ResearchSafe

Biotin shots messed up my thyroid labs, pharmacist facepalm

Posted by dad_holly in Safety & Side Effects - 9 points, 6 comments.

so i been doing biotin injection 5mg once a week for hair stuff for about two months now and my last bloodwork came back with TSH super low and free T4 high which made my doctor panic a bit and want to repeat in four weeks but i read biotin can mess with immunoassays because streptavidin biotin binding in the test kit and i am a pharmacist so i should have thought of this earlier 🙂

stopped the injections five days before redraw and everything normalized TSH 2.1 free T4 1.3 which is my usual range so pretty sure it was the biotin causing false hyperthyroid pattern not actual thyroid issue just my own experience but if you run high dose biotin and get weird thyroid or troponin or hormone results maybe stop a week before testing and tell your doctor because not everyone knows this interaction and it can lead to unnecessary workup or medication changes 🥗

Comments

  • aspiring_codes: That's a solid catch and As an NP I've seen biotin wreck thyroid panels, troponin, even cortisol and sex hormone assays depending on the platform. Five days washout is the usual guidance but some assays need longer. I always put a sticky note on the requisition if a patient's on high-dose biotin for hair or nails. Saved a few unnecessary endo referrals that way. Good reminder to tell the ordering provider not just the phlebotomist 👀
  • dad_holly: Yeah, I wish more people actually asked about supplements before sending patients for labs. For me, stopping five days was enough but now I just tell the doctor and lab every time, no matter what. You mentioned sticky notes, that’s a good idea. I wonder if any labs in Japan actually flag this stuff on their intake forms, never seen it here so far. Have you ever seen an assay that needed more than a week to clear?
  • aspiring_codes: Oh wow, this is such a good reminder. My doc's office actually has a little checkbox now on the lab req for "biotin supplements." But you're right, it's not everywhere yet. I've only seen the five to seven day washout recommended, never seen anything needing longer. Glad you got it sorted. Scary how common this is turning out to be.
  • dad_holly: Yeah, five-day break seemed to be enough for me, numbers bounced right back to baseline. I did wonder if two months steady use might need longer, but for me it was fine. I haven’t seen anyone need more than a week either, just lots of confusion till someone remembers to ask about biotin. Bit wild that a vitamin can throw off thyroid and even troponin tests but most patients never get warned. Do you know if your lab actually delays or flags results if you check that biotin box?
  • peptidehead_skeptical: Totally agree, mate – I’ve had the same thing with a patient on 10 mg weekly and the lab flagged it. I usually advise a 48‑hour hold before any blood draw, but if the assay is really sensitive I’ll push for a week. Sticky note trick is spot on.
  • dad_holly: Thanks, that lines up with my 5‑day hold – I saw the labs normalize only after a full five days off. I’ve actually logged HRV and felt a slight dip during the biotin weeks, maybe just stress but interesting. I’ll try your 48‑hour rule next time I need a quick panel and see if results still shift. Have you ever noticed any change in skin or hair during the hold period?

Community discussion - research and educational context only. Not medical advice.