Peptide Strips Under the Tongue: No Human Absorption Data for GLP-1 or BPC-157 Strips, and 0.25% for the One Approved Sublingual Peptide

Peptide products that dissolve in the mouth are spreading fast. They come as thin strips placed under the tongue, as drops, and as orally disintegrating tablets (ODTs), which melt on the tongue without water. Sellers offer them with tirzepatide, semaglutide, BPC-157, CJC-1295, and other peptides, often as a needle-free version of an injection.

The key question is bioavailability: the share of a dose that reaches the bloodstream. For an injection of semaglutide, the official label puts it at 89%. For the approved semaglutide tablets, which need a special absorption helper, it is about 0.4% to 2%. For desmopressin, the one peptide drug approved in a form that dissolves under the tongue, it is about 0.25%.

We found no published study measuring blood levels in people after a sublingual (under-the-tongue) dose of semaglutide, tirzepatide, BPC-157, CJC-1295, or ipamorelin. The closest evidence comes from rats, minipigs, and mice. A product can contain the labeled amount of peptide and still deliver only a tiny, unknown fraction of it.

This guide explains why the mouth is a hard route for peptides, what the approved products needed to work, what the animal studies found, and what to ask before paying for a strip. For the broader history of peptide pills, see Oral vs Injectable Peptides.

On November 8, 2026, the San Francisco Standard described a black-tie, alcohol-free peptide party hosted by Haus Fund, a startup accelerator, aboard the SS Jeremiah O'Brien, a World War II Liberty ship docked at Pier 35. Guests signed waivers and then sampled strips containing CJC-1295 and ipamorelin, two peptides sold to raise growth hormone. A company called Afterglow Science, which launched in September, offered strips that the paper said include tirzepatide and a "Glow" blend of BPC-157, TB-500, and GHK-Cu.

The hosts stressed that every peptide was made in the United States. The Standard noted that absorption under the tongue is unclear and that little research supports claims that it approaches injection levels. Where a peptide is made says nothing about how much of it gets into the blood.

Strips are only one format. In a review published in 2026, University of Connecticut pharmacists searched compounding pharmacy websites in early 2025 and found 17 single-ingredient compounded semaglutide or tirzepatide products that differed from the approved versions. Of those, 82% were sublingual and 18% were ODTs. The authors wrote that there is a rationale for these formats, but whether they offer any advantage over the approved oral tablets has not been determined.

Peptides are short chains of amino acids. Most drug peptides are far larger than ordinary pill medicines, and size matters for crossing the lining of the mouth or gut. The approved labels give the weights: desmopressin acetate is about 1,183 daltons (a unit of molecular mass), semaglutide is 4,114, and tirzepatide is 4,814, so the two GLP-1 drugs are roughly three and a half to four times the size of desmopressin.

A 2023 paper in Science Translational Medicine from ETH Zurich summed up the problem: most peptide and protein drugs need to be injected because of their high molecular weight and relative instability, and over 40 years only a few oral peptide drugs have even entered clinical trials, often with large amounts of permeation enhancers. A permeation enhancer is an added chemical that loosens the barrier so more drug can pass.

A strip under the tongue also sits in saliva, and whatever is not absorbed there is eventually swallowed. Once swallowed, a peptide meets the same stomach and gut conditions that keep most peptides from working as ordinary pills.

Desmopressin is a lab-made version of vasopressin, the body's water-retention hormone. In the United States, desmopressin tablets are approved for central diabetes insipidus and for bedwetting in children. The drug also comes as injections, nasal sprays, and, in the UK and elsewhere, a melt that dissolves under the tongue.

The UK product information for the DDAVP Melt, which is placed under the tongue, reports an average bioavailability of 0.25% (95% confidence interval 0.21% to 0.31%) at doses of 200 to 800 micrograms. It also says absorption varies moderately to highly, both from person to person and from dose to dose in the same person. The U.S. label for swallowed DDAVP tablets puts their bioavailability at about 0.16% of an intravenous dose and about 5% of a nasal spray dose.

