Is there an FDA-approved sublingual semaglutide, GLP-1 drop, or GLP-1 nasal spray?

No. As of May 2026, no FDA-approved sublingual tablet, troche, lozenge, oral spray, oral drop, or nasal spray contains semaglutide, tirzepatide, liraglutide, dulaglutide, exenatide, or orforglipron. The only two FDA-approved non-injectable GLP-1 receptor agonists are oral tablets that you swallow: Rybelsus (oral semaglutide, FDA-approved 2019 for type 2 diabetes) and Foundayo (oral orforglipron, FDA-approved April 1, 2026 for chronic weight management).

Why can't semaglutide or tirzepatide be delivered under the tongue?

Two reasons. First, the molecular-weight problem: semaglutide is 4,113 Da and tirzepatide is 4,813 Da. The oral mucosa is more permeable than skin but still maintains tight junctions and a practical molecular-weight ceiling for passive absorption, typically cited around 500-1,000 Da for peptide drugs without an absorption enhancer (Rawas-Qalaji et al., J Control Release 2022, PMID 36334858). Second, the SNAC problem: Rybelsus works because the SNAC excipient transiently increases stomach-epithelium permeability AND locally raises pH to protect semaglutide from peptic degradation. That mechanism is specific to the gastric environment. Sublingual and buccal mucosa have no equivalent FDA-approved excipient pathway. Without SNAC or an equivalent, swallowed or sublingually applied semaglutide is rapidly degraded and absorbed essentially nowhere.

What is actually in 'sublingual semaglutide' or 'GLP-1 drops' sold online?

It varies by seller, but consistently it is not an FDA-approved GLP-1 product. The recurring categories are: (a) compounded peptide formulations — actual semaglutide or tirzepatide dissolved in a sublingual or oral-drop vehicle by a 503A compounding pharmacy or unlicensed source, with no human bioavailability data demonstrating the route works; (b) homeopathic 'HCG-style' drops or 'semaglutide drops' diluted to homeopathic concentrations containing no measurable active drug; (c) herbal weight-loss tinctures (berberine, garcinia, chromium, green tea extract) relabeled with 'GLP-1' branding; and (d) outright fraud — products with no listed active ingredient. The FDA published a 2024 advisory on the risks of unapproved compounded and counterfeit GLP-1 products.

Has the FDA taken action on sublingual or oral-drop GLP-1 products?

Yes. The FDA's standing advisory on unapproved GLP-1 drugs (fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss) covers all routes — injectable compounded semaglutide, sublingual products, oral drops, and any other formulation marketed for weight loss without FDA approval. The agency has issued multiple warning letters to companies selling unapproved GLP-1 products through online pharmacies, medspas, and direct-to-consumer wellness brands. The FTC complements this with enforcement against false-advertising claims for non-FDA-approved weight-loss products of all formats including sublingual tablets and oral sprays.

What are the FDA-approved alternatives if I don't want to inject?

Two FDA-approved oral tablet GLP-1 receptor agonists exist. Rybelsus (oral semaglutide, Novo Nordisk) is FDA-approved for type 2 diabetes and is used off-label for weight loss; it requires a strict fasting protocol (empty stomach, at most 4 oz of plain water, 30+ minutes before food or other oral medication). Foundayo (oral orforglipron, Eli Lilly) was FDA-approved April 1, 2026 for chronic weight management — the ATTAIN-1 trial showed mean weight loss of -11.1% at 17.2 mg over 72 weeks (Wharton et al., NEJM 2025, PMID 40960239). Orforglipron is a non-peptide small-molecule (~487 Da), so it absorbs orally without needing an absorption enhancer or fasting protocol. Both require a prescription from a licensed prescriber.

Are there any preclinical sublingual or nasal GLP-1 products in development?

Some preclinical work exists, but none has reached the human Phase 2 or Phase 3 weight-loss trial stage. Intranasal GLP-1 receptor agonists have been studied in animal models — but for nose-to-brain delivery in Alzheimer's research, not systemic weight loss (Abdulhameed et al., Alzheimers Res Ther 2024, PMID 39085976). No transmucosal or intranasal GLP-1 product has filed an FDA New Drug Application for obesity or type 2 diabetes as of May 2026. A handful of pharmaceutical companies are exploring buccal-film and intranasal peptide platforms generally, but no GLP-1-specific product has published a registrational trial.

