If you are about to start laser hair removal, you may wonder how often do you need to come in for a session? How many sessions you may need? And also how long will the treatment take. We answer all those questions below but know that the answers will also vary from one person to another.
How does laser hair removal work?
Laser hair removal is a long-term hair growth reduction method. The treatment can reduce hair growth by up to 90%. Although it does not classify as a permanent hair removal method, a lot of patients do experience permanent hair removal. Others will need touch up sessions once a year or every other year. Different factors will impact the results for each individual.
Laser hair removal uses a concept called selective photothermolysis. It is an optical technique used to ablate tissue in targeted regions. The major goal of the technique is to heat targeted tissue with a laser and destroy it without damaging surrounding tissue. Here, the target is the pigment in the hair.
During a laser hair removal session, the laser emits light energy that targets the pigment in the hair. Once the energy is absorbed by the melanin, it travels to the hair follicle. There it turns into thermal energy and anchors itself to the follicle. The heat will damage the follicle, preventing any further growth.
Unfortunately, laser hair removal only works when the hair is in the anagen phase of growth. More on that below.
What is the hair growth cycle?
The efficiency and timing of laser hair removal relies on the hair growth cycle, which is unique to each hair and to each individual. The hair growth cycle has four different stages: anagen, catagen, telogen and exogen. However, laser hair removal will only work when the hair is in the anagen phase of growth.
Indeed, the anagen stage is the only time when the hair and follicle connect, thus allowing the energy to travel from the former to the latter. In any other phase of growth, the hair does not touch the follicle and the energy cannot make it to its destination.
Unfortunately, only 20% of all body hair is in the anagen phase of growth at any point in time. This means that one laser session can only treat up to 20% of the hair on the targeted area. Thus, this explains why patients will need to come back from multiple sessions. Each successive session will be able to treat the hair that was not in the right stage of growth previously.
Can anyone undergo the treatment?
Laser hair removal is a cosmetic procedure that works on all skin colors and hair colors. The common misconception says that laser treatments are not efficient on dark skin or fair hair. Although they are more difficult to treat, it is not true. New laser technology allows for the treatment of patients regardless of the hair-to-skin contrast.
Laser hair removal work on people of color. Even if the contrast between hair and skin is not sharp, there are lasers that can still target the hair and send energy to the follicle. Those lasers are ND: YAG and diode lasers. They use a 1064nm wavelength that bypasses the dermis regardless of melanin and get to the hair follicle.
Treating blonde or ginger hair is trickier. Indeed, while dark hair holds a lot of pigments, fair hair does not. Here, it is the lack of melanin that may be an issue. Indeed, the laser cannot, in theory, target the hair if there is not pigment. However, here again, ND:YAG and diode lasers can solve the issue.
Blonde and ginger people can have very light hair on some parts of their body but darker hair elsewhere, which of course can be treated. When it comes to contraindications for laser hair removal, there are very few and they usually are not permanent.
Why must you wait six weeks between sessions?
As mentioned above, laser hair removal relies on the hair growth cycle. Only hair in the anagen stage can be treated. Since only 20% of hair is in this stage at any point in time, patients will need several sessions to treat all the hair.
Waiting six weeks between sessions has two purposes. The first one is to give a break to the skin. Indeed, during a laser treatment, the skin is exposed to a very high amount of UV rays and heat. Therefore, it becomes more sensitive to outside aggressors and sun damage. Waiting between sessions simply let the skin recover.
The other purpose of this six weeks break is simply to allow body hair to move to the right stage of growth. The lifespan of a hair averages three months. Thus, it is possible that patients have hair in all stages of growth. Those six weeks will just let another 20% of hair be in the right stage for treatment.
In conclusion, you should undergo laser hair removal every six weeks.
How many sessions do you need?
The number of sessions you will need varies on many factors. Skin and hair color will play a role of course. Even though laser hair removal works on all skin tones and hair colors, the smaller the hair-to-skin contrast the trickier it is for the laser to find the hair. Thus, people with dark skin or fair hair may need additional sessions.
Factors such as genetics, hair growth, hormone levels, medication, past hair removal history, area treated can also play a role. People whose hair grows faster and coarser may need additional sessions. Hair growth is triggered by hormones so people with high hormone levels may also need more sessions.
The number of sessions a patient needs will also vary on the area treated. Some areas are not hormonal and therefore will need on average six sessions. Other areas like the bikini or the face are very hormonal. They will require more sessions, probably between eight and ten. They may also require touch up sessions later on.
Laser hair removal is a treatment that requires consistency. Patients must come in for a session every six weeks. This is the best way to ensure all body hair is treated as some point or another. How many sessions will also vary depending on different factors, which will impact the length of your treatment.