Supplements

[Piglet1956]

Could you knowledgable people remind me how long I must stop taking B12/Biotin supplements prior to a blood test please. Thank you.

[waveylines]

One week.

[Piglet1956 in reply to waveylines]

Thank you.

[SeasideSusie Remembering]

Piglet

B Complex should be stopped 3-7 days before a test because it contains biotin and this is what gives false results for any blood test. The 7 days is for high dose biotin that you'd find in a hair supplement or prescribed by a GP. The amount in a B Complex is usually around the 300-400mcg dose and 3 days should be enough to leave this off but if you want to err on the side of caution you can leave it longer.

B12 as a stand alone supplement - there is no need to stop B12 for thyroid tests, it doesn't affect the test in any way. If you are testing B12 then do you want a baseline to see how much you are holding on to? If so then stop it for 4 months before testing. Do you want to see what your dose of B12 is achieving and whether the dose needs adjusting? If so then continue taking it but take after the test on the day.

[Piglet1956 in reply to SeasideSusie]

Thanks for your response SeasideSusie. I have been consulting a functional doctor to try to get my supplements optimal as it looks like I'm not converting T4 to T3 very well. I'm having full thyroid bloods done next week to assess where I am now as last test was NHS in early August. I've been put on the following (amongst other things) and it contains both biotin and B12. I take 2 tablets twice a day rather than 3 x 3 times a day as recommended on the tin so my daily intake will be 4/9th of the amounts below.

naturaldispensary.co.uk/pro...

Bio-3B-G - Daily Intake Amount: 3 tablets/ three times each day

Niacin (as niacinamide) 200 mgNE

Pantothenic Acid (as calcium pantothenate) 10 mg

Thiamin (B1) (as cocarboxylase chloride) 4.5 mg

Vitamin B6 (as pyridoxal-5-phospate) 2 mg

Riboflavin (B2) (as riboflavin-5-phosphate) 1.7 µg

Folate (as calcium folinate) 400 µg

Biotin300 µg

Vitamin B12 (as methylcobalamin) 6 µg

Cultured Pea (Pisum Sativum) 360 µg

Superoxide Dismutase (from vegetable culture**) 60 µg

Catalase (from vegetable culture**) 60 µg

As I can't separate out the size of B12 from Biotin I will just need to stop taking both for 6 days.

[SeasideSusie Remembering in reply to Piglet1956]

Piglet1956

As I can't separate out the size of B12 from Biotin I will just need to stop taking both for 6 days.

As I said in my earlier reply, you wouldn't need to stop a stand alone B12 supplement unless you were want to get a baseline B12 level. If the only B12 taken is contained in a B Complex then you follow the advice for how long to leave off the B Complex.

The B Complex information applies to the biotin element of any B Complex regardless of what else it contains because it's only biotin that affects test results. So taking the biotin into account - 300mcg in your supplement - then leaving off for 3 days should be enough but if you want to err on the side of caution then leave it off for longer.

I would mention though that the amount of B12 in that complex is negligible and is unlikely to help a low level of B12. Presumably the 6mcg it contains is when you take the recommended dose of 9 tablets daily, so 4/9ths of 6mcg is 2.66mcg. If you were hoping that the B12 in this complex will raise your B12 level that you posted 3 months ago - 477ng/L - then it's very unlikely. If a B Complex contained 400mcg B12 - which many do - then that should help raise the level.

[Piglet1956 in reply to SeasideSusie]

Thank you. It’s a good point - I’ll hopefully know what my B12 levels are like after this coming blood test.