Expert Hair Brazilian Keratin Treatment 1L/33.8oz Formaldehyde Free. Expert Hair Bio Protein Brazilian Keratin Treatment is a professional-grade hair straightening formula that eliminates frizz and smooths hair for up to 6 months. This 1L (33.8oz) professional size provides up to 10 applications for short hair, 5 for medium length, or 3-4 for long or thick hair. The formaldehyde-free formula is safe for all hair types including color-treated, bleached, and chemically processed hair. Made with organic plant-based pr.