Sublingual vitamins:
questions... and more questions

Sublingual vitamins is a class of dietary supplements which is not as common as other types, like solid vitamins (tablets) or liquid vitamins.

The name clearly identifies how these supplements are delivered to the body. "Sublingual" literally means "under the tongue", and this is how sublingual vitamins are supposed to be taken. They come in a form of very small pills, sometimes called lozenges, which should quickly dissolve under the tongue.

The most common vitamin of this type is sublingual B12, but some other vitamins are also available in the form of sublingual pills.

Per manufacturers, this kind of vitamins has superior bioavailability, due to a quick absorption through oral tissues directly into bloodstream.

Spray vitamins, like sublingual vitamins, are claimed to bypass gastrointestinal by absorbing in the mouth through oral mucosa.

Without repeating the whole review from another page, here are the main points about the sublingual absorption:

• Drugs, or supplements, taken sublingually are absorbed quicker than in case of swallowing. Of course, a necessary condition is that the substance could be absorbed in the mouth.

• Sublingual absorption allows to bypass gastrointestinal, which may benefit people with particular digestive problems.

• Fat-soluble vitamins can be absorbed sublingually better than water-soluble.

• There is no scientific proof of better vitamin absorption when vitamins are taken sublingually. Some papers confirm that vitamins are absorbed at the same level when swallowed, or dissolved in the mouth.

In case of spray vitamins, lacking some solid proof of benefits, I wrote that they are at least as good as liquid vitamins from the perspective of absorption and bioavailability (you can always just swallow them).
Liquid vitamins do not have to be dissolved, like tablets, and so do spray vitamins.

What about sublingual vitamins - do they have any issues related to dissolution?

Because the most important ingredients in vitamin tablets
are not vitamins, let's have a look at the ingredients of typical sublingual vitamins tablets.

Some websites which sell dietary supplements claim that sublingual vitamins do not contain binders, fillers, and other inactive ingredients, which have a general name excipients. The role of these components is to form a tablet, and to assure its proper dissolution.

Some proponents of a natural approach to nutrition do not accept any presence of such components in dietary supplements.
You can check this post, for example.

Just bear in mind that any substance can be poisonous, even a plain water, or table salt - all depends on the consumed amount...

Here is the list of common inactive ingredients found in sublingual pills:

• Mannitol
  Sugar alcohol (sweetener). Mannitol is also used as a sweetener for people with diabetes, and as a sweetener in "breath-freshening" candies, where it adds the cooling effect.

• Sorbitol
  Sugar alcohol (sweetener). Also may be used as thickener.

• Magnesium stearate
  Magnesium salt, white substance, not soluble in water. Generally considered safe for human consumption. Primary source is beef (vegetarians among us, beware).
  Often used as a filling agent in medical tablets and capsules
  (no fillers in sublingual pills?..).
  Probably the most important use of magnesium stearate is that it serves as a lubricant, preventing ingredients from sticking to manufacturing equipment during the compression of chemical powders into solid tablets.
  In addition, it also can be used to bind sugar in hard candies (no binders too, huh?...)

• Silica
  Silicone dioxide, solid adsorbent material. “Adsorbent” refers to a material to which other materials will stick (another binder..)

• Stearic acid
  It is one of the useful types of saturated fatty acids that come from many animal and vegetable fats and oils. Has any uses, including the use in candles and soaps. It is used along with simple sugar or corn syrup as a hardener in candies.

• Cellulose
  An organic substance, polysaccharide, main material for producing paper.

As you can see, sublingual vitamins are not "innocent", and they have their portion of excipients, after all.
Let's just notice, that these pills are very small, and contain probably mostly sugars, so the amount of other inactive components is much smaller than in regular tablets.

Smaller amounts do not justify, of course, inaccurate marketing claims made by distributors of dietary supplements.

Speaking about dietary supplements: while researching the topic of sublingual vitamins, I made an unexpected and odd discovery...

Here are two documents by FDA (US Food and Drug Administration), which clearly state that any sublingual product cannot be considered as a dietary supplement.

Both documents are PDF files and require Acrobat Reader.

A quote from Document # 1:

A quote from Document # 2:

Companies which produce drugs must arrange series of tests, to prove that their medications do actually work. Moreover, the facilities where drugs are manufactured must be registered by FDA, and must meet FDA standards.

Dietary supplements are not medications, they are not intended to cure any condition, as stated of every vitamin label. FDA does not regulate - meaning, does not approve for selling based on the performance - any dietary supplements, as it does regulate drugs.

So, this finding leaves an open question: what are sublingual vitamins?
Are they drugs, or dietary supplements?
Oh, yes - the same question would be valid for spray vitamins.

Isn't this strange?..