7 Factors That Affect the Effect of Laser Hair Removal
wavelength
Most of the Laser Hair Removal Machines used clinically have a wavelength between 694 and 1200 meters, which can be well absorbed by the melanin in the hair follicles and hairs, while ensuring that it penetrates to the depth of the hair follicles. Currently, semiconductor lasers , long-pulse Nd:YAG lasers and various intense pulsed light are most commonly used in clinical practice.
From the comparison of curative effect, the curative effect of semiconductor laser is basically similar to that of various intense pulsed light. The curative effect of long-pulse Nd:YAG laser may be slightly worse than that of semiconductor laser and intense pulsed light under the same treatment times.
Laser Hair Removal Machines
Pulse width
The ideal pulse width range of Laser Hair Removal Equipment is 10-100ms or even longer. Long pulse width can slowly heat and destroy the hair follicles and the bulge containing hair follicle stem cells, and at the same time can avoid damage to the epidermis due to the sudden temperature rise after absorbing light energy, It is safer to increase the pulse width to hundreds of milliseconds for people with dark skin.
Nanni et al. compared the results of long-pulse alexandrite laser treatments with different pulse widths. A total of 36 patients were treated with an average energy density of 18J/cm², a spot diameter of 10mm, and a pulse width of 5, 10 , and 20 ms. There is no significant difference in the effect of laser hair removal with pulse width, but the side effects of laser with 20ms pulse width are less.
Energy Density
On the premise that the beauty seeker can tolerate and does not have obvious side effects, increasing the energy density can improve the efficacy. The suitable end point of laser hair removal treatment is that the recipient will feel the pain of being punctured by acupuncture. Soon after the treatment, there will be mild erythema on the local skin and small papules or wind masses at the mouth of the hair follicle. During treatment, if there is no pain or local skin does not respond, it often indicates that the energy density is too low.
Observing the hair removal cosmetic effect of the long-pulse Nd:YAG laser, the results show that increasing the energy density and increasing the pulse width can effectively improve the clinical hair removal effect.
Cooling device
The Professional Laser Hair Removal Machine with cooling device can protect the epidermis more effectively, and the hair removal device can safely use higher energy density for treatment.
Number of treatments
Hair removal treatment requires multiple times to achieve the desired effect, and the number of hair removal is positively correlated with the effect of hair removal.
Treatment interval
At present, most scholars believe that the treatment interval should be adjusted according to the hair growth cycle of different parts. If the hair on the depilatory site has a short resting period, the treatment interval can be shortened, otherwise the treatment interval needs to be lengthened. However, some current studies believe that a shorter treatment interval is better.
Bouzari et al. studied the 808nm semiconductor laser treatment of 24 cases of skin type Ⅱ to Ⅳ facial and neck hairy women. In the 45, 60, and 90-day interval groups, the average hair reduction was 78.1%, 45.8%, and 28.7%, respectively. Studies have shown that the shorter the treatment interval, the more hair loss.
Lloyd et al. treated 11 cases of skin type I to III patients with hirsutism in the bikini area, energy density 20Jcm², pulse width 20ms, spot 10mm, 3 weeks apart. After 5 treatments, the hair was reduced by an average of 78% in 1 year without scars and pigment changes. Studies have shown that shorter treatment intervals are more likely to damage the hair bulb and its upper bulge.
In some current studies, regardless of the anatomical location, the laser hair removal interval is 1 month. Whether or not the hair growth cycle will be changed after laser treatment remains to be further studied. A simple rule to grasp the treatment interval clinically is to perform laser hair removal as long as there is more hair regeneration.
Skin type, hair condition, and location of the person seeking beauty
The more latent the skin color of the person seeking beauty, the darker and thicker the hair, the better the hair removal effect. The effect of laser hair removal on different parts of the body is also different. It is generally believed that the effect of hair removal on the armpits, hairline and limbs is better, and the effect is not the best, and the effect of upper lip, chest and abdomen is poor, especially for women, the upper lip hair is the most difficult. Analysis The reason may be that the hair follicles are small and contain less melanin.
