Hello, I have Hashimoto’s hypothyroidism and recently have been taking iron and a vitamin b complex with biotin supplement due to having oral thrush/ cold sores and dry mouth.
Since my B complex vitamin has biotin, ; how long should I be off biotin/ b complex before having thyroid tests (TSH, T4, T3)? Is there any other vitamins that interfere with thyroid labs? Thanks for you guidance.
Advice is usually a week. 
Runner95
We generally advise leaving it off for 7 days; however, it would seem that applies to high dose Biotin and it if it is a couple of days less then it's doubtful there would be any problem with the test results.
As for other supplements and thyroid tests, just take them after the test on the day.
Medichecks says to avoid B vitamins for a week and that’s what I do. Seems to work ok.
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