Are compounded sublingual or oral-drop semaglutide formulations safe?

They are not FDA-approved, have no published Phase 2 or Phase 3 human bioavailability or safety data, and bypass the gastric-protected SNAC delivery system that makes the FDA-approved oral semaglutide product (Rybelsus) work. The pharmacological risk profile of a compounded sublingual peptide is unknown: dose absorbed is unknown, peak plasma concentration is unknown, half-life in this route is unknown, and the degradation products produced by oral or sublingual digestion are unknown. The clinical risk profile is also unknown. Patients taking compounded sublingual products are essentially participants in an uncontrolled, unmonitored experiment without informed consent. The FDA recommends using only FDA-approved GLP-1 products dispensed through licensed channels.

What about 'homeopathic semaglutide' drops?

Homeopathic preparations are diluted to concentrations at which little or no active ingredient remains. A homeopathic 'semaglutide drop' at typical 6X, 12X, or 30X dilutions contains essentially no semaglutide molecules at all. The FDA does not approve homeopathic drugs for safety or efficacy, and homeopathic weight-loss products have been the subject of multiple FDA and FTC enforcement actions over the past decade. A homeopathic GLP-1 drop is, by chemistry, not a GLP-1 product. It is a marketing label.

Sublingual Semaglutide, GLP-1 Drops & Nasal Sprays: Evidence Review

0FDA-approved sublingual or nasal-spray GLP-1s (May 2026)

This evidence review is part of Weight Loss Rankings’ living editorial database — 300+ research articles and 190+ clinically-reviewed GLP-1 telehealth providers, sourced only from FDA prescribing information on DailyMed and peer-reviewed PubMed literature.

Search “sublingual semaglutide”, “GLP-1 drops”, or “GLP-1 nasal spray” and you will find compounded peptide bottles, homeopathic tinctures, herbal “weight loss drops”, and direct-to-consumer dropper-bottle products all marketed as injection-free GLP-1 therapy. None has FDA approval. As of May 2026, the only FDA-approved non-injectable GLP-1 receptor agonists are oral tablets that you swallow: Rybelsus (oral semaglutide, type-2-diabetes-only) and Foundayo (oral orforglipron, approved April 2026 for chronic weight management). This article walks through why sublingual, buccal, and intranasal delivery cannot meaningfully replace either an injection or a swallowed SNAC-enhanced tablet, what these products actually contain, the FDA and FTC enforcement record, and the FDA-approved oral alternatives.

The honest answer

No FDA-approved GLP-1 drops, oral sprays, sublingual tablets, lozenges, troches, or nasal sprays exist. The only FDA-approved oral GLP-1s are Rybelsus tablets and Foundayo tablets. Sublingual peptide GLP-1 products bypass the gastric protection that makes Rybelsus work and have no peer-reviewed Phase 2 trials.

There is no FDA-approved GLP-1 drop, spray, or sublingual product

Seven GLP-1 receptor agonist drugs are FDA-approved in the United States. Every one is delivered either by subcutaneous injection or by a swallowed oral tablet — never as a sublingual tablet, troche, lozenge, oral drop, oral spray, or nasal spray:

Active ingredient	Brand	FDA-approved route	FDA-approved indication
Semaglutide	Wegovy, Ozempic	Subcutaneous injection	Chronic weight management (Wegovy); T2D (Ozempic)
Semaglutide	Rybelsus	Swallowed oral tablet (with SNAC)	T2D only (off-label for weight)
Tirzepatide	Zepbound, Mounjaro	Subcutaneous injection	Chronic weight management (Zepbound); T2D (Mounjaro)
Liraglutide	Saxenda, Victoza	Subcutaneous injection	Chronic weight management (Saxenda); T2D (Victoza)
Dulaglutide	Trulicity	Subcutaneous injection	T2D
Exenatide	Byetta, Bydureon	Subcutaneous injection	T2D
Orforglipron	Foundayo	Swallowed oral tablet	Chronic weight management (approved April 2026)

Searches of Drugs@FDA, the FDA Orange Book, and the FDA New Drug Application pipeline for any “sublingual,” “buccal,” “troche,” “lozenge,” “oral spray,” “oral drop,” or “nasal spray” dosage form containing a GLP-1 receptor agonist return zero results as of May 2026. This is consistent with our companion analysis of the parallel GLP-1 patches market, where no FDA-approved transdermal GLP-1 product exists either.

