Published 20 October 2026 · Reviewed by Dr Sin Yong
How many laser hair removal sessions a person needs cannot be stated before the skin and hair have been examined, because it is decided by the hair cycle in that area, the size and density of the area, the contrast between hair and skin, hormone status, previous treatment and the wavelength the skin allows. Dr Sin Yong plans one review at a time rather than selling a count.
Short answerThere is no fixed number. Each visit reaches only the follicles that happen to be in their growth phase, so the course is staged, the spacing follows the cycle of the area, and the next step is decided at review from how the hair came back. A count quoted before assessment describes a package, not a plan.
Why is there no fixed number of laser hair removal sessions?
There is no fixed number because a laser can only damage a follicle that is in its growth phase, and at any moment only some of the follicles in an area are. Every hair follicle cycles: a growth phase in which the hair is anchored to the structures that make it, a short regression, and a resting phase in which the old hair sits loosely in the follicle until it sheds and a new one begins. During the growth phase the pigmented bulb sits deep in the follicle next to the cells that need to be heated. During the resting phase it does not. A pulse delivered to a resting follicle heats a hair shaft to no purpose.
Illustrative image — not a patient.
A single visit therefore treats whichever cohort of follicles happened to be growing that day. The rest are reached on later visits, as they enter growth in their own time. How many visits that takes depends on how large each cohort is, how long the others take to arrive, and how the skin tolerates the settings needed to damage them, and those three things differ by area, by person and by what has been done to the hair before. A count given before the skin has been examined describes a package, not a plan, which is why nothing is sold in advance here; the page on how fees are quoted explains the principle.
Regulators describe what lasers achieve as a long-term, stable reduction in the number of hairs that regrow after a course of treatment, which is a reduction rather than an absence. Hair that does return is usually finer and lighter, and that changes the settings later visits need. The mechanism common to every area is on the laser hair removal page; what follows is what decides the length of a course.
How long does laser hair removal last?
Laser hair removal reduces regrowth; it does not remove every hair for good. Regulators describe what lasers achieve as a long-term, stable reduction in the number of hairs that regrow after a course of treatment, which is a reduction rather than an absence. Follicles heated sufficiently during their growth phase lose much of their capacity to produce a hair. Follicles that were resting at the time, or that received too little energy, may go on producing one.
Illustrative image — not a patient.
Hair that does return may be finer and lighter, which is part of why later treatments in a course behave differently from early ones. Hormones matter too: androgen-driven areas such as the chin and jawline in some women, and changes around pregnancy or with polycystic ovary syndrome, can bring new growth over time. That is not a failure of earlier treatment, and it is why occasional maintenance is discussed honestly at assessment rather than ruled out.
Whether a particular area is likely to respond well depends on hair colour, hair thickness and skin type, and that is said plainly at consultation rather than discovered afterwards.
How does the hair cycle in each area change the plan?
The proportion of follicles in growth at any moment, and the length of the resting phase, differ from one part of the body to another. That is why the underarm, the bikini area, the legs and the face are each planned on their own clock, and why areas treated on the same day are not necessarily on the same schedule later. Dierickx's review of hair removal lasers set out the cycle lengths that clinicians still work from, and the practical consequences are these:
Area
Cycle character
What it means for spacing
Upper lip and chin
Short cycle; a relatively large share of follicles in growth at once
Visits can follow each other more closely; hormonal drive on the chin recruits new follicles over time
Underarm
Short to moderate cycle; dense coarse hair
Early visits catch a large cohort; later ones are set for the finer hair that remains
Bikini and brazilian
Moderate cycle; coarse, curved hair on darker skin
Spacing set by regrowth, with settings held conservative for the skin
Legs
Long resting phase; a small share of follicles in growth at any moment
Visits spaced further apart; treating too soon reaches the same cohort twice
Beard, chest and back in men
Moderate cycle; the densest terminal hair on the body, androgen-driven throughout life
Staged zone by zone; maintenance discussed honestly
Arms
Long resting phase; often finer hair
Spaced like the legs; 755 nm on lighter skin for the finer hair
What Dr Sin Yong looks for at review is the pattern of regrowth: hair shed soon after a visit is the treated hair leaving the follicle; hair that returns finer and sparser is the expected response; a patch that returns as coarse as before was resting last time. The next visit is timed to when a fresh cohort has entered growth, judged from what the skin shows rather than from a calendar, and the plan for each area is revised at each visit.
“I cannot count the follicles that are asleep today. I can only treat the ones that are awake, and come back for the rest when they are.”
Dr Sin YongOn the number of laser hair removal sessions
How do the area, hair density and colour contrast decide it?
