At-home IPL (intense pulsed light) devices have made long-term underarm hair reduction genuinely accessible — no clinic appointments, no awkward positions under bright lights. But there is a real learning curve, and the marketing claims on device boxes tend to outrun the reality. This guide gives you an honest, step-by-step picture of what to do, what to expect, and what to watch out for.
What "At-Home Laser" Actually Means
The term "laser" is used loosely on most consumer devices. What you are almost certainly holding is an IPL handset — a broad-spectrum pulsed light device — not a true single-wavelength laser. IPL is effective for hair reduction, but it works differently from the diode or Nd:YAG lasers used in professional clinics, and at lower energy levels as a regulatory safety measure.
The mechanism is the same in principle: light energy is absorbed by melanin (the pigment) in the hair follicle, which heats and damages the follicle to slow or stop regrowth. For this to work, there needs to be a meaningful contrast between hair colour and skin tone.
IPL works best on:
- Light to medium skin tones (Fitzpatrick types I–III) with dark hair
- Underarm area specifically — studies show around 87% hair reduction after four weekly sessions, with only mild stinging reported
IPL is less effective or carries higher risk for:
- Very dark skin tones (Fitzpatrick types V–VI): the device cannot reliably distinguish follicle melanin from skin melanin, raising the risk of burns and hyperpigmentation
- Very light or white hair: there is not enough pigment for the device to target
- Tanned skin: always treat on your natural skin tone; avoid sun or self-tanner for at least four weeks before starting
If you have any doubt about your skin tone compatibility, check your device's included Fitzpatrick chart or consult a dermatologist first.
Before You Start: The Prep List
Getting the prep right protects your skin and makes each session more effective. Do these in the 24–48 hours before every treatment:
- Shave, do not wax or pluck. The follicle needs to be intact and present beneath the skin for the light to reach it. Waxing or plucking removes the root entirely, so there is nothing to target. Shave 24 hours before — not on treatment day — so the hair is at the surface of the follicle but not above the skin. A sharp single-blade safety razor gives a close, even shave without micro-nicks that could sensitise the skin before a light treatment.
- Clean, dry, product-free skin. Remove deodorant completely. Fragrance, aluminium compounds, and some skincare actives can interact with the heat. Wash and pat dry.
- No retinoids or AHAs for 48 hours before treatment. These thin the stratum corneum and raise photosensitivity.
- Check for contraindications. Photosensitising medications (some antibiotics, certain acne treatments) are a hard stop — the light can cause severe reactions. Check with your GP or pharmacist if you are unsure.
Step-by-Step: How to Treat Your Underarms
The underarm is a small, curved area. Take your time — rushing leads to overlap or gaps.
1. Set your device to the correct intensity level. Start one level below the recommended setting for your skin tone on your first session. You can increase gradually once you know how your skin responds.
2. Lift your arm and pull the skin taut. This ensures full contact between the treatment window and the skin, which improves energy delivery and reduces discomfort.
3. Use stamp mode, not glide mode. For a small, curved area like the underarm, stamp each flash individually and lift before moving to the next spot. Gliding risks overlap, double-dosing an area, and irritation.
4. Work systematically. Treat the front of the underarm, then the centre, then the back. Aim for complete coverage with no gaps and no double-flashing.
5. Do not go over the same spot twice in one session. One pass per session, even if you are not sure you caught a patch. You will be back next week.
6. Cool and calm after. A cool damp cloth immediately after is fine. Avoid heat (saunas, hot showers) for 24 hours. Skip deodorant for the rest of the day if your skin feels warm — fragrance-free roll-on is fine the following morning.
What to Expect Week by Week
Hair removal with IPL is not instant. Each session only targets follicles in their active growth phase (anagen), and at any given time only a portion of your follicles are in that phase. This is why multiple sessions are necessary.
Weeks 1–3: Little obvious change. Hair may feel slightly finer in places. Some treated hairs shed 7–14 days after a session — that is the device working, not falling out by itself.
