Underarm Laser Hair Removal in Singapore

Underarm laser hair removal uses laser light absorbed by the pigment in each hair to heat and damage the follicle. Underarm hair is coarse and dark, so it usually responds well over about six to eight sessions. At IN Eternity Clinic, Dr Sin Yong chooses 755 nm or 1064 nm on the Lutronic Clarity II for your skin.

Why do underarms respond well to laser hair removal?

Laser hair removal works by selective photothermolysis, the principle described in 1983 that a laser wavelength and pulse can be chosen so that energy is absorbed by one target and spares the tissue around it. In hair removal the target is melanin in the hair shaft and follicle. The light is absorbed, converted to heat and conducted to the structures that regrow the hair, which are damaged.

The method works when there is a clear contrast between a dark hair and the skin around it. Underarm hair is typically coarse, dark and closely packed, which makes it a good target. Reviews of laser hair removal consistently find that dark, thick hair responds more readily than fine or light hair. That is why the underarm is both the most requested area and one where people usually notice change early in the course.

White, grey, red and very blonde hairs contain little or no melanin and respond poorly to any laser, whatever the device. If some of your underarm hair is light, this is discussed at assessment.

Underarm skin, darkening and choosing the wavelength

Underarm skin is often darker than the surrounding skin. Friction, repeated shaving, deodorant irritation and hormonal factors all contribute. That matters, because melanin in the skin competes with melanin in the hair for the laser energy. Too much absorption in the skin can cause redness, blistering or pigment change.

The Lutronic Clarity II at IN Eternity Clinic has two wavelengths. The 755 nm Alexandrite laser is absorbed strongly by melanin and works efficiently on finer hair in lighter skin. The 1064 nm Nd:YAG laser is absorbed less by skin pigment and penetrates deeper, which is why it is generally the safer choice in darker skin. Published experience in darker skin types supports longer wavelengths, longer pulses and effective cooling. Dr Sin Yong chooses the wavelength for your skin type and hair, and may start with a test area if the picture is unclear.

For a fuller comparison of light-based options, see laser hair removal vs IPL vs SHR and diode vs dual-wavelength lasers.

How many underarm sessions will I need, and how far apart?

Hair grows in cycles: an active growth phase (anagen), a short transition, and a resting phase. Only follicles in the active phase have enough pigment in the right place to be affected. At any one time some underarm follicles are resting and effectively invisible to the laser. Sessions are spaced so that a new group of follicles has entered the active phase by the next visit.

Most people need a course of about six to eight sessions. Underarm hair cycles relatively quickly, so the interval is usually at the shorter end of the four-to-eight-week range used across the body, often four to six weeks. Treating more often does not reach more follicles; it treats the same skin again before new hairs are ready. After the course, some people need an occasional maintenance session, particularly if hormonal changes stimulate regrowth. The companion guide does laser hair removal last? explains why.

Most people notice the change in stages. After the first one or two sessions, regrowth is patchier and slower. By the middle of the course, many treated hairs do not return and those that do are finer. Towards the end, the remaining hairs are often sparse enough that shaving becomes occasional. Progress is reviewed at each visit, and settings are adjusted as the hair becomes finer and lighter.

Does underarm laser hair removal hurt?

Most people describe a quick snap, like a rubber band flicked against the skin, followed by brief warmth. The underarm is more sensitive than the legs but the area is small, so a session takes only a few minutes. The Clarity II uses cryogen cooling, a short burst of cold spray just before each pulse, which protects the skin surface and dulls the sensation. Numbing cream is rarely needed for the underarm, but it can be arranged if you are anxious.

Afterwards, the skin may be pink with small raised bumps around the follicles for a few hours. Treated hairs shed over the following one to three weeks; they can look as if they are still growing before they fall out.

If you have sensitive skin or a low pain threshold, say so at the start; the pace can be slowed, cooling increased and numbing used. Sessions are not done over broken, irritated or freshly waxed skin, or in the days after strong sun exposure on the area.

Preparing for a session and caring for the skin afterwards

Before. Shave the underarms the day before or on the morning of your session, so the hair is below the surface but the follicle is intact. Do not wax, pluck, thread or use an epilator for several weeks beforehand. Avoid tanning the area. On the day, come without deodorant or antiperspirant, which can irritate freshly treated skin. Tell the clinic about any new medicines, particularly those that make skin sensitive to light.

After. Leave deodorant off for the rest of the day, and use a gentle, fragrance-free one afterwards. Avoid hot showers, saunas, vigorous exercise and swimming in chlorinated pools for a day or so, because heat and friction can irritate the follicles. Keep the area out of strong sun. Shave between sessions if you need to, but do not wax or pluck.

Dark underarms, ingrown hairs and underarm sweating

Many people with dark underarms find the skin looks lighter once laser has reduced the hair. Part of that is simply less visible stubble under the skin; part is less shaving friction, which keeps irritation-driven darkening going. Laser hair removal does not bleach skin, and darkening with other causes needs its own assessment, covered on underarm pigmentation and dark underarms.

Recurrent ingrown hairs and shaving bumps under the arms often improve as hair density falls; see ingrown hairs and razor bumps. Sweating is a different matter. It comes from sweat glands, which laser hair removal does not target, so heavy sweating is assessed separately on underarm sweating treatment.

Hidradenitis suppurativa is a different situation again. It is a long-term inflammatory condition that causes painful lumps and tracts in the underarms and groin, and because it begins in the hair follicle, laser hair reduction is sometimes used as part of its medical management. That needs a diagnosis and a wider treatment plan, with laser timed around flares rather than through them.

How underarm laser hair removal is planned at IN Eternity Clinic

Dr Sin Yong assesses your skin type, the colour and coarseness of the hair, any darkening or irritation, and your medicines, then chooses the wavelength and settings. You are told how many sessions are likely, the interval, and what to expect from the course, including the possibility of maintenance later. The laser hair removal page covers every area treated, and Clarity II laser hair removal explains the platform.

Men are treated as well as women. Male underarm hair is often denser, and some men prefer to thin it rather than clear it, which can be planned with a lighter approach or fewer sessions. If you want other areas treated as well, such as the arms or bikini line, they can be planned alongside the underarms, each with its own interval.

Common myths, answered

• Myth: Underarm laser hair removal makes underarms darker.
  Fact: With the right wavelength and settings, the reverse is more common, because less shaving means less friction. Settings that are too strong for the skin type can cause pigment change, which is why skin type is assessed first.
• Myth: One session is enough for the underarms.
  Fact: Only hairs in the active growth phase respond at each session, so a course is needed.
• Myth: You must let the hair grow out before a session.
  Fact: Shave beforehand. Hair above the skin absorbs energy at the surface and can cause discomfort or burns; the target is the hair in the follicle.
• Myth: Laser hair removal also stops underarm sweat.
  Fact: Sweat comes from sweat glands, which laser hair removal does not target. Sweating is assessed and treated separately.