Laser Hair Removal: Complete Guide for Patients

Everything You Need to Know About Laser Hair Removal

Laser hair removal is a procedure that uses concentrated light energy to selectively damage hair follicles and achieve permanent hair reduction. It is not a single-session treatment: multiple sessions are needed because the laser is only effective on follicles in the active growth phase, and not all hairs are in that phase at the same time. The final result—after completing the protocol—is an 80-90% reduction in hair in the treated area.

This guide covers the complete patient journey: from initial evaluation to long-term results. If you are looking for technical information about the different types of lasers, consult our article on types of laser for hair removal. For specific information about the bikini area, check our guide to laser hair removal in intimate areas.

In Summary

• Laser hair removal produces permanent hair reduction (80-90%), not 100% total elimination.
• 6-8 sessions are needed on average because the laser only acts on hairs in the anagen phase (active growth), which represent only 20-30% of the total at any given time.
• Diode lasers are safe for Fitzpatrick skin types III-VI (brown to dark skin) when used with appropriate parameters.
• Preparation is key: shave (don't wax or pluck), avoid sun and discontinue retinoids before each session.
• Visible results begin from the second or third session; final results are consolidated 2-3 months after completing the protocol.

Advantages and Considerations

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What is Laser Hair Removal and How Does It Work

Laser hair removal works through selective phototermolysis: the laser emits a specific wavelength that is absorbed by melanin (pigment) present in the hair shaft. This light converts to heat, which travels through the shaft to the hair bulb and damages the stem cells responsible for hair growth. The damaged follicle loses the ability to generate new hair or produces one that is significantly thinner and lighter.

For a detailed explanation of the different laser systems available (diode, alexandrite, Nd:YAG, IPL), consult our article on types of laser for hair removal.

The key principle is contrast: the laser needs to distinguish between the melanin of the hair and the melanin of the surrounding skin. This is why dark hair on light skin has historically been the ideal scenario. However, modern diode lasers (800-810 nm) with cooling systems and long pulses allow safe and effective treatment of brown and dark skin (Fitzpatrick types III-VI), adjusting fluence and pulse duration to protect the epidermis.

Who Is a Candidate for Laser Hair Removal

Skin Type (Fitzpatrick Scale)

The Fitzpatrick scale classifies skin into six types based on its response to sun:

• Fitzpatrick Types I-II: Very light to light skin, burns easily. Excellent contrast with dark hair. Compatible with most lasers.
• Fitzpatrick Types III-IV: Light brown to brown skin. Compatible with diode laser and Nd:YAG with adjusted parameters.
• Fitzpatrick Types V-VI: Dark brown to dark skin. Diode laser with long pulses and low fluence, or Nd:YAG (1064 nm), are safe options. IPL and alexandrite are contraindicated.

The diode laser is particularly versatile because its wavelength (800-810 nm) penetrates deeper than alexandrite, is less absorbed by epidermal melanin and—with integrated cooling technology—offers a favorable safety profile for Fitzpatrick types III-VI, which represent most skin in Latin America, the Mediterranean and Asia.

Hair Color

The laser needs melanin to work. Dark hair (black or dark brown) responds best to treatment. Light brown hair may respond partially with more sessions. Blonde, red, white or gray hair lacks sufficient melanin to effectively absorb laser energy and is currently not a good candidate for conventional laser hair removal.

Hormonal Conditions

Conditions such as polycystic ovary syndrome (PCOS), hyperandrogenism, thyroid disorders or certain medications (birth control, corticosteroids) can stimulate new hair growth in treated areas. This does not mean the laser does not work, but rather that previously inactive follicles can be activated by hormonal stimulation and may require maintenance sessions. In these cases, controlling the underlying hormonal factor optimizes laser hair removal results.

Minimum Recommended Age

Laser hair removal is generally not recommended before hormonal development has stabilized. In women, this typically means after menarche (first menstruation), usually from age 15-16 onwards. In men, around age 16-18, when androgen levels have stabilized. Starting before follicular maturity means that new follicles can activate during puberty, requiring more sessions than expected.

Laser Hair Removal in Men

Laser hair removal in men is becoming increasingly common. The most requested areas are back, chest, abdomen, shoulders and linea alba. Male hair tends to be thicker and darker, which favors laser absorption per follicle. However, coverage density is greater, meaning sessions can be longer. The total number of sessions is similar to the general protocol (6-8), although the beard and neck may require 8-10 sessions due to their hormonal nature. The goal in many male patients is not total elimination but density reduction to achieve a more uniform and manageable appearance.