Three features of the area itself set the pace. The first is density and coarseness. Dense, coarse, dark hair carries a great deal of melanin, so it absorbs energy well and responds readily; but it also sheds in stages, and later visits are set for the finer hair that remains rather than repeating the first visit's settings. Fine, light or vellus hair carries little melanin, responds unpredictably, and is not promised a response at any number of visits. White and grey hair carries none and does not respond at all.
The second is the contrast between hair and skin. Dark hair on light skin is the condition under which a laser works most efficiently: most of the energy goes to the hair and little to the surface. As skin pigment rises, the epidermis takes a larger share, and the settings have to come down to protect it. Lower settings mean less heat reaching each follicle and a smaller share of the cohort damaged at each visit. Darker skin is therefore treated more conservatively and reviewed more closely, and a tan between visits has the same effect, which is why sun protection throughout a course is not an afterthought. The published reviews of darker skin treatment describe this trade-off directly.
The third is what has been done to the hair before. Previous IPL, diode or laser treatment elsewhere changes what hair is left and how it responds, usually leaving finer and lighter hair that needs the 755 nm wavelength on lighter skin. Years of waxing or plucking can distort follicles. Bringing records of earlier treatment lets the first visit here start from the right settings rather than the default ones.
Finer or lighter hair, and patients who started treatment elsewhere
Many of the patients who ask about hair removal here grew up in a different climate and a different clinic system — Japanese, Australian and European patients in particular. Two things tend to be true of them. Their hair is often finer and lighter than the coarse dark hair that most Singapore protocols are set for. And they have often had IPL or diode treatment abroad that stopped short of the result they wanted.
Finer, lighter hair on lighter skin is where the 755 nm alexandrite wavelength earns its place: its strong absorption by melanin is what makes it effective on hair that carries less of it. Darker or recently tanned skin moves the decision toward 1064 nm Nd:YAG. Neither is a default; the choice is made area by area at assessment, and previous treatment elsewhere is taken into account when settings are chosen.
Every session is doctor-supervised. Settings are determined by Dr Sin Yong after examining the skin and the hair in each area rather than taken from a fixed protocol, and the consultation is conducted in English or Chinese with time for questions.
Why hormone status can change the answer over time
Laser reduces the follicles it reaches; it does nothing to the signal that tells follicles to grow. In areas where hair is androgen-driven, the chin, jawline and upper lip in some women, the beard, chest and back in men, and the lower abdomen and inner thigh in both, follicles that were producing fine vellus hair can be recruited into producing coarse terminal hair long after a course has finished. That new growth is not a failure of the earlier treatment, and it is the reason occasional maintenance is discussed honestly at assessment rather than ruled out.
Some situations change the answer enough that they are addressed before any plan is made:
New or rapidly increasing facial or body hair in a woman: assessed for a cause such as polycystic ovary syndrome, with blood tests and a referral where needed, and laser planned alongside that rather than instead of it; the Endocrine Society's hirsutism guideline sets out the same sequence
Pregnancy, breastfeeding and the period afterwards: hair growth often changes, so treatment is deferred and the picture reassessed later
Perimenopause and menopause: the balance of hormones shifts, and some women notice chin hair for the first time; the plan is set for the hair that is present, with the drive acknowledged
Testosterone, anabolic steroids, some contraceptives and finasteride: each alters hair growth in one direction or the other, and is mentioned at consultation
Thyroid and adrenal conditions: uncommon causes of changed hair growth that need their own assessment
In a hormone-driven area the honest framing is that the course addresses the follicles that are there now, and that whether new ones are recruited later depends on the drive, not on the laser. The face and beard pages cover the two areas where this matters most.
Does the wavelength affect how many visits?
Yes, because the wavelength sets how much energy reaches the follicle at settings the skin can tolerate. The platform used here carries both a long-pulsed 755 nm alexandrite and a 1064 nm Nd:YAG, chosen area by area. The 755 nm wavelength is absorbed strongly by melanin, which heats fine and medium hair efficiently on lighter skin; it reaches a larger share of each cohort per visit, but only where the skin can take it. The 1064 nm wavelength is absorbed less by surface melanin and penetrates deeper, which is what makes it the wavelength for Fitzpatrick IV to VI and tanned skin; it is a weaker match for fine hair, so on darker skin fine hair may respond slowly or not at all, and that is said at consultation.
Epidermal cooling, spot size and pulse duration are set with the wavelength, and all of them move the balance between protecting the skin and heating the follicle. A single-wavelength device forces a compromise at one end of the skin-type range: on darker skin a diode or alexandrite can only be turned down, which costs follicular heating at every visit. Changing the wavelength instead keeps the heating where it is needed. The comparison is set out in diode vs alexandrite vs Nd:YAG.
