Hair Removal for Any Skin Type (QOOL-epilation®)

QOOL-epilation® (Q-switched Output Optimized for Low-thermal epilation) is LINLINE’s laser hair-removal method designed to work safely and effectively on all skin phototypes—including tanned skin. It runs on the MULTILINE™ base unit using the Nd:YAP 1079 nm Q-switched emitter, delivering millisecond-long trains of nanosecond pulses that concentrate energy inside the hair while the skin cools between pulses. The result is comfortable treatment with minimal skin burden and reliable reduction across face and body areas.

Why QOOL-epilation® is different

• Three kinds of selectivity in one method.
  Optical: 1079 nm penetrates deeply with low competition from skin chromophores.
  Thermal: total pulse-train time is matched to hair’s thermal relaxation time (TRT) so heat builds in the hair while skin cools in the gaps.
  Nonlinear: each nanosecond pulse can push melanin over a multiphoton “threshold,” boosting local absorption and generating acoustic waves that help fragment hair structures—without significant mechanical injury to skin.
• Energy stays where it works. Layer-by-layer, the pulse train heats the shaft/bulb while acoustic micro-effects assist disruption; skin’s shorter TRT lets it shed heat between pulses—so the thermal load on skin is far lower than with long pulses.
• Comfortable, year-round treatments. Most patients describe only a light pinch; no anesthesia or contact cooling is typically required.

What a session is like

• Sensation: a light “snap” as hairs enter the aperture; second passes are often sensation-free.
• On-table endpoints: treated hairs whiten and curl; skin should show no frosting or burns.
• Aftercare: resume activities straight away. QOOL is compatible with all phototypes and sun-exposed lifestyles; keep your usual SPF.

Practitioner essentials

• Emitter & wavelength: Nd:YAP 1079 nm (Q-switched) on the MULTILINE™ base unit. Deep reach supports body and facial zones.
• Pulse format: millisecond-long trains of nanosecond pulses (train duration ≤ hair TRT; interpulse gaps ~skin TRT).
• Spot sizes: 8 mm for dark hair; 4 mm (higher fluence) for light/red hair.
• Parameter logic: increase fluence carefully on 4 mm for low-melanin hair; on 8 mm, start high enough for end-points on dark hair. 

Indications & areas

• Unwanted hair the face, axillae, bikini, trunk, and limbs; suitable for all phototypes, including tanned skin, with protocols adapted to hair color/diameter and zone.
• Hirsutism  and hypertrichosis are not contraindications.

How QOOL compares to other laser/IPL methods

• Versus long-pulse/diode/IPL: long millisecond pulses heat skin for longer and rely solely on thermal selectivity; QOOL’s pulse-train deposits heat inside the hair while skin cools in the gaps, and adds acoustic assistance—improving comfort and broadening suitability across skin tones.
• Versus single-shot nanosecond devices: classical short-pulse systems struggle to deliver enough energy at follicle depth without over-concentrating it superficially; QOOL uses pulse trains to reach the bulb and stay below skin injury thresholds.

Benefits at a glance

For patients

• Safe for all phototypes—including tanned skin (protocol-guided).
• Comfortable: usually no anesthesia or contact cooling needed.
• Predictable end-points and quick return to routine. 

For practitioners

• High selectivity with lower skin load: optical + thermal + nonlinear mechanisms focused on the hair, not the skin.
• Efficient workflow: scanning passes at 1–5 Hz, presets by hair/skin type & zone, and no contact gels needed.
• Versatility: effective on dark and light/red hair (adjust spot/fluence). 

Key takeaway

QOOL-epilation® delivers selective, comfortable hair removal for any skin type by using millisecond-long trains of nanosecond pulses at 1079 nm—a design that heats the hair while giving the skin time to cool, with acoustic assistance to disrupt the follicle. It’s a clinic-friendly, year-round solution on the MULTILINE™ platform.