Why GLP-1s can’t be effective sublingually (the SNAC story)

The reason no manufacturer has launched a sublingual or oral-drop GLP-1 product is not a regulatory accident. It is a chemistry problem with two stacked failure modes.

Problem 1: peptide GLP-1s are massive molecules

The oral mucosa under the tongue (sublingual) and inside the cheek (buccal) is more permeable than skin because it lacks a keratinized stratum corneum. But it still has tight junctions, enzymatic activity, and a practical molecular-weight ceiling that limits passive peptide absorption. Reviews of oromucosal drug delivery cite a workable molecular-weight range of roughly 500-1,000 Da for unenhanced sublingual absorption of peptide drugs, with steep falloff above that threshold.^[7] The molecular weight of the peptide GLP-1s sits 4-10 times beyond that:

Semaglutide: 4,113.58 Da — a 31-amino-acid synthetic GLP-1 analogue^[2].
Tirzepatide: 4,813.53 Da — a 39-amino-acid dual GIP/GLP-1 receptor agonist peptide^[3].
Liraglutide: 3,751.20 Da — a 34-amino-acid acylated GLP-1 analogue.
Dulaglutide: ~63,000 Da — a fusion protein with Fc domain.

Bos and Meinardi’s classic 500 Dalton rule was framed for skin, but the underlying biology — tight junctions, lipid bilayer partitioning, enzymatic degradation — constrains every mucosal surface, including the sublingual epithelium.^[1] Drucker’s 2020 review in Nature Reviews Drug Discovery catalogues how vanishingly small the set of FDA-approved sublingual peptide products actually is, and why almost every therapeutic peptide is still injected.^[4]^[8]

Magnitude comparison

Molecular weights of FDA-approved GLP-1 receptor agonists versus the practical molecular-weight ceiling for unenhanced sublingual peptide absorption. Every injectable peptide GLP-1 is multiples larger than the sublingual permeability limit; only orforglipron (Foundayo), a non-peptide small molecule under the limit, is amenable to oral absorption without a special excipient — and it is still formulated as a swallowed tablet, not sublingual.^[1]^[2]^[3]^[7]^[12]

Tirzepatide (Zepbound, Mounjaro)4814 Da
39-amino-acid peptide — 4.8x over the sublingual ceiling
Semaglutide (Wegovy, Ozempic, Rybelsus)4114 Da
31-amino-acid peptide — 4.1x over the ceiling
Liraglutide (Saxenda, Victoza)3751 Da
34-amino-acid peptide — 3.8x over the ceiling
Sublingual peptide absorption ceiling (~1,000 Da)1000 Da
Practical upper limit for unenhanced oromucosal peptide delivery
Orforglipron (Foundayo)487 Da
Non-peptide small molecule — under the limit; formulated as swallowed tablet, not sublingual

Problem 2: the SNAC mechanism is gastric-specific

Rybelsus is the one FDA-approved oral semaglutide product. It works, but only because Novo Nordisk solved a very narrow chemistry problem. Buckley et al. (2018) in Science Translational Medicine showed that the SNAC excipient (sodium N-[8-(2-hydroxybenzoyl) amino]caprylate) does two things in the stomach: it locally raises pH, protecting semaglutide from peptic degradation, and it creates a transient localized increase in gastric epithelial permeability that lets a small fraction of the dose cross into circulation.^[5] Aroda et al. (2022) confirmed the resulting absolute oral bioavailability is approximately 1% — clinically useful because the tablet doses (3, 7, 14 mg daily) are large enough to compensate, but absolutely dependent on the narrow gastric environment.^[6]

That mechanism does not transplant to the mouth. SNAC needs the stomach lining and the acidic environment to do its job. A sublingual tablet, troche, or oral drop dropped under the tongue has none of that. The semaglutide is exposed to salivary peptidases, neutral oral pH, and a relatively small mucosal surface area before it can either be absorbed (it cannot, because of size) or be swallowed (at which point it goes through a stomach with no SNAC protection, unlike the Rybelsus tablet which is co-formulated with SNAC).

