What’s Actually Happening When You’re In a Red Light Therapy Session?
What’s Actually Happening When You’re Under the Red Light?
Red light therapy, explained in plain English
If you’ve ever lain under a panel of red light and quietly wondered whether anything is really happening or whether it’s just a pleasant warm glow that relaxes you, you’re asking exactly the right question. So here’s how red light therapy actually works, explained without the jargon.
It’s the question I hear most often usually from women who’ve done their reading and want something more substantial than a wellness buzzword before they commit to a protocol.
Your cells run on tiny batteries
Inside almost every cell in your body are structures called mitochondria. Think of them as tiny batteries. They take in oxygen and nutrients and produce the energy your cells need to do their work; repairing tissue, calming inflammation, or simply getting you through the day. That energy is stored in a molecule called ATP.
When your mitochondria are working well, your cells have the fuel to repair and recover. When they’re sluggish, through age, stress, illness or injury, everything tends to slow down with them.
How red light therapy works at the cellular level
Red and near-infrared light therapy — the clinical term is photobiomodulation — works at this cellular level. There are hundreds sometimes thousands of mitochondria in every cell. A particular part of the mitochondria is very good at absorbing red and near-infrared light. Research suggests that when it does, it helps the mitochondria produce energy more efficiently. One way this is thought to happen is that the light eases off a kind of internal “handbrake” on energy production, allowing the cell to get back to work. The result, studies indicate, is more cellular energy and a calmer inflammatory response. The detailed science is reviewed by Hamblin (2018) if you’d like to go deeper. There are now over 200,000 studies on red light therapy.
The science, in a little more detail
If you like the detail, here’s what’s actually happening. That “particular part of the mitochondria” is an enzyme called cytochrome c oxidase — Complex IV in the cell’s energy-production line (the electron transport chain). It carries copper and haem centres that absorb red and near-infrared light especially well.
Under stress, illness or inflammation, a molecule called nitric oxide can bind to cytochrome c oxidase and block it — a bit like a spanner in the works — which slows energy production and limits how much oxygen the cell can use. Research suggests that red and near-infrared light photodissociates (essentially knocks loose) that nitric oxide, freeing the enzyme to take up oxygen again and restart the electron transport chain.
The knock-on effects are what matter clinically: a stronger electrical gradient across the mitochondrial membrane, more ATP (the cell’s energy currency), a brief signalling burst of reactive oxygen species that switches on repair-related genes, and the released nitric oxide supporting local blood flow. Together, studies indicate, this is how a few minutes of light can translate into better cellular energy, reduced inflammation and improved recovery.
What red light therapy can help with
This is the part that matters to you. More cellular energy isn’t an abstract idea — it’s the foundation for the things people actually come to me for. Over a committed course of 4-12 sessions relatively close together because red light therapy has cumulative benefits, my clients report less joint stiffness, faster recovery after training or injury, reduced inflammation, better skin and hair health, and improved sleep to name a few outcomes.
Increasingly, I also work with people managing more complex health challenges — and the same underlying mechanism helps explain why:
Peripheral neuropathy —
the numbness, tingling and burning that can follow chemotherapy or come with diabetes. Because near-infrared light reaches the deeper tissue where nerves sit, and research suggests it supports local circulation and calms inflammation, clients living with neuropathy often report greater comfort and more sensation over a course of sessions.
Lymphoedema —
the swelling and tissue tightness that can follow and injury, cancer treatment or surgery. Studies indicate light therapy may help soften hardened tissue and support lymphatic flow, and it’s an area of active research here in Australia. I always work alongside a client’s medical team, never in place of them.
The side effects of chemotherapy —
particularly sore, inflamed mouths (oral mucositis), fatigue and fragile skin. This is one of the better-studied uses of red light therapy, and clients going through treatment report it takes the edge off some of what they’re managing. At Red Light Therapy Melbourne, we work alongside a client’s oncology team and with their oncologist’s approval.
The research is still developing and results vary from person to person, but the underlying mechanism is that red light therapy supports your cells’ own energy production, circulation and repair. This is well documented and increasingly well understood.
Red light vs near-infrared light: what’s the difference?
Here’s something most people don’t realise: not all of these wavelengths do the same job, and it comes down to how deep they travel into the body.
- Red light (around 630–700nm) is absorbed mainly at the surface — your skin and the tissue just beneath it. It’s well suited to skin health, wound healing and surface inflammation.
- Near-infrared light (around 800–850nm) is invisible to the eye but travels further, reaching muscle and joints. It’s the wavelength I reach for when someone’s concern sits deeper — persistent joint pain, muscular tension, recovery.
Both sit within what scientists call the skin’s “optical window” — the narrow band of light that passes into the body most easily. Outside that window, light is mostly absorbed right at the surface and never reaches where it’s needed. If you’re curious how this has been measured, Ash and colleagues (2017) modelled exactly how wavelength affects depth.
This is why the wavelength — and the practitioner — matter
A red light bed on its own is just light. What makes the difference is matching the right wavelength, intensity and protocol to what your body actually needs — and that starts with an assessment, not a timer. Once you understand that red works at the surface and near-infrared reaches deeper, it’s easy to see why a one-size-fits-all session isn’t the same thing as a protocol tailored to your concern. That tailoring is the heart of what I do.
If you’re wondering whether red light therapy could help with what you’re dealing with — pain, inflammation, sleep, recovery or skin — I’m always happy to talk it through. Send an email to info@redlight-therapy.com.au we’ll work out whether it’s the right fit for you, and what a sensible protocol would look like.
Frequently asked questions about red light therapy
Does red light therapy actually work?
Research suggests red and near-infrared light is absorbed by your cells and can support how efficiently they produce energy. The evidence is strongest for skin health, inflammation and recovery, and it’s still developing in other areas. In my clinic, clients report meaningful improvements over a committed course of sessions, though results vary from person to person.
What’s the difference between red and near-infrared light?
Red light (around 630–700nm) works mainly at the surface — your skin and the tissue just beneath it. Near-infrared light (around 800–850nm) is invisible to the eye and travels deeper, reaching muscle and joints. Which one suits you depends on what you’re trying to address, which is why I tailor each protocol.
How deep does red light therapy penetrate the skin?
It depends on the wavelength. Longer (near-infrared) wavelengths reach deeper than red, because the body scatters them less. Exactly how deep also depends on your skin, the area being treated and the device — which is why the blanket “number of millimetres” claims you see online are best treated with caution.
How many sessions will I need?
A single session can offer short-term relief, but most of the documented benefits come from a committed protocol over several weeks. I’ll recommend a realistic plan based on your goals at your first session.
Is red light therapy safe?
Red and near-infrared light therapy is non-invasive and generally well tolerated. I always take a health history first and, where relevant, work alongside your GP or specialist where neccessary.
