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Peptide drug (FDA approved, now discontinued)Human trialsFDA approved

Pramlintide

Pramlintide acetate

Last reviewed October 27, 2026 · 9 sources · Written for general readers · Compare with another compound →

The bottom line

Pramlintide is a lab made copy of the hormone amylin, approved in 2005 as Symlin to add to mealtime insulin in type 1 and type 2 diabetes. In placebo controlled trials it modestly lowered blood sugar, curbed appetite and caused a few percent of weight loss, even in people without diabetes. It carries a boxed warning for severe low blood sugar when used with insulin, and FDA now lists all Symlin products as discontinued.

Where the evidence stands

What it is

Pramlintide is a lab made copy of amylin, a hormone the pancreas releases along with insulin after meals. It is 37 amino acids long and differs from human amylin at three spots, where proline replaces the original building blocks.[1]

It was sold as Symlin, approved in March 2005 as an add on to mealtime insulin for adults with type 1 or type 2 diabetes whose blood sugar was not well controlled on insulin alone. It was given as a shot under the skin before meals.[1][2] FDA's Drugs@FDA database now lists every Symlin product as discontinued.[2]

It was never approved for weight loss, although it was tested for that.[1][3]

The label gives its formula as C171H267N51O53S2, supplied as an acetate salt.[1] FDA's substance registry lists its CAS number as 151126-32-8.[4]

Name
Pramlintide (Pramlintide acetate)
Other names
Symlin, SymlinPen
Type
Peptide drug (FDA approved, now discontinued)
CAS number
151126-32-8
Formula
C171H267N51O53S2
Molecular weight
About 3949 g/mol

How it works

Pramlintide mimics amylin. People with type 1 and type 2 diabetes make less amylin than normal.[1]

  • It slows how fast food leaves the stomach, without changing how much is absorbed overall.[1]
  • It lowers the rise in glucagon, a hormone that raises blood sugar, after meals.[1]
  • In human studies it increased feelings of fullness and lowered how many calories people ate.[1]

These effects were measured in people and are described in the FDA label. Newer amylin drugs in development build on the same idea.

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Animal studies found no tumors

  • Two year studies in mice and rats found no drug related tumors.[1]
  • In a rat fertility study, the highest dose caused difficult births in 8 of 12 females, which the label links to toxic effects in the mothers, including low blood calcium.[1]

Limit: Animal results say little about the main danger in people, which is severe low blood sugar when used with insulin.

Human studies

Placebo controlled trials showed modest benefits on blood sugar and weight

  • Type 1 diabetes: three trials lasting 26 to 52 weeks, with roughly 150 to 240 people per group, added mealtime shots of pramlintide or placebo to insulin. HbA1c fell about 0.25 to 0.34 points more than on placebo at six months, and people on pramlintide lost about 0.8 to 1.6 kg while people on placebo gained a little.[1]
  • Type 2 diabetes: in two trials of insulin users, HbA1c fell about 0.3 points more than on placebo, with weight loss of 1.4 to 1.6 kg versus small gains on placebo.[1]
  • A 2010 review of seven randomized trials, none longer than 52 weeks, found HbA1c gains of only 0.2 to 0.4 points. In type 1 diabetes with intensive insulin, it was no better than placebo, and severe low blood sugar was more frequent on the drug.[5]
  • Obesity without insulin: 204 adults with obesity, most of them women, took shots before meals or placebo for 16 weeks without a diet program. Those who finished lost about 3.7 percent more weight than placebo and about 3.6 cm more off the waist. Dropout was 29 percent on the drug and 25 percent on placebo.[3]
  • In that trial, more people on the drug reported better appetite control (72 versus 31 percent) and better sense of well being (52 versus 17 percent). Mild, passing nausea was the most common side effect, and people lost about the same weight with or without nausea.[3]
  • Appetite study: 88 adults with obesity took mealtime shots or placebo for 6 weeks with no diet program. Daily calorie intake fell about 680 calories by week 6 on the drug versus about 190 on placebo, weight changed by minus 2.1 percent versus plus 0.1 percent, and binge eating scores fell 45 percent more than on placebo.[8]
  • Obesity with a lifestyle program: 411 adults joined a 4 month placebo controlled trial, and most continued for 8 more months. At one year, two treatment groups lost about 5.6 and 6.8 percent more than placebo, and about 40 to 43 percent in those groups reached 10 percent weight loss versus 12 percent on placebo. Only 146 people were assessed at one year.[6]
  • In that trial, nausea affected about 9 to 29 percent on the drug versus about 2 percent on placebo in the first 4 months, and under 10 percent later.[6]
  • Combination trial: 244 adults with obesity or overweight on a lifestyle program were treated for 24 weeks. Weight fell about 11 percent with pramlintide plus phentermine or sibutramine, 3.7 percent with pramlintide alone and 2.2 percent with placebo. The combinations raised heart rate by about 3 to 4.5 beats per minute.[7]
  • Nausea in diabetes: reported by 48 percent of people with type 1 diabetes versus 17 percent on placebo, and by 28 percent of people with type 2 diabetes versus 12 percent. Loss of appetite and vomiting were also more common.[1]

Limit: The benefits on blood sugar and weight were modest, trials lasted a year or less, and the drug was only approved as an add on to insulin.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Lowers blood sugar for people on insulin

