How Are Sublingual Vitamins Absorbed?

It has been said that some vitamins may be diminished by the digestive acids in the stomach. Therefore, an alternative route for administration is either liquid or a soft pill placed under the tongue--the sublingual route. Three vitamins that are often found in sublingual preparations are Vitamin B-12, D and K2.

Dosing

If you have problems swallowing pills, the sublingual route of administration may be right for you. Interestingly, as reported by the University of Hawaii at Manoa in its article "Vitamin delivery doesn't change absorption rates," no differences were reported in circulating vitamin levels in the study subject's blood. The oral pill route and the sublingual route vitamin concentrations were the same.

Absorption

Sublingual vitamin preparations are absorbed through the mucous membrane under the tongue. The mouth area contains a significant number of tiny blood vessels called capillaries. The vitamin passes through the mucous membrane directly into the capillaries and is transported into the bloodstream via larger blood vessels.

Efficiency

Sublingual vitamins are directly absorbed into the bloodstream, bypassing digestion. This results in a faster delivery of the absorbed vitamin. Peak blood levels of many sublingual vitamins are reached in 10 to 15 minutes after taking them, which is generally faster than vitamins or medication taken via the oral route.

Efficacy

Because vitamins taken via the sublingual route remain in contact with the mucous membranes for a longer time, their absorption is increased. As reported by a PubMed study, "A single-center, double-blind, randomized controlled study to evaluate the relative efficacy of sublingual and oral vitamin B-complex administration in reducing total serum homocysteine levels," there was no difference in circulating blood levels of vitamins taken sublingually or swallowed.

Advantages and Drawbacks

If swallowing large vitamin pills is a challenge for you, consider sublingual vitamins. They are usually flavored and not unpleasant to take. They are easily absorbed directly into your bloodstream and work more quickly than vitamins taken by mouth, which are mostly absorbed in the small intestine. If you take medications in addition to vitamins, you can still take your medications that you swallow and your sublingual vitamins immediately afterward because the absorption mechanisms are different

If cost is a factor, sublingual vitamins may not be for you because they are generally more expensive than the same vitamin that is swallowed. As noted above, studies have shown that sublingual and oral vitamins have the same strength and effect in your body, so the extra cost does not result in a higher level of active vitamin product.