Red Light Therapy (RLT), also known as photobiomodulation (PBM), is a non-invasive technique using specific light wavelengths to stimulate biological processes. RLT typically employs red (around 630–700 nm) and near-infrared (around 800–1000 nm) light, which penetrates the skin and underlying tissues. While RLT is popular for skin health, muscle recovery, and reducing inflammation, many people worry about applying this technology near the sensitive thyroid gland in the neck. The core question is whether directing this light toward the neck poses a risk to the thyroid, or if it can be used safely.
How Red Light Interacts with the Thyroid Gland
The mechanism of RLT begins at the cellular level, specifically targeting the mitochondria, the powerhouses of nearly all cells. Inside the mitochondria, a molecule called cytochrome c oxidase absorbs photons from the red and near-infrared light. This absorption stimulates the mitochondria to produce adenosine triphosphate (ATP), the cell’s primary energy currency, more efficiently. The thyroid gland, an endocrine organ regulating metabolism, has a high demand for energy. RLT wavelengths, particularly near-infrared light, penetrate deep enough to reach the thyroid tissue, and this cellular energy boost can lead to improved cellular function within the thyroid, which is the underlying principle for its proposed therapeutic use.
The photobiomodulation effect also includes anti-inflammatory benefits and improved blood flow. For conditions like Hashimoto’s thyroiditis, where the immune system attacks the thyroid tissue, the reduction of inflammation and oxidative stress is thought to help protect the gland’s cells.
The Scientific Consensus on Safety
Current clinical research generally suggests that Red Light Therapy is safe when applied to the neck area and may even be beneficial for certain thyroid conditions. Multiple studies have focused on the intentional therapeutic application of RLT for chronic autoimmune thyroiditis, or Hashimoto’s disease. In these trials, RLT has been associated with a reduction in thyroid antibodies and an improvement in thyroid hormone levels, sometimes allowing patients to lower their thyroid medication dosage. A long-term follow-up study on patients with Hashimoto’s showed that the therapeutic application of RLT was safe, with no reported negative side effects. Research investigating the use of RLT for cosmetic purposes on the neck also confirmed its safety during general exposure, reporting no negative impact on thyroid function or hormone levels.
Contraindications and Cautions
The safety profile changes for individuals with hyperthyroidism, a condition where the thyroid gland is already overactive. Because RLT stimulates cellular activity, it is considered a contraindication for people with uncontrolled hyperthyroidism or Graves’ disease, as it could potentially worsen the hyperactive state. There is also a theoretical concern that RLT could stimulate cell growth, leading to caution against its use directly on the neck if there is a known history of thyroid cancer or suspicious nodules. For the majority of people with hypothyroidism, the existing evidence supports the safety of RLT when used according to recommended protocols.
Essential Safety Protocols and Usage Guidelines
To maximize the safety of Red Light Therapy near the thyroid gland, users should adhere to specific usage guidelines regarding device selection and application. For devices intended to target the thyroid, the most effective wavelengths are typically in the 600–850 nm range, as these penetrate deeply enough to reach the gland. Using a device that is too weak will not provide a therapeutic effect, while one that is too strong could potentially cause irritation.
The recommended duration for a session targeting the thyroid is typically brief, ranging from 5 to 15 minutes, with many protocols suggesting use a few times per week. The device should be positioned to target the lower front of the neck, but without applying excessive pressure.
Individuals who have a pre-existing thyroid condition, such as Hashimoto’s or hypothyroidism, must consult with a healthcare provider before beginning RLT. This is necessary to ensure the therapy complements their current treatment plan and to monitor thyroid hormone levels through regular blood tests. If a person is using RLT for another area of the body and wishes to avoid the thyroid, they can simply cover the gland with a small, opaque cloth or scarf to block the light. People with photosensitivity or those taking photosensitizing medications should also exercise caution and seek medical advice first.