Peptide Policy Watch

From insulin to Ozempic: a timeline of how peptide medicines went from niche to mainstream

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A dark wooden library desk under a green banker's lamp, with stacks of old leather-bound books, aged paper sheets with illegible handwriting and a brass magnifying glass.

If a type of medicine you barely heard of a few years ago keeps showing up in headlines, you are not imagining it. The odd part is how old the idea is. Peptide medicines have been around for roughly a century. What changed lately is the size of the audience, the size of the money and the number of rules suddenly in play.

Not medical advice, and the site owner isn't a medical professional. This is a history of approvals, rules and published numbers, not a guide to any substance, and nothing here is a recommendation. Facts are as of October 25, 2026. Sources with retrieval dates are at the bottom.

The short version

  • Insulin, a peptide hormone, was first tested in people in the early 1920s, and FDA approved a lab-made human version in 1982. [V]
  • The modern GLP-1 era runs through a string of FDA approvals from 2005 to 2023, first mainly for type 2 diabetes and later for long-term weight management. [V]
  • Demand strained supply, FDA listed and then delisted shortages, and the rules for compounded copies moved with them. [V]
  • Retatrutide, Lilly's triple-action candidate, is still investigational. Lilly says no approved medicine containing it exists in any country. [V]

A quiet century first

Peptides are short chains of amino acids, and a few have been prescription medicines for generations. The best-known case is insulin. Our plain-English explainer covers where the line between a peptide and a protein falls, and why insulin sits right on it. For this timeline the label matters less than the pattern: a hormone gets found, then made at scale, then re-made in a better way, then studied for new uses.

You can see that pattern in the early entries below. None of them involves a weight-loss pitch. They are about a hormone that people with diabetes could not do without, and the slow work of making it reliably.

The timeline

  1. 1921 to 1922

    Insulin goes from lab idea to first human studies

    FDA's history office dates the Toronto team's experiments to May 1921 and says clinical studies by January 1922 showed a drop in blood sugar. The first paper followed in February 1922. [V]

  2. 1923

    A Nobel Prize for the discovery

    The Nobel committee gave the 1923 medicine prize to Banting and Macleod "for the discovery of insulin" (Nobel Prize site). By the fall of that year, according to FDA's history, the University of Toronto let Lilly distribute it generally. [V]

  3. 1955 and 1958

    Chemists crack how these molecules are built

    du Vigneaud won the 1955 chemistry prize partly for "the first synthesis of a polypeptide hormone." Sanger won in 1958 for his work on protein structure, "especially that of insulin" (Nobel Prize site). [V]

  4. Oct 28, 1982

    Lab-made human insulin is approved

    FDA approved Humulin after about five months of review. FDA's history calls it the first biosynthetic human insulin and the first approved medicine of any kind made with that DNA technique. The Purple Book lists the same date. [V]

  5. Apr 28, 2005

    Byetta (exenatide) arrives for type 2 diabetes

    FDA approved this injectable for adults with type 2 diabetes who were not controlled on certain pills. Lilly and Amylin called it the first of a new class that mimics the hormone GLP-1. [V]

  6. Jan 25, 2010

    Victoza (liraglutide) is approved

    Another GLP-1 injectable for adults with type 2 diabetes, from Novo Nordisk, approved alongside diet and exercise. [V]

  7. Dec 23, 2014

    Saxenda, a liraglutide product, is approved for weight management

    FDA approved a liraglutide product, Saxenda, for long-term weight management in adults who have obesity, or overweight along with a related health condition. [V]

  8. Dec 5, 2017

    Ozempic (semaglutide) is approved for type 2 diabetes

    The semaglutide product that later became a household name started as a diabetes medicine. [V]

  9. Jun 4, 2021

    Wegovy (semaglutide) is approved for weight management

    FDA said it was the first approval of a new drug for chronic weight management since 2014. [V]

  10. May 13, 2022

    Mounjaro (tirzepatide) is approved for type 2 diabetes

    FDA called it first-in-class, acting on two hormone targets, GLP-1 and GIP. [V]

  11. 2022

    Shortages begin

    FDA's shortage list added Wegovy in March 2022 and Ozempic in August 2022. Tirzepatide was added on Dec 15, 2022. [V]

  12. Nov 8, 2023

    Zepbound (tirzepatide) is approved for weight management

    The same molecule as Mounjaro, now cleared for long-term weight management in adults who have obesity, or overweight along with a related health condition. [V]

  13. Oct 2 and Dec 19, 2024

    FDA says the tirzepatide shortage is over

    FDA first declared the shortage resolved on Oct 2, then reevaluated after a lawsuit and issued a new order on Dec 19 reaching the same conclusion. [V]

