The Alexandrite laser is considered the world reference in laser hair removal for fair skin. With its 755 nm wavelength, perfectly absorbed by melanin, it delivers fast, long-lasting results. But is it right for your skin? How does it compare with other technologies? CtrlZ tells you all about this must-have laser.
What is the Alexandrite laser?
The Alexandrite laser is a class IV laser used in aesthetic medicine, mainly for permanent hair removal. Its name comes from the alexandrite crystal that forms its active medium.
This laser emits a light beam at a wavelength of 755 nm, in the visible light spectrum (violet/pink beam). This wavelength has a particularly high melanin absorption coefficient, making it the most effective laser for targeting the pigment in hair.
How does it work?
The principle is that of selective photothermolysis:
- The laser beam passes through the skin without damaging it
- Light is absorbed by the melanin in the hair
- Light energy converts to heat
- This heat destroys the hair bulb and germ cells (bulge).
- The hair can no longer grow back
💡 Why 755 nm?
The 755 nm wavelength corresponds to the absorption peak of melanin. This is what makes the Alexandrite laser so effective: it precisely targets the hair pigment while preserving surrounding tissue. No other laser can match this selectivity on fair skin.
Who is the Alexandrite laser designed for?
Ideal candidates
The Alexandrite laser is particularly recommended for :
- Phototypes I to III: very fair to fair-dark skins
- Phototype IV: dark skins (with caution and adapted parameters)
- Dark hair: brown to black, containing sufficient melanin
- Fine to thick hair: thanks to its high selectivity
Contraindications
- Phototypes V and VI: dark to black skin (risk of burning and depigmentation)
- Tanned skin: tanning increases melanin in the epidermis, and the laser no longer distinguishes hair from skin.
- White, grey, red or very light blond hair: not enough melanin to absorb energy
- Pregnancy and breastfeeding: strict contraindication
- Tattooed areas: the laser targets the ink and could burn the skin
⚠️ Tanning and Alexandrite laser: incompatible
Tanned skin absorbs some of the laser energy instead of the hair. The risk of burns is therefore significant. Before resuming sessions, you need to wait until your skin is completely untanned (at least 4 weeks without exposure). At CtrlZ, tanning tests are systematically carried out.
Alexandrite laser vs Nd-YAG laser vs Diode laser vs Pulsed light laser
How does the Alexandrite laser compare with other hair removal technologies? Here’s a detailed comparison:
| Criterion | Alexandrite (755 nm) | Nd-YAG (1064 nm) | Diode (808 nm) | Intense pulsed light (IPL) |
|---|---|---|---|---|
| Adapted phototypes | I to IV | IV to VI | II to IV | I to III |
| Fair skin | ✅ Excellent | ⚠️ Less effective | ✅ Good | ✅ Correct |
| Dark skins | ❌ Contraindicated | ✅ Excellent | ⚠️ Limited | ❌ Risky |
| Tanned skin | ❌ Contraindicated | ✅ Possible | ⚠️ Caution | ❌ Contraindicated |
| Fine bristles | ✅ Very effective | ⚠️ Less efficient | ⚠️ Not very effective | ❌ Not very effective |
| Deep hair | ✅ Good | ✅ Excellent | ✅ Good | ⚠️ Limited |
| Melanin selectivity | ✅ Maximum | ⚠️ Weaker | ✅ Good | ⚠️ Diffuse |
| Sessions required | 6 à 8 | 8 à 12 | 8 à 12 | 10 à 15+ |
| Fast processing | ✅ Fast | ✅ Fast | ✅ Very fast | ⚠️ Variable |
| Pain | Mild to moderate | Moderate | Moderate | Variable |
| Risk of burns | Low if set correctly | Very low | Moderate | Higher |
Alexandrite vs Nd-YAG: complementary, not competitive
The Alexandrite laser and the Nd-YAG laser are not opposites: they complement each other. Alexandrite excels on fair skin thanks to its strong absorption by melanin. The Nd-YAG, with its 1064 nm wavelength, penetrates deeper and is absorbed differently, making it safe for darker skins.
That’s why top-performing centers like CtrlZ are equipped with both wavelengths to suit all patients.
Alexandrite vs Diode: the match of efficiency
The diode laser (808 nm) is often presented as an alternative to Alexandrite. In reality, its intermediate wavelength makes it less selective: it detects fine melanin less well and generally requires more sessions. Its main advantage is treatment speed, thanks to larger heads, but at the price of lower efficacy.
Alexandrite vs Intense Pulsed Light: laser or IPL?
