What Is Pramlintide (Symlin)? The First Amylin Analog and What Its Trials Found

Pramlintide, sold as Symlin, is a synthetic version of amylin, a hormone your pancreas releases alongside insulin after you eat. It was the first amylin drug to reach patients: the [FDA label on DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4aea30ff-eb0d-45c1-b114-3127966328ff) lists an initial U.S. approval in 2005, for people with type 1 or type 2 diabetes who use mealtime insulin and still are not reaching their glucose goals.

Pramlintide gets far less attention than the GLP-1 drugs, but it matters more now than it did a decade ago, because amylin is the second hormone in the newest weight loss combinations, including [cagrilintide](https://www.peptidepeppers.com/articles/cagrilintide-amylin-analog) and the single molecule [amycretin](https://www.peptidepeppers.com/articles/amycretin-glp-1-amylin-unimolecular-agonist). Most of what researchers know about how amylin behaves in people, including its effects on glucagon, stomach emptying, appetite and nausea, was first measured with pramlintide.

This article walks you through how pramlintide works, what its main trials found in diabetes and obesity, how the label doses it, and why it carries a boxed warning. It is educational content about published research and is not medical advice, so any decision about a prescription drug like this one belongs with your clinician.

Amylin is a peptide hormone made by the same pancreatic beta cells that make insulin. The two are stored in the same secretory granules and released together when food arrives, so in a healthy person amylin and insulin rise and fall on nearly the same schedule.

The Symlin label explains why this matters in diabetes. In both type 1 and type 2 diabetes, the beta cells release less of both hormones in response to food, and while insulin therapy replaces one of them, nothing in standard insulin therapy replaces the other. In type 1 diabetes, where the beta cells are largely destroyed, amylin is close to absent.

Amylin also does work that insulin does not do. According to the label, it slows the rate at which food leaves your stomach without changing how much is eventually absorbed, it suppresses glucagon (a hormone that tells the liver to release glucose), and it acts in the brain to reduce food intake. The label notes that the glucagon effect is "not normalized by insulin alone," and pramlintide was built to put that missing piece back.

Pramlintide is nearly identical to human amylin. According to the label, it is a synthetic 37 amino acid peptide that differs from human amylin at only three spots, where positions 25, 28 and 29 are swapped to proline in place of an alanine and two serines. It still acts as an amylin analog and produces the same set of effects on the stomach, glucagon and appetite.

The label describes Symlin as a clear solution in a disposable pen that holds 1000 mcg/mL of pramlintide, with a pH of approximately 4.0. It is injected under the skin as its own shot, separately from your insulin.

Pramlintide lowers glucose after meals through three routes, all of them aimed at the hours right after eating rather than at fasting glucose.

The first route is slower gastric emptying. Food reaches the small intestine more gradually, so glucose enters the blood more slowly and is easier for injected insulin to match.

The second route is blocking the glucagon spike that follows a meal. People with type 1 diabetes often release glucagon after eating, which pushes glucose up at exactly the wrong time. Fineman and colleagues ([Metabolism, 2002](https://doi.org/10.1053/meta.2002.32022)) tested this in two randomized, placebo controlled studies in type 1 diabetes, one with 18 patients and one with 84 patients over 14 days. In both studies, plasma glucagon rose after a standard meal in the placebo group but not in any of the pramlintide groups.

The third route is greater fullness. The label states that in human studies pramlintide "modulates satiety leading to decreased caloric intake," and this is the effect that later made amylin interesting for obesity research.

Pramlintide is short acting. The label puts its half life at approximately 48 minutes in healthy individuals, and in single dose studies across 30 to 120 mcg, peak blood levels arrived about 19 to 21 minutes after the injection. Absolute bioavailability after a subcutaneous injection is about 30% to 40%.

That profile explains the dosing pattern, because pramlintide is injected immediately before each major meal so that its peak lines up with the food, and it is largely gone before the next meal. Compare that with cagrilintide, a long acting amylin analog that Lau and colleagues ([Lancet, 2021](https://doi.org/10.1016/S0140-6736%2821%2901751-7)) tested as a once weekly injection for weight management. The difference between the two is mostly a difference in half life engineering, a theme covered in our guide to [peptide half life and dosing frequency](https://www.peptidepeppers.com/articles/peptide-half-life-dosing-frequency).

