Red Light Therapy and Your Thyroid: The Research

You've had your bloods done. Probably twice, maybe three times by now. And both times you've sat across from someone who looked at the numbers, told you everything's within range, and sent you on your way. Fine. Except you're not. You're cold when everyone else isn't, your hair's thinner than it was a couple of years ago, you need a nap by 2pm most days, and "fine" just doesn't match how you actually feel walking around in your own body. If any of that sounds familiar, you've probably already gone down the rabbit hole of reading about Hashimoto's, thyroid antibodies, and whether there's anything you can actually do beyond waiting for the numbers to get bad enough that someone takes it seriously.

This is one of the questions I get asked more than almost anything else, so let's get into what the research on red light therapy and the thyroid actually says. A handful of small, peer reviewed studies from a research group in Brazil have used low-level laser therapy, applied directly over the thyroid, in people with hypothyroidism caused by chronic autoimmune (Hashimoto's) thyroiditis. The results showed improvements in thyroid antibody levels, thyroid blood flow on ultrasound, and in some participants, a reduced need for levothyroxine to maintain normal hormone levels. This is early stage research, with small sample sizes, and it is absolutely not a replacement for thyroid medication, but it's an interesting signal worth understanding.

The studies, and what they actually found

The main body of work here comes from Danilo Höfling and colleagues at the University of São Paulo. Their first randomized, placebo-controlled trial applied low-level laser (830nm) directly over the thyroid in patients with Hashimoto's-induced hypothyroidism, twice a week for ten sessions, then followed them for nine months. The laser group needed a lower dose of levothyroxine to stay in normal range compared to the placebo group, and showed reductions in thyroid antibodies (TPOAb and TgAb). You can read the full study here: https://pubmed.ncbi.nlm.nih.gov/22718472/.

A related study from the same group used colour Doppler ultrasound to look specifically at blood flow within the thyroid gland itself before and after treatment, and found measurable improvements in vascularisation in the laser group compared to placebo. That one's here: https://pmc.ncbi.nlm.nih.gov/articles/PMC3534372/.

Then, six years later, the same researchers went back and followed up with the original participants to check on safety and whether the effects had held. They looked specifically at the frequency of thyroid nodules and the long-term hormone picture in both groups. That long-term follow-up is here: https://pmc.ncbi.nlm.nih.gov/articles/PMC6247385/.

Three studies, same small Brazilian cohort, but a consistent picture, lower medication requirements, reduced antibodies, better blood flow on imaging, and nothing alarming on long-term safety follow-up. That's not nothing. It's also not enough to build a treatment protocol on its own, and nobody serious is claiming it replaces levothyroxine.

Why light might do anything to a gland at all

Here's where it connects to everything else I write about. The proposed mechanism for photobiomodulation generally is that red and near-infrared light gets absorbed by cytochrome c oxidase in the mitochondria, which can increase ATP production and reduce oxidative stress inside cells. The thyroid is an extremely metabolically active gland, it has a huge mitochondrial density relative to its size, because making thyroid hormone is energetically expensive. In autoimmune thyroiditis, the gland is under constant low-grade attack from the immune system, which is itself an inflammatory, energy-demanding process.

So the theory isn't that light "fixes" an autoimmune condition. It's that supporting mitochondrial function in a gland that's working under chronic immune stress might shift the balance slightly, less inflammation, better local blood flow, cells that are better resourced to cope. That's a much more modest claim than "red light cures Hashimoto's", and it's the claim the actual research supports.

This isn't me telling you to stop your medication

I want to be really direct about this, because I know how these things get read. If you're on levothyroxine, or any thyroid medication, this is not a reason to stop, reduce, or skip doses without your doctor involved. The Höfling studies didn't have participants stop medication, they measured whether the dose needed to stay adjusted downward over time, under medical supervision, with blood tests. That's a completely different thing to someone deciding off their own back that a red light panel means they don't need their prescription anymore.

If you've got Hashimoto's, or suspect you might, the actual useful move is to get properly tested (TSH alone often isn't enough, ask about free T3, free T4, and thyroid antibodies), work with your doctor, and think of something like red light therapy as a possible adjunct sitting alongside that, not instead of it. So go on, when did you last actually get the full antibody panel done, rather than just TSH?

