SkinMedica's TNS Essential Serum features a dual chamber with two active formulas that combine to smooth wrinkles and regenerate skin cells for a more youthful appearance. The TNS complex is a Growth Factor protein- and amino acid-rich serum to reduce inflammation and the signs of aging. The APS corrective complex is a mixture of anti-aging ingredients, peptides and antioxidants to strengthen sagging skin. For best results use after Cleansing and toning your skin, a.m. & p.m.