Trulicity is not insulin. It belongs to a completely different drug class called GLP-1 receptor agonists, sometimes referred to as incretin mimetics. While both Trulicity and insulin are injectable medications used to manage type 2 diabetes, they work in fundamentally different ways inside your body.
How Trulicity Works
Trulicity (dulaglutide) mimics a natural gut hormone called GLP-1 that your body releases after eating. This hormone signals your pancreas to produce more insulin when your blood sugar is high, while also dialing back the release of glucagon, a hormone that raises blood sugar. The key distinction: Trulicity tells your pancreas to make its own insulin rather than replacing insulin from outside the body.
This “glucose-dependent” mechanism is important for safety. Because Trulicity only boosts insulin production when blood sugar is elevated, it carries a lower risk of causing dangerously low blood sugar on its own compared to injecting insulin directly. Trulicity also slows the rate at which food leaves your stomach, which helps prevent the sharp blood sugar spikes that follow meals. That slower digestion can reduce appetite and lead to weight loss, something insulin therapy typically does not do.
How Insulin Differs
Insulin is a hormone your body naturally produces, and injectable insulin is a synthetic or biosimilar version of that hormone. When you inject insulin, it enters your bloodstream and directly helps cells absorb glucose. It doesn’t depend on your pancreas doing anything at all, which is why it works for people with type 1 diabetes whose pancreas produces little or no insulin.
Basal (long-acting) insulin primarily works by suppressing the liver’s glucose output between meals and overnight, lowering fasting blood sugar. Trulicity, by contrast, targets both fasting and post-meal blood sugar through multiple pathways: stimulating insulin release, suppressing glucagon, and slowing digestion. In clinical comparisons, this difference means Trulicity tends to be more effective at controlling blood sugar spikes after eating, while basal insulin has a stronger effect on overnight fasting levels.
Who Trulicity Is For
Trulicity is FDA-approved for adults and children aged 10 and older with type 2 diabetes, used alongside diet and exercise. It also has a separate approval to reduce the risk of heart attack, stroke, and cardiovascular death in adults with type 2 diabetes who have existing heart disease or multiple cardiovascular risk factors.
Trulicity is not for type 1 diabetes. Because it works by prompting your pancreas to release more insulin, it requires functioning insulin-producing cells. People with type 1 diabetes have lost those cells, so Trulicity would have little effect. It’s also not recommended for anyone with a history of severe gastrointestinal disease or pancreatitis.
Current Treatment Guidelines
The American Diabetes Association’s 2025 guidelines now recommend GLP-1 receptor agonists like Trulicity over insulin for adults with type 2 diabetes who don’t have insulin deficiency. This preference is based on comparable blood sugar control, lower hypoglycemia risk, weight loss benefits, and cardiovascular protection. For people with type 2 diabetes and heart disease, kidney disease, or heart failure, GLP-1 drugs are specifically prioritized regardless of blood sugar levels because of their proven organ-protective effects.
When someone does need insulin, the guidelines recommend combining it with a GLP-1 receptor agonist for better blood sugar management, less weight gain, and fewer episodes of low blood sugar than insulin alone.
Using Trulicity With Insulin
Some people with type 2 diabetes use both Trulicity and insulin. This is safe but comes with important practical rules. The two medications are always given as separate injections and should never be mixed in the same pen or syringe. You can inject them into the same general body area, like your abdomen, but not right next to each other.
Combining the two increases the risk of low blood sugar. If you’re adding Trulicity to an existing insulin regimen, your insulin dose may need to be reduced. The same applies if you take a sulfonylurea, another type of diabetes medication that stimulates insulin release.
Weight Loss Effects
Unlike insulin, which often causes weight gain, Trulicity promotes weight loss. In the AWARD-11 clinical trial, patients on the standard 1.5 mg dose lost an average of 3.1 kg (about 7 pounds) over 36 weeks. Higher doses produced greater losses: 4.0 kg at 3.0 mg and 4.7 kg at 4.5 mg. Weight continued to decrease through 52 weeks. At the highest dose, roughly 5 kg (11 pounds) of total weight loss was observed, and a significantly larger proportion of patients achieved 5% or greater body weight reduction compared to the lower dose.
Dosing and Storage
Trulicity is injected once a week, on the same day each week, using a prefilled single-dose pen. The recommended dose is 1.5 mg per week, though higher doses (3.0 mg and 4.5 mg) are available when more intensive blood sugar control is needed. Insulin, by comparison, is typically injected daily or even multiple times per day depending on the type.
Trulicity pens should be stored in the refrigerator between 2°C and 8°C. If refrigeration isn’t available, a pen can stay at room temperature (below 30°C) for up to 14 total days, which can be split across multiple exposures as long as the cumulative time doesn’t exceed 14 days. A pen that has been frozen should not be used.
Safety Warnings
Trulicity carries an FDA boxed warning, the most serious type, related to thyroid tumors. In animal studies, dulaglutide caused thyroid C-cell tumors in rats at all tested doses. Whether this translates to humans is unknown. Trulicity is contraindicated for anyone with a personal or family history of medullary thyroid carcinoma or a condition called Multiple Endocrine Neoplasia syndrome type 2. If you notice a lump in your neck, difficulty swallowing, or persistent hoarseness, those symptoms warrant prompt evaluation.