Oral GLP-1 Receptor Agonists: Formulation Science and the 2026 Pipeline

In December 2025, the FDA approved oral semaglutide (Wegovy pill) for body-weight reduction, the first GLP-1 receptor agonist available as a daily pill for obesity (Novo Nordisk announcement). It launched in US pharmacies on 5 January 2026, and Novo Nordisk reported around 1.3 million prescriptions in the first quarter of 2026 (Q1 2026 report). This development is reshaping the entire peptide and metabolic research space.

Removal of the Injection Barrier

Published surveys have identified injection-related concerns, such as fear of needles, as a leading factor associated with patients declining or discontinuing injectable treatments, including GLP-1 receptor agonists (Spain et al., 2016; Khatib et al., 2022). Oral semaglutide removes that barrier.

• 36.1% of early oral Wegovy users had no prior GLP-1 exposure, indicating a population new to the drug category (Truveta Research analysis of 8,762 patients in the first six weeks after approval)
• Among patients with prior GLP-1 use, most had previously used injectable obesity treatments: injectable semaglutide accounted for 33.2% of all early users and tirzepatide for 24.5%
• The oral format removes cold-chain storage and injection administration requirements associated with injectable formulations

Current Regulatory Status

Oral Semaglutide (Wegovy Pill)

• FDA approved: December 22, 2025
• MHRA approved: 11 June 2026, not available on the NHS at approval (MHRA announcement)
• Indication: Chronic weight management in adults with BMI ≥30 (or ≥27 with comorbidity)
• Formulation: Semaglutide co-formulated with the absorption enhancer SNAC (US prescribing information)
• Trial data: Mean body-weight reduction of 13.6% at 64 weeks against 2.2% with placebo in the OASIS 4 trial (Wharton et al., 2025), compared with 14.9% at 68 weeks for the injectable formulation in the separate STEP 1 trial (Wilding et al., 2021). Novo Nordisk's headline figure of about 17% (16.6%) assumes all participants stayed on treatment.

Rybelsus (Oral Semaglutide for Diabetes)

• FDA approved: September 2019 (Drugs@FDA)
• Indication: Type 2 diabetes
• Note: Same compound, different approved indication

Compounds in Development

Oral Tirzepatide (Eli Lilly)

• Status: No oral formulation of tirzepatide is registered in clinical trials on ClinicalTrials.gov; Lilly's oral GLP-1 medicine is orforglipron, a different molecule (see below)
• Context: Injectable tirzepatide (Mounjaro/Zepbound) has outperformed semaglutide in trial data, including the head-to-head SURMOUNT-5 trial (20.2% vs 13.7% body-weight reduction at 72 weeks, Aronne et al., 2025)
• Mechanism: Dual GLP-1 and GIP receptor agonism

Oral Retatrutide

• Status: No oral formulation of retatrutide is registered in clinical trials on ClinicalTrials.gov
• Context: Injectable retatrutide reported 28.7% body-weight reduction at 68 weeks in the Phase 3 TRIUMPH-4 trial, on an efficacy-estimand basis that assumes participants stayed on treatment (Lilly topline release, December 2025), and 25.0% at 80 weeks counting all randomised participants in the published TRIUMPH-1 trial (Jastreboff et al., 2026)
• Research material: Injectable retatrutide reference material is stocked factory-direct for laboratory use only

Orforglipron (Eli Lilly)

• Status: FDA approved for obesity in April 2026 as Foundayo (Lilly announcement) and authorised by the MHRA for weight management and type 2 diabetes in August 2026 (MHRA announcement)
• Mechanism: A small molecule (not a peptide) that activates GLP-1 receptors orally (Kawai et al., 2020), without requiring an absorption enhancer (US prescribing information)
• Trial context: Reported to be taken without the fasting requirements associated with semaglutide (Ma et al., 2024); 11.2% mean body-weight reduction at 72 weeks with the highest dose in the Phase 3 ATTAIN-1 trial (Wharton et al., 2025)

Implications for Peptide Research

1. Market Expansion

Novo Nordisk said early Wegovy pill prescriptions were mainly driven by people new to GLP-1 medicines (Q1 2026 report), suggesting oral formulations can widen the treated population by removing the injection barrier, generating a larger volume of clinical and research data across the peptide category.

2. Category Normalisation

As oral GLP-1 formulations reach a wider population, public perception of peptide therapeutics has shifted from niche interest toward mainstream medicine. This shift extends to research interest in other peptides in the same broad category, including BPC-157 and Thymosin Alpha-1.

