Laser hair removal is one of those treatments that seems like it’s from the future. It’s a good thing that the future is now. This incredible technology reduces unwanted hair with speed and efficiency, providing very long-lasting results.
If this sounds too good to be true, we can’t fault you — but as you’ll soon discover, the technology and science behind laser hair removal make a lot of sense.
Once you finish this post, you’ll have a very clear understanding of the process behind laser hair removal and what results to expect.
The Basics of Laser Technology
A laser is a device that emits amplified light. It can penetrate through surfaces and materials with precision, which makes this technology useful in everything from manufacturing to surgery.
The word laser originally came from an acronym that stands for light amplification by stimulated emission of radiation. This acronym is also an explanation of the complex process behind laser work.
Most lasers have a specific core material (called a gain medium), such as a crystal, conductor, or even a gas, that is stimulated with radiation to create light.
Unlike the average light bulb, which emits light on a wavelength spectrum, laser emits a tight and focused light that travels at a narrow wavelength. The wavelengths, which are measured in nanometers, affect the results of each type of laser.
Melanin and Laser Hair Removal: How it Targets the Hair
If you remember your High School science classes, you know that dark absorbs light — it’s why black cars turn into sweltering hot boxes in the summer.
That’s exactly how laser hair removal works. Melanin, the pigment in human hair and skin, absorbs the light from the laser. This causes a thermal reaction that damages the follicle’s ability to grow new hair. Over time and with regular treatments, it results in significant and long-lasting hair reduction.
Types of Lasers Used in Hair Removal Today
There are only 3 types of laser machines used in clinics and med spas today, each one with its own unique abilities that make it suitable for different skin types.
Best for Fair to Medium Skin Tones: Alexandrite Lasers
The Alexandrite laser is built with an alexandrite crystal, which acts as a gain medium for light amplification. It delivers light at a 755 nanometer wavelength, which is the ideal depth for fair to medium skin types.
Studies show that alexandrite laser consistently delivers a slightly greater percentage of hair reduction compared to other lasers, no matter which area is treated.
Across all SEV locations, we use dual-wavelength devices that include the Alexandrite laser, to provide our clients with lighter skin tones the best results.
Best for Dark Skin Tones: Nd:YAG Lasers
On the other end of the laser hair removal spectrum there’s the Nd:YAG laser, with 1064 nanometer wavelength. The gain medium in this laser is a synthetic crystal similar to garnet.
This longer wavelength allows the laser to travel easily past the top layers of skin. It bypasses the melanin-holding layers of skin (right at the cusp of the dermis and epidermis), and reaches the base of the hair follicle which sits well below.
This way, the Nd:YAG can distinguish hair from skin. It is the safest laser for those with dark skin who are looking for meaningful and lasting hair reduction.
At SEV, we always use Nd:YAG lasers on our clients with deeper skin tones.
Average Across the Board: Diode Lasers
Diode lasers are semiconductors, so they’re available with different wavelengths between 810 and 980 nm. This range makes diode lasers a popular option in some clinics, since they’re a more affordable method of treating clients with different skin tones.
However, diode lasers are less precise, which is why we don’t use them at SEV. They may take longer to show results in clients with lighter skin tones, while presenting a slightly greater risk of side effects for clients with darker skin tones.
“The average long-term hair reduction reported for neodymium:yttrium-aluminum-garnet (Nd:YAG) laser ranged from 30 to 73.61%, Alexandrite laser ranged from 35 to 84.25%, and Diode laser ranged om 32.5 to 69.2%.” Source: Krasniqi, A., McClurg, D. P., Gillespie, K. J., & Rajpara, S. (2022). Efficacy of lasers and light sources in long-term hair reduction: a systematic review. Journal of Cosmetic and Laser Therapy, 24(1–5), 1–8:
The Hair Growth Cycle and Laser Efficacy
Every single one of your hairs is on a journey called the hair growth cycle.
- This cycle starts with the anagen phase, when the hair is attached to the follicle and actively growing.
- Next comes the catagen phase (transitional phase as the hair starts to detach).
- Finally, there’s the telogen phase (the final stage before shedding, when the hair rests in the follicle). The start of a new anagen phase is usually what triggers the shedding of the old hair.
For the laser’s thermal reaction to actually impact the hair follicle, the root of the hair needs to be in contact with the base of the follicle. This is only possible during the anagen phase.
Because we don’t know how many hairs are in the active growth phase at any given time, it’s hard to estimate how long it will take for laser hair removal to work or how much hair reduction each patient will achieve.
Factors Affecting Treatment Success
There are many factors that can affect laser hair removal success, and they’re often intermingled — that’s why it’s so hard to estimate exactly how many sessions of laser hair removal each client will need.
You’ll be able to make a more educated guess by considering the following factors:
- The type of laser hair removal machine, as well as the intensity of the settings.
- Your hair color. Darker hair responds better while light hair might be totally resistant.
- Skin tone. Those with lighter skin can usually tolerate more intense treatment settings for better or faster results.
- Body part. Body parts like the legs and arms tend to respond faster than areas where hormones play a big role like the face or neck.
- Hormones. Your endocrine system and conditions related to hormone production have a big impact on hair growth, and how your hair will react to treatment.
Advancements and Future Innovations in Laser Hair Removal
The industry is innovating continuously with laser hair removal technologies, in ways that make the treatment more effective for more people, while maintaining safety and comfort. Some of the current innovations you should know about, as well as innovations we predict may come in the future include:
- Cooling systems: Nowadays, advanced laser hair removal machines always feature a cooling mechanism of some sort, including cooling gusts, cryogenic sprays, and even just blocks of ice. This is an imperative addition to every treatment, since cooling systems have been found to reduce pain and risk of skin damage.
- Skin sensor technology: The latest laser machines, including the Candela and Cynosure devices we use at SEV, feature skin sensor technology that further ensures patient safety. The device senses factors like temperature and skin tone in order to continuously calibrate settings and keep patients safe.
- Pulse length: There have been studies in recent years looking at how adjusting the pulse length of the alexandrite laser might make it a safe option for patients with dark skin. However, this hasn’t been sufficiently established, so at the moment, the safest laser for clients with dark skin is the Nd:YAG.
- Gray and blonde hair removal: Researchers are experimenting with introducing a tint into the hair follicle, to make laser hair removal effective even on gray or blonde hair.
08 Aug, 2024 
10 min read
Share
https://sevlaser.com/blog/how-laser-hair-removal-works-demystifying-laser-technology/