Pernicious Anaemia Society
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sublingual methylcobalamin

Hi. I have been taking 5000mcg sublinguals for a week following advice and research. I thought I'd go for the biggest dose I could find. How long do they take to have any effect? The reviews on Amazon were fantastic, but I've noticed nothing at all.

I've had my six loading doses, I've not got anti-intrinsic factor antibodies and I've been waiting for weeks for a follow up appt with my GP, hence the supplementing (I'm taking folate too). I should have had more doses as I have tingly toes and a twitching eye, but he was very reluctant and has not yet arranged for any further injections.

How long should I wait for the sublinguals to have an effect? Could I increase the dose? Or should I think about self-injecting?

8 Replies

It really depends on exactly what your symptoms were and what was actually causing them as to whether methyl sublinguals are going to help.

Have you been back to your doctor and pointed out that you don't seem to have been treated correctly with the correct regime of loading shots given that you have neurological symptoms?

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The reviews on Amazon were fantastic

Unfortunately this is often the case - Amazon reviews can be pure fantasy.

If they're not doing anything for you (which is exactly what they did for me) then I'd carry on for a few weeks (until the bottle runs out) then decide if it was worth buying any more.

The important thing is to get the correct treatment. Just because you are negative for anti-IF antibodies doesn't mean your treatment should be any different from those with the antibodies. Half of those with PA test negative.

Download my summary (third pinned post) and read through what the experts say. Then go see the doc and say that the British National Formulary (she/he will have a copy) says that people with neurological symptoms (like you) need maintenance doses every 8 weeks. Tell them that you need the treatment now - not after another test. All the experts agree that testing once supplementation has been started is pointless.

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Thanks Gambit62 and fbirder. I'll be raising the issue of treatment with my GP when I eventually get to see him. I did start to feel a bit better after the loading shots, but within a fortnight I was starting to feel tired again. The neuro symptoms didn't really start to improve at all - guess they didn't have time, but the GP insisted that I should 'go away and let the doses get into my system' and that the symptoms would improve over the next weeks. It's now been a month since my last injection, and the twitching eye in particular is getting worse. I'm now noticing that my brilliantly improved sleep is also getting pretty rubbish again. The GP did bloods for B12 right after the shots, and of course it was sky high; I'm hoping he won't use that as an excuse not to treat me further. I'm convinced this is PA; he wants to 'blame' my diet (I'm a dairy-and-egg-eating veggie and I eat really well).

I'll carry on with my sublinguals for the time being - at least I know they can't do any harm, and they might possibly be stopping the symptoms being even worse!


This is from a survey I did (2000 B12def patients) on improvement with tablets:

Improvement of symptoms: :

In the first 8 weeks of treatment: 55%

After 2 to 6 months: 11%

After more than 6 months: 6%

No improvement: 26%


I was on oral 10,000 µg a day and after two months I noticed my major symptom had disappeared. (Gastroparesis) My son's Autism had improved starting in 1-2 weeks on the same dose. Usually use Now brand on Amazon.


Hi MensaKaren - sorry to jump in 🌞

But was just wondering in what ways your son'Autism has improved on Vitamin B 12 ? Also how old is he and what dose is he given ? I am interested because we have a 10 year old in the family. Thank you. 🐯🐯🐯🐯


No problem Bernie,

I posted all that information on my blog (non-monetized)

He started taking it at almost 10 ½ yrs old ~80 pounds in 6/2015

Tinyurl dotc*m forward slash b12autism


Thank you so much MensaKaren - it makes for very interesting reading. ⚽⚽⚽⚽⚽⚽⚽. 👨👨👨👨🌞🌞


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