Sudden thinning hair most commonly affects women and can be triggered by various factors such as pregnancy, stress, an unbalanced diet or medication. RF 80 has a double patented and scientifically proven formula that combats the two major factors of sudden thinning hair: Vascular and Nutritional. It works against these 2 causes to naturally encourage the growth of stronger hair and improve hair structure for thicker and faster growing hair. Usage: Use once a week for twelve weeks as needed. Carefully snap ampoule in a paper towel and place applicator tip on vial. Massage into scalp. Do not rinse. Proceed to styling. 12 vials - 4ml / .16oz Rene Furterer Women's RF 80 Concentrated Serum A great designer gift. Shop Rene Furterer at Barneys New York.