Key takeaways
- Laser hair removal starts working after the first session, with about 10% to 25% less hair, and results build over 2 to 6 sessions.
- Shedding: Treated facial hairs usually work their way out within the first week.
- Regrowth: Hairs that were resting on treatment day surface later, which is why sessions are spaced 4 to 6 weeks apart.
- In a ruby laser study, the remaining coarse hair dropped to 65.5% after one session and 34% after three.
You'll usually notice a difference after the first session, but it's a small one. Expect roughly 10% to 25% less hair after one treatment, and most people need 2 to 6 sessions to clear an area. The hairs that work their way out in the first days aren't new growth, and the hair that comes back weeks later mostly came from follicles that were resting on treatment day. So if it feels like laser hair removal didn't work after one visit, it's usually too early to judge.
How Soon Do Treated Hairs Fall Out?
How Soon Do Treated Hairs Fall Out?
Treated hairs don't drop out the moment the laser touches them. They loosen and get pushed out of the skin over several days. On the face, damaged hair shafts usually shed within the first week*.
Based on a 2022 review of facial laser hair reduction.
During that window, the tips can poke above the skin and look like stubble. That's easy to mistake for fast regrowth. In fact, it's the heated hair working its way out, not a new hair growing in. Once it's gone, the skin tends to look smooth for a while, and that's a good moment to take stock of what one session did.
Redness and swelling right after treatment are common and typically last 1 to 3 days. If you notice blisters or oozing, contact the clinic that treated you right away, whatever your results look like.
How Soon Do Treated Hairs Fall Out?
Why Is Hair Growing Back Between Sessions?
Why Is Hair Growing Back Between Sessions?
Regrowth between sessions doesn't mean the treatment failed. Every hair cycles through a growing phase (anagen), a short transition, and a resting phase. The laser works best on hairs in the growing phase, because that's when the root holds the most pigment for the light to target.
Anagen: The active growth phase, when the hair root sits deep in the skin and carries the most pigment (melanin).
Hairs that happened to be resting on treatment day take less of a hit. A few weeks later, they enter a new growth phase and show up on the surface. The share of growing hairs differs by body area. On the face, about 56% to 76% of hairs are in the growing phase at any given time. That's why one session can't reach every follicle, and why treatments are typically spaced every 4 to 6 weeks*.
Based on American Academy of Dermatology guidance on laser hair removal.
Keep in mind that regrowth tends to change as sessions add up. Hair that comes back is often finer and lighter in color than before. So don't just count hairs. Look at how thick and dark they are, too.
How Many Sessions Until You See a Difference?
How Many Sessions Until You See a Difference?
After one session, most people see a modest thinning rather than bare skin. The bigger change shows up as sessions stack. In one older study, 25 people had 48 face and body areas treated with a long-pulsed ruby laser, and the team counted coarse hairs 4 weeks after each session. Compared with the starting count, the hair that grew back was 65.5% after the first session, 41% after the second, and 34% after the third.
How Many Sessions Until You See a Difference?
That study had no control group, and ruby lasers are rarely used for hair removal today. Treat the numbers as a picture of the trend, not a promise. Individual results vary. Here's what to look for at each stage.
| When | What you may notice | Context |
|---|---|---|
| First week after a session | Treated hairs push out and shed | Facial hair |
| After session 1 | About 10% to 25% less hair | Depends on hair color, thickness, and area |
| After sessions 2 to 3 | 41% to 34% of coarse hair left | Ruby laser study, 25 people |
| 12 months after 4 sessions | 84% to 85% less hair | Underarms, 15 people, 4 to 6 weeks apart |
| After the full series | Little visible hair for months or years | Touch-up sessions may be needed |
The underarm numbers come from a small study where 15 people had one armpit treated with an alexandrite laser and the other with a diode laser, four times each. Twelve months after the last session, hair was down 85% and 84%. That's an encouraging result for armpit laser hair removal, but 15 people is a small group.
Why Might Laser Hair Removal Seem Not to Work for You?
Why Might Laser Hair Removal Seem Not to Work for You?
Results depend on your hair color and thickness, the area treated, your skin tone, and the type of laser. Laser hair removal works best on light skin with dark hair, because the light has a clear target. Very fine, light hair like peach fuzz carries little pigment, so it responds less.
Hormones matter too. Conditions such as polycystic ovary syndrome (PCOS) and thyroid problems can drive regrowth, and people with PCOS typically need more sessions than average.
PCOS: A common hormonal condition that can increase hair growth on the face and body.
Very thick hair is another case. For men with coarse hair, the doctor first asks about any past hair removal and checks how thick the hair is. The 755 nm and 1064 nm wavelengths of the GentleMax Pro Plus reach different depths, so they suit different kinds of hair. If earlier hair removal didn't clear the hair well, or the hair is very thick, it's likely to sit deeper too, so the 1064 nm wavelength is mixed in. Mixing wavelengths doesn't lock in a result, so progress is still checked at every session.