  14. Feb 21, 2025

    FDA says the semaglutide shortage is over

    Compounders got transition periods that ran to Apr 22 (state-licensed pharmacies) and May 22, 2025 (outsourcing facilities). [V]

  15. Nov 2025

    About one in eight US adults report currently taking a GLP-1 drug

    KFF published this on Nov 14, 2025, from a poll fielded Oct 27 to Nov 2. [V]

  16. Oct 1, 2026

    FDA restates its position on unapproved GLP-1 copies

    FDA's GLP-1 page says federal law bars retatrutide from compounding, and that it is not an ingredient in any FDA-approved drug. [V]

  17. Now

    Retatrutide is still investigational

    Lilly says it is in Phase 3 trials, with a plan to submit an application to FDA in the first quarter of 2027. A plan is not a filing, and nothing is approved. [V]

From diabetes drug to household word

Look at the middle of that list and you can see a quiet handoff. The first GLP-1 approvals were for type 2 diabetes. Weight-management approvals came later, with Saxenda in 2014 and Wegovy in 2021. In 2023 the tirzepatide molecule got a second brand and a second job. The same family of medicines moved from a specialist's prescription pad into an everyday conversation, and FDA's own paperwork shows the steps.

FDA's 2021 announcement is a good marker. The agency said it was the first approval of a drug for chronic weight management since 2014, and it called the new option something to use alongside a reduced-calorie diet and physical activity. [V] That framing, a medicine added to a broader program, is part of the approved labels, and we leave the medical details to the labels and to clinicians.

What happened to the money

You can follow the money in two company filings. Lilly's annual report for 2025 lists total revenue of $65.2 billion, up from $34.1 billion in 2023. Lilly also says Mounjaro and Zepbound together made up 56 percent of its 2025 revenue. [V] Novo Nordisk's annual filing for 2025 reports sales of 82.3 billion Danish kroner for its obesity-care products, Saxenda and Wegovy,, against 65.1 billion the year before. [V] These are company-reported sales, in each firm's own currency, and they say nothing about how well any medicine works for any person.

  • $65.2 billionLilly's total 2025 revenue, versus $34.1 billion in 2023 [V]
  • 56%share of Lilly's 2025 revenue from Mounjaro and Zepbound, per Lilly [V]
  • 1 in 8US adults who said in late 2025 they were currently taking a GLP-1 drug, per KFF [V]

KFF's poll adds the public-interest side. About one in eight adults said they were taking one of these drugs at the time, and nearly one in five said they had taken one at some point. Among adults who had not, roughly one in five said they were interested in trying one for weight. About half of the people who had taken one said it was difficult to afford. [V] A poll like this describes what people say about themselves. It does not tell you what is right for anyone.

Why the rules shifted

Big demand met finite supply. Once a drug is on FDA's shortage list, compounders have more room to make copies of it. When FDA decides a shortage has ended, that room narrows. That is why the two shortage decisions above matter, and why FDA gave compounders timed transition periods rather than an instant cutoff. [V] For the full rulebook, see our explainers on FDA's compounding categories and on telehealth and compounded drugs.

unapproved versions do not undergo FDA’s review for safety, effectiveness and quality before they are marketed

FDA, GLP-1 drugs page, current as of Oct 1, 2026

That sentence, from FDA's page on unapproved GLP-1 drugs, is the thread connecting the money and the rules. When demand is huge, the market around an approved medicine gets crowded with look-alikes, and regulators spend more of their time on what is and is not approved. [V]

Where retatrutide fits

Retatrutide gets mentioned in the same breath as the approved medicines, so here is the plain status. Lilly describes it as investigational, meaning it is still being tested. It says five Phase 3 studies have produced what it calls positive topline results, and it plans to submit an application to FDA in the first quarter of 2027. [V] FDA's October 2026 page says FDA has not found it safe and effective for any condition, and that federal law rules it out for compounding. [V] Our rule on this subject is simple: we track the milestones that primary sources confirm and leave out claims about results for people.

Questions worth asking

Not advice, just a starting set when you read a new headline about this family of medicines:

  1. Is the thing being discussed an FDA-approved product, or a copy or an unapproved substance? The approved-versus-wellness comparison shows how to tell.
  2. What kind of source is it? A regulator's page, a company filing and a poll are three different kinds of evidence. Our evidence ladder explains why that matters.
  3. Is a number a sales figure, a survey answer or a trial result? Each means something different.
  4. Is this something to raise with a clinician or pharmacist who knows my health history? They can say what applies to you. This site cannot.

For the rule changes in one place, see our regulation timeline.