Other Candidacy Factors

• Pregnancy: Laser hair removal is not performed during pregnancy as a precautionary principle, although there is no evidence of fetal harm.
• Photosensitizing medications: Certain antibiotics (doxycycline, tetracycline), oral retinoids (isotretinoin) and anticonvulsants increase skin sensitivity and should be discontinued prior to treatment.
• Tattoos: Laser cannot be applied over tattooed skin, as the ink absorbs energy and can cause burns.
• Recent tanning: It is recommended to avoid intense sun exposure 2-4 weeks before each session.

The Hair Growth Cycle

Understanding the hair growth cycle explains why multiple sessions of laser hair removal are needed.

Anagen Phase (Active Growth)

The follicle is fully active: hair grows, is connected to the bulb and contains the highest concentration of melanin. This is the only phase in which the laser is effective, because the melanin in the shaft allows heat to be conducted to the stem cells in the bulb and destroy them. At any given time, only 20-30% of follicles in an area are in the anagen phase.

Catagen Phase (Transition)

Hair stops growing, the follicle contracts and separates from the dermal papilla that nourishes it. This phase lasts only 2-3 weeks. The laser is ineffective because hair is no longer connected to the bulb.

Telogen Phase (Rest)

The follicle remains inactive and old hair eventually sheds. This phase can last from weeks to months, depending on the body area. The follicle is not visible or accessible to the laser. Eventually, new hair begins to grow (returns to anagen).

Why Multiple Sessions Are Needed

In each session, the laser can only destroy follicles in the anagen phase (20-30% of the total). Follicles in catagen and telogen phases are not affected. By spacing out sessions, it allows follicles that were resting to enter the growth phase and be treated in the next session. Typically 6-8 sessions are needed for most follicles to have passed through at least one anagen phase during the treatment period.

The duration of each phase varies by body area, which determines the optimal interval between sessions.

What to Expect: Before, During and After

Before the Session

Shave the area 12-24 hours before. Shaving leaves the hair shaft just below the skin surface, allowing laser energy to transmit efficiently to the bulb without wasting energy burning visible hair on the skin.

What you should NOT do before:

• Do not wax, pluck or use threading. These methods extract hair from the root, removing the melanin the laser needs as a target. If hair was pulled out, wait 4-6 weeks before the session.
• Do not expose yourself to the sun or tan for 2-4 weeks before. Tanned skin increases the risk of burns because the laser cannot distinguish well between hair melanin and darkened epidermis melanin.
• Do not apply topical retinoids (retinol, tretinoin) for 5-7 days before, as they sensitize the skin.
• Do not use self-tanning creams at least 2 weeks before.
• Do not take anticoagulants or anti-inflammatories (aspirin, ibuprofen, naproxen) 3-5 days before, as they can affect healing and increase the risk of bruising. Consult your treating physician if you take chronic anticoagulant medication.
• Do not apply deodorant, creams or makeup to the area on the day of the session.

During the Session

The professional cleans the area, adjusts the laser parameters according to skin type and hair thickness, and applies conductive gel or activates the equipment's cooling system. The laser handpiece slides over the skin emitting pulses of light.

Sensation: Most patients describe the sensation as a snap of a warm elastic band against the skin, repeated with each pulse. Intensity varies by area: areas with thin skin and higher nerve density (upper lip, bikini, armpits) tend to be more sensitive than large areas with thicker skin (legs, back). Integrated cooling systems (sapphire tip, cold air, cryogenic) significantly reduce discomfort.

Duration: Varies depending on the size of the area, from 5-10 minutes for the upper lip or armpits to 30-45 minutes for full legs or back.

After the Session

First hours: It is normal for the treated area to show mild redness, perifollicular edema (small bumps around each follicle) and heat sensation similar to mild sunburn. These effects resolve in 1-4 hours in most cases.

First days:

• Apply soothing cream (aloe vera or fragrance-free moisturizing cream) if there is discomfort.
• Avoid direct sun and use SPF 30+ sun protection on the treated area.
• Do not do intense exercise, sauna or swimming for 24-48 hours (heat and sweating can irritate follicles).
• Do not scratch or rub the area.

Week 1-3 (shedding): Treated hairs do not fall out immediately. During the 1-3 weeks following, damaged hairs are naturally expelled from the follicle (a process called shedding). It may seem like hair is still growing, but it is actually being pushed outward. Gentle exfoliation starting from day 5-7 can facilitate removal of these hairs.

Between sessions: Do not wax or pluck (shave only). Maintain sun protection. Inform the professional at the next appointment about the duration of redness and when significant regrowth was observed.

Session Protocol by Body Area

The number of sessions, the interval between them and the duration of each session vary by area, due to differences in the hair growth cycle:

Hormonal vs. Non-Hormonal Areas: Hormonal areas (face, bikini, armpits, linea alba) tend to require more sessions (8-10) and periodic maintenance sessions because hormonal changes can reactivate previously inactive follicles. Non-hormonal areas (legs, arms, back) usually achieve more stable results with 6-8 sessions.

