LASER HAIR REMOVAL – IN-DEPTH ANALYSIS OF MECHANISM, EFFECTIVENESS AND SAFETY

I. MECHANISM OF LASER ACTION IN HAIR REMOVAL – NOT JUST “BURNING ALL HAIR”

Laser hair removal is not simply burning the hair with heat. In essence, this technology is based on the selective photothermolysis effect . The four targets only melanin – the pigment of the hair follicle , which determines the growth of the hair. When the light energy from the laser comes into contact with melanin, it will be converted into heat energy. This temperature will controllably damage the surrounding stem cells , preventing

However, hair follicles do not exist in one state all at once – they cycle through three phases : anagen (growing), catagen (regressing), and telogen (resting). Only hair follicles in the anagen phase have 5–8 phases spaced 3–6 weeks apart ,

Laser does not damage surrounding tissues because the energy is only strongly absorbed in the melanin-containing area. Therefore, if performed with the right parameters and technology suitable for each skin type, laser hair removal can be completely safe, non-invasive and dry.

II. ANALYSIS OF TYPES OF LASER TECHNOLOGY IN HAIR REMOVAL – THE DIFFERENCES

Each type of laser has a different wavelength of light, corresponding to the depth of skin penetration , the level of melanin absorption , and the appropriate skin type . Below are the 3 most popular laser technologies in the medical hair removal industry:

1. Diode Laser – Balance between efficiency and safety

• Common wavelength: 800–810nm

• Deep penetration: Enters the dermis, where most hair follicles are located.

• Highlights:

  • Diode lasers absorb melanin at a moderate level – strong enough to destroy the hair follicle without causing much damage to surrounding tissue.

  • Considered the “gold standard” technology for hair removal because it is suitable for many skin types, including Asian skin, sensitive skin or tanned skin 

  • The laser beam can be cooled simultaneously through the integrated sapphire tip – helping the user feel almost no burning sensation.

• Effective: High on areas such as armpits, arms, legs, lips, bikini area.

2. Alexandrite Laser – Powerful for Fine Hair and Fair Skin

• Wavelength: 755nm

• Superficial penetration: Mainly in the epidermis and upper dermis.

• Advantage:

  • Very effective on fine hair, facial hair or areas with light hair .

  • However, due to its strong melanin absorption, it is not suitable for dark or tanned skin , and can easily cause burns and hyperpigmentation after treatment.

• Recommendation: Use only on fair, non-tanned skin.

3. Nd :YAG Laser – The optimal solution for dark skin

• Wavelength: 1064nm – longest among cosmetic laser technologies.

• Penetrates very deeply: Through the epidermal melanin layer, reaching the hair follicles deep under the dermis.

• Characteristic:

  • Very little melanin absorption, so safe for dark skin, does not cause hyperpigmentation after treatment.

  • However, due to lower energy, the effect requires more sessions compared to Diode or Alexandrite.

• Application: Bikini area removal on dark skin, soft tissue areas such as arms, thighs, abdomen.

III. ACTUAL RESULTS AND FACTORS DETERMINING SUCCESS

To achieve the highest efficiency, laser hair removal depends not only on technology but also on the following professional and biological factors :

1. Hair follicle condition:

• People with thick, dark hair are easier to remove because there is more melanin → absorbs light better.

• Fine, blonde or white hair with little melanin → laser is less effective.

2. Skin type and skin sensitivity:

• White skin can use many types of lasers.

• Dark skin is only suitable for Diode or Nd :YAG to avoid post-treatment hyperpigmentation.

3. Technician skills and machine parameters:

• Energy (joules), firing frequency, pulse duration… need to be customized according to skin area, hair color, tissue thickness.

• Using the wrong parameters can cause burns, blisters, hyperpigmentation or ineffective removal.

4. Scientific treatment schedule:

• 5–8 sessions is minimum, 3–6 weeks apart depending on the individual.

• Do not interrupt or change technology midway because hair follicles are adaptive.

IV. FEELING OF LASER HAIR REMOVAL – IS IT PAINFUL?

Most users describe the sensation of laser hair removal as a “light hot prick”. With a good cooling device (sapphire tip or cold gel), the pain is almost negligible . However:

• The armpits, lips, and bikini area are more sensitive because the skin is thin and has many nerve endings.

• The arms, legs, and back are usually more comfortable and less reactive.

If you have a low pain threshold, the facility may apply a numbing cream 15–20 minutes beforehand to help make you more comfortable.

V. RISKS AND HOW TO DEAL WITH THEM – NOT JUST “NO HAIR GROWTH” IS SUCCESSFUL

✅ Temporary side effects (normal):

• Skin is red and slightly hot for the first 2–24 hours.

• Mild blistering may occur in people with thin skin – resolves spontaneously after 1–3 days.

⚠️ Serious side effects (if done incorrectly):

• Skin burns: Due to wrong wavelength or too dense pulse stacking.

• Post-inflammatory hyperpigmentation: Skin is damaged but not properly cared for.

• Folliculitis: Not cleaning thoroughly after waxing, especially in private areas or areas with sweat glands.

Therefore, laser hair removal must be performed at a medical facility or spa supervised by a dermatologist .

VI. WHO SHOULD NOT DO LASER HAIR REMOVAL?

• Women who are pregnant or breastfeeding (due to hormonal changes, laser is less effective).

• People who are using photosensitizing drugs (isotretinoin, tetracycline…).

• People with skin diseases such as eczema, psoriasis, atopic dermatitis in the treatment area.

• People with keloid scars – need to be carefully evaluated before laser treatment.

VII. CONCLUSION

Laser hair removal is a long-term, highly aesthetic and safe solution if performed with the right technique and technology suitable for the skin type. Not only does it help remove unwanted hair, this technology also helps brighten the skin, reduce folliculitis, tighten pores and significantly improve self-confidence. However, the person performing it needs to understand their body, choose a reputable facility and persistently follow the correct procedure to achieve optimal results and minimize risks.