In type 1 diabetes, pramlintide produced modest HbA1c reductions and small weight losses on top of insulin in yearlong, placebo controlled trials.

Whitehouse and colleagues ([Diabetes Care, 2002](https://doi.org/10.2337/diacare.25.4.724)) randomized 480 people with type 1 diabetes to placebo or 30 mcg pramlintide four times daily, added to their usual insulin, for 52 weeks. By week 13, HbA1c had fallen 0.67% on pramlintide versus 0.16% on placebo, and a significant difference held through week 52. The authors reported that the HbA1c drop came with "an average weight loss, rather than weight gain" and without an increase in the overall rate of severe hypoglycemia.

Ratner and colleagues ([Diabetic Medicine, 2004](https://doi.org/10.1111/j.1464-5491.2004.01319.x)) randomized 651 people with type 1 diabetes, with an average baseline HbA1c of 8.9%, to placebo or pramlintide for 52 weeks. At 60 mcg three or four times daily, HbA1c fell 0.29% and 0.34% from baseline, compared with 0.04% on placebo. Three times as many pramlintide patients as placebo patients reached an HbA1c below 7%, and body weight fell 0.4 kg on pramlintide while it rose 0.8 kg on placebo.

These are small numbers, and pramlintide was never a large HbA1c drug. Its appeal in type 1 diabetes was that it lowered glucose without the weight gain that usually comes with tighter insulin control.

In insulin treated type 2 diabetes, pramlintide at 120 mcg twice daily lowered HbA1c and body weight compared with placebo over a year.

Hollander and colleagues ([Diabetes Care, 2003](https://doi.org/10.2337/diacare.26.3.784)) enrolled 656 people with type 2 diabetes on insulin, with an average BMI of 34.0 and a baseline HbA1c of 9.1%. On 120 mcg twice daily, HbA1c fell 0.68% at week 26 and 0.62% at week 52, both significantly more than on placebo. The share of patients reaching an HbA1c below 8% was 46% on pramlintide versus 28% on placebo, weight fell 1.4 kg on pramlintide and rose 0.7 kg on placebo, and the overall severe hypoglycemia event rate did not increase.

A pooled analysis found no sign of increased cardiovascular risk in type 2 diabetes. Herrmann and colleagues ([Clinical Diabetes and Endocrinology, 2016](https://doi.org/10.1186/s40842-016-0030-z)) combined five randomized phase 3 and 4 trials lasting 16 to 52 weeks, covering 2,016 adults with type 2 diabetes, of whom 1,434 took pramlintide and 582 took comparators. Major adverse cardiovascular events were reported in 4.7% of pramlintide patients and 4.5% of comparator patients.

You should read that result for what it is, a pooled look back at trials that were not designed to measure heart outcomes, and the analysis was authored by the companies that owned the drug at the time. It is reassuring, but it is not the same as a dedicated cardiovascular outcomes trial such as the [SELECT trial for semaglutide](https://www.peptidepeppers.com/articles/glp-1-heart-health-select-trial-cardiovascular).

Pramlintide did produce weight loss in obesity trials, and those trials are the clearest early human evidence that amylin can act as a weight loss hormone, although the drug was never approved for weight loss.

Aronne and colleagues ([Journal of Clinical Endocrinology and Metabolism, 2007](https://doi.org/10.1210/jc.2006-2003)) gave 204 adults with obesity either pramlintide, escalated up to 240 mcg three times daily, or placebo for 16 weeks with no lifestyle program. Among people who finished, placebo corrected weight loss was 3.7% (3.6 kg), and about 31% of pramlintide patients lost at least 5% of their weight, versus 2% on placebo. Most people tolerated the dose escalation, since 88% reached the top dose and withdrawal rates were similar at 25% on placebo and 29% on pramlintide.

Smith and colleagues ([Diabetes Care, 2008](https://doi.org/10.2337/dc08-0029)) ran a longer test. They randomized 411 adults with obesity to placebo or one of six pramlintide regimens alongside a structured lifestyle program, then followed a subset to 12 months. At month 12, placebo corrected weight loss was 6.1 kg (5.6%) on 120 mcg three times daily and 7.2 kg (6.8%) on 360 mcg twice daily, and the share of people losing at least 10% of body weight was 40% and 43% in those two groups, compared with 12% on placebo. The placebo group regained its early weight loss by month 12, while most pramlintide groups held theirs.

