Thicken thin hair instantly with Dense Fx™ Duo hair diameter thickening treatment. Featuring Cerafill System Technology, the treatment strengthens fibre to prevent breakage & energises hair follicles to re-densify hair. The treatment plumps existing hair & expands fibres to increase diameter by 9% to create fullness & density. Suitable for all hair types, the thickening treatment also nourishes to promote a healthy scalp.