How long should a red light session last?

A rule of thumb is about 10 minutes at 20 cm with a strong device. At a greater distance, sessions get longer. Try what works for your skin within that range.

How often can I use red light?

Ideally every day. Up to three times a day is possible if a few hours pass between sessions.

What is the difference between red and near-infrared light?

Red light (peak 660 nm) is visible and reaches skin level. Near-infrared (peak 850 nm) is invisible and reaches deeper tissue. Helsi™ panels have half red and half near-infrared LEDs.

Does red light therapy have side effects?

Used correctly it is very safe. The skin may be slightly red and warm afterwards, which fades quickly. If your skin reacts strongly or unpleasantly, stop and ask a doctor.

Do I need safety goggles?

If the brightness is uncomfortable, yes. Helsi™ panels come with safety goggles.

Which Helsi™ panel is right for me?

It depends on the area: Go for travel, Mini for face and targeted areas, Plus for half the body, Pro and Max for the full body. The device finder helps in 60 seconds.

Learn · Red light

What is red light? Red and near-infrared explained

Updated 2 October 2026

Red light therapy uses red light around 660 nm and near-infrared around 850 nm from LEDs. Unlike the classic heat lamp it works with hardly any heat: the light itself is taken up by the cells.

In short

Red light therapy (photobiomodulation) exposes the skin to red light (600–660 nm) and near-infrared (800–850 nm). Helsi™ panels use flicker-free 5 W LEDs, half red and half near-infrared. A common rule of thumb is about 10 minutes at 20 cm, ideally every day.

Red: 660 nm
Near-infrared: 850 nm
Rule of thumb: 10 min at 20 cm
Panels: Go to Max

What are red and near-infrared light?

Visible light runs from about 380 to 780 nm. Red light sits at the long end, at around 650 to 780 nm. Infrared starts right next to it. For therapy and wellness, the range from 780 to 1,400 nm matters most: near-infrared.

You can see red light, but not near-infrared. Helsi™ panels combine both: red peaking at 660 nm for the skin level and near-infrared peaking at 850 nm for deeper tissue.

Visible light (380–780 nm) and near-infrared (780–1,400 nm). Helsi™ LEDs: red peaking at 660 nm, near-infrared peaking at 850 nm.

Red light therapy is not the classic heat lamp

The classic red lamp is a bulb with a filter. It mainly gives off heat, which widens blood vessels and boosts circulation. Used too close or too long, it can burn the skin.

LED red light therapy works with hardly any heat. It relies on light of specific wavelengths that reaches the cells. LEDs can be arranged in panels to cover large areas of the body at once, and they need none of the safety measures of medical lasers.

What happens in the cell?

Red and near-infrared light penetrate the tissue. The mitochondria, the power plants of the cells, respond to it most. They produce the energy carrier ATP. Studies investigate whether light at these wavelengths affects ATP production. The process is called photobiomodulation.

What people use red light for, and what studies look at

Red light therapy is well researched. The areas below are the subject of studies Helsi™ links on its pages. They describe research, not promises for a particular device.

Recovery after exercise: studies look at muscle soreness, fatigue and recovery after exertion.
Performance: research includes strength, endurance and time to exhaustion.
Sleep: one study looked at red light in the evening and sleep quality in female athletes. Many people use the warm, soft light as an evening routine.
Skin: collagen production, which is linked to fine lines, is under study.

Studies

None of these studies used Helsi™ devices.

How to use it: distance, duration, frequency

How long and how often depends on your goal, the part of the body and how your skin responds. The skin should be free of clothing and make-up.

As a rule of thumb for a strong device: at 20 cm and an intensity above 100 mW/cm², cells take up about 6 joules per minute. With around 60 joules as the upper limit, that makes about 10 minutes. At a greater distance, sessions get longer.

Regularly: ideally every day. Up to three times a day is possible, with a few hours in between.
Routine: plan red light as a fixed slot over several weeks, not as a one-off session.
Afterwards the skin may be slightly red and warm. If so, shorten the session or increase the distance.

Safety

Used correctly, red light therapy is very safe. Keep three things in mind:

Eyes: wear goggles if the brightness is uncomfortable. Helsi™ panels come with safety goggles.
Skin: only expose healthy or slightly irritated skin. With a rash or skin changes, check with a doctor first.
Medication: some drugs make the skin more sensitive to light (for example some antibiotics and acne treatments). If unsure, ask a doctor first.