Intense pulsed light (IPL) hair removal uses short flashes of broad-spectrum light that the pigment in hair absorbs. The light turns into heat, which damages the hair follicle and reduces or slows regrowth. Because IPL mainly affects hairs that are actively growing, it works over a series of sessions spaced weeks apart, and it works best on dark hair.
Here is what that means in practice, from the science to what a session feels like.
How intense pulsed light targets hair
A laser gives off a single wavelength of light. IPL gives off many wavelengths at once, and filters in the handpiece narrow that range to suit the treatment. For hair reduction, the target is melanin, the pigment that gives hair its color.
When a flash hits the skin, dark hair absorbs the light and heats up. That heat travels down the hair to the follicle, the small structure under the skin that produces the hair. Enough heat damages the follicle so it grows hair more slowly, grows finer hair, or stops for a long time.
This also explains IPL's limits:
- Hair color matters. White, gray, red and light blonde hair has too little pigment to absorb the light, so IPL generally will not reduce it.
- Skin color matters. Skin contains melanin too. Darker skin absorbs more of the light, which raises the risk of burns, blisters and lighter or darker patches. IPL is generally better suited to light and medium skin tones. If your skin is darker or tans easily, ask whether IPL is appropriate for you at all, since another method may be a better fit.
- It is reduction, not guaranteed removal. IPL lowers the amount of hair that grows back. It does not promise that every hair is gone, and individual results vary.
What happens during a session
The exact steps and session length vary from clinic to clinic, so ask about them at your consultation. In general, an IPL session follows a similar pattern.
Before the visit
- Stay out of the sun and avoid tanning, including self-tanner, as your clinic advises.
- Shave the area beforehand if asked. Shaving removes the hair above the skin so the light goes to the follicle instead of heating surface hair.
- Avoid waxing, plucking and threading for the period your clinic recommends. These remove the hair root, which is the part the light needs to reach.
During the visit
- The area is cleaned, and a cool gel may be applied.
- Everyone in the room wears eye protection, because the flashes are very bright.
- The clinician places a smooth handpiece against the skin and releases a flash, then moves to the next spot until the area is covered.
- Small areas like the upper lip or chin usually take a few minutes. Larger areas like the legs or back take longer.
After the visit
- The skin may be cooled, and most people go back to their usual day.
- Protect treated skin from the sun between sessions. Sun exposure raises the risk of side effects.
What it feels like, and typical short-term redness
Many people describe each flash as a quick, warm snap, a bit like a rubber band against the skin. How much it bothers you depends on the area and on your own sensitivity. Thin-skinned or bony areas, such as the upper lip, often feel more intense than the legs.
After a session, it is common to see:
- Redness in the treated area
- Small bumps or mild swelling around the hair follicles
- A warm or sunburn-like feeling
These usually settle within hours to a day or two. Over the following weeks, many treated hairs loosen and shed.
Less common side effects include blistering, crusting, swelling that does not go down, and patches of skin that turn lighter or darker. Contact the clinic that treated you if you notice any of these.
Why several sessions are needed (hair growth cycles)
Each hair follicle moves through a cycle with three phases:
- Anagen, the active growth phase
- Catagen, a short transition phase
- Telogen, a resting phase, after which the hair sheds and a new one starts
IPL works best on hairs in the growth phase, when the hair is still connected to the base of the follicle and carries the most pigment. At any one time, only some of the hairs in an area are in that phase. The rest are resting or in transition and will not respond as well to that day's treatment.
That is why sessions are spaced several weeks apart: each visit catches a new group of hairs as they enter the growth phase. The number of sessions depends on the area, your hair color and thickness, your skin tone and hormones. For comparison, the American Academy of Dermatology notes that laser hair removal takes a series of treatments, and IPL is similar: plan on a series rather than a single visit.
Some hair can return over time, especially in hormone-sensitive areas like the face, so occasional maintenance sessions are common.
Who is a good candidate, and who should be evaluated first
People who often do well with IPL have:
- Dark hair, ideally coarse rather than fine
- Light to medium skin
- Skin that is not tanned or sunburned
- Healthy, intact skin in the area to be treated
It makes sense to be evaluated by a dermatologist first if:
- Your hair growth is new or increasing quickly, especially on the face, or comes with acne, irregular periods or scalp hair thinning. This can have a medical cause, and the practice's medical dermatology team evaluates hair disorders.
- Your skin is darker or recently tanned.
- You take a medicine that makes your skin sensitive to light, such as some antibiotics and acne medicines. Tell your clinician everything you take, and do not stop a medicine on your own.
- You are pregnant. Ask whether to wait.
- You scar easily or form raised scars (keloids).
- You have a rash, infection, open sore, mole or tattoo in the area you want to treat.
- Your hair is white, gray, red or light blonde. IPL is unlikely to help, and a dermatologist can talk through other options.
IPL at Bay Ridge Dermatology
Bay Ridge Dermatology provides IPL for hair reduction as part of its cosmetic dermatology services. If you want to know how a session works at the practice, including how long yours would take, you can ask during a complimentary cosmetic consultation: a no-cost conversation about your goals, your skin and hair, and whether IPL fits, with no obligation to book treatment. IPL is a cosmetic treatment and is not covered by insurance. If you are new to the practice, you can read what to expect at your first visit.
When you are ready, you can book online or call (347) 497-4984 with any questions first.
This article is general information, not medical advice. For advice about your own skin, see a dermatologist.