The empirical confirmation: zero FDA-approved sublingual peptide GLP-1 products exist. Zero published human Phase 2 or Phase 3 trials of a sublingual peptide GLP-1 exist in PubMed as of May 2026.

Intranasal GLP-1: also preclinical, and aimed at the brain not the gut

The intranasal route has been studied for GLP-1 receptor agonists, but the published work is preclinical (rodent) and targets nose-to-brain delivery for Alzheimer’s disease research — not systemic weight loss. Abdulhameed et al. (2024) compared regional brain uptake of incretin receptor agonists after intranasal delivery in CD-1 mice and an Alzheimer’s mouse model.^[13] Even this work shows limited and variable systemic bioavailability. No human Phase 2 or Phase 3 trial of an intranasal GLP-1 product for obesity or type 2 diabetes has been published in PubMed. No FDA New Drug Application for a nasal-spray GLP-1 has been publicly announced as of May 2026.

What “sublingual semaglutide” actually is — compounded formulations explained

Products marketed online as “sublingual semaglutide”, “sublingual tirzepatide”, “GLP-1 drops”, “GLP-1 oral spray”, “GLP-1 troches”, “GLP-1 lozenges”, or “GLP-1 nasal spray” fall into four recurring categories. None has FDA approval. None has published Phase 2 or Phase 3 human evidence for the route.

1. Compounded peptide formulations

The most pharmacologically plausible category — and the most commonly sold. Compounding pharmacies (typically 503A pharmacies, and a smaller number of 503B outsourcing facilities) compound semaglutide or tirzepatide active pharmaceutical ingredient into sublingual troches, oral drops, lipid-based oral sprays, or nasal sprays. The active ingredient is real semaglutide or tirzepatide. The problem is the route: there is no published human bioavailability data demonstrating that meaningful drug crosses sublingual, buccal, or nasal mucosa from these formulations. Without SNAC or an equivalent absorption enhancer with documented mucosal activity, the absorbed fraction is unknown and almost certainly far below the Phase-3-validated subcutaneous or SNAC-enabled oral doses. The FDA does not consider compounded GLP-1 products in non-approved routes to be FDA-approved drugs.^[14]

After the FDA declared the national semaglutide and tirzepatide shortages resolved in February 2025, the legal pathway for 503A pharmacies to compound semaglutide or tirzepatide closed for most use cases (with narrow medical-necessity carve-outs). Many compounded sublingual and oral-drop GLP-1 sellers have continued operating despite this status change — a regulatory grey zone that is the subject of ongoing FDA enforcement.

2. Homeopathic “semaglutide drops”

A separate market sells dropper bottles labeled “homeopathic semaglutide,” “HCG-style weight-loss drops,” or “Ozempic-style drops” at homeopathic dilutions (typically 6X, 12X, or 30X). At those dilutions, the formulation contains essentially no semaglutide molecules at all — the original active ingredient has been diluted past Avogadro’s number. The FDA does not approve homeopathic drugs for safety or efficacy, and homeopathic weight-loss products (most famously homeopathic HCG drops) have been the subject of multiple FDA and FTC enforcement actions over the past two decades. A homeopathic GLP-1 drop is, by chemistry, not a GLP-1 product.

3. Herbal “GLP-1 drops” with no GLP-1 in them

Many dropper bottles marketed with “GLP-1” in the product name contain only herbal weight-loss extracts — berberine, garcinia cambogia, chromium picolinate, green tea extract (EGCG), l-carnitine, apple cider vinegar concentrate. These are dietary supplements regulated under DSHEA, not drugs. They do not contain a GLP-1 receptor agonist. The “GLP-1” label is a search-and-conversion device, not a pharmacological description.