The practical consequence is that two people with the same hair on different skin are on different courses, and that the right question at consultation is not how many visits but which wavelength and settings the skin allows, since that is what the pace follows.
What happens at the review, and what you can do between visits
Each visit begins with a look at the treated area: how much hair has returned, how coarse it is, where the gaps are, and how the skin responded to the last settings. From that, Dr Sin Yong decides whether the area is ready for another pass, whether the settings or the wavelength should change, whether one region of a large area is ahead of another, and whether to pause. Areas treated together are reviewed separately, because the underarm is often well ahead of the legs on the same person.
What shortens a course, within what the biology allows
Shaving, never waxing, plucking or epilating, between visits, so that each visit finds the hair shaft in the follicle
No tanning, sunbeds or self-tan, and daily sunscreen on exposed areas, so that the settings do not have to come down for the skin
Coming to review when the regrowth is visible rather than after shaving it off the morning before, since the pattern is the information
Declaring new medicines, pregnancy plans and any change in hair growth, which change the plan
Bringing records of treatment elsewhere
What lengthens it
Inflamed folliculitis, shaving rash or broken skin at a visit, which is settled first
A tan at a visit, which defers the tanned region or moves it to 1064 nm at lower settings
Fine, light or grey hair, which responds poorly at any number of visits
An untreated hormonal drive recruiting new follicles
Aftercare between visits is on the laser hair removal aftercare page. Questions between visits come back through WhatsApp during clinic hours and are answered in English and Chinese.
Your next step
1. MessageWhatsApp +65 8023 7170 with what is bothering you. A reply comes from the clinic, not a bot.
2. AssessmentDr Sin Yong examines you himself on Orchard Road, with ultrasound where earlier filler is involved.
3. A plan in writingWhat he would do, what he would not, the fee factors, and the option of no treatment.
Every treatment is performed by Dr Sin Yong personally. Singapore Medical Council registered · invited to share his clinical expertise internationally for CLASSYS, DEKA, Fotona, Hironic and Ilooda.
Book an assessment with Dr Sin Yong on Orchard Road; come with the regrowth visible rather than freshly shaved, so the pattern can be read. How consultations work.
Because a laser only damages follicles in their growth phase, and at any moment only some of the follicles in an area are. Each visit treats that day's cohort; the rest are reached as they enter growth in their own time. How many visits that takes depends on the area's cycle, hair density, the contrast between hair and skin, hormones, previous treatment and the wavelength the skin allows. A count given before examination describes a package, not a plan.
Because each area has its own hair cycle. The face and underarm have shorter cycles with a larger share of follicles in growth at once, so visits can follow more closely. The legs and arms have a long resting phase, so a fresh cohort arrives slowly and treating too soon reaches the same follicles twice. The next visit is timed to the regrowth seen at review, and areas treated together are reviewed separately.
Often the course runs differently, because darker skin takes a larger share of the energy at any wavelength, so settings are kept more conservative and each visit damages a smaller share of the cohort. The 1064 nm Nd:YAG keeps more of the heating at the follicle on Fitzpatrick IV to VI, which is why it is chosen there. Fine hair on darker skin may respond slowly or not at all, and that is said at consultation.
Laser reduces the follicles it reaches but does nothing to the hormonal signal that recruits new ones. In androgen-driven areas such as the chin in women and the beard in men, follicles that were making fine hair can later switch to coarse hair, long after a course. That is not a failure of the earlier treatment, and it is why maintenance is discussed honestly. New or rapid growth in a woman is assessed for a cause first.
No. Shaving cuts the hair at the surface and does nothing to the follicle; the blunt cut end can feel coarser, but the hair is the same. Shaving is used between visits precisely because it leaves the hair shaft and its pigment in the follicle for the next session to heat. Waxing, plucking and epilating remove that target and are avoided during a course, and they also restart the ingrown-hair cycle in the bikini area and beard.
References
Hair removal by lasers and intense pulsed light sources. Dermatologic Clinics 20(1), 2002. source
Evidence-based review of hair removal using lasers and light sources. Journal of the European Academy of Dermatology and Venereology 20(1), 2006. source
Laser hair removal: a review. Dermatologic Surgery 39(6), 2013. source
Evaluation and Treatment of Hirsutism in Premenopausal Women: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism 103(4), 2018. source
About this page: written and medically reviewed by Dr Sin Yong, MBBS (NUS), MRCS (Edinburgh) · Last reviewed 6 November 2026 · Illustrative images only, not patients · Editorial policy
