Diode, Alexandrite, Nd:YAG or IPL? Which Laser Suits Your Skin
Almost every conversation about laser hair removal is about the clinic. The more useful question is about the machine — because a single number, the wavelength, decides whether a treatment will work on your hair and whether it is safe on your skin.
One number does most of the work
Laser hair removal works by a principle called selective photothermolysis, which is a long way of saying: put energy into the pigment in the hair, not into anything around it. The laser light is absorbed by melanin in the follicle, converts to heat, and damages the structure that grows the hair.
The catch is that melanin is also what gives skin its colour. So the laser is being asked to find pigment in the hair while ignoring pigment in the skin directly above it, and how well it manages that is almost entirely a function of wavelength.
Shorter wavelengths are absorbed more eagerly by pigment. That makes them fast and effective on hair — and it also makes them less able to tell hair from skin. Longer wavelengths penetrate deeper and are absorbed far less by surface pigment, which makes them the safe option on deeper skin, at the cost of needing more energy to do the same job.
That trade-off is the whole story. Everything below is a consequence of it.
The four wavelengths, and what each is for
Four wavelengths, one pass
Each reaches a different depth and suits a different hair-and-skin combination. The bars show relative depth of reach, shallowest to deepest.
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755 nmAlexandrite range
The shortest of the four, and the most strongly absorbed by pigment. That makes it quick and efficient on fine and light-brown hair. The same eagerness for pigment is its limitation: it does not distinguish well between the melanin in a hair and the melanin in the skin around it, so it belongs on lighter skin — roughly Fitzpatrick I to III.
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808 nmDiode range
The workhorse of hair removal, and the reason most clinics you walk into are running a diode. It sits at a useful compromise between depth and absorption, handling the widest span of hair and skin together, and it is the wavelength doing most of the work in a typical session.
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940 nmDeeper diode
Reaches further down the follicle for coarser, deeper-rooted hair, while depositing less energy at the surface on the way through. It is rarely the headline wavelength but it widens what a single pass can cover.
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1064 nmNd:YAG range
The longest reach and the least interested in surface pigment — which is precisely why it is the wavelength used to treat deeper skin tones safely. It passes through the epidermis with far less absorption and does its work at the follicle. If you have Fitzpatrick IV to VI skin, this is the number that matters.
IPL is not on this scale, because IPL is not a laser. It scatters a broad band of wavelengths at once rather than delivering one, which is a different mechanism with different results.
755 nm — the alexandrite end
Alexandrite lasers are quick and they are good at what they do. On fine or light-brown hair against fair skin, the strong pigment absorption at 755 nm gets results in fewer passes than a longer wavelength would.
The limitation is the same property. Because it is so readily absorbed by melanin, it does not discriminate well between the hair and the skin around it. On Fitzpatrick IV and above, that stops being an efficiency and starts being a burn risk. A good clinic running an alexandrite will simply decline to treat deeper skin on it — and that is the correct answer, not a sales failure.
808 and 940 nm — the diode middle
If you have had laser hair removal in Canada, there is a good chance it was a diode at or around 808 nm. It sits in a useful middle: deep enough to reach the follicle properly, restrained enough not to dump its energy into the epidermis on the way.
Adding 940 nm extends that reach for coarser, deeper-rooted hair. Neither wavelength is exotic; between them they do the bulk of the work in most sessions, on most people.
1064 nm — the wavelength that matters for deeper skin
This is the one worth knowing the number for.
At 1064 nm the light is absorbed by melanin far less readily. It passes through the epidermis with comparatively little interaction and delivers its energy down at the follicle. That is what makes it possible to treat Fitzpatrick IV, V and VI skin without cooking the surface — and it is why a clinic’s ability to treat deeper skin tones comes down to whether their equipment offers it.
The reputation laser hair removal acquired on darker skin — the burns, the patches of post-inflammatory pigmentation — came overwhelmingly from being treated on equipment that could not do the job, by people who ran a standard protocol instead of matching settings to skin. It was rarely the concept that failed. It was the wavelength.
If you have deeper skin and you take one question to a consultation, make it this one: does your machine run 1064 nm?
IPL is not a laser
This distinction gets blurred constantly in advertising, so it is worth being plain about it.
A laser emits a single wavelength, coherently, in one direction. IPL — intense pulsed light — is a flashlamp. It fires a broad band of wavelengths at once, cut down with filters rather than focused. Some of that energy does what you want. The rest scatters.
In practice that means IPL can reduce hair, but usually with more sessions and less permanent reduction than a laser, and with less predictability on deeper skin — because part of that broad output is the short, pigment-hungry end of the spectrum that a longer laser wavelength deliberately avoids.
IPL is not a scam. It is a different tool. The problem is only that it is frequently sold as though it were the same thing at a better price.
What about at-home devices?
Nearly all of them are IPL, regardless of what the box says, and they are deliberately limited to a small fraction of clinical energy — which is the right call for a device used without supervision, but it does cap what they can achieve. They can thin hair and they can maintain a result. They are not doing the same job as a clinical diode. Most also exclude deeper skin tones in their own safety instructions, which is worth reading before you buy rather than after.
