In short. Both devices clear pigment with light. The choice follows from the target and from the skin it sits in, not from which machine is newer.
Key points
- A defined particle — a single dark spot, a patch of tattoo ink, pigment packed at a depth — is what a very short pulse suits.
- Pigment scattered across an area in the upper layer responds to either device.
- Deciding which of those you have is the assessment, and it is made from the skin rather than from the machine.
Two lasers, both designed to clear pigment, both widely used, and a decision that patients usually frame as choosing between an older and a newer machine. That framing does not survive the mechanism, and the actual question is more useful.
Two ways of breaking pigment up
Pigment in skin absorbs light and converts it into energy. If that energy is delivered slowly, it becomes heat, and the particle is warmed until it breaks down, which also heats the skin around it. If the energy is delivered fast enough, heat has no time to travel before the pulse is over, and the particle is broken apart mechanically instead. Both approaches work. They differ in how much the surrounding skin is heated while they work.
That is the entire technical difference between the two devices, and everything practical follows from it. Less heating of surrounding skin means less collateral change in colour, which matters most in skin that pigments easily. It also means some pigment that resists a slower pulse can be broken up, because the particle is shattered rather than gradually warmed.
What follows from the target
A defined particle — a single dark spot, a patch of tattoo ink, pigment packed at a depth — is what a very short pulse suits. Pigment scattered across an area in the upper layer responds to either device. Deciding which of those you have is the assessment, and it is made from the skin rather than from the machine.
Why neither is the default
The shorter pulse is not an upgrade, and the longer pulse is not obsolete. A short pulse that breaks pigment with heat clears freckles, sun spots and a good deal of tattoo ink, and has done so for a long time. The very short pulse adds precision and reduces surrounding heating, and it does not replace the other device for every target. A clinic that offers only one of the two is describing its equipment list rather than your skin.
The skin matters as much as the target
Light is absorbed by pigment everywhere in the skin, not only in the mark being treated. In skin that tans readily, more of the energy goes into the surrounding skin, which narrows the margin between a useful treatment and a pigmentary injury. That applies to both devices, and it is why settings are chosen conservatively, why a test area is sometimes treated first, and why identical settings for every patient are a warning sign.
What neither device will do
- Treat a lesion that has not been identified. A mark that is new, changing, bleeding or irregular is assessed first.
- Stop pigment from returning. Sun-related and hormonal pigment both come back; only cleared ink does not.
- Change skin structure. Neither repositions tissue, removes a fold or restores volume.
The useful question is not which device is stronger but what the target is and whose skin it sits in. Those two answers, taken together, decide the plan.
Frequently asked questions
What actually separates the two devices?
How the pulse delivers its energy. One delivers it in the shortest pulses in clinical use, so pigment particles are broken apart mechanically with little heating of the surrounding skin. The other delivers shorter-than-millisecond pulses that break pigment up substantially through heating the particle. Neither is a newer version of the other, and each suits targets the other handles less well.
Which one would a clinic recommend for a dark spot?
That depends on the spot and on the skin, and a recommendation made before the lesion has been examined is not an assessment. A discrete spot in the upper layer responds to either device. Pigment sitting deeper, or ink, favours the shorter pulse. Skin that tans readily changes the calculation for both, and sometimes the honest answer is that neither should be used.
Is the more expensive device the better one?
Not in general. A device that costs more to acquire and maintain is reflected in session pricing, and a shorter course does not necessarily produce a smaller total. What decides the choice is the target, the depth, the ink or pigment involved and the skin type. A clinic that recommends by device rather than by finding has answered a commercial question.
Risks & Limitations
- Pigmentary change in the treated area, darker in most cases and lighter in some, particularly in darker skin types and after recent sun exposure.
- Blistering, crusting or a burn if the settings do not match the skin, with a small risk of scarring.
- Frosting of a treated spot after a short-pulse treatment, which is expected rather than a complication and settles within hours to a day.
- Pinpoint bleeding and, with some settings, a bruise-like change after a very short pulse, taking a week or more to clear.
- A cold sore outbreak around the mouth after treatment in people who carry the virus.
- Pigment commonly darkens before it flakes away over the following days, and is judged once the area has settled.
- Pigment recurs. Sun-related freckling and sun spots return with further exposure and hormonal pigment returns most readily of all; only cleared tattoo ink does not.
- No outcome is guaranteed, and individual response varies with the lesion, the depth it sits at, the ink and the skin type.
When to Seek Care
- Blistering, crusting or a burn in the treated area — contact the treating team the same day.
- Rapidly increasing redness, swelling, pain or warmth, or discharge from the treated area.
- A fever, or a cold sore outbreak around the mouth after treatment.
- New or changing pigmentation in the treated area that is not settling as expected.
- A lesion anywhere on the skin that is new, changing in size, shape or colour, bleeding, itching or failing to heal — seek assessment rather than treatment.
- Difficulty breathing, or swelling of the lips, tongue or throat — seek emergency care immediately.
References & Further Reading
- American Academy of Dermatology Association (AAD) — patient information on laser and light-based treatment
- British Association of Dermatologists (BAD) — guidance on laser and light therapy
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance on skin lesions and referral
- Cochrane Library — systematic reviews in laser treatment of pigmented lesions and tattoos
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.