Weeks 3–6: Noticeably slower regrowth. You may shave less often. Patches where hair does not return at all.
Weeks 6–12: Significant reduction. Most people are down to maintenance at this point — sporadic hairs, much finer texture.
Ongoing maintenance: Once the initial course (typically 8–12 sessions) is complete, most people need a top-up session every 4–8 weeks to catch any follicles that cycle back in.
One honest note: results are genuinely permanent for some follicles and not for others. "Permanent hair reduction" (the regulated term, not "permanent removal") is an accurate description.
While You Are Waiting for Results: Keep Shaving
Between IPL sessions you will still need to shave — the goal is to keep hair at the skin surface so the device can work each week, and regrowth between sessions is real and sometimes patchy.
This is exactly where technique matters. Irritation from a poor shave compounds with post-IPL skin sensitivity. A sharp, single-blade safety razor is gentler on the underarm than a multi-blade cartridge, which tends to tug and cause friction on curved surfaces. Our shaving-by-body-area guide walks through underarm shaving angles and technique in detail.
Short on time? Freya's starter kit includes everything for a clean, close underarm shave — and it fits neatly into the routine alongside your IPL sessions.
When to Pause or Stop
Stop and let your skin recover — and reassess the intensity level — if you notice:
- Redness that lasts more than a few hours
- Blistering or crusting of any kind
- Hyperpigmentation (darkening of the skin) appearing in the treated area
- Any active skin condition in the underarm (folliculitis, eczema, open cuts)
If you develop blistering, seek medical advice. Burns from IPL, though uncommon at home-device energy levels, do happen when the device is used on incompatible skin tones or when settings are too aggressive.
Quick Reference: Things Not to Do
- Do not use IPL over tattooed skin (the ink absorbs the light and can cause burns)
- Do not treat over moles or raised lesions
- Do not use if pregnant (insufficient safety data)
- Do not wax, thread, or pluck between sessions — shaving only
- Do not skip the patch test on your first session (inner arm, wait 24 hours before full treatment)
At-home IPL is a legitimate long-term investment in reducing underarm hair — as long as your skin tone and hair colour are a good fit, and you go in with realistic expectations about timeline. Pair it with a solid shaving routine between sessions and you have a combination that actually works.
Frequently Asked Questions
Do I need to shave before using an at-home IPL device on my underarms?
Yes — shave 24 hours before every session, not on treatment day. The follicle needs to be intact below the skin surface for the light to reach and damage it. Waxing or plucking removes the root entirely, which means there is nothing for the device to target. A clean, close shave the day before gives the best result.
How many IPL sessions do underarms need before I see results?
Most people notice slower, finer regrowth by weeks 3–4. Significant reduction typically requires 8–12 weekly sessions. Underarms tend to respond faster than other body areas — one study observed around 87% hair reduction after just four weekly treatments. After the initial course, monthly maintenance sessions extend the results.
Is at-home IPL safe for dark skin tones?
IPL devices work by targeting melanin contrast between the hair and the surrounding skin. On deeper skin tones (Fitzpatrick types V–VI), the device cannot reliably distinguish follicle melanin from skin melanin, which raises the risk of burns and hyperpigmentation. If you have a darker complexion, look for devices with specific settings for deeper skin tones, or consult a dermatologist about professional alternatives.
Can I use deodorant after an IPL underarm session?
Skip deodorant for the rest of treatment day — especially any products containing fragrance, alcohol, or aluminium compounds, which can irritate heat-sensitised skin. A fragrance-free roll-on is generally fine from the next morning onwards. Avoid anything that might trap heat, like tight clothing, for the first 24 hours after treatment.
Do I still need to shave between IPL sessions?
Yes. Hair regrowth between sessions is normal — IPL only targets follicles in their active growth phase, so multiple treatments are needed to catch all of them. Continue shaving as needed between sessions. Keep the technique gentle: a sharp single-blade safety razor reduces friction on the underarm, which is especially helpful when skin is more sensitive post-treatment.
Last updated: 2026-06-17