I've just had a telephone appt with my endocrinologist who chopped and changed what she proposed to do as the next steps and did a complete turnaround within about 10 minutes of talking to me!
At first, she said I'm over replaced with my current Levothyroxine dosage (100mcg) as my latest TSH is 0.08 (0.35-4.94). My latest T4 is 12.7 (9.0-19.1), but she said this reading "doesn't matter" and it's my TSH level that "indicates over replacement".
When I talked about significant weight gain over the last year (over a stone), she suggested that this might be due to too much levothyroxine. She said weight gain at my age (58, post menopause) is quite usual and much harder to lose. She suggested I might not be on a high enough dose of HRT and I might need to supplement testosterone.
She asked me about any other tablets I was taking and when I said the Liposomal Vitamin B Complex, she asked whether it contained biotin and how much. She then said that my test results are not valid if I take biotin (even though I told her I had stopped some days before my blood test). She now wants me to stop taking anything with biotin and have another blood test in 3 months. She said to stay on 100mcg levothyroxine and after 3 months, if my TSH has increased, I may need to increase my prescription for levothyroxine (NOT decrease as she was suggesting at the beginning of my appointment).
So, my question is... is there a Vitamin B complex which does not contain biotin? Or, should I just stop this supplement altogether?
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Feelingrubbish
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Considering it wasn't that long ago they had no idea about biotin, this sounds an over-the-top reaction!
Below you will find what I managed to collect in an attempt to get a balanced view.
helvella - Biotin supplementation and testing
A short article about how and why biotin can affect blood tests. Includes information about how to avoid any problems and how much biotin some foods contain.
Thank you, that's an interesting read. The Liposomal complex I've been taking contains high levels of biotin (500 mcg) but I usually stop it for several days before my blood tests.
I don't have a lot of confidence in my endo as she didn't want to discuss my low T4 result at all and kept changing the subject when I asked about it, even though I said to her I used to feel much better when my T4 level was higher. I am prepared to stop any supplement containing biotin as she seemed to be sure that is skewing my results.
In typical competitive immu- noassays for small molecules such as free thyroxine (fT4), free triiodothyronine (fT3), testosterone, estradiol, and cortisol, biotin interference blocks assay signal. Because signal is inversely proportional to analyte concentration in competitive assays, biotin can cause falsely high results. In the 2-site “sandwich” immunoassay format [typical for larger protein analytes such as thyroid-stimulating hor- mone (TSH), thyroglobulin, follicle-stimulating hor- mone (FSH), luteinizing hormone (LH), insulin, and for autoantibodies], excess biotin competes with the bio- tinylated complex causing a reduction in signal and a falsely lower result. This combination of 2 types of biotin interference can create the perfect factitious biochemical evidence of Graves thyrotoxicosis …
Looking at the B-complex I have on hand, biotin is 300 to 3000 times the daily requirement. (Thorne with B12 and Life Extension which is way too high)
was thyroid test done as recommended…..early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Are you ONLY taking levothyroxine?
Free T4 (fT4) 12.7 pmol/L (9 - 19.1)
Ft4 only 36.6% through range
No Ft3 result?
How long have you been on 100mcg Levo
Do you always get same brand at each prescription
Have you tried splitting the dose…..50mcg waking and 50mcg at bedtime….just might increase TSH
As you have Hashimoto’s have you had coeliac blood test
Once you have it’s always worth trying strictly gluten free diet
vitamins
What were most recent vitamin D, folate, ferritin and B12 results
essential to test folate, ferritin and B12 annually
Vitamin D test twice a year
It’s absolutely fine to stop vitamin B approx 5-7 days before blood test
In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg) and continue separate B12 if last test result serum B12 was below 500 or active B12 (private test) under 70:
Other members may have suggestions of B complex that doesn’t contain biotin
The test was about 10.30am. I forgot to book my test due to Christmas so I had to go to our local hospital and it was very busy. I didn't take my levo that morning and stopped the B complex about 3 days before. I normally test at about 9am and stop the B complex about 5 or so days before.
I've been back on 100mcg since Feb 2024 - previously I had been reduced from 100mcg to 87.5mcg but I didn't feel good at that lower dose.
I'm not sure splitting the dose would work for me as I take my Utrogestan and magnesium at bedtime.