4. Outright fraud

A residual category includes products with no listed active ingredient, products that ship with no ingredient label at all, and products imported from unregulated overseas manufacturers. Identity and purity of these products is unverified. The FDA has issued warning letters to multiple online distributors of unapproved and unregistered GLP-1 products.^[15]

FDA and FTC enforcement on unapproved GLP-1 products

Federal enforcement against unapproved sublingual, oral-drop, and nasal-spray GLP-1 products is active and ongoing across both the FDA and the FTC.

FDA standing advisory on unapproved GLP-1 drugs

The FDA maintains a standing public advisory specifically on the risks of unapproved GLP-1 receptor agonist products marketed for weight loss. The page covers all unapproved formats — compounded injectables, sublingual tablets, troches, lozenges, oral drops, oral sprays, nasal sprays, and topical products — and reiterates the agency’s position that none of these are FDA-approved formulations of semaglutide, tirzepatide, or any other GLP-1.^[14] The page accompanies the agency’s broader compounded-drug guidance and is referenced in multiple recent FDA warning letters.

FDA warning letters and enforcement actions

The FDA Warning Letters database documents enforcement actions against online pharmacies, medspas, telehealth brands, and direct-to-consumer wellness sellers distributing unapproved GLP-1 receptor agonist products in sublingual tablet, troche, lozenge, oral-drop, oral-spray, and nasal-spray formats.^[15] Letters typically cite violations under sections 502 (misbranding) and 505 (unapproved new drug) of the Federal Food, Drug, and Cosmetic Act.

FTC companion actions

The Federal Trade Commission addresses the false-advertising and deceptive-marketing side of the same product set under FTC Act section 5. Historic FTC enforcement against weight-loss products in novel dosage forms is substantial — the FTC’s 2018 action against Redwood Scientific Technologies (case 172-3117-X190001), which targeted deceptive weight-loss and smoking-cessation strip products, is one of multiple federal cases against fraudulent weight-loss dosage forms catalogued in our companion GLP-1 patches debunker.

Red flags on any sublingual, oral-drop, oral-spray, troche, lozenge, or nasal-spray “GLP-1” listing

Claims of semaglutide, tirzepatide, or Ozempic under the tongue, as drops, as an oral spray, as a troche, or as a nasal spray.
No FDA approval number, no NDA number, no DailyMed entry, no full ingredient label.
“Homeopathic” framing at any X or C dilution.
“Natural Ozempic” drops where the ingredient list is herbal extracts only.
Sold without prescription on social media, MLM sites, or unbranded e-commerce.
Compounding-pharmacy-sourced sublingual or nasal GLP-1 with no documented mucosal bioavailability data.
Direct-to-consumer GLP-1 dropper bottles from overseas shippers.

If you don’t want injections, here are the FDA-approved alternatives

The reason people search for sublingual semaglutide, GLP-1 drops, or GLP-1 nasal spray is usually straightforward: they want a needle-free option. That goal is legitimate. The good news is that two FDA-approved oral tablet GLP-1 receptor agonists exist, both available by prescription from a licensed prescriber.

Rybelsus (oral semaglutide)

Rybelsus (Novo Nordisk) is the oral-tablet form of semaglutide, FDA-approved in September 2019 for type 2 diabetes. It is not FDA-approved for weight loss — clinicians prescribe it off-label for that purpose. The tablet is swallowed, not held under the tongue. Absorption depends on the SNAC excipient (Buckley et al., 2018^[5]; Aroda et al., 2022^[6]) and requires a strict fasting protocol: empty stomach, at most 4 oz of plain water, at least 30 minutes before any food, drink, or other oral medication. Absolute oral bioavailability is approximately 1%, which is why the daily tablet dose (3 / 7 / 14 mg) is far higher than the weekly injectable dose (0.25 / 0.5 / 1 / 2 mg). For a deeper Rybelsus profile, see our oral GLP-1 comparison.

