Several types of injections are used to manage type 2 diabetes, falling into three main categories: GLP-1 receptor agonists, dual GIP/GLP-1 receptor agonists, insulin, and a less common option called pramlintide. Which one your doctor recommends depends on your blood sugar levels, weight goals, heart and kidney health, and whether oral medications are doing enough on their own.
GLP-1 Receptor Agonists
GLP-1 receptor agonists are among the most widely prescribed injectable medications for type 2 diabetes. They work by mimicking a gut hormone called GLP-1, which signals your pancreas to release insulin when blood sugar rises after a meal. They also slow digestion and reduce appetite, which is why most people lose weight while taking them.
The GLP-1 agonists currently available include:
- Semaglutide (Ozempic): once-weekly injection
- Dulaglutide (Trulicity): once-weekly injection
- Exenatide extended-release (Bydureon): once-weekly injection
- Liraglutide (Victoza): once-daily injection
- Lixisenatide (Adlyxin): once-daily injection
- Exenatide (Byetta): twice-daily injection
Weekly options have largely become the standard because they’re more convenient and easier to stick with. Semaglutide is also available as a daily tablet (Rybelsus) for people who prefer not to inject at all. Beyond blood sugar control, GLP-1 agonists have shown benefits for heart health, kidney function, and heart failure risk, which is why current guidelines from the American Diabetes Association prioritize them for people with cardiovascular or kidney disease.
One major advantage over insulin: GLP-1 agonists carry virtually no risk of causing low blood sugar on their own. A large meta-analysis found that insulin use carried roughly twice the risk of hypoglycemic events compared to GLP-1 agonists.
Dual GIP/GLP-1 Receptor Agonists
Tirzepatide (Mounjaro) is the first in a newer class sometimes called “twincretins.” It activates two gut hormone receptors instead of one, targeting both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual action stimulates insulin release, lowers blood sugar, and reduces appetite more effectively than GLP-1 agonists alone. It’s given as a once-weekly injection.
In the SURPASS clinical trials, tirzepatide produced greater improvements in blood sugar control and weight loss compared to semaglutide, dulaglutide, and two forms of long-acting insulin. A head-to-head meta-analysis found tirzepatide was associated with roughly 4.6% more body weight reduction and about 4.8 kg (around 10.5 pounds) more absolute weight loss than semaglutide. The ADA now includes dual GIP/GLP-1 agonists as preferred options for people with type 2 diabetes who also need help with weight management.
Insulin
Insulin remains essential for many people with type 2 diabetes, particularly when the pancreas can no longer produce enough on its own. Current guidelines say insulin should be considered at any stage of the disease when blood sugar is significantly elevated or other medications aren’t reaching your target. It comes in several formulations, each designed to work on a different timeline.
Long-Acting (Basal) Insulin
Basal insulin provides a steady background level of insulin throughout the day and night. Common options include insulin glargine (Lantus, Basaglar, Toujeo) and insulin degludec (Tresiba). These are typically injected once daily at the same time each day. For many people with type 2 diabetes, basal insulin alone, often combined with oral medications or a GLP-1 agonist, is enough to reach blood sugar goals.
Rapid-Acting (Bolus) Insulin
Rapid-acting insulin covers blood sugar spikes from meals. Options include insulin aspart (Novolog), insulin lispro (Humalog), and insulin glulisine (Apidra). These start working within 15 minutes and last 2 to 5 hours. They’re injected just before eating, sometimes immediately after.
Intermediate-Acting Insulin
NPH insulin (Novolin N, Humulin N) takes about 1 to 2 hours to start working and peaks around 4 to 8 hours later. It’s the only insulin that can be physically mixed with rapid-acting insulin in the same syringe, which some people prefer to reduce the number of injections.
The main downside of insulin compared to non-insulin injectables is the risk of low blood sugar. Across multiple randomized trials, insulin carried about 2.2 times the risk of hypoglycemic events compared to non-insulin diabetes medications overall. It also tends to cause weight gain rather than weight loss, which can work against metabolic goals for many people with type 2 diabetes.
Pramlintide
Pramlintide (Symlin) is a synthetic version of amylin, a hormone your pancreas normally releases alongside insulin after meals. It’s specifically designed for people already using mealtime insulin who still can’t control post-meal blood sugar spikes. It works through three mechanisms: slowing how quickly food leaves the stomach, suppressing a post-meal surge of glucagon (a hormone that raises blood sugar), and increasing the feeling of fullness. Pramlintide is injected before meals and is always used alongside insulin, never as a standalone treatment. It’s far less commonly prescribed than GLP-1 agonists or insulin.
When Injections Are Started
Most people with type 2 diabetes begin treatment with oral medications like metformin. Injections typically enter the picture when pills alone aren’t bringing blood sugar to target, or earlier if there are reasons to prioritize heart or kidney protection. The ADA’s 2024 guidelines emphasize early combination therapy, meaning your doctor may add an injectable sooner rather than waiting for oral medications to fail over many months.
For someone with established heart disease, heart failure, or chronic kidney disease, a GLP-1 agonist or dual GIP/GLP-1 agonist is often the preferred first injectable because of the cardiovascular and kidney benefits these drugs offer beyond blood sugar control. Insulin is more likely to be started when blood sugar is very high at diagnosis, when someone is losing weight unintentionally, or when other medications haven’t been enough after appropriate dose increases.
What the Injections Feel Like
Modern diabetes pens use very thin, short needles that make injections far less painful than most people expect. Expert guidelines recommend pen needles of 4 to 6 millimeters in length for all adults, regardless of body size. These are 31- or 32-gauge needles, thinner than a standard sewing pin. Studies consistently show that patients rated shorter needles as much less painful, with 89% preferring the shorter options. Most people inject into the abdomen, thigh, or upper arm, rotating sites to avoid irritation.
GLP-1 agonists and tirzepatide come in prefilled pens that are simple to use. You dial the dose, press the pen against your skin, and click a button. Weekly injections mean you only do this four or five times a month.
Managing Side Effects
The most common side effects of GLP-1 agonists and tirzepatide are gastrointestinal: nausea, vomiting, diarrhea, and constipation. Nausea is the most frequent, appearing consistently across clinical trials, but for most people it’s mild to moderate and fades over time. These medications are started at a low dose and increased gradually over weeks to minimize stomach issues.
Practical strategies that help reduce nausea and other gut symptoms include eating smaller portions more frequently, choosing bland and low-fat foods, eating slowly, stopping when you feel full, and avoiding lying down after meals. Staying hydrated with clear fluids in small sips helps as well. Some people find that crackers, apples, mint, or ginger-based drinks ease nausea, though it’s best to wait at least 30 minutes after your injection before eating these. Keeping a food diary can help you identify which foods or meal timings make symptoms worse.
Insulin’s primary side effect is low blood sugar, which can cause shakiness, sweating, confusion, and dizziness. Learning to recognize these symptoms and keeping a fast-acting sugar source on hand is important for anyone using insulin, particularly rapid-acting formulations.