Red Light Therapy: How Long to See Results in Your First Month

By the WECCT Care Editorial Team · Published 14 October 2026

The most common question before a first purchase is simple: red light therapy, how long to see results? It deserves a straight answer, and the straight answer is that nobody can tell you in advance, including us. What we can do is set out what the published research supports, what people tend to report, and how to decide after a month whether the routine is worth keeping.

We are not going to promise you a result. We are also not going to pretend the evidence is stronger than it is. Both of those things would be easier to write, and neither would be useful to you.

We are not going to promise you a result

Read the conclusion of the most favourable review in this field and you will find a hedge. A 2024 systematic review and meta-analysis in Physical Therapy pooled ten randomised placebo-controlled trials with 542 participants and reported a moderate reduction in the pain-at-rest score. Then it graded the certainty of the evidence as very low and concluded that using light therapy on its own is not justified, while it may be used as an addition to other widely recommended approaches.

"May be used as an addition" is not a promise. It is the most that a careful reading of the evidence allows, and it is the basis on which we describe these devices anywhere on this site.

Red light therapy: how long to see results

There is no fixed timeline, and anyone offering one is guessing. What the research does tell you is the shape of the thing.

Two findings are worth knowing before you start, because they prevent disappointment later. The first comes from a meta-analysis in Archives of Physical Medicine and Rehabilitation covering 14 randomised controlled trials in people aged 60 and over. It found significant improvements in overall joint scores, pain and movement range. It also found no significant improvement on the stiffness measure specifically. If stiffness is your main complaint, that is a result you should hear from us rather than discover for yourself.

The second is that different studies used very different wavelengths, doses and durations, which is the main reason an earlier review of nine randomised trials concluded that the evidence available at the time did not support using this kind of light for knee osteoarthritis at all. When studies disagree that much, the honest summary is that the effect, if there is one, is small and inconsistent.

So what does that mean for a first month? Realistically, approach the first month as a test of whether the routine fits your life, not a test of whether the device works. Those are different questions, and the first one is the one you can actually answer.

Week one: getting used to it

The first week is about repetition, not results. Set the device up in the position you expect to use it most, keep it on the second of the five levels, and set the timer for twenty minutes. Do not climb through the levels looking for something to happen. Research on this kind of light has described a biphasic dose response, in which low and high doses have been associated with different directions of effect, so more is not automatically better.

Two practical things to sort out in week one. First, where the device lives between sessions; if it ends up back in a cupboard, the routine has already failed. Second, what you do during the twenty minutes. If the answer is "watch the clock", the routine will not last. Reading, a programme, a phone call or a rest all work better.

Things to watch for in week one are simple: any skin irritation, any discomfort rather than a mild sensation, or a session that feels like a chore on the first day. The last one is worth taking seriously, because it rarely improves.

Weeks two and three: what people report

By the second week, the routine is either happening or it is not. This is the point at which the honest reporting has to come in, because we are describing reports from users, not outcomes from a trial.

What people report most often is not a change in a joint. It is that the routine was easier to keep than they expected, precisely because it asks nothing while it runs. Many people say the twenty minutes became the quietest part of the day. Some people find that getting up afterwards feels a little easier, which is a modest thing to say and is as far as we will go. Others notice nothing at all, and that is a common experience rather than a sign that something has gone wrong.

If you are looking for the kind of change you can point at, the first month is unlikely to deliver one. That is the expectation the evidence supports, and it is better to hold it now than to be disappointed in week five.

Week four: deciding whether to carry on

At the end of the first month, ask three questions rather than one.

Is the routine happening? If you are using it four or five times a week without effort, that is the main thing the first month was for. If you are using it once a week and resenting it, the format is probably wrong rather than the device being useless. A wearable instead of a mat, or a different placement, may fix that.

Does it fit your day? If sessions only happen when you remember, move the device. Somewhere visible beats somewhere tidy every time. The easy-use mat rolls up to fit beside a bed or in a cupboard, which makes it easy to keep within reach rather than out of sight. The wider choice of surfaces is laid out in the light therapy mats collection, and if lying down is the obstacle, a wearable from the light therapy belts range can be worn while you get on with things.

Would you miss it? This is the honest test, and it is worth trusting. Many people say they keep using it because it gives them twenty quiet minutes that they would not otherwise take. That is a legitimate reason to carry on. It is not a reason to expect a clinical outcome, and we would rather you knew the difference.

Four things that change the experience

Regularity. A short session most days is a better bet than a long session occasionally. One-off use has no good rationale behind it.

Position. Contact matters more than settings. A mat on a soft mattress that bunches under the hips is not doing what a mat on a firm surface does. Check that the surface is actually touching the area you care about.

Duration in the wrong direction. Longer is not better here. Published guidance recommends modest doses, and the biphasic dose response described in the literature is a reason to stay low.

Individual difference. Age, skin tone, the thickness of tissue over the joint and how much someone moves during the day all affect what a session feels like. Two people using the same device at the same setting will not have the same experience, and neither of them is wrong.

When to stop and ask a doctor

Stop and speak to a doctor if you notice any of the following:

• Skin irritation, redness or discomfort that does not settle
• A joint that becomes swollen, hot or more painful after starting
• Any new symptom you cannot explain
• Medication changes, particularly anything that makes your skin sensitive to light
• No change at all after a month, combined with symptoms that are getting worse

That last one is important. This is a comfort routine, not a diagnostic tool. If something is getting worse, stopping the routine and getting a professional opinion is the right sequence, not the other way round.

Frequently Asked Questions

Q: How long does light therapy take to work?

There is no fixed timeline and no reliable way to predict one. The published research describes effects as small and inconsistent, so the practical approach is to approach the first month as a test of whether the routine suits your day.

Q: How soon will I notice a difference?

Some people report that getting up after a session feels a little easier within the first few weeks. Many report nothing in the first month. Both are normal.

Q: Should I use a higher level to get there faster?

No. Published dosage guidance for this kind of light is modest, and the research describes a biphasic dose response in which low and high doses have been associated with different directions of effect. Stay on the lower levels.

Q: What if it does nothing after a month?

Then you have learned something useful for the price of one device. Warmth and daily movement are cheaper, better established and worth prioritising. There is no obligation to keep going with something that has stopped earning its place.

This article is for general information only and is not medical advice. If you have ongoing health concerns, speak to a qualified healthcare professional.

References

1. Oliveira S, Andrade R, Valente C, et al. Effectiveness of photobiomodulation in reducing pain and disability in patients with knee osteoarthritis: a systematic review with meta-analysis. Physical Therapy, 2024. https://pubmed.ncbi.nlm.nih.gov/38775202/
2. Li B-M, Zhang C-K, He J-H, et al. The effects of photobiomodulation on knee function, pain, and exercise tolerance in older adults: a meta-analysis of randomized controlled trials. Archives of Physical Medicine and Rehabilitation, 2024. https://pubmed.ncbi.nlm.nih.gov/37419235/
3. Current advances of photobiomodulation therapy in treating knee osteoarthritis. Frontiers in Cell and Developmental Biology, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC10687633/
4. Tanya S, Srisilapanan P. Clinical efficacy and safety of photobiomodulation therapy for orofacial conditions in older adults: a systematic review of randomized controlled trials. Dentistry Journal, 2026;14(4):231. https://www.mdpi.com/2304-6767/14/4/231