Symlin (pramlintide)

A peptide diabetes medicine used with mealtime insulin. FDA records now list Symlin as discontinued.

AI illustration of an injector pen labeled Pramlintide — AI illustration

FDA statusOff market

It was approved once, but the FDA lists it as discontinued.

Proof it works in people for blood sugar with mealtime insulinSome

A big trial showed a small drop in blood sugar (A1C).

Safety data in peopleWell studied

Was FDA approved with a full label.

These are 3 different questions. FDA status is about the law. Proof is about whether it works. Safety data is about how much we know about its risks. A lack of safety data does not mean it does not work, and "not approved" does not mean "illegal."

By the Peptide Science Desk Editorial TeamFact-checked against FDA and official sources · Oct 18, 2026Not yet reviewed by a licensed clinician. How we check facts

What is it?

Pramlintide is a lab-made peptide. It is a copy-like version of amylin, a hormone your body makes along with insulin. The brand was Symlin.

Why do people use it?

Symlin was used by people with type 1 or type 2 diabetes who take mealtime insulin but still have high blood sugar. It is a cousin of cagrilintide, the amylin part of the new shot CagriSema.

Does it really work?

In a 52-week study of 651 people with type 1 diabetes, adding pramlintide to mealtime insulin lowered A1C (a long-term blood sugar test) about 0.3 points more than a fake shot (placebo). That is a real but small effect. FDA records now list every Symlin product as discontinued.

Studies in people

Study	People	What they found	Limits
Randomized trial	651	A1C dropped about 0.3 points more than placebo over 52 weeks.	Type 1 diabetes. The effect was small.

We only list studies we read on PubMed or ClinicalTrials.gov. Checked October 18, 2026.

The numbers in a chart

How much 3 peptides lowered blood sugar (A1C)

Change in A1C in percentage points, drug vs placebo. A minus sign means lower (better)

Retatrutide 12 mgNot FDA approvedTRANSCEND-T2D-1 · 537 adults, type 2 · 40 weeks

−1.94

−0.81

Exenatide 10 µg (Byetta)336 adults, type 2, with metformin · 30 weeks

−0.78

+0.08

Pramlintide (Symlin) + insulin651 adults, type 1 · 52 weeks · 2 dose groups

−0.29 to −0.34

−0.04

Different trials, different people: not a head-to-head comparison. Type 1 and type 2 diabetes are different diseases.

Show the numbers as a table

How much 3 peptides lowered blood sugar (A1C): Change in A1C in percentage points, drug vs placebo. A minus sign means lower (better)
Drug	Drug	Placebo
Retatrutide 12 mg (Not FDA approved) TRANSCEND-T2D-1 · 537 adults, type 2 · 40 weeks	−1.94	−0.81
Exenatide 10 µg (Byetta) 336 adults, type 2, with metformin · 30 weeks	−0.78	+0.08
Pramlintide (Symlin) + insulin 651 adults, type 1 · 52 weeks · 2 dose groups	−0.29 to −0.34	−0.04

A1C shows average blood sugar over about 3 months. The striped bar means the placebo group's A1C went up a little. Sources: TRANSCEND-T2D-1, Lancet 2026 (PMID 42250575); DeFronzo et al., Diabetes Care 2005 (PMID 15855572); Ratner et al., Diabet Med 2004 (PMID 15498087).

More charts: Peptides by the numbers

Is it safe? Side effects

The label had a boxed warning: used with insulin, it raises the risk of very low blood sugar, usually within 3 hours of a shot.
Common side effects on the label included feeling sick, throwing up, less hunger, and headache.

Is it legal in the US?

There is no Symlin on the US market now. (The FDA is the US agency that checks if medicines are safe and work.) The FDA lists all Symlin products as discontinued.

What "not approved" does and does not mean

"Off the market" means the FDA-approved brand is no longer sold. That does not by itself mean "illegal." Any copy sold today is not that approved product.
Outside the narrow pharmacy rules below, selling it as a medicine for people breaks federal law. The FDA has warned companies that sold unapproved drugs labeled "for research" or "not for human consumption" to people. (FDA)
A regular pharmacy may only mix (compound) a drug from a raw ingredient that has an official quality standard, is part of an FDA-approved drug, or is on the FDA’s 503A list. Big "outsourcing" pharmacies (503B) have their own list. (FDA)
The FDA says that in most cases it is illegal for people to bring unapproved drugs into the US for their own use. (FDA)
State rules differ. State boards of pharmacy oversee most pharmacies day to day. Sports leagues and the military have their own bans. (FDA)

Banned in sports? Drug tests

Not named, but may be banned.

Pramlintide is not named on WADA’s list. The FDA lists Symlin as discontinued, and WADA’s S0 rule covers discontinued drugs with no approval anywhere. Ask USADA before you use it.

Check work, NCAA, and military rules for Symlin

Talk to your doctor

Do not start any peptide on your own. Ask a doctor first. We never share doses or tell you where to buy. Print our doctor questions sheet.

Check any peptide in 1 secondFree FDA Status Checker: approved, being tested, or not proven.

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Not medical advice. Medical disclaimer.