Foundayo (oral orforglipron)

Foundayo (Eli Lilly) is the oral-tablet form of orforglipron, FDA-approved April 1, 2026, for chronic weight management — the first oral medication specifically FDA-approved for weight loss in the GLP-1 era. Orforglipron is a non-peptide small molecule (approximately 487 Da), which means it sidesteps the peptide delivery problem entirely. There is no absorption enhancer, no fasting protocol, and no injection. The ATTAIN-1 trial showed mean body-weight reduction of −11.1% (about −24.9 lbs) at the 17.2 mg dose over 72 weeks in adults without type 2 diabetes.^[12] For more on orforglipron, see what is orforglipron (Foundayo) and how does it work.

If oral isn’t enough, the injection options

For most patients pursuing maximum weight-loss efficacy, the injectable GLP-1s remain the highest-efficacy option: tirzepatide (Zepbound) at −20.9% body weight at 72 weeks^[10], semaglutide (Wegovy) at −14.9% at 68 weeks^[9], and liraglutide (Saxenda) at −8.0% at 56 weeks^[11]. The needle is a small subcutaneous pen, used once weekly (Zepbound, Wegovy, Ozempic), once daily (Saxenda), or via prefilled syringe. For an evidence-based comparison of the oral and injectable options, see our full GLP-1 medication reference.

Bottom line

No FDA-approved GLP-1 sublingual tablet, troche, lozenge, oral drop, oral spray, or nasal spray exists as of May 2026.
The peptide GLP-1s (semaglutide 4,113 Da; tirzepatide 4,813 Da; liraglutide 3,751 Da) are 4-10 times larger than the practical molecular-weight ceiling for unenhanced sublingual peptide absorption.
Rybelsus is the only FDA-approved oral semaglutide product, and it works only because the SNAC excipient creates a transient gastric permeability window — a mechanism specific to the stomach, not the mouth.
Products sold as “sublingual semaglutide,” “GLP-1 drops,” or “GLP-1 nasal spray” are compounded peptide formulations with no published mucosal bioavailability data, homeopathic dilutions containing essentially no drug, herbal tinctures with no GLP-1, or outright fraud.
The FDA maintains a standing advisory on unapproved GLP-1 products covering all of these formats, and has issued multiple warning letters to distributors.
The two FDA-approved needle-free options are swallowed oral tablets: Rybelsus (oral semaglutide; T2D-only, off-label for weight) and Foundayo (oral orforglipron; FDA-approved April 2026 for chronic weight management, −11.1% mean weight loss in ATTAIN-1).

Frequently asked questions

Are GLP-1 patches real? FDA approval status and honest evidence review — sister debunker covering the parallel transdermal-patch market: same scam landscape, different route.
Full GLP-1 medication list reference — every FDA-approved GLP-1 with brand, manufacturer, indication, dose ladder, and DailyMed SetID links.
Oral GLP-1 pills: Rybelsus vs Foundayo vs Wegovy oral — the two FDA-approved oral GLP-1 tablet products side by side, with dose, mechanism, and indication detail.
What is orforglipron (Foundayo) and how does it work — the first FDA-approved oral medication for chronic weight management; trial data, mechanism, and dose schedule.
Peptides for weight loss: evidence review — the three categories of weight-loss peptides; which have Phase 3 evidence and which do not.
Where to buy Foundayo legally — legitimate purchasing pathways for the FDA-approved oral GLP-1.
Where to buy semaglutide legally — Wegovy, Ozempic, Rybelsus, and the compounded landscape post-February 2025.