Shown in people

In three type 1 diabetes trials of 26 to 52 weeks with roughly 150 to 240 people per group, HbA1c (a three month blood sugar average) fell about 0.25 to 0.34 points more than on placebo at six months. In two type 2 diabetes trials of insulin users, it fell about 0.3 points more.[1] A review of seven trials found the gain was small, 0.2 to 0.4 points, and in type 1 diabetes on intensive insulin it was no better than placebo.[5]

Causes weight loss

Mixed results

In 204 adults with obesity, 16 weeks of shots before meals without a diet program led to about 3.7 percent more weight loss than placebo, and 31 percent lost at least 5 percent of their weight versus 2 percent on placebo.[3] In 411 adults with obesity who also followed a lifestyle program, two treatment groups lost about 5.6 and 6.8 percent more than placebo after a year, though only 146 people were assessed at that point.[6] In a third trial, it beat placebo by only about 1.5 points (3.7 versus 2.2 percent) after 24 weeks.[7] The effect is real but small.

Curbs appetite

Shown in people

The FDA label reports that in human studies it increased fullness and lowered calorie intake.[1] In a 6 week placebo controlled study of 88 adults with obesity, people on mealtime shots ate about 990 fewer calories in a day early on and about 680 fewer by week 6, versus drops of about 240 and 190 on placebo. Binge eating scores fell 45 percent more than on placebo.[8] In a 16 week trial, 72 percent on the drug said their appetite control improved, versus 31 percent on placebo.[3]

Boosts weight loss when stacked with diet pills

Mixed results

In a 24 week trial of 244 adults with obesity or overweight and no diabetes, all on a lifestyle program, pramlintide plus phentermine or plus sibutramine led to about 11 percent weight loss. Pramlintide alone gave about 3.7 percent and placebo about 2.2 percent.[7] The combination groups were not blinded, and both combinations raised heart rate and blood pressure a little.[7]

Prevents weight gain from insulin

Shown in people

Insulin often causes weight gain. In the label trials, people with type 1 diabetes on pramlintide lost about 0.8 to 1.6 kg at six months, and people with type 2 diabetes lost 1.4 to 1.6 kg, while people on placebo gained a little.[1] A review of seven trials agreed that placebo patients tended to gain weight while treated patients lost.[5]

Safe because it copies a natural hormone

No benefit in trials so far

Trials found clear harms. Nausea hit 48 percent of people with type 1 diabetes versus 17 percent on placebo.[1] Severe low blood sugar was more frequent than on placebo, and the label carries a boxed warning for it.[5][1]

Known risks and side effects

  • Boxed warning for severe low blood sugar. Used with insulin, pramlintide raises the risk of severe low blood sugar, especially in type 1 diabetes, usually within about 3 hours of a shot. This can cause serious injury if it happens while driving.[1]
  • Nausea is very common. Nausea affected 48 percent of people with type 1 diabetes versus 17 percent on placebo, and 9 to 29 percent of people with obesity in a weight loss trial.[1][6]
  • Not for some people. It must not be used by people who cannot sense low blood sugar or who have gastroparesis, a condition where the stomach empties too slowly.[1]
  • Delays other medicines. Because it slows stomach emptying, it can delay the absorption of pills taken by mouth.[1]
  • Allergy and injection site reactions. Injection site and allergic reactions can occur.[1]

Regulatory status

Today: Pramlintide was FDA approved as Symlin in 2005, but Drugs@FDA now lists all three Symlin products as discontinued.[2] WADA's 2026 Prohibited List does not name it.[9]

  1. FDA approved Symlin as an add on to mealtime insulin.[2]
  2. Most recent labeling update listed in Drugs@FDA.[2]

Sources

  1. AstraZeneca. SYMLIN (pramlintide acetate) injection: prescribing information. Revised 12/2019. DailyMed. FDA label (DailyMed)
  2. U.S. Food and Drug Administration. Drugs@FDA: NDA 021332, Symlin (pramlintide acetate). Drugs@FDA
  3. Aronne L, Fujioka K, Aroda V, et al. Progressive reduction in body weight after treatment with the amylin analog pramlintide in obese subjects: a phase 2, randomized, placebo-controlled, dose-escalation study. J Clin Endocrinol Metab. 2007;92(8):2977-2983. PMID 17504894
  4. U.S. Food and Drug Administration, Global Substance Registration System. Pramlintide (UNII D3FM8FA78T): codes. FDA GSRS
  5. Lee NJ, Norris SL, Thakurta S. Efficacy and harms of the hypoglycemic agent pramlintide in diabetes mellitus. Ann Fam Med. 2010;8(6):542-549. PMID 21060125
  6. Smith SR, Aronne LJ, Burns CM, Kesty NC, Halseth AE, Weyer C. Sustained weight loss following 12-month pramlintide treatment as an adjunct to lifestyle intervention in obesity. Diabetes Care. 2008;31(9):1816-1823. PMID 18753666
  7. Aronne LJ, Halseth AE, Burns CM, et al. Enhanced weight loss following coadministration of pramlintide with sibutramine or phentermine in a multicenter trial. Obesity (Silver Spring). 2010;18(9):1739-1746. PMID 20094043
  8. Smith SR, Blundell JE, Burns C, et al. Pramlintide treatment reduces 24-h caloric intake and meal sizes and improves control of eating in obese subjects: a 6-wk translational research study. Am J Physiol Endocrinol Metab. 2007;293(2):E620-E627. PMID 17505051
  9. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. September 2025. WADA Prohibited List 2026
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

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