Red light therapy claims to heal wounds, improve pain and reduce wrinkles. But the evidence for it working is dim | Antiviral

The world of wellness is constantly expanding. There are new fads coming out almost every week, from the weird new mushroom powders that are suddenly essential for everyone’s health to the newest diet that is supposed to shave kilograms off your figure. It’s a quagmire of unproven, disproven and almost certainly ineffective things that grows every day.

But one mainstay is red light therapy. While red lights are seeing a massive renewed surge in popularity – it’s hard to go on TikTok or Instagram without being assaulted by at least one very confusing video of a person wearing what appears to be a horror mask shining red light on their face – they’ve been around for quite some time. You can find people discussing red light and its possible benefits all the way back to the 1990s.

The question is, then, what in the world can shining red lights on your skin actually do?

A mountain of studies but the evidence is unclear

Given the decades of interest we have in this technology, we should have a very solid answer. If this was a standard medical treatment, we’d have dozens of high-quality studies, probably funded at least in part by the sale of expensive red light machines.

But this is wellness, not medicine, and so the evidence is far less clear. If you go online, there are pretty amazing claims made about red light therapy – it causes cellular regeneration, it can heal wounds, reduce pain and help with acne. The therapy is also meant to reduce wrinkles, rejuvenate your skin and make you appear younger in just a few short sessions.

The data behind all of this is remarkably weak. It is very easy to run a small trial on red light therapy because all you need is a few red LEDs and some people willing to lend you their skin. That has led to a massive proliferation of papers looking into various applications of the treatment. The problem is that most of these trials are small and very poorly done.

Here’s an example of a trial conducted by a “medical light” company that used their own employees as the control group. Another study I found has fairly obvious errors in their percentages, as well as numeric inconsistencies within the paper.

We have limited information on what really works

This seems to be fairly common in the literature. There are quite literally thousands of papers looking at shining LEDs on people’s skin for everything from post-operative pain to acne scars. Most of them are tiny, poorly controlled and tell us very little about whether these treatments do anything. There’s very little standardisation as well – the wavelengths of the light are important, as is the intensity and the length of each red light session. Most of the papers just make a judgment call, which means that even in a best-case scenario we have limited information on what really works.

It is also basically impossible to blind people to their therapy – you can tell if you’re not getting the red light – and most of the measurements are very subjective. For example, researchers may be subconsciously influenced to measure wrinkles differently if they know whether the person in question got the red lights or was in the placebo group. Some of the studies control for some of these things but they are quite challenging to eliminate completely from the experimental design.

Not every study is terrible but don’t expect miracles

Despite all of this, I was somewhat surprised. While there certainly isn’t what I’d consider to be strong evidence, there’s at least a bit of data supporting the use of red light therapy. Some of it is so bad I would ignore it entirely but not every study is that terrible.

Without strong evidence, or at least one decent trial, I don’t think we can know with any sureness whether shining red lights on to your skin does anything. It’s possible that it might reduce your wrinkles but the evidence is really quite weak.

If I had really bad acne scarring, or a wound that was healing very slowly, I might try pointing some red LEDs at it. At worst, you’ve wasted some money and look a bit foolish, and there’s some evidence it might have a benefit. Just don’t expect miracles – it is, after all, just a bit of light shining on your skin. You could probably get a similar benefit from a 10-minute walk outside.

Dr Gideon Meyerowitz-Katz is an epidemiologist and science communicator and a senior research fellow at the University of Wollongong

Antiviral is a fortnightly column that interrogates the evidence behind the health headlines and factchecks popular wellness claims