I'm in the process of taking a radioactive iodine pill for a 1-123 thyroid uptake scan, will smoking pot affect the results?

No: No effect on result of the scan.

LIMITED DATA: Thc, one of marijuana’s active ingredients, depresses the function of the thyroid gland. Animal models have demonstrated that cannabinoid administration acutely alters multiple hormonal systems, including the suppression of the gonadal steroids, growth hormone, prolactin, and thyroid hormone and the activation of the hypothalamic-pituitary-adrenal axis. Talk with your doctor.

Not much: Avoid consumption of iodine (e.g. Seafood, iodinated salt, milk). Smoking should not directly interfere with radioiodine uptake by the thyroid, although you should stop smoking anything for your overall health.

Unlikely: Unless the strain of cannabis contains Iodine, it is unlikely to effect the thyroid uptake and scan results. The Thyroid scan is based on how much iodine your blood stream absorbs from the intestines.