Retatrutide vs Pramlintide
A weekly weight-loss injection not yet approved. In trials people lost up to about a quarter of their body weight in 48 weeks. A shot added to mealtime insulin in diabetes. Controlled trials show a small drop in blood sugar and weight, with more nausea and low blood sugar.
Pramlintide has the stronger evidence, grade A (strong human evidence) against grade B for Retatrutide. Retatrutide: In clinical trials. Pramlintide: FDA approved.
Evidence
BSome human evidence
AStrong human evidence
Human studies cited
Animal or cell studies cited
Why the grade
There is one published randomized phase 2 trial in obesity (338 adults, 48 weeks), a 98-person liver fat substudy of that trial, and one published phase 3 trial, TRIUMPH-2, in 1,152 adults with obesity and type 2 diabetes over 80 weeks; other phase 3 results exist only as press releases. Multiple randomized trials point the same way, but the drug is not approved, most of the roughly 5,800-person TRIUMPH program is unpublished, and there is no long-term safety data, so the grade is B and not A.
Approval rested on randomized, placebo-controlled trials in type 1 and type 2 diabetes lasting up to a year; the label summarizes six placebo-controlled trials (four in type 1 and two in type 2 diabetes), the largest with 480 type 1 patients, in which pramlintide lowered HbA1c by about 0.25 to 0.34 percentage points more than placebo and reduced weight. The effect is real but small, and the drug has largely been displaced by GLP-1 agonists.
FDA
In clinical trials
Retatrutide is an investigational drug and is not approved by the FDA for any use. Eli Lilly has said it plans to file for approval in the first quarter of 2027 after completing manufacturing data. Vials sold online as retatrutide are not a legal product; the FDA has stated that unapproved GLP-1 class drugs cannot be used in compounding.
FDA approved
Pramlintide is FDA-approved as Symlin (approved March 2005) for adults with type 1 or type 2 diabetes who use mealtime insulin and have not reached their glucose targets. The label carries a boxed warning about severe hypoglycemia, which is why insulin doses are reduced when it is started.
Sold for
Retatrutide is talked about as the next step beyond tirzepatide, a triple-hormone injection that produced the largest weight loss yet seen in a drug trial.
Pramlintide is the only approved amylin drug, used as an add-on to mealtime insulin to blunt after-meal glucose spikes and help with weight.
Studies say
Randomized trials show about a quarter of body weight lost over 48 weeks and roughly a fifth over 80 weeks in people with diabetes, with gastrointestinal side effects and heart rate increases, which supports a B pending approval and full phase 3 publication.
Randomized trials show pramlintide modestly lowers HbA1c and body weight when added to insulin, at the cost of nausea and a higher risk of insulin-related hypoglycemia, which supports its narrow approved use.
Class
Triple GLP-1 / GIP / glucagon agonist
Amylin analog
Route
Injection
Injection