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Pramlintide

Also known as Symlin, SymlinPen, AC-137, tripro-amylin

Synthetic amylin analogue injected with meals as an add-on to insulin in diabetes.

clinically proven Metabolic & weight approved drug

At a glance

Category
Metabolic & weight
Status
approved drug
Route
subcutaneous, immediately before major meals
Half-life
approximately 48 minutes in healthy individuals 1
Onset
acts within the same meal; glycaemic and weight effects over weeks
Molecular weight
3949.4 (pramlintide acetate) 1
Sequence
KCNTATCATQRLANFLVHSSNNFGPILPPTNVGSNTY (37 residues, C-terminal amide, disulfide bridge Cys2-Cys7; proline substitutions at positions 25, 28 and 29 relative to human amylin)

Approved by the FDA in March 2005; the current label indicates it as adjunctive treatment in patients with type 1 or type 2 diabetes who use mealtime insulin therapy and have failed to achieve desired glucose control despite optimal insulin therapy 1. Marketed in the United States as Symlin/SymlinPen. It was never granted a European marketing authorisation; the EU application was withdrawn.

Doping status: Not listed by WADA

Checked against the WADA 2026 Prohibited List. For a specific product and country, Global DRO is the lookup athletes are expected to use — the List names substances, not brand names.

Mechanism of action

Amylin (islet amyloid polypeptide, IAPP) is co-secreted with insulin by pancreatic beta cells after a meal. In type 1 diabetes, and in advanced type 2 diabetes, amylin is deficient along with insulin, so replacing insulin alone restores only half of the beta-cell signal. Pramlintide is a synthetic amylin analogue designed to fill that gap.

Human amylin readily aggregates into amyloid fibrils and is unusable as a drug. Pramlintide substitutes proline for the residues at positions 25, 28 and 29, which blocks fibril formation and makes the peptide soluble and stable enough to formulate.

Pramlintide binds amylin receptors — complexes of the calcitonin receptor with receptor-activity-modifying proteins (RAMP1-3) — concentrated in the area postrema, a circumventricular structure outside the blood-brain barrier. Three downstream effects follow: gastric emptying is slowed, so glucose enters the circulation more gradually; postprandial glucagon secretion is suppressed, blunting hepatic glucose output after eating; and a central satiety signal reduces meal size.

The net clinical effect is a flatter postprandial glucose curve and modest weight loss, rather than a large reduction in fasting glucose. Because pramlintide slows glucose entry while injected insulin acts on its usual schedule, the mealtime insulin dose must be cut when pramlintide is started — this mismatch is the mechanism behind its boxed warning.

What the research shows

Pramlintide is a licensed medicine supported by multiple randomised, placebo-controlled trials of 26 to 52 weeks in type 1 and type 2 diabetes. The evidence is solid but the effect is modest: HbA1c falls by roughly 0.3-0.6 percentage points and weight by roughly 1-2 kg beyond insulin alone. Commercial uptake has been poor, largely because of three-times-daily injection, nausea, and the need to reduce insulin.

Research in humans

The pivotal programme comprised long-term randomised, double-blind trials in type 1 diabetes (for example the one-year study with open-label extension published in Diabetes Care in 2002, and the 52-week study reported in Diabetic Medicine in 2004) 23 and comparable trials in insulin-treated type 2 diabetes. A later double-blind trial in the setting of intensive insulin therapy (Diabetes Care 2006) found HbA1c fell by the same 0.5 percentage points in both arms; what separated them was weight, with pramlintide-treated participants losing 1.3 kg while the placebo arm gained 1.2 kg, alongside a 28% reduction in insulin dose against 4% on placebo 4. That is a weight and insulin-sparing effect on top of intensive insulin therapy, not a glycaemic one. Paediatric and adolescent data exist but are limited. More recently pramlintide has been studied as the second hormone in dual-hormone closed-loop (artificial pancreas) systems 5.

Animal and lab research

Rodent work established that amylin acts on the area postrema to suppress food intake, slow gastric emptying and inhibit glucagon, and that the proline-substituted analogue retains this activity without forming amyloid.

Caveats. Nearly all pivotal trials were sponsored by Amylin Pharmaceuticals, the developer. The average glycaemic benefit is small and is partly attributable to reduced food intake from nausea. Dropout rates due to gastrointestinal side effects were substantial. There are no cardiovascular outcome trials. The drug is not available in Europe, so most real-world experience is American.

What it is used for

  • Adjunct to mealtime insulin in type 1 diabetes where glucose control has not been achieved despite optimal insulin therapy 1
  • Adjunct to mealtime insulin in type 2 diabetes on the same terms 1
  • Second hormone in experimental dual-hormone closed-loop insulin delivery systems
  • Off-label interest as a weight-loss agent, although modern GLP-1 drugs have largely displaced it for that purpose

Dosing

Dose
Type 1 diabetes: start at 15 mcg per meal, titrate in 15 mcg steps to 30-60 mcg. Type 2 diabetes: start at 60 mcg per meal, increase to 120 mcg if tolerated
Frequency
Immediately before each major meal containing at least 250 kcal or 30 g carbohydrate — typically three times daily
Route
Subcutaneous injection into the abdomen or thigh, at a site distinct from the insulin injection
Duration
Chronic, as long as it is tolerated and useful
  • The prescribing information requires reducing mealtime insulin doses, including premixed insulins, by 50% when pramlintide is started, specifically to reduce the risk of hypoglycaemia 1. Failing to do this is the main route to severe hypoglycaemia.
  • Titration proceeds only when the current dose has been tolerated without clinically significant nausea for at least three days 1.
  • Pramlintide and insulin must never be mixed in the same syringe — the label directs separate administration, because mixing alters the pharmacokinetics of both 1.
  • These figures are taken from the approved US prescribing information and are descriptive, not a recommendation to self-treat. Pramlintide is used under medical supervision with glucose monitoring.

