Red Light Therapy for Thyroid: Hashimoto's & Hypothyroid

The thyroid gland sits at the front of the neck, weighs roughly 20 grams, and controls metabolic rate, energy production, body temperature, and hormone balance across virtually every organ system. When it malfunctions — whether through autoimmune destruction (Hashimoto’s thyroiditis), idiopathic hypothyroidism, or overactivity (Graves’ disease) — the consequences ripple through the entire body.

Conventional treatment for hypothyroidism is levothyroxine replacement, which is effective but lifelong. For hyperthyroidism, options include antithyroid drugs, radioactive iodine ablation, or surgery — all with significant trade-offs. This has driven interest in whether photobiomodulation (PBM) could support thyroid function, reduce autoimmune antibody levels, or even allow patients to reduce their medication dose.

The evidence here is genuinely interesting. Unlike many conditions covered on this site where research is preliminary or animal-only, there is a landmark randomised controlled trial (RCT) and several supporting studies specifically examining low-level laser therapy (LLLT) applied directly to the thyroid gland.

How the thyroid works — and how it fails

The thyroid gland produces two primary hormones: thyroxine (T4) and triiodothyronine (T3). T4 is the storage form, converted to the active T3 in peripheral tissues. Production is regulated by the hypothalamic-pituitary-thyroid axis: the hypothalamus releases TRH, the pituitary releases TSH, and the thyroid responds by producing T4 and T3.

Hashimoto’s thyroiditis

Hashimoto’s is the most common cause of hypothyroidism in iodine-sufficient countries. It is an autoimmune condition where the immune system produces antibodies — primarily thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (TG-Ab) — that attack thyroid tissue. Over time, this chronic inflammation destroys thyroid cells, reducing the gland’s capacity to produce hormones.

The destruction is gradual. Patients may have elevated antibodies for years before becoming clinically hypothyroid. The gland undergoes characteristic changes: lymphocytic infiltration, fibrosis, and reduced vascularity. TSH rises as the pituitary attempts to stimulate a failing gland.

Hypothyroidism (non-autoimmune)

Not all hypothyroidism is autoimmune. Post-surgical hypothyroidism (after thyroidectomy), post-radioactive-iodine hypothyroidism, iodine deficiency, and certain medications (lithium, amiodarone) can all reduce thyroid function. The relevance of PBM to these non-autoimmune causes is less clear, as the mechanism of action appears to be primarily anti-inflammatory and regenerative.

Hyperthyroidism and Graves’ disease

Graves’ disease involves stimulatory antibodies (TSH receptor antibodies) that cause the thyroid to overproduce hormones. The question of whether an immunomodulatory therapy like PBM could help — or potentially worsen — hyperthyroidism is more complex and less studied.

The biological rationale for PBM on the thyroid

Several established PBM mechanisms are relevant to thyroid dysfunction:

1. Anti-inflammatory and immunomodulatory effects

PBM at 630–850nm has been shown to reduce pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6) and modulate immune cell activity. In Hashimoto’s specifically, this could theoretically reduce the autoimmune assault on thyroid tissue. PBM has been shown to shift the Th1/Th2 immune balance and reduce lymphocytic infiltration in other tissues (Hamblin, 2017).

2. Improved microcirculation

Red and near-infrared light increase nitric oxide (NO) release from endothelial cells, improving local blood flow. Hashimoto’s thyroiditis is characterised by altered thyroid vascularity — initially increased (during active inflammation) then reduced (as fibrosis progresses). Improved microcirculation could enhance nutrient delivery and waste removal from thyroid tissue.

3. Cellular regeneration

PBM stimulates mitochondrial function via cytochrome c oxidase, increasing ATP production. This enhanced cellular energy could support the survival and function of remaining thyroid follicular cells, potentially slowing the decline in hormone production capacity.

4. Reduction of fibrosis

Chronic Hashimoto’s leads to progressive fibrosis of the thyroid gland. PBM has been shown to modulate fibroblast activity and reduce excessive collagen deposition in other tissues (wound healing studies). Whether this translates to reduced thyroid fibrosis is plausible but unconfirmed.

The key clinical evidence

Hofling et al. (2010) — The landmark RCT

The most important study in this area is the randomised, placebo-controlled trial by Hofling and colleagues, published in Lasers in Surgery and Medicine. This Brazilian study examined whether LLLT could improve thyroid function in patients with Hashimoto’s thyroiditis and hypothyroidism.

Study design:

• 43 patients with chronic autoimmune thyroiditis (Hashimoto’s) already on levothyroxine
• Randomised to LLLT or placebo (sham laser)
• Treatment: 830nm laser, 50mW per point, applied directly to the thyroid gland
• 10 sessions over approximately 5 weeks
• Follow-up at 30 days post-treatment

Results:

• Levothyroxine dose reduction: 47% of LLLT-treated patients were able to reduce their levothyroxine dose, compared to only 15% of placebo patients
• TPO antibody reduction: Significant reduction in thyroid peroxidase antibodies in the treatment group
• Improved thyroid echogenicity: Ultrasound showed improved tissue characteristics, suggesting reduced inflammation and possibly some tissue regeneration
• No adverse effects reported

This is a striking result. The idea that a non-invasive light treatment could allow hypothyroid patients to reduce their medication dosage — even partially — is clinically meaningful. Levothyroxine is well-tolerated by most people, but dose optimisation is often difficult, and some patients report persistent symptoms despite “normal” TSH levels.

Hofling et al. (2012) — 9-month follow-up

The same research group published follow-up data showing that benefits persisted at 9 months post-treatment. The levothyroxine dose reductions achieved were maintained, and antibody levels remained lower than baseline.

