There is some evidence that Vitamin B1 supplementation could help with thyroid issues.
“The researchers conducted a small study of three patients who were on thyroid hormone replacement treatment for Hashimoto’s thyroiditis, and who also suffered from fatigue. The study took place from May to July 2011. The fatigue was measured during the Fatigue Severity Scale. The patients all had free thiamine blood tests measured before and after the thiamine therapy — which was either 600 mg/day of thiamine orally, or 100 mg/ml every four days by IV.
The researchers found that the patients had partial or complete regression of fatigue within a few hours or days of the start of the treatment. They concluded that giving large quantities of thiamine restores “thiamine-dependent processes,” and relieves fatigue.”