How Laser Settings Are Customised to Your Skin

Laser settings are chosen for each person based on what is being treated, the skin type, the body area and how the skin responds on the day. The main dials are wavelength, energy, pulse length and spot size, along with cooling and how many passes are made. Getting these right is what balances a useful effect against the risk of burns, pigment change or scarring.

Wavelength: choosing the target

Each laser emits light at a particular wavelength, measured in nanometres. Different wavelengths are absorbed by different targets in the skin, called chromophores. The three main ones are water, melanin (pigment) and haemoglobin (in blood).

• Erbium wavelengths are absorbed very strongly by water, so energy is taken up at the surface. They are used for resurfacing and texture.
• Nd:YAG wavelengths penetrate deeper with less surface absorption. They are used for hair reduction in darker skin, some vascular work and deeper heating.
• Other wavelengths are chosen for redness or pigment, depending on the device.

Some systems, including Fotona, combine more than one wavelength in a single device, which allows the provider to switch based on the concern. For an overview, see what a Fotona laser is.

Energy: how much is delivered

Energy, often described as fluence, is the amount delivered to a given area of skin. Higher energy creates a stronger effect but also more heat and more risk. Lower energy is gentler but may need more sessions.

Energy is rarely set at the maximum. It is usually started conservatively, especially for a first session or for pigment-prone skin, and then adjusted at later visits based on how the skin responded.

Pulse length: how fast it is delivered

Pulse duration is how long each burst of light lasts, from billionths of a second to fractions of a second. This matters because different targets cool down at different speeds.

A rough rule is that the pulse should be about as long as the target takes to lose its heat. Small targets, like pigment granules, suit very short pulses. Larger targets, like hair follicles or blood vessels, suit longer pulses. Long, gentle pulses also allow heat to build slowly in deeper tissue for tightening, while very short pulses vaporise the surface for resurfacing with less heat spreading sideways.

Pulse length is also a safety tool. In darker skin, longer pulses can let surface pigment shed heat while the deeper target is still treated.

Spot size and coverage

Spot size is the diameter of the laser beam on the skin. Larger spots penetrate a little deeper and cover ground quickly, useful for hair reduction on the legs or back. Smaller spots give precise control for small lesions or delicate areas.

Other choices include whether to treat the whole surface or in a fractional pattern of tiny columns, the density of those columns, how much the passes overlap and how many passes are made. More density and more passes mean more effect and more downtime.

Cooling

Cooling protects the surface while energy reaches deeper. It may come from chilled air, a cooled tip, gel or cold packs. Good cooling makes treatment more comfortable and lowers the risk of surface burns, particularly in hair removal and in deeper skin tones.

What shapes your settings

Several things about you are weighed before and during treatment:

• Skin type. Skin tone and how easily it tans or develops dark marks after injury. Medium and deeper tones usually need longer wavelengths, longer pulses, lower energy and more cooling. See laser hair removal and skin types.
• Recent sun. A tan increases surface pigment and usually means postponing or lowering settings.
• The concern. Hair, pigment, redness, texture and laxity each call for different combinations.
• The area. Thin skin around the eyes and neck, and slower-healing skin on the body, are treated more gently than the cheeks.
• Health and medications. Light-sensitising medicines, isotretinoin, healing problems, pregnancy, cold sore history and keloid tendency may change the plan or rule treatment out for now. Never stop a prescription on your own; bring a list to your appointment.
• Your goals and downtime. How much recovery time you can manage influences intensity.

Why one machine can do several jobs

People are sometimes surprised that the same device is used for hair reduction one day and resurfacing the next. The difference lies almost entirely in the settings. Changing wavelength alters what absorbs the light; changing pulse length and energy alters whether tissue is gently warmed, quickly heated or vaporised; changing spot size and pattern alters depth and coverage.

This flexibility is useful, but it also means the person operating the laser carries real responsibility. A combination that is appropriate for a thick, fair-skinned back could be harmful on the thin skin of a darker-toned neck. Training, a careful skin assessment and a written plan for each visit help keep treatment within safe limits.

Test spots and adjusting over time

A test spot in a less visible area is often done before full treatment, especially for new patients, pigment-prone skin or a new type of treatment. The skin's reaction over the following days helps guide settings.

During treatment, the provider watches the skin's immediate response, such as mild redness, swelling around hair follicles or a slight whitening, and adjusts as needed. Records from each visit guide the next. Settings may increase gradually as your skin shows it tolerates treatment.

Risks when settings are not right

Settings too low may simply give little result. Settings too high, or poorly matched to skin type, raise the risk of blistering, burns, darkening or lightening of the skin and, rarely, scarring. That is why careful assessment matters more than speed. Even with well-chosen settings, results vary from person to person.

Frequently asked questions

Why are my settings different from my friend's?

Different skin, hair, concerns and history lead to different settings. Comparing numbers between people is not useful.

Can I ask to have the energy turned up?

You can ask, but increases are made only when the skin's response suggests it is safe.

Do settings change between sessions?

Often, yes. Seasons, tanning, healing and earlier results all inform each visit.

If you would like to understand how a laser plan would be set up for your skin, a consultation at HealthPark Medical Aesthetics can explain each choice in plain terms before any treatment begins.