B12 sublingual spray

[Gsmandin]

Is vitamin B12 taken as a sublingual spray more effective than B12 taken orally

[JanD236]

If you have absorption problems neither is likely to be effective.

[fbirder]

No. The B12 molecule is too large, and too hydrophilic to cross biological membranes unaided.

All the studies that compare them say that you absorb about 10 mcg from a 1000 mcg dose.

That strongly indicates that B12 is not absorbed sublingually.

The studies show about 1% of an oral dose of 1000 mcg is absorbed across the gut.

If 10 mcg is absorbed sublingually, then 990 mcg is swallowed. It becomes an oral dose. So you would expect about 1% of that dose to be absorbed from the gut, to give a total of 19.9 mcg absorbed. But you don't - you just get the same 10 mcg as if you'd swallowed all of the dose. The simplest interpretation is that you have swallowed 100% of the dose and none of it is absorbed sublingually.

In an amazing coincidence, the maximum amount of an oral dose of B12 that people without any absorption problem can absorb (using Intrinsic Factor) is about 13 mcg. Which is almost exactly what people with PA are supposed to be able to absorb passively and almost exactly what is supposed to be absorbed sublingually.

Occam's Razor says that the obvious explanation is that all of those studies have measured the absorption of oral B12 via the IF method.

[helvella in reply to fbirder]

The studies show about 10% of an oral dose of 1000 mcg is absorbed across the gut.

1%, surely???

[fbirder in reply to helvella]

D'oh!

Thanks. Edited.

[helvella in reply to fbirder]

At least I read your posts.

[Ryaan in reply to fbirder]

Does that mean that the sublingual spray can’t give you an ‘Instant boost’........which I thought it would.

So it’s the same as taking a 1000mcg tablet ?

[fbirder in reply to Ryaan]

Yup, exactly the same.

[helvella in reply to fbirder]

Have just sneaked in and copied your response to Thyroid UK forum.

healthunlocked.com/thyroidu...

[Gambit62 Administrator]

There aren't really that many studies out there on different delivery methods - they are giving averages but show a lot of variation between individuals in the studies. Studies also tend to be relatively small scale meaning it is impossible to really draw reliable conclusions that can be applied to a specific individual.

This study showed sublingual as marginally better than oral but the difference is so small that it doesn't make much practical difference.

ncbi.nlm.nih.gov/pmc/articl...