Cannabis and Thyroid Disease: What the Evidence Actually Shows
There is currently no good evidence that cannabis or CBD treats hypothyroidism, hyperthyroidism, Hashimoto’s disease, or Graves’ disease. Although cannabinoids interact with biological systems involved in hormone regulation and immunity, research in people remains limited—and does not show that cannabis can correct thyroid dysfunction or slow autoimmune thyroid disease.
The thyroid is a small gland in the neck that produces hormones controlling metabolism, body temperature, heart rate and other functions. Hashimoto’s disease is an autoimmune condition in which the immune system attacks the thyroid and often causes hypothyroidism, while Graves’ disease can cause hyperthyroidism. These conditions require appropriate testing and, when indicated, established medical treatment.
What researchers know about cannabis and thyroid function
The endocannabinoid system is a network of receptors and signaling molecules involved in processes such as appetite, mood, sleep, pain and immune activity. THC and CBD can affect this system, but activity in the endocannabinoid system does not establish that cannabis is an effective treatment for thyroid disease.
Some laboratory and animal studies have suggested that THC and other cannabinoids can influence the hypothalamic-pituitary-thyroid axis, the hormonal pathway that helps regulate thyroid activity. In animal research, THC has been associated with reduced circulating thyroid hormone levels. These findings may help scientists understand how cannabinoids interact with endocrine systems, but they cannot be used to predict that cannabis will benefit people with Hashimoto’s, Graves’ disease or another thyroid disorder.
Human evidence is sparse and mixed. A 2017 cross-sectional analysis of 5,280 adults from the National Health and Nutrition Examination Survey found that recent marijuana users had lower TSH levels than nonusers or past users. However, recent use was not associated with thyroid dysfunction after the researchers accounted for other factors, and the association with thyroid antibodies did not remain significant after adjustment. Because the study measured cannabis use and thyroid markers at one point in time, it could not determine whether cannabis caused the lower TSH levels.
Another small study of 39 people with chronic cannabis dependence found that TSH, total T3 and free T4 were within the reference range. Thyroid hormone levels also did not correlate significantly with blood concentrations of THC or its metabolites. The authors concluded that the findings did not support a clinically important effect of chronic cannabis use on thyroid function in those participants. Read the study on chronic cannabis use and thyroid function.
Claims about CBD, inflammation and symptoms
CBD has been studied for several potential effects, including effects on inflammation, pain and anxiety. However, there is no established clinical evidence that CBD reduces the autoimmune attack involved in Hashimoto’s or Graves’ disease, restores thyroid hormone production, or treats thyroid eye disease. Symptom relief, even when reported by an individual, would not show that the underlying thyroid condition is being treated.
CBD products are also not risk-free. The U.S. Food and Drug Administration warns that CBD can cause liver injury, interact with medications and produce other adverse effects. Product strength and purity can vary, and most over-the-counter CBD products have not been evaluated or approved as treatments for thyroid disease. More information is available in the FDA’s guidance on cannabis- and CBD-containing products.
What patients should do
People with possible thyroid disease should rely on medical evaluation, including thyroid blood tests and antibody testing when appropriate. Treatment depends on the diagnosis: hypothyroidism is commonly treated with thyroid hormone replacement, while hyperthyroidism may require antithyroid medication, radioactive iodine, surgery or other care. The National Institute of Diabetes and Digestive and Kidney Diseases explains how thyroid testing is used.
Anyone using cannabis or CBD should tell their doctor, particularly if they take thyroid medication or other prescription drugs, have liver disease, are pregnant or breastfeeding, or are being treated for Graves’ disease. Cannabis may eventually have a role in managing selected symptoms or medical conditions, but current evidence does not support using it as a treatment for thyroid disorders or replacing standard thyroid care.
