The best-supported peptides for diabetes are prescription drugs you may already know: insulin, the GLP-1 drugs such as semaglutide and liraglutide, and tirzepatide. In a head-to-head trial, tirzepatide lowered A1C by up to 2.30 percentage points versus 1.86 for semaglutide 1 mg.[3] Pramlintide is approved but discontinued in the US, and wellness peptides marketed for blood sugar, such as MOTS-c, have no human diabetes data.[9][12]
A peptide is a short chain of amino acids. Many of the body’s blood-sugar hormones, including insulin, GLP-1, GIP, glucagon and amylin, are peptides, which is why so many diabetes drugs are too. For how the newer drugs work, see how GLP-1 drugs work and our GLP-1 basics hub.
Evidence at a glance
| Peptide or drug | Evidence level | What was shown | FDA status | Our profile |
|---|---|---|---|---|
| Insulin | FDA-approved for this use | Intensive therapy cut new retinopathy risk by 76% in type 1[2] | Approved (type 1 and 2) | — |
| Semaglutide (Ozempic, Rybelsus) | FDA-approved for this use | Fewer heart attacks, strokes and CV deaths (6.6% vs 8.9%); kidney protection[4][7] | Approved for type 2[10] | Semaglutide |
| Tirzepatide (Mounjaro) | FDA-approved for this use | Larger A1C and weight drops than semaglutide 1 mg[3] | Approved for type 2, age 10+[11] | Tirzepatide |
| Liraglutide (Victoza, generics) | FDA-approved for this use | 13.0% vs 14.9% major CV events[5] | Approved for type 2 | Liraglutide |
| Dulaglutide (Trulicity) | FDA-approved for this use | Comparator in SURPASS-CVOT[6] | Approved for type 2 | Dulaglutide |
| Pramlintide (Symlin) | FDA-approved for this use | Lower A1C, weight and insulin dose in type 1[8] | Approved 2005; now discontinued[9] | Pramlintide |
| MOTS-c | Animal or lab only | Less insulin resistance in mice[12] | Not approved[13] | MOTS-c |
| BPC-157 | No evidence, marketing only | No diabetes trials | Not approved[13] | BPC-157 |
Standard care comes first
Diabetes treatment is built on daily habits, education and regular checkups. The American Diabetes Association’s 2026 Standards list healthy behaviors and diabetes self-management education and support as essential parts of glucose-lowering care for everyone.[1]
- Type 1 diabetes: the body makes little or no insulin, so insulin is lifesaving. The ADA recommends treating most adults with an insulin pump or multiple daily injections of mealtime and long-acting insulin.[1]
- Type 2 diabetes: metformin has historically been the first-line pill and is still used when no other factor guides the choice. For people with heart disease, kidney disease or heart failure, the ADA recommends drugs with proven heart or kidney benefit, such as a GLP-1 drug or an SGLT2 inhibitor, regardless of A1C.[1]
Our metformin vs semaglutide guide compares the two most common starting points.
Insulin: the original peptide drug
Insulin is a peptide hormone made of two linked chains. The landmark Diabetes Control and Complications Trial showed why tight control with insulin matters in type 1 diabetes. Compared with conventional therapy, intensive insulin treatment:[2]
- reduced the risk of developing retinopathy (eye damage) by 76%
- reduced clinical nerve damage by 60%
- reduced albuminuria, a sign of kidney damage, by 54%
The main downside was a two- to threefold rise in severe low blood sugar. Modern insulins, pumps and continuous glucose monitors aim to keep the benefit while lowering that risk.
GLP-1 drugs and tirzepatide
GLP-1 drugs copy a gut hormone that boosts insulin release when blood sugar is high, lowers glucagon, slows stomach emptying and reduces appetite. Tirzepatide also acts on the GIP receptor.
Blood sugar and weight. In SURPASS-2, tirzepatide 5, 10 and 15 mg lowered A1C by 2.01, 2.24 and 2.30 points versus 1.86 with semaglutide 1 mg, and produced 1.9 to 5.5 kg more weight loss.[3] See semaglutide vs tirzepatide for more.
Heart protection. Several GLP-1 drugs lower the risk of heart attack, stroke or cardiovascular death in people with type 2 diabetes:
- Semaglutide (SUSTAIN-6): 6.6% vs 8.9% on placebo over two years.[4]
- Liraglutide (LEADER): 13.0% vs 14.9% over a median 3.8 years, with fewer cardiovascular deaths.[5]
- Tirzepatide (SURPASS-CVOT): matched dulaglutide, a drug with proven heart benefit (12.2% vs 13.1%), but was not shown to be better.[6] Mounjaro’s label now includes reducing major cardiovascular events in high-risk adults with type 2 diabetes.[11]
Kidney protection. In FLOW, semaglutide 1 mg cut major kidney disease events by 24% in people with type 2 diabetes and chronic kidney disease.[7] Ozempic is now approved for this use.[10]
Children. Mounjaro is approved for type 2 diabetes from age 10.[11]
Side effects. Nausea, vomiting, diarrhea and constipation are common, especially when the dose goes up. In SUSTAIN-6, diabetic eye complications were more frequent on semaglutide, mostly in people with existing retinopathy whose glucose dropped quickly.[4] See our GLP-1 side effects guide and GLP-1 and eye health guide.
Type 1 diabetes. GLP-1 drugs are not approved for type 1. The ADA notes small studies of semaglutide or tirzepatide showing benefits for weight and glucose, but higher rates of ketoacidosis and stomach side effects.[1]
Pramlintide: an amylin peptide
Amylin is released with insulin and helps control after-meal glucose. Pramlintide copies it. A meta-analysis of 10 placebo-controlled trials in type 1 diabetes found it lowered A1C, mealtime insulin needs and body weight, but caused nausea, vomiting and more low blood sugar when first started.[8] The ADA describes the A1C drop as modest, about 0.3 to 0.4 points.[1]
FDA approved Symlin in 2005, but its drug database now lists all Symlin products as discontinued.[9] The amylin idea lives on in newer drugs such as cagrilintide, which is being studied with semaglutide.
Peptides with no diabetes evidence
- MOTS-c is a peptide made by mitochondria. In mice fed a high-fat diet, it prevented obesity and insulin resistance.[12] It has not been tested for diabetes in a published human trial.
- BPC-157 is sometimes promoted for “metabolic health,” but there are no diabetes trials.
FDA lists both among bulk substances nominated for compounding that raised safety concerns, noting limited human safety data and possible impurity and immune-reaction risks.[13] Products sold as research chemicals are not approved, and their contents and dose are not verified. Our research-use-only peptides guide explains why.
Questions to ask your care team
- Which drugs fit my heart and kidney health?
- Would a GLP-1 drug or tirzepatide help me, and what will it cost with my plan?
- How should I adjust insulin or other drugs if I start one?
- What eye checks do I need before my blood sugar drops quickly?
For practical tips, see our guides on GLP-1 injection sites and missed GLP-1 doses.