References

1.Bos JD, Meinardi MMHM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Canonical reference establishing that only molecules with a molecular weight under approximately 500 Daltons reliably traverse the human stratum corneum. The same general permeability logic — tight junctions, enzymatic degradation, lipophilicity ceiling — constrains oral mucosa and nasal epithelium for large peptide drugs. Exp Dermatol. 2000. PMID: 10839713.
2.Lau J, Bloch P, Schäffer L, Pettersson I, Spetzler J, Kofoed J, Madsen K, Knudsen LB, McGuire J, Steensgaard DB, Strauss HM, Gram DX, Knudsen SM, Nielsen FS, Thygesen P, Reedtz-Runge S, Kruse T. Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide. Semaglutide is a 31-amino-acid synthetic GLP-1 receptor agonist analogue with a C18 fatty-diacid side chain enabling albumin binding; molecular weight 4113.58 Daltons. J Med Chem. 2015. PMID: 26308095.
3.Coskun T, Sloop KW, Loghin C, Alsina-Fernandez J, Urva S, Bokvist KB, Cui X, Briere DA, Cabrera O, Roell WC, Kuchibhotla U, Moyers JS, Benson CT, Gimeno RE, D'Alessio DA, Haupt A. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Tirzepatide is a 39-amino-acid dual GIP/GLP-1 receptor agonist peptide; molecular weight 4813.53 Daltons. Mol Metab. 2018. PMID: 30473097.
4.Drucker DJ. Advances in oral peptide therapeutics. Definitive review of why peptide drugs are predominantly injected: poor oral bioavailability, gastric and intestinal protease degradation, the molecular-weight barrier to membrane permeation, and the limitations of sublingual, buccal, and nasal routes for high-molecular-weight peptide delivery. Nat Rev Drug Discov. 2020. PMID: 31848464.
5.Buckley ST, Bækdal TA, Vegge A, Maarbjerg SJ, Pyke C, Ahnfelt-Rønne J, Madsen MR, Schéele SG, Alanentalo T, Kirk RK, Pedersen BL, Skyggebjerg RB, Benie AJ, Strauss HM, Wahlund PO, Bjerregaard S, Farkas E, Fekete C, Søndergaard FL, Borregaard J, Hartoft-Nielsen ML, Knudsen LB. Transcellular stomach absorption of a derivatized glucagon-like peptide-1 receptor agonist. The canonical mechanism paper for SNAC-enabled oral semaglutide (Rybelsus). Demonstrates that SNAC (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate) creates a transient localized increase in gastric epithelial permeability AND lifts local pH to protect semaglutide from peptic degradation — a route specific to the gastric environment. Sci Transl Med. 2018. PMID: 30429357.
6.Aroda VR, Blonde L, Pratley RE. A new era for oral peptides: SNAC and the development of oral semaglutide for the treatment of type 2 diabetes. Comprehensive review of the SNAC/Rybelsus delivery system; absolute oral bioavailability approximately 1%; absorption requires a strict fasting protocol because food, other oral medications, or even small amounts of water disrupt the SNAC permeability window. Rev Endocr Metab Disord. 2022. PMID: 35838946.
7.Rawas-Qalaji M, Thu HE, Hussain Z. Oromucosal delivery of macromolecules: Challenges and recent developments to improve bioavailability. Review of the oral mucosa as a drug delivery route. Documents the tight-junction barrier, enzymatic degradation by oral peptidases, and the practical molecular-weight ceiling for unenhanced sublingual and buccal peptide absorption. J Control Release. 2022. PMID: 36334858.
8.Zhang Y, Zhang H, Ghosh D. Just how prevalent are peptide therapeutic products? A critical review. Confirms the dominance of subcutaneous and intravenous administration across the FDA-approved peptide-therapeutic class; documents the small number of FDA-approved peptide drugs delivered by oral, buccal, sublingual, or nasal routes — and the formulation engineering each one required. Int J Pharm. 2020. PMID: 32622810.
9.Wilding JPH, Batterham RL, Calanna S, Davies M, Van Gaal LF, Lingvay I, McGowan BM, Rosenstock J, Tran MTD, Wadden TA, Wharton S, Yokote K, Zeuthen N, Kushner RF; STEP 1 Study Group. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). Semaglutide 2.4 mg subcutaneous weekly produced mean body-weight reduction of -14.9% vs -2.4% placebo at 68 weeks. N Engl J Med. 2021. PMID: 33567185.
10.Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, Kiyosue A, Zhang S, Liu B, Bunck MC, Stefanski A; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). Tirzepatide 15 mg subcutaneous weekly produced mean body-weight reduction of -20.9% vs -3.1% placebo at 72 weeks. N Engl J Med. 2022. PMID: 35658024.
