Reading Time: <1 minuteRecently, I have been asked to supervise hair removal websites and check the medical suitability of articles. There seem to be very few medical institutions where doctors themselves perform hair removal with a solid understanding of hair removal theory. Nurses seem to be in charge of hair removal treatments at almost all medical institutions, but I wonder if they actually read papers and understand hair removal theory before applying it clinically. The target when removing hair is the melanin pigment of the "hair". Oxidized hemoglobin is the color of blood, that is, the color of the red blood cells in the capillaries in the dermis. The shorter the wavelength of laser light, which is easily absorbed by melanin and easily raises the temperature of melanin, the better, but in reality, if it is 400 nm, for example, it will just be absorbed by the melanin in the epidermis and the light will not reach the hair papilla or bulge area, and it will only cause epidermal burns. Also, if you want to destroy only melanin without burning blood vessels, you might think that a wavelength of 694 nm (ruby laser) would be good, but in reality, the shorter the wavelength, the more light is scattered, and with ruby's 15 nm, only 750% of the light reaches the dermis. For this reason, the wavelength suitable for destroying melanin in hair and hair roots with medical hair removal lasers is around 790-755nm, so 515nm Alexandrite light is suitable for medical hair removal lasers. In the case of beauty salons, hair removal is performed using IPL light containing various wavelengths starting from 1200nm. This is because only doctors are permitted to use lasers under the Medical Practitioners Act. For hair removal, IPL is used in beauty salons, so the wavelength is limited (IPL with a wavelength of 1-2nm was used for medical hair removal). *Factors that affect hair removal effect 10: Wavelength 30: Pulse width XNUMX: Fluence XNUMX: Number of irradiations XNUMX: Number of hair removals *Situation on the client's side XNUMX: Thickness of hair to be removed XNUMX: Color of hair to be removed XNUMX: Hair density XNUMX: Hair removal area XNUMX: Skin color These factors are taken into consideration when performing hair removal. Theoretically, the IPL spectrum is almost complete, and the only way to develop hair removal devices is to combine it with high frequency, increase the cooling power, and increase the fluence, as long as there are no problems under the Medical Practitioners Act and the Pharmaceutical and Medical Device Act. It is important that heat is transferred firmly to the bulge area and hair papilla to cause tissue destruction. Unlike lasers, IPL has the disadvantage that it is difficult to transfer energy only to shallow areas due to a lot of diffusion. Increasing the fluence unnecessarily can easily cause epidermal burns, so care must be taken when hair removal is performed on sunburned or dark-skinned clients. Unlike lasers, IPL is a pulsed light with the characteristics of incoherence, multi-wavelength, and scattering. It generally uses a xenon lamp as a light source, and uses wavelengths from XNUMX to XNUMX nm by cutting the short wavelength region with a filter. Depending on the application, one or two more filters are added to limit the wavelength band to be used in actual treatment. The energy intensity is not uniform, but has a peak on the short wavelength side of the oscillation wavelength band. In IPL treatment, pulsed light oscillated in milliseconds is irradiated onto the skin surface through a sapphire irradiation filter. The spot size is often a large rectangle of about XNUMX x XNUMX mm, allowing for wide-area treatment in a short time. IPL devices vary greatly in settings and performance, including the oscillation wavelength band, settable pulse width (e.g., a few milliseconds to tens of milliseconds), pulse division method (e.g., single, double, triple), uniformity of output within the pulse, and the presence or absence of a cooling device for the skin irradiation surface and the type of cooling device used.