These figures describe what the literature and published protocols report. They are not advice and not a dosing instruction.

Protocols

Symlin initiation and titration (type 1 diabetes)

approved product information

Source: FDA prescribing information for SymlinPen (DailyMed)

Initiation15 mcg subcutaneously immediately before each major meal
Second increment30 mcg before each major meal
Third increment45 mcg before each major meal
Fourth increment60 mcg before each major meal

Move up only when no clinically significant nausea has occurred for at least 3 days. If significant nausea persists at 45 or 60 mcg, the label says to go back to 30 mcg. Mealtime insulin, including premixed insulin, is cut by 50% when pramlintide is started — the severe hypoglycaemia risk carried in the boxed warning comes from that combination, not from pramlintide alone.

Symlin initiation and titration (type 2 diabetes)

approved product information

Source: FDA prescribing information for SymlinPen (DailyMed)

Initiation60 mcg subcutaneously immediately before each major meal
After at least 3 days without clinically significant nausea120 mcg before each major meal

The type 2 schedule starts at the dose the type 1 schedule finishes on. If significant nausea persists at 120 mcg the label says to drop back to 60 mcg. Mealtime insulin is cut by 50% at initiation.

Off-label weight-loss use in non-diabetics (user-reported)

user protocol — not validated

Source: The pattern repeated across weight-loss and GLP-1 forums together with research-chemical vendor labelling of 'pramlintide' powder

This is not a validated schedule. It is a pattern that circulates among users and sellers, reproduced because it is what people actually follow — not because it has been tested. No trial established these doses, this interval or this duration, and nobody is checking what is in the vial. Treat every number below as an assertion, not a finding.

Reported starting amount15 mcg subcutaneously before meals, titrated up as nausea is tolerated
Reported upper endup to 120 mcg before meals, one to three times daily
Reported stackingoften run alongside a GLP-1 agonist for appetite suppression

The label is for diabetics using mealtime insulin, and its central safety instruction — cut insulin by 50% at the start — exists because the boxed severe-hypoglycaemia risk comes from the pramlintide-plus-insulin combination. The circulating use inverts the setting: non-diabetics self-inject research-chemical pramlintide before meals for appetite suppression and weight loss, usually with no insulin at all, so the specific driver of the boxed warning is largely absent — though hypoglycaemia can still occur, and the risk returns if it is stacked with other glucose-lowering agents. Reported amounts track the label's 15-120 mcg per-meal range but the titration and frequency do not converge, and the whole practice rests on no controlled data in people without diabetes. Nausea is the dominant effect and is partly the mechanism of the appetite reduction rather than a side issue; the powder is unverified for identity and purity.

Schedules are reproduced as their source states them. Units, IU and milligrams explains why the figures are not interchangeable between products.

Reconstitution

Vial sizes
1000 mcg/ml in 5 ml vial (older presentation), 1000 mcg/ml or 1500 mcg/ml prefilled SymlinPen 60 and SymlinPen 120
Solvent
None — pramlintide is supplied as a sterile ready-to-use solution, not as a lyophilised powder
Storage
Unopened: refrigerated at 2-8 °C, protected from light, do not freeze. In use: pen or vial may be kept refrigerated or at room temperature and discarded after 30 days.

Worked example

Not applicable. The SymlinPen is dialled directly in fixed steps of 15 mcg (Pen 60) or 60 mcg (Pen 120).

A discarded or frozen product must not be used. Because no reconstitution step exists, there is also no home-compounding practice for this drug; any lyophilised 'pramlintide' powder sold as a research chemical is outside the approved supply chain and of unverified identity and sterility.

Safety

Side effects

  • Severe hypoglycaemia, particularly within the first three hours after injection and mainly in type 1 diabetes — the boxed warning states that use with insulin increases the risk of severe hypoglycaemia, particularly in type 1 diabetes 1
  • Nausea, which is the most common side effect, usually dose-dependent and worst during titration
  • Vomiting, anorexia, abdominal pain
  • Headache, fatigue, dizziness
  • Injection site reactions
  • Modest weight loss, generally regarded as desirable in this population
  • Allergic reactions, uncommon

Do not use if

  • BOXED WARNING: pramlintide is used with insulin and has been associated with an increased risk of insulin-induced severe hypoglycaemia, particularly in type 1 diabetes 1. Severe hypoglycaemia usually occurs within three hours of injection and may impair the ability to drive or operate machinery. Mealtime insulin must be reduced by 50% when starting 1.
  • Confirmed hypoglycaemia unawareness — a labelled contraindication 1
  • Confirmed gastroparesis — a labelled contraindication; pramlintide slows gastric emptying further 1
  • Serious hypersensitivity reaction to pramlintide or to any of its components, including metacresol — a labelled contraindication 1
  • Poor compliance with glucose monitoring or insulin regimen, or HbA1c above roughly 9%
  • Concomitant use of drugs that stimulate gastrointestinal motility 1
  • Paediatric use is not established in the US label

Interactions

Because pramlintide delays gastric emptying, it can slow and reduce the absorption of orally administered drugs; the label advises separating administration by one to two hours for medicines whose timing matters, such as analgesics 1. Pramlintide and insulin must be given separately, since mixing them alters the pharmacokinetics of both 1. The risk of severe hypoglycaemia is amplified by insulin, sulfonylureas and alcohol; the effect on gastric emptying is antagonised by prokinetics such as metoclopramide and erythromycin, and additive with anticholinergics. Agents that mask hypoglycaemia symptoms, such as beta blockers and clonidine, increase the hazard from the boxed-warning risk.

Sources