help plump and hydrate the skin. It helps even skin tone and increase skin elasticity, while restoring its firmness with the power of peptides. Booster serum features a proprietary peptide, myristoyl pentapeptide-9, exclusive to philosophy.