If you have Hashimoto's thyroiditis or an underactive thyroid, you may have read that red light therapy can help the thyroid, or even reduce the need for medicine. This guide looks at the trials those claims come from, what they actually found, why they are not yet enough to change treatment, and what to discuss with your GP or endocrinologist.
Important: thyroid conditions are not an approved use of THOR devices in the UK, and we make no treatment claims for them. Never stop or change your thyroid medicine without speaking to your GP or specialist.
Quick answer
A small set of studies from one research team in Brazil tested low-level laser applied directly over the thyroid in people with an underactive thyroid caused by autoimmune thyroiditis (Hashimoto's). In a placebo-controlled trial of 43 people, those who had laser needed a lower dose of levothyroxine nine months later, and a six-year follow-up reported that a lower dose was still needed. These results are interesting, but the studies are small, come from a single team, and used a targeted laser at a set dose, not a whole-body bed or a home panel. Levothyroxine remains the treatment for an underactive thyroid.
Hashimoto's and an underactive thyroid
An underactive thyroid (hypothyroidism) means the thyroid gland does not make enough thyroid hormone. In the UK the most common cause is the immune system attacking the thyroid, known as Hashimoto's disease or autoimmune thyroiditis. The NHS treats an underactive thyroid with levothyroxine tablets taken every day, with regular blood tests to check the dose is right, and most people need treatment for life.
Symptoms can include tiredness, weight gain, feeling low, feeling cold, dry skin and hair, and aching muscles. They overlap with many other conditions, so a blood test is the only way to know. Our guide to underactive thyroid symptoms explains more.
What the thyroid laser trials found
All four papers below come from the same research team at the University of São Paulo and describe the same group of 43 patients, all already taking levothyroxine. Each person had 10 sessions of 830 nm low-level laser applied over the thyroid, or 10 placebo sessions, twice a week. Levothyroxine was stopped under medical supervision 30 days later, and the dose each person then needed to keep normal hormone levels was measured over the following nine months.
- Randomised trial, 2013, Lasers in Medical Science. 23 people had laser and 20 had placebo. Nine months after levothyroxine was stopped, the laser group needed an average of about 39 micrograms a day to keep normal hormone levels, compared with about 107 micrograms in the placebo group. Levels of one thyroid antibody (TPO antibody) were lower in the laser group, while another (thyroglobulin antibody) did not differ.
- Doppler ultrasound, 2012, ISRN Endocrinology. In the same patients, a normal pattern of blood flow in the thyroid was seen more often after laser than after placebo, on scans 30 days after treatment.
- Blood marker, 2014, Photomedicine and Laser Surgery. Levels of TGF-beta1, a signalling protein involved in regulating the immune system, rose 30 days after laser compared with placebo. The authors said further studies were needed to confirm what this means.
- Six-year follow-up, 2018, International Journal of Endocrinology. The follow-up reported on 43 people, 25 in the laser group and 18 in the placebo group. Three people in each group had a thyroid nodule, and those in the laser group were all classed as benign. The laser group still needed a significantly lower levothyroxine dose, and the authors concluded the treatment was safe.
Why these results are not enough to change treatment
- One team, one group of patients. All four papers describe the same 43 people. In the research we have reviewed so far, we have not found an independent trial repeating the result.
- Small numbers. 43 people is a small trial, and a single small study can overstate an effect.
- A targeted laser at a set dose. The light was applied by clinicians directly over the thyroid. The results do not tell us what a whole-body bed, a face mask or a home panel would do.
- UK treatment is levothyroxine. NICE guideline NG145 on thyroid disease recommends levothyroxine as the first treatment for primary hypothyroidism.
Do not stop your thyroid medicine
In the trial, levothyroxine was stopped only under close medical supervision, with regular blood tests. Stopping or cutting your dose on your own can bring your symptoms back. If research like this interests you, take it to your GP or endocrinologist rather than changing your treatment yourself.
Is red light therapy safe if you have a thyroid condition?
Red and near-infrared light is generally well tolerated, and the six-year follow-up authors concluded that the laser treatment was safe. Because the thyroid sits close to the skin of the neck, tell any practitioner about a thyroid condition, thyroid nodules or a history of thyroid cancer before any light treatment, and do not use home devices over the neck without advice from your doctor. Read more in is red light therapy safe.
When to see a GP
See your GP if you have symptoms of an underactive thyroid, such as tiredness, weight gain and feeling cold, that are not going away. If you already take levothyroxine and your symptoms return, or you are planning a pregnancy, speak to your GP about checking your levels. Our thyroid results guide explains what the numbers mean.
Frequently asked questions
Can red light therapy cure Hashimoto's?
No. No study has shown that red light therapy cures Hashimoto's. A small trial from one research team found that people needed a lower dose of levothyroxine after laser treatment over the thyroid, but this has not been confirmed by other teams in the research we have reviewed.
Does red light therapy help hypothyroidism?
The trial evidence comes from a single team studying a targeted laser over the thyroid in 43 people. Its results were encouraging, but they are not enough to recommend it, and levothyroxine remains the treatment for an underactive thyroid.
Can a red light bed treat the thyroid?
The thyroid studies used a laser applied directly to the neck at a set dose. In the research we have reviewed, there are no published trials of whole-body red light beds for thyroid conditions.
Is it safe to use red light on my neck?
Talk to your doctor first if you have a thyroid condition, nodules or a history of thyroid cancer. Many home devices give no clear information about their dose, and the thyroid studies were carried out under clinical supervision.
Read more
For every study we have reviewed, including those that found no benefit, see our red light therapy research library. For the approved uses of red light therapy and laser, see red light therapy in Chiswick and low level laser therapy in London.
This article is general information, not medical advice. Never stop or change prescribed medicine without speaking to your doctor.
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