Myths Debunked

"Laser Hair Removal Is 100% Permanent"

It is a permanent reduction, not total elimination. After completing the protocol (6-8 sessions), an 80-90% reduction in hair is achieved. Destroyed follicles do not regenerate hair. However, some follicles may not have been completely destroyed, and in hormonal areas, previously dormant follicles can be activated. This is why 1-2 maintenance sessions per year may be needed, especially on the face and bikini area.

"It Is Too Painful"

The sensation of modern laser hair removal with integrated cooling systems is significantly more tolerable than waxing. Most patients describe it as a quick snap, not sustained pain. More sensitive areas (bikini, upper lip) can cause more discomfort, but cooling systems (sapphire tip, cryogenic) significantly reduce sensation. Tolerance improves with each session as the amount of hair decreases.

"It Doesn't Work on Dark Skin"

This myth stems from limitations of older lasers (alexandrite, IPL), which absorbed too much epidermal melanin on dark skin, causing burns. Modern diode lasers (800-810 nm) with long pulses and active cooling are safe and effective on Fitzpatrick types III-VI. Nd:YAG (1064 nm) is also an option for types V-VI. The key is laser selection, parameter calibration and operator experience.

"I Can't Get Laser in Summer"

With diode laser, treatment is possible year-round, as long as intense direct sun exposure and active tanning are avoided 2-4 weeks before and after each session. Tanned skin is a risk factor, but the season itself does not prevent treatment. Daily sun protection and sensible management of exposure allow you to continue the protocol without seasonal interruptions.

"Hair Grows Thicker After Laser"

This is false. The laser damages the follicle, resulting in progressively thinner, lighter and less hair with each session. What some patients perceive as "regrowth" between sessions is actually hair from follicles that were in the telogen phase during the previous session and now enter anagen for the first time. In rare cases, paradoxical hypertrichosis can occur (stimulation of fine hair at the periphery of the treated area), which is an infrequent and treatable effect with additional sessions.

"At-Home Devices Work Just As Well As Professional Equipment"

At-home IPL devices emit a fraction of the energy of professional medical equipment. They can produce some temporary hair reduction, but do not reach the fluence necessary to permanently destroy the hair bulb. Professional diode equipment is significantly more powerful, has superior cooling systems and allows precise calibration according to skin type and hair thickness. The difference in results and safety is substantial.

Results Timeline

After Session 1-2

• Treated hair shedding (shedding) between 1-3 weeks after the session.
• Visible reduction in hair density: approximately 10-25%.
• Regrowth is finer and takes longer to appear.
• Do not expect dramatic results: this phase establishes the foundation for treatment.

After Session 3-4

• Cumulative hair reduction of 40-60%.
• Regrowth is noticeably finer, lighter and slower.
• Intervals between sessions can be adjusted based on regrowth speed.
• Many patients notice significant improvement in skin quality (less folliculitis, fewer ingrown hairs).

After Session 5-6

• Hair reduction of 70-80%.
• Areas with persistent hair become visibly sparse.
• The professional evaluates whether additional sessions are needed.

After Session 7-8 (and Maintenance)

• Final hair reduction of 80-90%.
• Residual hairs are very fine, light and spaced.
• Annual maintenance is scheduled (1-2 sessions) depending on the area and hormonal factors.
• Results are consolidated 2-3 months after the last session.

Factors Influencing Results Speed:

• Thick and dark hair responds faster than fine hair.
• Skin types with greater hair-skin contrast can achieve better results in fewer sessions.
• Hormonal areas are more unpredictable and may require additional sessions.
• Adherence to the protocol (correct intervals, no waxing between sessions) is determining.

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Frequently Asked Questions

How Many Laser Hair Removal Sessions Do I Need?

Most people need between 6 and 8 sessions to achieve an 80-90% reduction in hair, although hormonal areas (face, bikini, armpits) may require 8-10 sessions. The exact number depends on hair color and thickness, skin type, body area and individual hormonal factors. Sessions are spaced 4-10 weeks apart depending on the area. After completing the protocol, 1-2 maintenance sessions per year may be needed to treat follicles that reactivate due to hormonal stimulation.

Is Laser Hair Removal Permanent?

Laser hair removal produces permanent hair reduction, not total elimination. Follicles destroyed by the laser do not regenerate hair. However, some follicles may not be completely destroyed during the treatment cycle, and in hormonal areas (face, bikini) previously dormant follicles can be activated. The standard result is an 80-90% reduction upon completing the protocol. Maintenance sessions (1-2 annually) allow treatment of any hair that reappears.

