Do you put liquid B12 under your tongue? A guide to proper supplementation

November 20, 2025 •

3 min read

Approximately 40% of the US population may have vitamin B12 deficiency or borderline levels. This is why many people ask, "do you put liquid B12 under your tongue?" as they seek more effective ways to supplement and correct their levels.

Quick Summary

Placing liquid B12 under the tongue for sublingual absorption is a recommended method for certain supplements, bypassing the digestive system for direct bloodstream entry. This is especially beneficial for individuals with malabsorption issues.

Key Points

Sublingual Absorption: Holding liquid B12 under the tongue allows absorption through mouth tissues, bypassing digestion.
Not Always Superior: High-dose oral and sublingual B12 can be equally effective due to passive diffusion.
Beneficial for Malabsorption: This method aids individuals with conditions hindering intrinsic factor function.
Method Matters: Hold sublingual liquid B12 under the tongue for 30-60 seconds as directed.
Consult a Doctor: Seek professional advice on the best B12 form and dosage for your needs.

Understanding the Benefits of Liquid B12

Vitamin B12 is an essential nutrient crucial for red blood cell formation, neurological function, and DNA synthesis. Deficiency can result from insufficient dietary intake, particularly in vegetarians and vegans, or from poor absorption due to age or digestive disorders. Liquid B12 supplements offer an alternative to pills for those who struggle with swallowing tablets, providing a potentially more direct route to the bloodstream.

The Mechanism of Sublingual Absorption

Sublingual administration involves placing a substance under the tongue for absorption into the bloodstream through the mucous membranes and capillaries. This method bypasses the digestive system and liver, potentially leading to faster absorption than traditional oral supplements. For sublingual liquid B12, hold it under the tongue for 30 to 60 seconds for absorption.

Intrinsic Factor vs. Passive Diffusion

Normal B12 absorption requires intrinsic factor from the stomach, which can be impaired by conditions like pernicious anemia or low stomach acid. However, B12 can also be absorbed via passive diffusion, independent of intrinsic factor. This is the main absorption method for the high doses in supplements, whether oral or sublingual. Research suggests that for many, sublingual and oral tablets may have similar effectiveness because both rely on this passive diffusion.

How to Properly Take Liquid B12 Under the Tongue

For sublingual liquid B12 products, follow label instructions. General steps include shaking the bottle, measuring the dose with the dropper, placing the liquid under the tongue, holding for 30-60 seconds, and then swallowing any remainder. Taking it on an empty stomach in the morning may optimize absorption and energy support.

Who Is Sublingual Liquid B12 Most Suitable For?

Sublingual liquid B12 is particularly suitable for:

Individuals with malabsorption issues: Conditions like Crohn's, celiac disease, or post-gastric bypass.
Older adults: Who may have reduced intrinsic factor and stomach acid production.
Vegans and Vegetarians: Requiring reliable B12 supplementation.
Children or those with difficulty swallowing: Providing an easy-to-take format.

Liquid B12 vs. Other Supplement Forms: A Comparison


Feature	Sublingual Liquid B12	Oral Tablet B12	B12 Injections
Absorption Mechanism	Passive diffusion via mucous membranes and GI tract	Passive diffusion via GI tract; active transport with intrinsic factor	Intramuscular injection for direct bloodstream delivery
Speed of Action	Potentially faster for those with malabsorption	Slower than sublingual or injections; depends on digestion	Fastest and most reliable for severe deficiency
Target Audience	Individuals with malabsorption, elderly, vegans, children	General population needing dietary B12 support	Those with severe deficiency or pernicious anemia
Convenience	High (easy to take, no water needed)	High (simple to take, widely available)	Low (requires a healthcare provider to administer)
Cost	Varies by brand and dosage	Generally inexpensive	Higher cost, especially with administration fees

Choosing the Right Liquid B12 Supplement

When choosing a liquid B12, check the type of B12 (methylcobalamin or cyanocobalamin). Opt for reputable brands with third-party testing. Always consult a healthcare professional for the right dosage and to ensure it suits your needs.

Conclusion

Yes, you put liquid B12 under your tongue if it is a sublingual formulation to utilize direct absorption into the bloodstream, bypassing digestive issues. While high-dose oral and sublingual B12 are often comparable in effectiveness due to passive diffusion, the sublingual method is convenient and reliable, particularly for the elderly, those with malabsorption, or those avoiding pills. Consult a healthcare provider to determine the best method for your individual health circumstances before starting supplementation. More information about vitamin B12 can be found at the National Institutes of Health Office of Dietary Supplements.

Frequently Asked Questions

Not necessarily. While sublingual delivery offers a rapid entry into the bloodstream, studies have shown that high-dose oral tablets are often equally effective in correcting B12 deficiency because both rely on passive diffusion for absorption.

For optimal sublingual absorption, you should hold the liquid B12 under your tongue for about 30 to 60 seconds before swallowing the remainder.

Many people find it best to take liquid B12 in the morning or before exercise. This can help support energy levels and may improve absorption when taken on an empty stomach.

If you swallow the liquid immediately, it will still be absorbed, but primarily through the intestinal tract rather than sublingually. For products specifically designed for sublingual use, holding it under the tongue is recommended for the intended effect.

Yes, different chemical forms of B12 are used in supplements, such as methylcobalamin and cyanocobalamin. Methylcobalamin is considered a more bioavailable, active form, but both can be effective.

Individuals with digestive issues that impair absorption (like pernicious anemia), older adults with reduced stomach acid, and people who have difficulty swallowing pills may benefit most from sublingual liquid B12.

Vitamin B12 is water-soluble, so any excess is typically excreted in the urine. However, it's always best to follow dosage instructions and consult a doctor to avoid unnecessary over-supplementation.

While some claims suggest this, injections are generally considered the gold standard for rapid and reliable B12 delivery, especially for those with severe deficiencies. Studies comparing sublingual and injections have shown varying results, but sublingual is often seen as a highly effective alternative to injections.