It depends what you consider to be permanent.
The clinical results of hair removal laser treatments were submitted and reviewed by the FDA in the 1990s when laser hair removal technology started growing in popularity. There was, and continues to be, the debate surrounding the certification that was issued. The crux of the debate centers around the definition of permanent reduction – that hair will be destroyed and never able to regrow.
Laser hair removal provides permanent hair reduction but cannot guarantee that treated areas will permanently remain 100% hair free. As such, it is generally accepted that laser hair removal is not permanent, despite marketing strategies using spin to generate business. The FDA has certified laser hair removal procedures as permanent hair reduction treatments while stating that it cannot be claimed that this method of hair removal is permanent. In other words, laser hair removal is able to permanently reduce the total hair in a given area of skin being treated, but it cannot completely prevent hair regrowth. This is because laser hair removal treatments usually only remove 70% – 90% of hair permanently, while the remaining 10% – 30% will grow back softer, finer and lighter in color. However, Laser hair removal is only effective on hair in the active,
anagen phase of the hair growth cycle.
Hair growth is not a uniform process, and while some hair follicles are in the active, anagen phase of the hair growth cycle, others are in the catagen (intermediate) and telogen (resting/shedding) phases. This means that multiple sessions are needed in order to treat each batch of hair as they enter the anagen phase. These sessions need to be spaced appropriately in order to allow batches of hair to move through the different phases of the hair growth cycle. The necessary time between sessions varies and is determined by a combination of a number of factors, including hair color; skin
tone; hair texture; hair density; and the area being treated. Usually, though, initial sessions are scheduled for between 5 – 10 weeks apart. The frequency of these sessions will decrease over the course of the treatment, until eventually maintenance sessions are only required once a year, or even less, depending on the individual patient. However, even if laser hair removal treatments are only required every few years, hair growth cannot be said to be permanently halted. Despite this, the vast majority of patients are reportedly satisfied with the results of their laser hair removal