Intense pulsed light (IPL) is not a laser. It’s a flash lamp that emits several wavelengths simultaneously (500-1200 nm). This diffused light is less precise and less powerful than the monochromatic beam of Alexandrite. The result: more sessions, less lasting results and a higher risk of burns on sensitive skin. To find out more, read our article CtrlZ unravels the myths.
🔬 Did you know?
The risk of paradoxical regrowth (stimulation of hair instead of its destruction) is slightly higher with the Alexandrite laser, particularly on downy areas of the face. An experienced practitioner will adapt his or her parameters to minimize this risk.
The benefits of the Alexandrite laser
- Maximum effectiveness on fair skins: this is the laser that best captures melanin
- Fast processing: modern machines allow up to 5 shots per second
- Fewer sessions: 6 to 8 sessions on average versus 10+ for IPL
- Treats fine hairs: unlike diode and Nd-YAG
- Long-lasting results: 85-95% reduction in hair growth
- Little pain: especially with modern cooling systems
- Versatile: treats all areas of the body and face
The limits of the Alexandrite laser
- Incompatible with darker skin types (phototypes V-VI): risk of burning and depigmentation
- Prohibited on tanned skin: wait until tanning is complete
- Ineffective on light coats: white, grey, red, very light blond.
- Risk of paradoxical regrowth in certain areas (face, shoulders)
- Compulsory medical supervision: not a trivial act
How does a session work?
Before the session
- Shave the area the day before or the same day (the hair must be under the skin).
- Avoid the sun for at least 4 weeks
- No wax or epilator for at least 1 month
- Clean skin: no creams, deodorants or make-up on treated areas
During the session
- Comfortable installation, protective eyewear mandatory
- The practitioner sets the laser parameters according to your phototype and the area to be treated.
- Applying the laser beam with the skin cooling system
- Sensation of “rubber band” – generally well tolerated
- Time: 10 minutes (underarms) to 45 minutes (full legs)
After the session
- Slight redness for 1 to 2 hours (like a mild sunburn)
- Application of a soothing cream
- Avoid the sun and apply SPF 50 protection
- Hair gradually falls out over the next 5 to 30 days
✓ How many sessions should you plan?
On average, 6 to 8 sessions spaced 4 to 8 weeks apart are sufficient for non-hormone-dependent areas (legs, underarms, bikini line). Hormone-dependent areas (face, stomach, back) may require 10 to 12 sessions, plus annual maintenance sessions. Find out how CtrlZ sessions work.
Alexandrite laser: frequently asked questions
Does the Alexandrite laser hurt?
The sensation is comparable to small rubber band blows on the skin. Modern lasers are equipped with cooling systems (pulsed cold air, cooled sapphire glass) that considerably reduce discomfort. If you are sensitive, an anaesthetic cream can be prescribed and applied 2 hours before the session.
Is the Alexandrite laser dangerous?
When properly set up and used by a trained professional, the Alexandrite laser is extremely safe. It is neither carcinogenic nor sterilizing. The main risks (burns, depigmentation) arise from tanned skin or unsuitable parameters – hence the importance of medical supervision.
Can the Alexandrite laser be used on the face?
Yes, the Alexandrite laser is widely used for facial hair removal: upper lip, chin, sideburns, cheeks. However, the risk of paradoxical regrowth is higher in these hormone-dependent areas. Prior assessment (sometimes hormonal) and adjustment of parameters are essential. At CtrlZ, we’ll never ask you to shave your face: we use clippers to shorten the hair.
Alexandrite or Nd-YAG laser: which to choose?
It depends on your phototype. Light skins (I to III) → Alexandrite. Matt to dark skin (IV to VI) → Nd-YAG. Slightly tanned skin → Nd-YAG. Ideally, consult a center equipped with both technologies to benefit from the laser best suited to your situation.
Does the Alexandrite laser work on blond hair?
Very light blond, red, white or gray hairs contain little or no melanin. The Alexandrite laser cannot target them effectively. For these cases, onlyelectrolysis offers a solution.
Why does CtrlZ use the Alexandrite laser?
At CtrlZ, we have chosen to equip all our centers with dual-wavelength lasers: Alexandrite (755 nm) and Nd-YAG (1064 nm). This technology allows us to :
- Treating all phototypes: from the fairest to the darkest skins
- Adapt the treatment to the area, the season and your tan.
- Optimize efficacy: each patient receives the most appropriate wavelength
- Minimizing risks: the right laser on the right skin = fewer burns
Our protocol also includes :
- Systematic medical appraisal during information consultation
- Preliminary laser test to assess your skin’s tolerance
- Follow-up questionnaire before each session
- 24/7 medical hotline in the event of an adverse reaction
The information consultation is free. Book an appointment to assess your phototype and discover the laser best suited to your skin.
