Does medical marijuana affect thyroid hormone levels?
In a study done in Germany published in 2012, researchers measured both thyroid hormone levels (TSH, total T3, and free T4) and THC (tetrahydrocannabinol) levels in 39 patients that had been using about 2.5 grams of marijuana daily over about one and half years.
To make it more topical, one joint on average has about .5 grams of marijuana. So, these patients were using 5 joints in a day. That’s tremendously much more than what I see my patients use on average. But in any case, the study found the thyroid hormone levels in all these patients fell within a normal range. So, the research points in the direction that marijuana doesn’t seem to affect thyroid hormone levels.