Ercetin et al. (2021) — Thyroid nodules

A separate line of research has examined PBM for benign thyroid nodules. Ercetin and colleagues found that LLLT reduced nodule volume in some patients, though this study was small and results were variable. The clinical significance for nodules remains unclear.

Heiskanen and Hamblin (2018) — Review

This narrative review in Photobiomodulation, Photomedicine, and Laser Surgery covered the thyroid PBM literature and concluded that the evidence, whilst limited in volume, was “promising” and warranted larger multi-centre trials. They noted that the Hofling RCT was methodologically sound and that the effect sizes were clinically relevant.

Azevedo et al. (2005) — Ultrasonographic changes

An earlier Brazilian study by Azevedo and colleagues demonstrated that LLLT applied to the thyroid gland improved parenchymal characteristics on ultrasound in Hashimoto’s patients, suggesting reduced inflammation and improved tissue quality, even before changes in blood markers became apparent.

What about hyperthyroidism?

The evidence for PBM in hyperthyroidism is essentially non-existent. There are theoretical reasons for caution:

• If PBM stimulates thyroid cell function, it could theoretically worsen hyperthyroidism by increasing hormone output from an already overactive gland
• However, the immunomodulatory effects could potentially calm the autoimmune stimulation in Graves’ disease
• Without clinical data, this remains speculation

Recommendation: If you have hyperthyroidism or Graves’ disease, do not use red light therapy on your thyroid without explicit guidance from your endocrinologist. The potential for worsening thyroid hormone levels is real and untested.

Recommended protocol

Based on the Hofling RCT and supporting studies, the following protocol reflects what has been used in successful clinical research:

Wavelength

• 830nm (near-infrared) — This was the wavelength used in the Hofling RCT and has the best evidence. NIR at 830nm penetrates deeply enough to reach the thyroid gland, which sits approximately 1–2cm below the skin surface
• 660nm (red) may offer complementary anti-inflammatory effects at more superficial tissue layers, but was not the primary wavelength studied

Power and dosage

• 50mW per point was used in the Hofling study with a laser
• Total dose: Approximately 39–48 J/cm² per session across the thyroid area
• With an LED panel, aim for 20–40 J/cm² delivered to the anterior neck area
• Hold the device approximately 2–5cm from the throat

Treatment area

• Apply directly to the anterior neck, covering the thyroid gland area (below the Adam’s apple, roughly 4–5cm wide)
• The thyroid has two lobes connected by an isthmus — coverage should span both lobes

Frequency and duration

• 3 sessions per week for 5 weeks (as per the Hofling protocol) is a reasonable starting point
• Each session: 2–5 minutes per side of the neck, depending on device power output
• After the initial course, consider maintenance sessions of 1–2 per week

Important caveats

• Do not stop or reduce thyroid medication based on red light therapy alone. Any dose changes must be made by your prescribing doctor based on blood test results (TSH, free T4, free T3)
• Monitor thyroid function with blood tests before starting, after completing the initial course, and regularly thereafter
• This protocol is based on one well-conducted RCT. Whilst promising, it needs replication in larger, multi-centre studies before it can be considered standard practice

Who should NOT use RLT on the thyroid

• People with thyroid cancer — Any form of stimulatory therapy to a malignant gland is contraindicated until cleared by an oncologist
• People with untreated hyperthyroidism — As discussed above, the risk of worsening thyroid overactivity is theoretical but unquantified
• People with thyroid nodules of unknown nature — Get ultrasound and/or biopsy first. Do not apply stimulatory therapy to nodules that have not been evaluated for malignancy
• Pregnant women — Thyroid function is tightly regulated during pregnancy. Do not experiment with treatments that could alter thyroid hormone levels without obstetric guidance

Frequently asked questions

Can red light therapy cure Hashimoto’s?

No. Hashimoto’s is a chronic autoimmune condition with no known cure. The Hofling RCT showed that PBM could reduce antibody levels and allow some patients to reduce their medication dose, but it did not eliminate the autoimmune process entirely. PBM should be considered a potential adjunct therapy, not a replacement for medical management.

How long before I see results?

The Hofling study showed measurable changes after 10 sessions over 5 weeks. Ultrasound changes may appear before blood marker improvements. Allow at least 6–8 weeks before assessing whether PBM is making a difference, and always base assessment on blood tests rather than symptoms alone.

Should I use red or near-infrared light?

The strongest evidence uses 830nm near-infrared. If your device has both red (660nm) and NIR (830nm), using both is reasonable, but prioritise NIR for thyroid applications due to the deeper penetration required.

Is it safe to shine red light on my neck?

For most people, yes. The thyroid area is routinely treated in clinical PBM research without adverse effects. However, the neck also contains the carotid arteries, jugular veins, and other structures. There is no evidence that PBM at standard therapeutic doses affects these structures adversely, but if you have a vascular condition affecting the neck (e.g., carotid stenosis), consult your doctor first.

The bottom line

Red light therapy for thyroid conditions — specifically Hashimoto’s thyroiditis with hypothyroidism — has better evidence than many conditions in the PBM literature. The Hofling 2010 RCT is a properly conducted, placebo-controlled trial showing clinically meaningful results: nearly half of treated patients were able to reduce their levothyroxine dose, antibody levels fell, and ultrasound appearances improved.

That said, this remains a single-centre study with a small sample size. The results need replication before PBM can be recommended as a standard adjunct therapy for Hashimoto’s. But for patients already on levothyroxine who are looking for evidence-based complementary approaches, the data here is among the most compelling in the entire PBM literature.

Work with your endocrinologist. Monitor your bloods. Do not stop your medication. But the science suggests that, for Hashimoto’s at least, there may be something genuinely useful here.