Melasma and Lasers: Why Lower Energy Usually Wins

Melasma looks like a pigment problem, so it is tempting to treat it like one: point a pigment-targeting laser at the brown patches, break up the melanin, and watch it fade. In practice, that logic fails often enough that experienced laser clinicians treat melasma as a special category with its own rules. Understanding why requires looking at what melasma actually is at the cellular level.

Melasma is a dysfunction, not a deposit. Conditions like sun spots or lentigines are essentially stable collections of excess pigment. Melasma is different. The melanocytes, the cells that produce pigment, are overactive and hypersensitive. They respond to hormones, ultraviolet light, visible light, and, critically, heat and inflammation. A laser that destroys existing pigment does nothing to calm the cells producing it. Worse, the thermal injury from an aggressive treatment can trigger those same melanocytes to produce more pigment than before. This is why some patients see their melasma darken weeks after a treatment that initially looked successful. For an independent overview, see Melasma and pigmentation: diagnosis and treatment.

Why high-energy settings backfire. Traditional Q-switched and picosecond lasers at standard tattoo or sun spot settings deliver enough energy to rupture pigment-containing cells. In melasma, that rupture releases inflammatory signals into skin that is already primed to overreact. The result can be rebound hyperpigmentation, or in some cases post-inflammatory hypopigmentation, where the treated area turns permanently lighter than surrounding skin. Hypopigmentation is often harder to correct than the original melasma, which is why cautious clinicians consider it the more serious risk.

The low-fluence approach. The strategy that has gained the most clinical traction uses the 1064 nm Nd:YAG wavelength at deliberately low fluence, sometimes called laser toning. Instead of destroying melanocytes, the goal is subthreshold injury: enough energy to fragment melanin granules within the cell and gently downregulate pigment production, but not enough to kill the cell or provoke a strong inflammatory response. The 1064 nm wavelength penetrates deeply and is absorbed less strongly by epidermal melanin than shorter wavelengths, which matters because melasma patients frequently have Fitzpatrick skin types III to V, where epidermal absorption raises burn risk.

The tradeoff is that low-fluence work requires many sessions, often six to ten spaced two to four weeks apart, and the improvement is gradual. There is also a documented risk of mottled hypopigmentation when low-fluence toning is repeated too frequently or continued too long, so treatment intervals and total session counts matter as much as the settings on the screen.

Where picosecond devices fit. Picosecond lasers deliver energy in pulses so short that they fragment pigment primarily through photoacoustic effects rather than heat. In theory, less heat means less inflammatory stimulus to the melanocyte. Early clinical data on low-energy picosecond protocols for melasma is encouraging, particularly with fractionated handpieces that treat only a fraction of the skin surface per pass. But picosecond is a pulse duration, not a guarantee of safety. A picosecond device at aggressive settings can still provoke rebound. The protocol matters more than the platform.

Lasers are an adjunct, not a cure. This is the point most often lost in marketing. No laser addresses the hormonal and light-driven biology that keeps melasma active. Standard of care still centers on daily broad-spectrum sunscreen, ideally a tinted mineral formula, because iron oxides block the visible light that stimulates melasma and that chemical sunscreens miss. Topical agents remain foundational: hydroquinone in supervised courses, or alternatives such as azelaic acid, tranexamic acid, and retinoids. Oral tranexamic acid, prescribed selectively after screening for clotting risk, has some of the strongest recent evidence for stubborn cases. Lasers work best layered on top of this regimen, not instead of it.

Questions worth asking before treatment. If you are considering laser treatment for melasma, a few questions separate careful practices from aggressive ones. Ask whether a Wood's lamp or similar assessment was used to gauge pigment depth, since dermal-dominant melasma responds less predictably. Ask what fluence range will be used and why. Ask what the plan is if pigment darkens after a session, because a good answer involves pausing treatment, not escalating it. And ask whether you will be on a topical regimen and strict photoprotection before the first laser session, since pretreatment for several weeks is common practice and reduces rebound risk.

The honest bottom line. Melasma is a chronic, relapsing condition, and even excellent treatment produces improvement measured in shades, not erasure. Recurrence after a sunny summer is common regardless of how well the initial treatment went. The patients who do best are the ones who treat lasers as one tool inside a long-term maintenance plan, and who choose clinicians willing to use less power over more. In melasma, restraint is not caution for its own sake. It is what the biology demands.

Related reading: Melasma and Lasers: Why More Power Usually Makes It Worse.