Laser hair removal and hair regrowth: reassuring explanations

Laser hair removal offers a lasting reduction in hair growth, but it doesn't provide instant results. After the session, it's normal for some hairs to remain visible on the skin . In fact, the laser has burned the hair follicles (bulbs) during the active growth phase (anagen), but these hairs fall out gradually , not immediately. It generally takes about 2 to 3 weeks to see the treated hairs fall out.

During this period, the skin "rejects" the inactive hairs: you may see diffuse regrowth that becomes finer before falling out. Specialists confirm that most treated hairs fall out within 10 to 21 days following the session. This phase of gradual shedding is normal and does not mean that the treatment has failed. On the contrary, it is a sign that the laser has reached its target deep within the skin.

Hair growth cycle and the need for multiple sessions

Each hair follows its own life cycle (anagen, catagen, telogen), and only those in the anagen phase are affected by the laser . In the same area, hairs do not grow simultaneously: typically, only 20–70% of hairs are in the growth (anagen) phase at any given time. The other hairs (resting or transition phase) are not eliminated during the session and will grow back later.

• Anagen phase (growth) : the hair is pigmented and well anchored, this is when the laser effectively destroys the root.

• Catagen phase (transition) : the hair has finished growing, the laser is less effective.

• Telogen phase (resting) : the dead hair remains in place and then falls out naturally, the follicle awaits the next cycle.

To remove all the hair from an area, several sessions are therefore necessary. Professionals generally schedule 4 to 10 weeks between each session to allow the hair to enter the anagen phase.

A complete treatment cycle requires approximately 4 to 7 initial sessions . In Switzerland, most centers (Geneva, Lausanne) recommend a total of 6 to 12 sessions. Each successive session reduces the density of the remaining hairs and weakens their regrowth.

Post-session fall: procedure and precautions

After the session, the treated area may remain slightly red or sensitive for a few hours. It is advisable to moisturize the skin and avoid sun exposure (without protection) for a few weeks. The treated hairs will then fall out naturally : small scabs (falling hairs) are often observed and can be gently removed. The first results are visible after 10–21 days .

Tip: If you're bothered by any remaining hairs, you can shave them (since the root is already weakened) rather than plucking them. This won't affect the already destroyed hair follicle. However, avoid waxing or plucking between sessions, as this will remove the hairs that the laser will target during the next treatment.

Expected results and number of sessions

After each session , you'll notice fewer hairs growing back , and they'll be finer and lighter . The laser gradually reduces the thickness and color of the hair. Ultimately, it's estimated that an average of 80% of the hair in a given area can be eliminated. This is referred to as long-term or sustainable hair removal rather than "permanent."

Indeed, it is common for a small percentage of hairs to reappear (especially in hormone-dependent areas like the face), particularly due to hormonal fluctuations. These remaining hairs are generally finer and less visible.

In practice, a typical protocol yields approximately 70–90% hair reduction after 6 to 8 sessions. These figures may vary depending on the area treated and the individual hair growth cycle, but they provide a general idea of ​​what to expect. Additional maintenance sessions may be necessary, particularly on the face or in men, to maintain the results.

At the end of the complete treatment, regrowth is slowed so much that the majority of patients enjoy smooth skin for several years.

Skin and hair types

The laser's ability to remove hair depends heavily on the skin/hair contrast. Optimal effectiveness is seen on fair skin with thick, dark, and pigmented hair.

The more melanin a hair contains, the more effectively the laser can heat the hair follicle. Conversely, very light or fine hairs are more difficult to treat . White hairs are impossible to remove with a laser (due to the absence of melanin); red or blond hairs have very little pigment and respond less well, although modern lasers (Alexandrite, diode, Nd:YAG) can gently target dark or tanned skin.

• Skin phototype : Darker skin absorbs more surface light, which increases the risk of burns if the wavelength is not adjusted. Professional devices such as diode or Nd:YAG lasers are designed to penetrate deeper without causing surface burns.

• Hair type : The treatment is most effective on pigmented hair (brown or black). Blonde, fine, or gray hair sometimes requires more sessions and gives less dramatic results.

For all these reasons, the quality of the device and its settings are crucial. Experienced practitioners use state-of-the-art lasers (often combining several wavelengths) and adjust the power to the patient's skin type. A high-quality device, suited to the hair and skin type, and above all, properly calibrated, is essential.

In Switzerland, reputable clinics (such as SSSKIN, a leader in Lausanne and Geneva) invest in multi-wavelength lasers (755, 808, 1064 nm) suitable for all skin tones. This ensures a customized treatment and minimizes risks (burns, hyperpigmentation, paradoxical regrowth). For example, SSSKIN offers lifetime hair removal packages (unlimited sessions) and publishes its current promotions on its "Our Current Offers" page.

In summary, hair that remains or regrows after several sessions is due to: untreated follicles (inappropriate phase during the session), hormonal factors (pregnancy, menopause, hyperandrogenism), or, more rarely, paradoxical regrowth . In all cases, visible regrowth can generally be corrected with additional maintenance sessions.

Looking for a tailor-made plan in Geneva or Lausanne?

Our specialists will guide you on the best strategy (areas, frequency, technology). Discover our current promotions and book your first session on SSSKIN.ch or via our Current Offers page.

FAQ - Your Frequently Asked Questions

Is it normal for some hairs not to fall out after a session?

Yes, that's perfectly normal. The laser targets the hair follicles, but the hairs remain in place for a few days before falling out. It takes 10 to 21 days for the hair loss to be clearly visible. Hairs that don't fall out immediately were at a different stage of growth; they will be targeted during subsequent sessions.

How long does it take to see the full results?

Laser hair removal should be considered a long-term process. In practice, it often takes several months . A complete treatment generally involves 6 to 12 sessions spread over approximately one year. A noticeable reduction is already visible after 2–3 sessions, and the final result is assessed at the end of the treatment.

Are all hair types sensitive to laser hair removal?

No. The laser targets melanin : dark hair responds best. White hair cannot be treated, and blond/red hair responds less well. However, modern lasers can treat all skin phototypes by adjusting the parameters.

Can the hair grow back after several sessions?

Yes, some regrowth is possible. Even with a complete treatment, not all hairs will be 100% removed . The hairs that reappear are generally finer and less visible. Occasional maintenance sessions will help maintain a smooth result.

How can you tell if a session was effective?

Observe the area 10 to 21 days after the session: most of the treated hairs should have fallen out or become finer . If the density is significantly reduced and regrowth is slower, the session was successful. Your practitioner will also assess the progress between appointments to adjust the parameters if necessary.