What was left out, and why

We left out weight-loss percentages from trials. Numbers like that depend on dose, population and time, and they invite a read-across to individuals that we cannot make. We also left out anything about how these medicines are used, obtained or prepared. Where a date could not be tied to a document we opened, it is not here.

Sources (all retrieved October 25, 2026)

  1. FDA History Office, "100 Years of Insulin" [V] — https://www.fda.gov/about-fda/fda-history-exhibits/100-years-insulin
  2. NobelPrize.org, "The Nobel Prize in Physiology or Medicine 1923," "The Nobel Prize in Chemistry 1955" and "The Nobel Prize in Chemistry 1958" [V] — https://www.nobelprize.org/prizes/medicine/1923/summary/ , https://www.nobelprize.org/prizes/chemistry/1955/summary/ , https://www.nobelprize.org/prizes/chemistry/1958/summary/
  3. FDA Purple Book, BLA 018780 (Humulin R), original approval Oct 28, 1982 [V] — https://purplebooksearch.fda.gov/
  4. FDA, approval package for NDA 21-773 (Byetta), approval date April 28, 2005 [V] — https://www.accessdata.fda.gov/drugsatfda_docs/nda/2005/021773_Byetta_approv.PDF
  5. Amylin Pharmaceuticals and Eli Lilly, release of April 29, 2005 [V, company statement] — https://investor.lilly.com/news-releases/news-release-details/amylin-and-lilly-announce-fda-approval-byettatm-exenatide
  6. FDA, approval letter for NDA 022341 (Victoza), January 25, 2010 [V] — https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2010/022341s000ltr.pdf
  7. FDA, approval package for NDA 206321 (Saxenda), approval date December 23, 2014 [V] — https://www.accessdata.fda.gov/drugsatfda_docs/nda/2014/206321Orig1s000Approv.pdf
  8. FDA, approval package for NDA 209637 (Ozempic), approval date December 5, 2017 [V] — https://www.accessdata.fda.gov/drugsatfda_docs/nda/2017/209637Orig1s000Approv.pdf
  9. FDA news release, "FDA Approves New Drug Treatment for Chronic Weight Management, First Since 2014," June 4, 2021 [V, archived copy] — https://web.archive.org/web/20210604235421/https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014
  10. FDA news release, "FDA Approves Novel, Dual-Targeted Treatment for Type 2 Diabetes," May 13, 2022, and approval package for NDA 215866 [V, archived copy] — https://web.archive.org/web/20220513192349/https://www.fda.gov/news-events/press-announcements/fda-approves-novel-dual-targeted-treatment-type-2-diabetes
  11. FDA news release, "FDA Approves New Medication for Chronic Weight Management," November 8, 2023 [V] — https://www.fda.gov/news-events/press-announcements/fda-approves-new-medication-chronic-weight-management
  12. FDA, Declaratory Order on tirzepatide injection shortage, December 19, 2024 [V] — https://www.fda.gov/files/drugs/published/2024.12.19_tirzepatide_declaratory_order.pdf
  13. FDA, Declaratory Order on semaglutide injection shortage, February 21, 2025 [V] — https://www.fda.gov/media/185526/download
  14. FDA, "FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize," content current as of December 19, 2024 with the February 21, 2025 update [V] — https://www.fda.gov/drugs/drug-alerts-and-statements/fda-clarifies-policies-compounders-national-glp-1-supply-begins-stabilize
  15. Eli Lilly and Company, Form 10-K for fiscal year 2025, filed February 12, 2026 [V] — https://www.sec.gov/Archives/edgar/data/59478/000005947826000013/lly-20251231.htm
  16. Novo Nordisk A/S, Form 20-F for fiscal year 2025, filed February 4, 2026 [V] — https://www.sec.gov/Archives/edgar/data/353278/000035327826000012/nvo-20251231.htm
  17. KFF, "Poll: 1 in 8 Adults Say They Are Currently Taking a GLP-1 Drug...," November 14, 2025 [V] — https://www.kff.org/public-opinion/poll-1-in-8-adults-say-they-are-currently-taking-a-glp-1-drug-for-weight-loss-diabetes-or-another-condition-even-as-half-say-the-drugs-are-difficult-to-afford/
  18. FDA, "FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss," current as of October 1, 2026 [V] — https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
  19. Eli Lilly and Company, release of July 23, 2026 on TRIUMPH-2 and TRIUMPH-3 (retatrutide status and filing plan) [V, company statement] — https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-successful-two-additional

Reading this for health reasons? This site reports on regulation; it is not medical advice. See our disclaimer, how we source and corrections policy.

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