The dosing table in the UK document shows the practical difference: a 120 microgram melt matches the blood levels of a 0.2 mg (200 microgram) swallowed tablet. So the under-the-tongue form absorbs somewhat better than swallowing, but more than 99% of the dose still never reaches the blood.

Desmopressin gets away with this because it is very potent. At 0.25%, a 200 microgram dose puts only about half a microgram into the blood, and that is enough to act on the kidneys. Most peptides people are putting under their tongues are not known to work at such tiny amounts.

Semaglutide is the only GLP-1 peptide approved as a pill. Novo Nordisk sells it as Rybelsus, as Ozempic tablets, and as Wegovy tablets. Each tablet contains an absorption enhancer called salcaprozate sodium, or SNAC, and the labels say absorption happens mainly in the stomach, not the mouth.

The labels estimate absolute bioavailability at about 0.4% to 1% for Rybelsus and about 1% to 2% for Ozempic and Wegovy tablets, compared with 89% for the Wegovy injection. To make up for that, the doses are much larger. The Wegovy tablet maintenance dose is 25 mg every day, or 175 mg a week, while the injection is 2.4 mg once a week. That is about 73 times more drug by mouth to reach blood levels the label predicts are comparable.

Even then, blood levels vary more with the pill. The Wegovy label reports that 90% of patients had average levels between 27 and 186 nmol/L on the 25 mg tablet, compared with 51 to 110 nmol/L on the 2.4 mg injection. The pill also comes with strict rules: take it on an empty stomach with no more than 4 ounces of plain water, wait at least 30 minutes before eating, and swallow it whole. The labels say not to split, crush, chew, or dissolve it.

A 2026 review by S.K. Niazi of the University of Illinois College of Pharmacy, who discloses that he runs a company developing GLP-1 drugs, called oral semaglutide a boundary case rather than proof that oral peptides work in general. He argued that it succeeds because of a rare combination: a half-life of about a week, high potency, and a wide safety margin that can absorb low and variable uptake. Most peptides, including most of those sold as strips, have none of those features. (Foundayo, Lilly's newer GLP-1 pill, is a small molecule rather than a peptide, so it avoids these limits; see the oral GLP-1 race.)

The evidence for under-the-tongue GLP-1 drugs is limited to animals and one unfinished human trial.

• Rats, from a compounding supplier. Researchers at the Professional Compounding Centers of America (PCCA), a supplier to compounding pharmacies, gave rats semaglutide under the tongue in a water-free suspension. Blood exposure was about five and a half times higher than with swallowed tablets at the same dose, but the paper still reported relative bioavailability of only 0.34% using tablets and 0.29% using peptide powder, compared with 0.06% for swallowed tablets. The authors called it a proof-of-concept study and said human pharmacokinetic (PK) research is needed. PK means how a drug is absorbed, spread, and cleared over time.
• Minipigs, from a strip maker. A 2026 study by InStar Technologies, which makes electrospun strips, and the contract lab Scantox gave 40 young female minipigs semaglutide strips, Rybelsus, or Ozempic injections for 8 weeks. Strips that included SNAC or another enhancer slowed weight gain by 24.9% compared with placebo. The authors noted the small group and short duration.
• Mice, from a university lab. University of British Columbia researchers mixed semaglutide or insulin with custom carrier peptides and gave it under the tongue to mice, with blood sugar effects comparable to injection. The carriers were new molecules, not ingredients in any product on sale.
• People. A Phase 1b/2a trial of sublingual liraglutide, an older GLP-1 drug, sponsored by Biolingus and run at the Chinese University of Hong Kong, started in April 2023 with a planned 15 participants. Its ClinicalTrials.gov record (NCT05268237) still listed it as recruiting, with no results posted, as of November 8, 2026.

We found no published human study of sublingual semaglutide or tirzepatide in PubMed or ClinicalTrials.gov. The animal results also depended on specific enhancers and carriers. A compounded strip or drop made with different ingredients cannot borrow those numbers.

For the wellness peptides at the party, the data are thinner still. A PubMed search on November 8, 2026 found no studies of sublingual CJC-1295, ipamorelin, or GHK-Cu.

