Sublingual, Oral Spray and Dissolvable Supplements: What Is Known
What trials of sublingual vitamin B12, vitamin D oral sprays and dissolving tablets found, and why "bypasses digestion" claims need checking against the evidence.
Content last updated . This page has not been medically reviewed.
Quick answer
Sublingual means held under the tongue. An oral or buccal spray is sprayed into the mouth. A dissolvable product, such as an orally disintegrating tablet, breaks up in the mouth without chewing or water. [1] In the trials we read, these formats raised blood levels of vitamin B12 or vitamin D about as well as ordinary swallowed forms. They did not clearly beat them. A claim that a spray or melt "bypasses digestion" is a marketing claim unless a trial shows a difference for that product.
What the research found
| Format and nutrient | What the source found | Strength of evidence |
|---|---|---|
| Sublingual vs oral vs injected B12 | A 2025 meta-analysis of 16 studies (6,098 people) found no statistically significant difference between oral, sublingual and intramuscular routes for serum B12 or homocysteine, but heterogeneity was high and publication bias was possible. [2] | Mixed; blood markers only |
| Sublingual vs oral B-complex | In 41 people aged 50 to 80 over six weeks, sublingual and oral B-complex both lowered homocysteine with no significant difference between them. [3] | Small |
| Oral vs injected B12 in deficiency | A Cochrane review of three trials (153 people) found low-quality evidence that oral and injected B12 had similar effects on B12 levels; no trial reported clinical signs and symptoms. [4] | Low quality |
| Buccal vitamin D spray vs other delivery | A systematic review of four randomized trials found the spray did not appear superior to other modes of delivery; the trials differed too much to combine. [5] | Insufficient evidence |
| Vitamin D spray vs capsule | In 75 healthy adults over six weeks, capsule and spray were equally efficacious at raising 25(OH)D. [6] | Small, healthy adults |
| Vitamin D spray vs drops in children | In 90 children and adolescents with low vitamin D, buccal spray and oral drops were equally effective over six weeks. [7] | Short term |
| Vitamin D spray in inflammatory bowel disease | In an open-label trial of 120 patients, 25OHD rose by a similar amount (about 9 nmol/L) with the spray and a conventional oil emulsion; authors reported the spray amount per day was lower. [8] | Open-label; one condition |
Blood-level changes are a biomarker, not a health outcome, and trials in people with a deficiency or absorption problem do not transfer to people who are well nourished. The reverse is also true.
Dissolvables
The sources we read describe orally disintegrating tablets as disintegrating in the mouth in seconds without chewing or water. [1] That review is about drug technology. Proper evidence not found for supplement-specific melt tablets comparing absorption with swallowed tablets (we searched PubMed for orally disintegrating and fast-melt supplements).Vitamin B12 deficiency: see a clinician first
Vitamin B12 deficiency needs a clinician's assessment. MedlinePlus notes B12 comes in a sublingual form and that a prescription form can be given by injection or nasal gel. [10] Whether to use a tablet, spray or injection is a care-team decision. See vitamin B12 deficiency, vitamin B12 and B12 forms compared. For vitamin D, see vitamin D.Frequently asked questions
Is sublingual B12 better than a swallowed tablet?
In the meta-analysis we read, no statistically significant difference was found. [2]
Do vitamin D sprays work?
In small trials they raised vitamin D blood levels about as much as capsules or drops. [6] [7]
Do sprays bypass digestion?
Proper evidence not found that this gives an advantage; a systematic review found sprays not clearly superior. [5]
Can oral B12 replace injections?
That is a clinician's decision. A Cochrane review found low-quality evidence of similar effects on B12 levels. [4]
What are dissolvable tablets?
Tablets that break up in the mouth without chewing or water. [1]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: established nutritional role / deficiency treatment, evidence in adequately nourished people, mixed, insufficient evidence, marketing claim. Study amounts are what researchers used, not advice.
A word on regulation
The FDA says dietary supplements are ingested and "must be swallowed," so topical or inhaled products are not supplements. [9] The page we read does not discuss sublingual or spray products in particular, so ask a pharmacist how a given product is classed.
Safety and who should ask first
- Medicines: supplements may interact with medicines. [11] See medication interactions.
- Pregnancy, breastfeeding and children: many supplements have not been tested in these groups. [11]
- Surgery, kidney and liver conditions: tell your care team about every supplement. [11] Spray products can be hard to measure; check the serving size on the label.
- Quality: the FDA says it does not approve supplements before they are marketed. [9] See quality testing and certifications.
References
- The technologies used for developing orally disintegrating tablets: a review (Acta Pharm 2011). Read 2026-10-23.
- Efficacy of sublingual and oral vitamin B12 versus intramuscular administration: systematic review and meta-analysis (2025). Read 2026-10-23.
- Sublingual and oral vitamin B-complex administration and total serum homocysteine (J Altern Complement Med 2006). Read 2026-10-23.
- Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency (Cochrane 2018). Read 2026-10-23.
- Efficacy of Vitamin D3 Buccal Spray Supplementation Compared to Other Delivery Methods: A Systematic Review (Nutrients 2020). Read 2026-10-23.
- Rate of change of circulating 25-hydroxyvitamin D following sublingual and capsular vitamin D preparations (2019). Read 2026-10-23.
- Vitamin D Administration with Buccal Spray in Children and Adolescents (J Clin Res Pediatr Endocrinol 2021). Read 2026-10-23.
- Buccal nanoemulsion vitamin D versus conventional oral supplementation in inflammatory bowel disease (Front Med 2025). Read 2026-10-23.
- FDA: Questions and Answers on Dietary Supplements. Read 2026-10-23.
- MedlinePlus: Vitamin B12. Read 2026-10-23.
- NCCIH: Using Dietary Supplements Wisely. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.