3. Oral Bioavailability Research Advances

The technology behind oral semaglutide (co-formulation with the SNAC absorption enhancer, which allows absorption in the stomach) is studied as a model for turning other injectable peptides into tablets (Buckley et al., 2018; Drucker, 2020). Delivering a peptide of 4,000+ daltons orally opens research avenues including:

• Oral BPC-157 formulations under laboratory investigation
• Oral KPV for gastrointestinal research
• Oral growth hormone secretagogue research
• Oral immune peptide research

4. Competitive Development

Novo Nordisk (oral semaglutide), Eli Lilly (orforglipron, a non-peptide alternative), and numerous biotechs are developing oral GLP-1 therapies. This competition may bring:

• Improved absorption technologies
• Lower production costs over time
• An expanding body of clinical trial data
• Faster regulatory pathways for peptide medicines

Comparative Trial Data

Oral versus Injectable: Reported Differences

Bioavailability figures are from the US prescribing information for semaglutide, tirzepatide (Zepbound) and orforglipron. Body-weight figures count all randomised participants: injectable 14.9% (STEP 1) and 20.9% (SURMOUNT-1, Jastreboff et al., 2022); oral 11.2% (orforglipron, ATTAIN-1), 13.6% (oral semaglutide, OASIS 4) and 15.1% (a higher oral semaglutide dose, OASIS 1, Knop et al., 2023). These come from separate trials.

Population-Level Trial Differences

Trial and prescribing data indicate distinct usage patterns between formulations: oral semaglutide has drawn many people new to GLP-1 medicines (36.1% of early users in the Truveta analysis), while injectable formulations remain associated with marginally higher trial efficacy (14.9% in STEP 1 against 13.6% in OASIS 4, in separate trials) and weekly administration frequency.

Outlook (as of October 2026)

• 2025 to 2026: Oral semaglutide approved for weight management in the US (December 2025) and UK (June 2026); orforglipron approved in the US (April 2026) and UK (August 2026), after its Phase 3 ATTAIN-1 results were published in 2025
• 2027: Lilly has said it plans to submit injectable retatrutide for US approval in the first quarter of 2027 (Lilly, July 2026)
• Not yet in clinical trials: no oral tirzepatide or oral retatrutide study is registered on ClinicalTrials.gov

Conclusion

The approval of oral Wegovy marks the beginning of a new phase of oral peptide research. As body-weight reduction compounds with strong trial data become available in oral form, research and clinical interest in the wider peptide category is expected to expand substantially.

2026 marks a shift toward mainstream peptide research. The injection barrier that limited earlier adoption has been substantially reduced.

Explore the Peptide Database to see which compounds are available as oral formulations, or use the reconstitution calculator for laboratory handling of lyophilised material.

References

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2. Buckley ST, et al. (2018). Transcellular stomach absorption of a derivatized glucagon-like peptide-1 receptor agonist. Science Translational Medicine. PubMed 30429357
3. Drucker DJ. (2020). Advances in oral peptide therapeutics. Nature Reviews Drug Discovery. PubMed 31848464
4. Jastreboff AM, et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine. PubMed 35658024
5. Jastreboff AM, et al. (2026). Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. New England Journal of Medicine. PubMed 42814954
6. Kawai T, et al. (2020). Structural basis for GLP-1 receptor activation by LY3502970, an orally active nonpeptide agonist. Proceedings of the National Academy of Sciences of the United States of America. PubMed 33177239
7. Khatib R, et al. (2022). Perceptions of injectable therapies with cardiovascular benefit: an ACNAP survey of healthcare professionals to explore facilitators and barriers. European Journal of Cardiovascular Nursing. PubMed 34849708
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9. Ma X, et al. (2024). Effect of Food Consumption on the Pharmacokinetics, Safety, and Tolerability of Once-Daily Orally Administered Orforglipron (LY3502970), a Non-peptide GLP-1 Receptor Agonist. Diabetes Therapy. PubMed 38402332
10. Spain CV, et al. (2016). Self-reported Barriers to Adherence and Persistence to Treatment With Injectable Medications for Type 2 Diabetes. Clinical Therapeutics. PubMed 27364806
11. Wharton S, et al. (2025). Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity. New England Journal of Medicine. PubMed 40934115
12. Wharton S, et al. (2025). Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment. New England Journal of Medicine. PubMed 40960239
13. Wilding JPH, et al. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. New England Journal of Medicine. PubMed 33567185