BPC-157 has the most research of the group, but almost all of it is in animals. A 2026 review in Pharmaceutics by researchers in Timișoara and Bucharest, Romania, found that its human PK profile remains poorly characterized, that no pharmaceutical-grade formulation has been developed or validated, and that the available human data come from fewer than 30 people across three uncontrolled pilot studies. The review notes that BPC-157 is unusually stable in gastric juice and has shown activity by mouth in preclinical studies. Those findings do not show how much enters the blood of a person holding a strip under the tongue.

What is known about BPC-157's behavior in the body comes from a 2022 study in rats and dogs. After injection into a vein, it disappeared from the blood with a half-life under 30 minutes and was broken into small fragments. Even injected into muscle, only about 14% to 19% reached the blood in rats and 45% to 51% in dogs. For more on the gut-healing claims, see BPC-157 and gut healing.

Researchers are working on ways to push peptides through the cheek lining. The ETH Zurich team built a small suction patch, inspired by octopus suckers, that stretches the inside of the cheek while releasing the drug with an enhancer. In dogs, the patch gave desmopressin bioavailability up to two orders of magnitude (about 100 times) higher than the commercial desmopressin tablet, and semaglutide exposure comparable to the approved oral tablet. A first study in 40 healthy volunteers confirmed that people found the patch acceptable to use; the paper's summary reports no drug levels in people.

The point is the effort involved. Getting a peptide through the mouth lining at useful levels has taken custom devices, purpose-built enhancers, and animal blood testing. None of the strips sold at parties or online has published results from that kind of testing.

In the United States, compounded drugs are made by two kinds of pharmacies. Section 503A pharmacies compound for individual patients based on prescriptions. Section 503B covers outsourcing facilities, a separate, voluntary category of compounders. The FDA says plainly that compounded drugs are not FDA approved and that the agency does not review them for safety, effectiveness, or quality before they are sold.

The University of Connecticut review explains that with the semaglutide and tirzepatide shortages resolved, compounding pharmacies can legally sell only products that differ from the approved ones, for example by route of administration or added ingredients. Sublingual and ODT versions are one result.

The FDA has started to question whether such differences are real. In a warning letter dated September 18, 2026, it told Empower Pharmacy in Houston that three of its injectable semaglutide and tirzepatide combination products appeared to be essentially copies of approved drugs, and that some prescriptions lacked a genuine prescriber finding of a significant difference for the patient. That letter concerned injections, not ODTs. Its details are covered in our article on the Empower warning letter.

Products sold outside pharmacies, such as those labeled for research use only, are not compounded prescriptions at all. See what "research use only" means.

• Has anyone measured blood levels in people? Ask for a human PK study of the exact product. A study of a different formula, an injection, or an animal does not count.
• How was the dose chosen? If a strip claims to equal a weekly injection, ask what that claim is based on. Without human blood-level data, any milligram-for-milligram comparison is a guess, and the approved semaglutide pill needs about 73 times the weekly injected amount.
• What absorption enhancer does it contain, if any? The approved tablets depend on SNAC. A product without a tested enhancer has no reason to perform like them.
• Who made it, and under what rules? Ask whether it came from a licensed 503A pharmacy, a 503B outsourcing facility, or a seller outside the pharmacy system, and ask for a certificate of analysis. Our guide to evaluating a compounding pharmacy covers what to look for.
• What happens if it does not work? With a low, unpredictable dose, a person may see no effect and stop, or may later switch to an approved product without knowing their real starting exposure. Discuss dosing with a prescriber before switching.

Getting a peptide into the blood through the mouth is possible, but it has taken years of engineering for each approved product, and even then most of the dose is lost. Desmopressin under the tongue reaches the blood at about 0.25%. Semaglutide tablets reach 0.4% to 2%, but only with an enhancer, a strict empty-stomach routine, and about 73 times the weekly injected amount.

For tirzepatide, semaglutide, BPC-157, CJC-1295, and ipamorelin strips, no human absorption data have been published. Animal studies show some peptide can cross the mouth lining under specific lab conditions, which is a reason to study these products, not proof that a given strip works. Until a seller can show human blood levels for its own product, the dose a strip delivers is unknown.