Those numbers look small next to what you may have read about semaglutide or tirzepatide. That gap, together with the burden of injecting before every meal, is why the field moved toward long acting amylin analogs like cagrilintide and toward combining amylin with GLP-1 activity in a single treatment.

The label doses pramlintide differently for type 1 and type 2 diabetes, and both paths start with a cut in mealtime insulin of 50%. People with type 1 diabetes start at 15 mcg before each major meal and move up in 15 mcg steps to 30, 45 or 60 mcg, while people with type 2 diabetes start at 60 mcg and move up to 120 mcg. In both cases, the label says to wait at least 3 days without significant nausea before each increase.

The label also says pramlintide should be used only by people who can manage insulin adjustments and frequent glucose checks, and that if it is stopped for any reason, the same starting steps should be repeated when it is restarted.

Nausea is the dominant side effect of pramlintide, and it is most common at the start of treatment. In the label's pooled placebo controlled trials, nausea affected 48% of type 1 patients on pramlintide versus 17% on placebo, and 28% of type 2 patients on 120 mcg versus 12% on placebo. Anorexia and vomiting were also more common than on placebo in both groups, and headache was more common in type 2 diabetes at 13% versus 7%.

The label notes that nausea is highest early on and fades over time in most patients, and that slow titration reduces it. In the Aronne obesity study, people who never reported nausea lost about as much weight as those who did, which suggests the weight effect is not simply people eating less because they feel sick. For background on why these gut effects happen across this whole family of drugs, see our guide to [GLP-1 nausea and gut side effects](https://www.peptidepeppers.com/articles/glp-1-nausea-gi-side-effects-titration).

Symlin carries a boxed warning because using it with insulin raises the risk of severe hypoglycemia, particularly in type 1 diabetes. The label states that when severe hypoglycemia happens, "it is seen within 3 hours following a SYMLIN injection," and that serious injuries can follow if it occurs while you are driving or operating machinery.

The mechanism is a timing mismatch. Pramlintide slows the arrival of food glucose, so if your usual mealtime insulin dose is given, the insulin can act before the glucose shows up. That is why the label requires the 50% insulin cut at the start and calls appropriate patient selection, careful instruction and insulin dose reduction "critical elements for reducing this risk."

The label also lists three contraindications, which are a serious hypersensitivity reaction to pramlintide or its ingredients, hypoglycemia unawareness, and confirmed gastroparesis, since pramlintide slows stomach emptying even further.

Current pramlintide research focuses on combining it with insulin in a single delivery system, so that patients do not need separate injections.

One approach is the artificial pancreas. Haidar and colleagues ([Diabetes Care, 2020](https://doi.org/10.2337/dc19-1922)) tested an automated system that delivered rapid insulin and pramlintide together in adults with type 1 diabetes, in a randomized crossover trial built around 24 hour inpatient visits. Compared with an insulin only system, time in the target glucose range rose from 74% to 84%, driven by daytime control that rose from 63% to 78%, while gut symptoms followed 6% of meals with the dual system versus 0% with insulin alone. This was a small, short study, so you should treat it as early evidence.

Another approach is a single injection that contains both drugs. Andersen and colleagues ([Diabetes, Obesity and Metabolism, 2024](https://doi.org/10.1111/dom.15827)) tested ADO09, which combines pramlintide with an insulin analog, against insulin lispro in 80 people with type 1 diabetes for 16 weeks. Weight was 2.1 kg lower with ADO09 and mealtime insulin doses fell 21%, while gut symptoms were more frequent and there was no clear difference in hypoglycemia. ADO09 is an investigational product, not an approved drug.

Pramlintide is an approved prescription drug with a defined indication, a manufacturer and a boxed warning, and it is not a gray market research compound. Its value for anyone following peptide science is as a reference point, because it is the most studied amylin analog in people.

The bottom line is that pramlintide's record shows both what amylin can do, such as blunting glucagon, slowing the stomach and trimming appetite and weight, and what it costs in nausea and in hypoglycemia risk when it is stacked with insulin. Those same tradeoffs are now being worked through again with cagrilintide and amycretin, and if you are curious about the newer amylin drugs, the pramlintide trials are the best place to understand what to expect from them.