Yes, laser treatments can cause hyperpigmentation, and it’s one of the most common side effects across nearly every type of laser procedure. The dark patches that develop afterward are a form of post-inflammatory hyperpigmentation (PIH), the same kind of discoloration that follows acne, burns, or other skin injuries. How likely it is depends on your skin tone, the type of laser used, and how your skin is cared for before and after treatment.
Why Lasers Trigger Dark Spots
Laser energy works by delivering controlled heat or light into the skin, which inevitably causes some degree of inflammation. That inflammation is actually the point for many treatments, since it triggers the skin’s healing response. But the same inflammatory process also activates melanocytes, the cells responsible for producing pigment.
When the laser damages the base layer of skin cells, the body releases inflammatory signaling molecules (prostaglandins and related compounds) that stimulate melanocytes to ramp up melanin production. The result is excess pigment deposited in the skin, creating dark patches in the treated area. In some cases, pigment-laden cells also accumulate in the upper layer of the dermis, where they can linger for weeks or months. Repeated subthreshold laser exposures, where the energy isn’t quite strong enough to achieve full treatment, can also stimulate melanin production in surrounding areas, leading to what’s called rebound hyperpigmentation.
How Common It Is by Laser Type
Not all lasers carry the same risk. The biggest distinction is between ablative lasers, which remove layers of skin, and non-ablative lasers, which heat tissue without breaking the surface.
Ablative lasers, particularly CO2 lasers, carry the highest risk. Up to 55% of patients report side effects including hyperpigmentation after traditional CO2 resurfacing. Even with newer fractional CO2 technology, which treats only a portion of the skin’s surface, PIH rates remain significant. One review found PIH incidence ranged from 16% to over 50% depending on what post-treatment care was used.
Non-ablative lasers are generally safer for pigmentation because they don’t destroy the outer skin layer. They’re often recommended for people with darker skin tones specifically because they’re less likely to trigger abnormal pigmentation. That said, temporary hyperpigmentation still occurs with non-ablative devices; it’s just milder and resolves faster.
Among lasers used for tattoo removal, a study comparing different pulse durations in Asian patients found PIH rates of 35% with 532 nm nanosecond lasers and 24% with 532 nm picosecond lasers. At the 1064 nm wavelength, rates were 27% for nanosecond and 22% for picosecond. Picosecond lasers consistently produced less hyperpigmentation, and no severe complications have been reported with picosecond technology to date.
Skin Tone Is the Biggest Risk Factor
Your natural skin color is the single strongest predictor of whether you’ll develop hyperpigmentation after a laser procedure. People with darker skin tones (Fitzpatrick skin types IV through VI) face substantially higher risk because their melanocytes are more reactive and produce pigment more readily in response to inflammation. Most laser safety studies have been conducted on lighter skin types (I through III), meaning the published complication rates may actually underestimate the risk for darker-skinned patients.
For people with very dark skin, laser therapy is considered less effective than chemical peels for pigmentation concerns and should be approached with extreme caution. Irreversible pigment changes, both darkening and lightening, can occur in these skin types.
Medications That Increase Risk
Certain medications make skin more sensitive to light and can amplify the risk of hyperpigmentation after laser treatment. These photosensitizing drugs include some antidepressants (like citalopram, imipramine, and amitriptyline), the heart medication amiodarone, the blood pressure drug diltiazem, the antipsychotic chlorpromazine, and some cancer treatments. The photosensitivity reaction these drugs cause can be triggered not just by sunlight but also by medical lasers.
Isotretinoin, a powerful acne medication, is typically required to be stopped at least six months before any laser procedure. Other topical treatments like retinoids and bleaching creams are generally discontinued for several months beforehand as well.
Reducing Your Risk Before Treatment
Pre-treatment preparation plays a real role in outcomes. Many dermatologists prescribe a topical brightening agent containing 2% to 4% hydroquinone for several weeks before laser procedures, sometimes combined with a retinoid and a mild steroid. This combination helps suppress melanocyte activity before the skin is exposed to laser energy, lowering the chance of a pigment flare afterward.
Sun exposure before treatment is another modifiable risk factor. Tanned skin has more active melanocytes, so most practitioners will delay procedures if you’ve had significant recent sun exposure. The energy settings and density of the laser also matter: higher energy levels cause more inflammation and correspondingly more pigmentation risk, which is why conservative settings are typically used on darker skin.
Post-Treatment Care That Makes a Difference
What you do after a laser procedure can meaningfully change your odds of developing dark spots. The core strategy is reducing inflammation as quickly as possible, since inflammation is what drives the melanocyte response.
Anti-inflammatory topical medications applied after treatment have been shown to lower PIH rates. In one review of CO2 laser outcomes, ultra-potent topical corticosteroids reduced PIH incidence to 39%, while platelet-rich plasma treatments brought it down to 16%. Sun protection is critical in the weeks following treatment. UV exposure on healing skin acts as an additional trigger for melanin production, compounding the effect of the laser-induced inflammation. Broad-spectrum sunscreen and physical sun avoidance are standard recommendations during recovery.
How Long Laser-Induced Hyperpigmentation Lasts
The good news is that most laser-induced hyperpigmentation is temporary. Mild cases from non-ablative lasers often fade within a few weeks. PIH from ablative procedures typically takes longer, resolving over several months. The timeline varies widely based on skin tone, the severity of the initial inflammation, and whether any additional triggers (like sun exposure) prolong the process.
In some cases, particularly with older, fully ablative CO2 lasers, permanent hyperpigmentation can occur, though this is rare. Permanent lightening of the skin (hypopigmentation) is actually more common as a long-term complication of aggressive ablative resurfacing. For persistent dark spots, topical brightening agents, chemical peels, and carefully selected laser treatments (including picosecond lasers at appropriate settings) can help accelerate fading. A study using a 755 nm picosecond laser on stubborn pigmentation showed significant clearance after a single session, with no recurrence at two-year follow-up.