11.Pi-Sunyer X, Astrup A, Fujioka K, Greenway F, Halpern A, Krempf M, Lau DC, le Roux CW, Violante Ortiz R, Jensen CB, Wilding JP; SCALE Obesity and Prediabetes NN8022-1839 Study Group. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management (SCALE Obesity and Prediabetes). Liraglutide 3.0 mg subcutaneous daily produced mean body-weight reduction of -8.0% vs -2.6% placebo at 56 weeks. N Engl J Med. 2015. PMID: 26132939.
12.Wharton S, Blüher M, Hovingh GK, Pedersen SD, Wilding JPH, Hesse D, et al.; ATTAIN-1 Investigators. Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment (ATTAIN-1). Orforglipron 17.2 mg oral daily produced mean body-weight reduction of -11.1% over 72 weeks in adults with obesity and without type 2 diabetes. Orforglipron is a non-peptide small-molecule (approximately 487 Da), enabling once-daily oral dosing without an absorption enhancer or fasting protocol. N Engl J Med. 2025. PMID: 40960239.
13.Abdulhameed N, Babin A, Hansen K, Weaver R, Banks WA, Talbot K, Rhea EM. Comparing regional brain uptake of incretin receptor agonists after intranasal delivery in CD-1 mice and the APP/PS1 mouse model of Alzheimer's disease. Preclinical animal study of intranasal GLP-1 receptor agonist uptake for nose-to-brain delivery in Alzheimer's research — not a weight-loss trial and not a study of systemic GLP-1 bioavailability. Cited here as the closest published intranasal GLP-1 work in PubMed; no human Phase 2 or Phase 3 intranasal GLP-1 weight-loss trial exists as of May 2026. Alzheimers Res Ther. 2024. PMID: 39085976.
14.U.S. Food and Drug Administration. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. Standing FDA advisory covering compounded, counterfeit, and otherwise unapproved GLP-1 receptor agonist products in all formulations: injectable compounded semaglutide, sublingual tablets and lozenges, oral drops and sprays, transdermal preparations, and any other route lacking FDA approval. Companion guidance: FDA Warning Letters database. U.S. Food and Drug Administration. 2025. https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
15.U.S. Food and Drug Administration. FDA Warning Letters database — full-text-searchable archive of warning letters issued under section 502 of the Federal Food, Drug, and Cosmetic Act, including letters to online pharmacies, medspas, and direct-to-consumer brands distributing unapproved GLP-1 receptor agonist products in sublingual, oral-drop, lozenge, troche, nasal-spray, and topical formats. U.S. Food and Drug Administration. 2025. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/compliance-actions-and-activities/warning-letters
16.Novo Nordisk Inc. RYBELSUS (semaglutide) tablets, for oral use — US Prescribing Information. FDA-approved September 2019 for type 2 diabetes; not FDA-approved for weight loss. Absorption depends on the SNAC excipient (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate) and requires strict fasting administration: empty stomach, at most 4 oz of plain water, at least 30 minutes before any food, drink, or other oral medication. Absolute oral bioavailability is approximately 1%. FDA Approved Labeling (DailyMed NIH). 2025. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=27f15fac-7d98-4114-a2ec-92494a91da98
17.Eli Lilly and Company. FOUNDAYO (orforglipron) tablets, for oral use — US Prescribing Information. FDA-approved April 1, 2026 for chronic weight management. Orforglipron is a non-peptide small-molecule GLP-1 receptor agonist (molecular weight approximately 487 Da); once-daily oral dosing without absorption enhancer or fasting protocol. ATTAIN-1 mean body-weight reduction -11.1% at 17.2 mg over 72 weeks. FDA Approved Labeling (DailyMed NIH). 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8ac446c5-feba-474f-a103-23facb9b5c62

Important disclaimer. This article is educational information only — not medical advice and not a substitute for consultation with a licensed prescriber. “Sublingual semaglutide,” “GLP-1 drops,” and “GLP-1 nasal spray” are YMYL (Your Money or Your Life) topics. Every regulatory and molecular claim in this article is anchored to a primary source (DailyMed, PubMed, FDA) and should be independently verified by your prescriber. Weight Loss Rankings does not prescribe, dispense, or endorse any specific medication, compounding pharmacy, or sublingual / drop / spray product. Product categories are described generically; no individual seller is named.