How this might fit into a routine, practically

The studies used a laser device applied directly over the thyroid, at the base of the front of the neck, for short sessions a couple of times a week. With an LED panel at home, that translates roughly to standing or sitting with the neck area exposed to the panel for a short session, the kind of dose and distance guidance I've written about elsewhere applies here too, this is very much a less-is-more area given how sensitive the thyroid is to both too little and too much of almost everything.

This is also a good moment to mention the biphasic dose response again, because I think it matters more here than almost anywhere else. The thyroid is a gland that responds to tiny shifts, that's the whole point of a hormone feedback system. If a little light exposure to the neck area might support mitochondrial function, there's no reason to assume more is automatically better, and I'd treat short, consistent sessions as the sensible default rather than long ones. I've written more generally about this idea here: why the right dose of red light therapy matters.

If you want the wider picture on red light and hormones generally, thyroid, menstrual cycle, testosterone, I covered that here: red light therapy for hormonal balance. And if you're the sort of person who likes reading the primary research rather than summaries, I do a regular roundup of what's actually been published, which you can find here: red light therapy 2025, a half-year review of significant papers.

If you want to look at the panels and smaller portable devices that would actually work for neck placement, the portable and specialist devices collection has the smaller units, and the red light panels collection has the full sized options. And if you've had bloods done and you're trying to work out whether any of this is relevant to your specific numbers, message me, I'm not a doctor and I won't pretend to be one, but I'm happy to talk through what the research does and doesn't say.

Disclaimer: This post is for educational purposes and does not constitute medical advice. Thyroid conditions, including Hashimoto's thyroiditis, require diagnosis and ongoing management by a qualified healthcare professional. Never stop, start, or adjust thyroid medication without medical supervision. If you have a thyroid condition, speak with your doctor before starting red light therapy.

Frequently Asked Questions

Can red light therapy replace my thyroid medication?

No. The research on red light therapy and the thyroid, while promising, is based on small studies where participants remained on their medication, with dose adjustments made and monitored by doctors using blood tests. Stopping or reducing thyroid medication without medical supervision can have serious health consequences. Red light therapy should be considered, if at all, as something discussed with your doctor alongside your existing treatment, not instead of it.

Where do you point a red light panel for thyroid support?

The research studies applied low-level laser directly over the thyroid gland, at the base of the front of the neck, just below the Adam's apple area. With a home panel, this would mean positioning yourself so that area of the neck is exposed to the light for a short session, following general dosing guidance for distance and time.

Is red light therapy safe to use if I have Hashimoto's thyroiditis?

The available research, including a long-term follow-up study, did not identify safety concerns with low-level laser applied to the thyroid in people with Hashimoto's, but the studies were small. If you have Hashimoto's or any autoimmune thyroid condition, speak with your doctor before starting red light therapy, particularly around the neck and thyroid area.

How long before you'd see any change in thyroid markers?

In the research, sessions were given twice weekly over several weeks, with thyroid antibody levels, blood flow on ultrasound, and medication requirements assessed over a follow-up period of nine months. This isn't a fast intervention, and any changes to thyroid hormone levels or medication should only be assessed and adjusted through blood tests ordered by your doctor, not by how you feel.

Kan rødlysterapi hjelpe med Hashimotos tyreoiditt?

Noen små studier fra Brasil har funnet at lavnivå laserbehandling rettet mot skjoldbruskkjertelen hos personer med Hashimotos kan være knyttet til lavere behov for tyroksindosering, reduserte antistoffnivåer og bedre blodgjennomstrømning i kjertelen, målt over ni måneder. Dette er tidlig forskning med få deltakere, og det er ikke en erstatning for medisinering. Snakk alltid med legen din før du justerer noe knyttet til skjoldbruskkjertelen.

References

Höfling DB, Chavantes MC, Juliano AG, et al. Low-level laser in the treatment of patients with hypothyroidism induced by chronic autoimmune thyroiditis: a randomized, placebo-controlled clinical trial. Lasers in Medical Science. 2013. https://pubmed.ncbi.nlm.nih.gov/22718472/

Höfling DB, Chavantes MC, Juliano AG, et al. Assessment of the effects of low-level laser therapy on the thyroid vascularization of patients with autoimmune hypothyroidism by colour Doppler ultrasound. ISRN Endocrinology. 2012. https://pmc.ncbi.nlm.nih.gov/articles/PMC3534372/

Höfling DB, Chavantes MC, Buchpiguel CA, et al. Safety and efficacy of low-level laser therapy in autoimmune thyroiditis: long-term follow-up study. International Journal of Endocrinology. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6247385/