How to work out what a clinic is running
You do not need to become an expert. Two questions at consultation will tell you almost everything:
- What machine do you use? A clinic confident in its equipment answers immediately and by name.
- What wavelengths does it run? If the answer is IPL, you now know it is a different technology. If it is a single-wavelength laser and you have deeper skin, ask directly whether it offers 1064 nm.
Two more things that matter as much as the hardware: you should be assessed on the Fitzpatrick scale before anything is switched on, and you should be patch tested before a first full session — not after something goes wrong.
What we run, and why
Every Femme clinic uses the same device: the FEMME 4D, a Health Canada and FDA approved diode laser that blends all four wavelengths — 755, 808, 940 and 1064 nm — in a single pass.
The practical benefit is that one device covers fine facial hair and coarse body hair without swapping equipment mid-session, and the 1064 nm component means we treat the full range of skin tones rather than turning people away. Settings come from your Fitzpatrick assessment and patch test, not from a standard protocol.
For how a course actually runs, what it costs and which of our twelve clinics is nearest, see our laser hair removal page.
Ask us what we run, and why
You now know which questions separate a good clinic from a confident one. Ask us both at consultation — every Femme clinic runs the FEMME 4D, including the 1064 nm wavelength that makes deeper skin tones safe.
Consultation, Fitzpatrick assessment and patch test are free and happen before any full session.
Questions we hear
What is the difference between diode and alexandrite laser hair removal?
Wavelength, and therefore depth. An alexandrite laser runs at 755 nm, which is absorbed strongly by pigment and works quickly on fine, light-brown hair — but it is absorbed by skin pigment too, so it suits lighter skin. A diode runs longer, typically 808 nm, which reaches deeper and discriminates better between hair and skin. That is why diode systems handle a wider range of skin tones.
Which laser is best for dark skin?
The 1064 nm Nd:YAG wavelength. Longer wavelengths are absorbed far less by the melanin in the epidermis, so the energy reaches the follicle rather than heating the surrounding skin. That is the mechanism behind safe treatment on Fitzpatrick IV to VI. If a clinic cannot tell you whether their machine offers 1064 nm, that is the answer to your question.
Is IPL the same as laser hair removal?
No. A laser emits one wavelength, in one direction, coherently. IPL is a flashlamp that fires a broad band of wavelengths at once, filtered rather than focused. It can reduce hair, but the energy is scattered instead of targeted, which generally means more sessions for less permanent reduction — and less predictability on deeper skin, because some of that broad band is the short, pigment-hungry end.
Do at-home laser hair removal devices use the same technology?
Almost all of them are IPL, not laser, whatever the packaging says. They are also capped at a fraction of clinical energy for safety reasons, which is sensible in an unsupervised device but does limit what they achieve. They can thin hair. They are not doing the same job as a clinical diode, and most exclude deeper skin tones in their own instructions — worth reading before buying.
Does a longer wavelength hurt more?
It can feel different rather than simply worse. 1064 nm deposits energy deeper and is often described as a deeper, duller heat, where shorter wavelengths feel sharper and more surface-level. Modern systems offset this with contact cooling and a motion technique that spreads the energy. Discomfort is also very dependent on the area — the upper lip and bikini line are more sensitive than legs on any wavelength.
How do I find out what laser a clinic is actually using?
Ask two questions at consultation: what is the machine, and what wavelengths does it run. A clinic that treats a wide range of skin tones should be able to answer without hesitating. If the answer is IPL, it is a different technology with different results. If it is a single-wavelength laser and you have deeper skin, ask specifically whether it offers 1064 nm.
What does Femme use?
The FEMME 4D, in every one of our twelve clinics. It is a Health Canada and FDA approved diode laser that blends all four wavelengths — 755, 808, 940 and 1064 nm — in a single pass, so one device covers fine facial hair and coarse body hair without swapping equipment mid-session. The 1064 nm component is what lets us treat the full range of skin tones.
Can the wrong laser cause burns or pigmentation?
That is the main risk, and it is largely a matching problem rather than a technology problem. Using a short, pigment-hungry wavelength on deeper skin means the epidermis absorbs energy meant for the follicle, which is where burns and post-inflammatory pigmentation come from. Most of the reputation laser hair removal earned on darker skin came from exactly this — being treated on equipment that could not do it.
Where this leaves you
If your hair is dark and coarse and your skin is fair, almost any properly run system will work, and your decision is about the clinic rather than the machine. If your hair is fine, light, grey or red, absorption is the constraint and it is worth reading what we have written about blonde hair and grey hair before you book anything.
And if your skin is deeper than Fitzpatrick IV, the machine is the decision. Ask for the number.
We treat women only, across twelve clinics in Ontario and British Columbia. If you are not sure whether your hair and skin combination is a good candidate, that is exactly what a consultation is for — and we would rather tell you no than sell you a course that will not work. Once you have started, our aftercare guide covers the week that follows.