I haven't tested Vit D, folate, ferritin or B12 since April 2024 so I should send off for those tests.
Re. Minoxidil - yes, she does know about this as she has access to my medical notes.
"... is there a Vitamin B complex which does not contain biotin? Or, should I just stop this supplement altogether?"
No, the B vits are important and commonly low in hypo peeps.
"She now wants me to stop taking anything with biotin and have another blood test in 3 months". You only need stop biotin a few days before a thyroid hormone test, and certainly not 3 months!
Your endo sounds as if she has just read some new-to-herself article facts that the rest of us have known for ages, and so is spreading the word a bit over enthusiastically 🙄.
I said I usually stop taking the biotin several days before my blood tests, but my endo seemed to think it stays in your system for a lot longer. I have lost confidence in her because all she was focused on was my low TSH reading. She didn't ask how I was feeling and didn't want to discuss my low T4 reading at all.
The half-life of 100-300 mcg biotin supplementation is between 7.8 and 18.8 hours, so if you stop biotin 5-7 days before the blood test, it will be sufficient for not interfering with an assay (and after 5 days you will have less than the daily requirement left). And no, due to the half-life it does not stay in the system for longer, and the endocrinologist clearly has no understanding of this (insert eye roll here!).
However, this is not surprising, as she does not understand thyroid results either, if she is of the opinion that a low TSH indicates over-treatment, when clearly a low T4 value would suggest you would need a dose increase!
If I was you, I would ignore her ramblings as she clearly has not much of a clue.
Thank you for that information, I did think she was wrong to tell me to stop biotin altogether but as she has the power to increase my levothyroxine, I have been treading carefully. I am puzzled as to why my T4 has been low recently. It used to be much higher even on a lower dose of levothyroxine.
Have you had an infection recently as infections can lower T4. Our T4 requirements can also change. In the beginning, your thyroid might still be producing some thyroid hormones, so your levels could have been higher even though you took a lower dose. As time goes on, your thyroid will produce less and less and hence your T4 requirements will increase over time.
Fingers crossed you can find a physician that would be willing to increase your dose!🤞
No, I've been very healthy recently (crossed fingers!) Your comments sound so reasonable as I thought having Hashimotos means my thyroid is getting attacked by antibodies and therefore less able to produce the thyroid hormones naturally hence that's why I've been prescribed levothyroxine. When I suggested this to my endo she just confused me with talking about my pituitary gland and I gave up. I hate this condition and wish it would go away!🤬
The pituitary gland gives the feedback in response to levels of thyroid hormones. So if the TSH is high, the thyroid responds by producing more thyroid hormones. If the TSH is low, the thyroid stops the hormone output. However, in thyroid disease, this feedback is clearly not working, as evidenced by your low thyroid hormone and your low TSH. If it was properly working, your TSH would be much higher to signal thyroid hormones are needed!
This is why the TSH should never guide your treatment, as it is not a reliable indicator of what is really going on. Sadly not many HCPs seem to grasp this, hence many patients are not treated correctly!
I don’t know what BComplex you take but Ingennus BComplex is Excellant and only has 300ug of Biotin per 2 tablets. You don’t actually have to take 2 tablets. I manage on one tablet a day so that’s quite a low dose of biotin. I stop a few days before blood tests and have had no issues with blood tests.
This is a popular brand on this forum which you can buy direct from Ingennus or from Amazon. I ordered last night and it arrived today!
Their website says 300 mcg (ug), not IU, 600% of requirement. Thorne B-complex B12 has only 80 mcg (but the Thorne basic has 400 mcg - have to read labels 🙃).
This spreadsheet might help, there are many more out there but it’s something we put together ages ago to compare …. Scroll down the replies for the most recent and zoomable spreadsheet image
Thank you Regenallotment - that's a really useful link. I think I need to test my levels as I've sort of forgotten why I'm taking the b-complex every day! I think it was initially to see if it would help my hairloss but that has been ruled out by my dermatologist as being linked to my thyroid. He diagnosed I have 'female pattern hairloss' which was confirmed by a biopsy and is being treated with minoxidil. My hairloss is very much improved so I'm going to concede he was right and continue with the minoxidil.
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New Medichecks Blood Test
Is a B Complex really needed?
forgot to stop taken my biotin and levothyroxine before a blood test