What Can Slow Down Your Results?
What Can Slow Down Your Results?
A few everyday habits can get in the way. Plucking, waxing, and hair removal creams pull or dissolve the hair the laser needs to find. Stop them at least 3 weeks before your first session.
A tan is the other big one. When the surrounding skin carries extra pigment, it absorbs laser energy along with the hair, which raises the risk of burns. If the energy is turned down to stay safe, the treatment works less well. If you're tanned or sunburned, wait until it fades before your session.
- Pause plucking, waxing, and hair removal creams at least 3 weeks before starting
- Avoid tanning and sunburn before each session
- Keep sessions at least 4 to 6 weeks apart rather than squeezing them closer
- Tell your provider about PCOS, thyroid issues, or other hormone conditions
Planning Around a Seoul Trip
Unless you've had IV sedation that day, there's no reason to delay a flight because of laser hair removal.
One visit isn't a finished result. Laser hair removal is done as a series, usually 4 to 6 weeks apart, and hair thins out gradually from session to session. How much you see depends on your hair and skin, so it helps to plan return visits if you're in Seoul more than once.
After you get home, you can message the clinic with photos if questions come up. If you notice blisters, spreading redness, or pain that keeps getting worse, see a local doctor first rather than waiting for a reply.
What Should You Check Before Your Next Session?
A better time to judge laser hair removal than the shedding week is right before your next session, when you can see what came back. Look at how many hairs returned and whether they're finer or lighter than before.
Before you decide on next steps, ask which wavelength suits your hair thickness and how many weeks apart your sessions should be. That one answer makes the plan easier to follow. STON Clinic is in Seoul's Myeongdong area, inside Lotte Hotel Seoul near Euljiro 1-ga Station. When you reach out, include the treated area, how many sessions you've had, and the date of your last one.
If this raised a question about your own skin
Ask a questionReferences
- First-session results, number of sessions, spacing, and regrowth after laser hair removal — American Academy of Dermatology — American Academy of Dermatology
- When treated facial hair sheds and why results can be slow — J Clin Aesthet Dermatol, 2022 — PubMed Central
- Hair regrowth after each ruby laser session in 25 people — Dermatol Surg, 1998 — PubMed Central
- Underarm results 12 months after four sessions in 15 people — Dermatol Surg, 2001 — PubMed Central
Frequently asked questions
Q. Does laser hair removal work after just one session?
A. Yes, but only partly. One session typically reduces hair by about 10% to 25%, because hairs that were resting that day aren't affected yet. A review of facial laser hair reduction estimated roughly 20% less hair with each session done during the growth phase. Most people need 2 to 6 sessions.
Q. Is laser hair removal permanent once I finish?
A. Not fully. After finishing a series, most people see little hair for months or even years, but some regrowth is common. Hair that comes back tends to be sparser, finer, and lighter. For the face, touch-up sessions about 2 to 4 times a year may be needed to keep results.
Q. Will spacing sessions closer than 4 weeks speed up results?
A. There's little evidence that it does. Sessions are usually 4 to 6 weeks apart, and facial treatments should be at least 4 to 6 weeks apart. Hairs that were resting need time to reenter the growth phase before the next session can reach them.
Q. Does PCOS mean I'll need more laser hair removal sessions?
A. Often, yes. A review of facial laser hair reduction suggested people with PCOS may need around 10 to 15 sessions. Thyroid problems and other hormonal conditions can also affect regrowth, so mention any diagnosis before you start.
Q. Can I shave between laser hair removal sessions?
A. Plucking, waxing, and hair removal creams should stop at least 3 weeks before you start, because they remove the hair root the laser targets. Ask your provider how to handle shaving between sessions so it fits your treatment plan.
Q. Should I postpone laser hair removal if I'm tanned?
A. Yes. If you're tanned or sunburned, wait until it fades. Tanned skin absorbs more laser energy, which raises the risk of burns. Lowering the energy to compensate makes the treatment less effective, so waiting usually helps your results too.
Q. How many sessions does armpit laser hair removal take?
A. In one small study, 15 people had four underarm sessions spaced 4 to 6 weeks apart. Twelve months after the last session, hair was reduced by 84% to 85%. Because the study was small, the right number for you depends on your hair thickness and how much remains.
Jangju Kim Senior Director
JANGJU KIM
Dr. Jangju Kim is a clinic director at STON Clinic, LOTTE HOTEL in Myeongdong.
Career / Education
- 현) 스톤클리닉 명동 롯데호텔 원장
- 경희대학교 의과대학 졸업
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