Does Laser Hair Removal Hurt?

The most common sensation is that of a quick snap of a warm elastic band against the skin with each laser pulse. Intensity varies by area: the upper lip, bikini and armpits tend to be more sensitive than legs or back. Modern equipment with integrated cooling systems (sapphire tip, cryogenic) significantly reduces discomfort. Most patients tolerate the procedure without anesthesia, although topical anesthetic cream can be applied in very sensitive areas. Tolerance improves with each session as the amount of hair decreases.

Does Laser Hair Removal Work on Brown or Dark Skin?

Yes. Modern diode lasers (800-810 nm) with long pulses and cooling systems are safe and effective for Fitzpatrick types III-VI, which include most Latin American, Mediterranean and Asian skin. The key is adjusting the equipment parameters: lower fluence, longer pulses and active cooling to protect epidermal melanin while destroying follicle melanin. Nd:YAG (1064 nm) is another option for types V-VI. Systems contraindicated on dark skin are IPL and alexandrite laser due to their greater epidermal melanin absorption.

Can I Shave Between Laser Sessions?

Yes, shaving is the only hair removal method allowed between sessions. The blade cuts hair at skin surface level without extracting the bulb, preserving the melanin inside the follicle that the laser needs as a target in the next session. You should not wax, pluck, use threading or electric epilators, as these methods pull hair from the root and eliminate the laser's target, significantly reducing the effectiveness of the next session.

What Areas of the Body Can Be Treated With Laser?

Practically any area with unwanted hair: face (upper lip, chin, sideburns), armpits, arms, back, chest, abdomen, linea alba, full legs, and bikini area (from bikini line to full coverage). The only limitations are: not on eyebrows (eye hazard), not on tattooed skin and not on mucous membranes. Each area has a different session protocol and interval depending on local hair cycle speed.

Can I Get Laser Hair Removal While Pregnant?

Laser hair removal is not recommended during pregnancy. Although there is no evidence that the laser causes fetal harm (energy does not penetrate beyond the dermis), controlled studies have not been conducted in pregnant women, so the precautionary principle prevails. Additionally, pregnancy's hormonal changes can alter hair growth and make results less predictable. The recommendation is to postpone sessions until after delivery; if in the middle of a protocol, resume when possible.

How Long Do Laser Hair Removal Results Last?

Destroyed follicles do not regenerate hair, so the reduction achieved is permanent. However, hormonal factors (PCOS, menopause, medication changes) can activate follicles that were dormant, especially in hormone-dependent areas like face, bikini and armpits. Most patients who complete a 6-8 session protocol maintain their results with 1-2 maintenance sessions per year. In non-hormonal areas (legs, back), results tend to be more stable and maintenance is minimal or unnecessary.

How Long Before Should I Stop Sun Exposure?

It is recommended to avoid intense direct sun exposure and active tanning for 2-4 weeks before each session. Tanned skin has more epidermal melanin, which increases the risk of the laser affecting the skin instead of the follicle, causing burns or hyperpigmentation. This does not mean you should stay indoors: you can live normally using SPF 30+ broad-spectrum sun protection and avoiding deliberate sun tanning or tanning beds. With diode laser, treatment is possible year-round with these precautions.

Does Laser Remove Ingrown Hairs?

Yes, reduction of ingrown hairs is one of the most valued benefits of laser hair removal. Ingrown hairs (pseudofolliculitis) occur when hair, as it is trimmed or waxed, grows curving inside the skin. By destroying the follicle, the laser eliminates the root cause of the problem. Most patients notice significant improvement in ingrown hairs from the first sessions, even before completing the protocol. This is especially relevant in the bikini area and male neck, where pseudofolliculitis is most common.

Are There Side Effects From Laser Hair Removal?

The most common side effects are mild and transient: redness, perifollicular edema (small bumps) and heat sensation, which resolve in 1-4 hours. Less frequently, mild crusting, temporary hyperpigmentation (more likely in dark skin without proper preparation) or temporary hypopigmentation may appear. Rare effects include burns (usually from inadequate parameters), scars (extremely rare with trained operators) and paradoxical hypertrichosis (stimulation of fine hair at the periphery). Most complications are prevented with proper skin type evaluation, appropriate parameter selection and patient adherence to pre- and post-session care.

How Often Do I Need Maintenance Sessions?

Maintenance sessions are scheduled according to individual need, typically 1-2 sessions per year after completing the initial protocol. Hormonal areas (face, bikini, armpits) usually require more frequent maintenance than non-hormonal areas (legs, arms, back). Some patients with stable hormonal balance do not need maintenance for years; others with conditions like PCOS may need sessions every 4-6 months. The professional evaluates the need for maintenance based on observed regrowth and the patient's hormonal factors.