The science of light

What red light therapy
actually does for you

Red light therapy — also known as photobiomodulation — uses specific wavelengths of red and near-infrared light to stimulate cellular function. Below is a closer look at each major benefit, the science behind it, and what the Spare Sun panel delivers.

Two wavelengths. Two depths. One panel.

Spare Sun delivers 660nm red light and 850nm near-infrared light simultaneously — covering surface-level skin benefits and deep tissue benefits in every single session.

660nm
Surface
850nm
Deep tissue
660nm 01 — Skin

Skin rejuvenation

660nm red light is absorbed efficiently by skin cells, where it stimulates fibroblasts — the cells responsible for producing collagen and elastin. These two proteins are what keep skin firm, elastic, and smooth. As we age, fibroblast activity naturally declines, which is part of why skin loses firmness over time.

Regular exposure to 660nm light has been shown to increase collagen density, improve skin texture, reduce the appearance of fine lines, and even out skin tone by reducing inflammation-related redness.

What to expect
Texture and tone improvements typically begin within 2–4 weeks of daily use. Fine lines and firmness improvements compound over 8–12 weeks.
How to use it
6 inches from clean, bare skin. 10 minutes. Eyes closed or protective eyewear. Daily for best results.
850nm 02 — Recovery

Muscle recovery

850nm near-infrared light penetrates significantly deeper than 660nm — reaching muscle fibres, tendons, and joint tissue. At this depth, light energy is absorbed by mitochondria, boosting ATP (cellular energy) production and accelerating the cellular repair processes that occur after exercise.

This translates to reduced inflammation, decreased oxidative stress, and faster clearance of metabolic by-products from muscle tissue — the combination of which is widely reported as reduced soreness and quicker return to training.

What to expect
Reduced post-exercise soreness can be noticeable within days. Cumulative recovery improvements build over 2–4 weeks of consistent use.
How to use it
6–10 inches from the affected muscle group. 10–20 minutes. Most effective directly before or after training.
660nm + 850nm 03 — Energy

Energy & focus

At a cellular level, both wavelengths are absorbed by cytochrome c oxidase — an enzyme in the mitochondria that plays a central role in ATP production. ATP is the energy currency your cells run on. More efficient ATP production means more available cellular energy throughout the body.

Many users describe this as a noticeable lift in mental clarity and sustained energy — particularly when sessions are done in the morning, setting a positive cellular tone for the rest of the day.

What to expect
Some users report a difference after the first few sessions. More consistent, noticeable energy shifts build over 1–2 weeks of daily morning use.
How to use it
6–12 inches, 10 minutes, ideally within an hour of waking. Face and upper body exposure works well.
660nm 04 — Sleep

Sleep quality

Unlike blue light — which suppresses melatonin production and signals to your brain that it's daytime — red light does not interfere with your circadian rhythm. Evening exposure to red light has been shown to support natural melatonin production, helping the body transition into a restful state.

This makes red light therapy a useful addition to an evening wind-down routine — particularly for those who spend their evenings around screens, where blue light exposure is already working against sleep onset.

What to expect
Many users notice improved sleep onset within the first few days. Sleep quality improvements continue to build with consistent evening use.
How to use it
10 minutes, 30–60 minutes before bed. Dim other lights in the room during your session for best effect.
850nm 05 — Joints

Joint & pain relief

850nm near-infrared light reaches deep enough to affect joint tissue, tendons, and ligaments. At this depth it helps reduce inflammatory markers and supports the body's natural tissue repair processes — both of which contribute to chronic discomfort when left unmanaged.

This makes it particularly useful for areas that experience repetitive strain or chronic stiffness — knees, lower back, shoulders, and hands — as well as general post-exercise joint soreness.

What to expect
Some users notice reduced stiffness within the first week. More significant changes in chronic discomfort typically build over 3–4 weeks.
How to use it
6–10 inches directly over the affected joint. 10–20 minutes. Can be used daily, including on both sides of a joint for full coverage.
660nm 06 — Hair

Hair growth

Hair follicles are highly metabolically active — they require significant cellular energy to produce new hair. 660nm red light increases blood flow to the scalp and boosts ATP production within follicle cells, supporting the follicle's natural growth cycle.

This is one of the slower benefits to materialise — hair growth cycles are measured in months, not weeks — but consistent use over a sustained period has been shown to improve hair density and thickness in clinical settings.

What to expect
This is the slowest benefit to show. Measurable density improvements are typically seen at 16–24 weeks of consistent use.
How to use it
6 inches from the scalp, parting hair to expose skin where possible. 10 minutes, daily.
Curious how it works?
See the step-by-step process and full panel specifications.
How it works