Hair loss is one of the permanent effects caused by constant keratin treatments, while nausea is a temporary side effect since the process can take anywhere from two to four hours to complete. The hair loss is due to the ingredients in the treatment breaking down the hair follicle over time.
Keratin treatments also contain a potent ingredient called formaldehyde, which can be very dangerous when exposed to sensitive areas on your face. Formaldehyde can cause extreme eye irritation and even blindness if used in large quantities. This ingredient causes breathing difficulty, redness and bleeding of the nose as well.