Trulicity and Mounjaro come from the same maker, treat the same condition and are both sold on LillyDirect. The self-pay gap between them is $110 a month. Lilly prints Trulicity as “starting at” $389 beside every dose[3], and Mounjaro at $499 beside every dose[4], so on those printed figures the gap does not change with the dose.
What separates them on the label
| Trulicity | Mounjaro | |
|---|---|---|
| Molecule | Dulaglutide (GLP-1) | Tirzepatide (GIP and GLP-1) |
| Adult doses | 0.75 mg, 1.5 mg, 3 mg, 4.5 mg | 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg |
| LillyDirect self-pay month | Starting at $389, every dose | $499, every dose |
| Card, covered plan | As little as $25 | As little as $25 |
| Card, plan excludes it | No tier printed | As low as $499 a month |
Both labels cover blood sugar control in adults and in children 10 and older with type 2 diabetes[1][2]. The children’s ceilings differ: 1.5 mg a week for Trulicity and 10 mg for Mounjaro[1][2]. Both add a heart indication, for adults with established cardiovascular disease or multiple risk factors on Trulicity and for adults at high cardiovascular risk on Mounjaro[1][2].
The molecules are where the drugs part. Trulicity is dulaglutide, a GLP-1 receptor agonist[1]. Mounjaro is tirzepatide, which acts on the GIP receptor as well as the GLP-1 receptor[2]. Neither label covers weight loss; the weight-loss brand of tirzepatide is Zepbound, set against Mounjaro in Mounjaro vs Zepbound.
The trial that compared them
The direct comparison comes from SURPASS J-mono, a double-blind, Lilly-funded trial of 636 Japanese adults with type 2 diabetes who were new to treatment or had stopped a single oral drug[7]. They took tirzepatide at 5, 10 or 15 mg, or dulaglutide 0.75 mg, once a week for 52 weeks[7].
HbA1c fell 2.4, 2.6 and 2.8 points on the three tirzepatide doses and 1.3 points on dulaglutide[7]. Weight fell 5.8, 8.5 and 10.7 kg on tirzepatide against 0.5 kg on dulaglutide[7]. Nausea affected 12%, 20% and 20% of the tirzepatide groups and 8% of the dulaglutide group[7].
Paying with insurance
The two savings cards are built the same way for a plan that covers the drug: as little as $25 per fill of up to three months. Savings are capped at $150 for a one-month fill and $1,950 a year, over 13 fills.[5][6] Both define a month as 28 days and up to 4 pens, and both end December 31, 2026[5][6].
The difference is the plan that says no. Mounjaro’s card lets a commercially insured patient whose plan excludes it pay as low as $499 a month, with savings up to $647 a month[6]. The Trulicity card terms print only the covered tier[5], so a Trulicity patient in that position falls back on the LillyDirect price. The single-brand detail is in Trulicity price and Mounjaro cost.
Military families get a different answer. TRICARE covers both drugs for type 2 diabetes with prior authorization, and it says Trulicity has the lower copayment[8]. It also waives Trulicity’s prior authorization form when another diabetes drug appears in your TRICARE pharmacy record within the last 720 days[8]. The plan-by-plan rules are in does TRICARE cover Wegovy.
Medicare
On January 27, 2026, CMS named Trulicity among 15 drugs selected for its third round of Medicare price negotiation, with prices that apply from 2028[9]. Mounjaro is not on that list[9]. Part D plans already list tirzepatide widely: enrollment-weighted coverage reached 92.9% in the third quarter of 2024, and 83.2% of covering plans required prior authorization[10]. What that means for a Mounjaro prescription is in does Medicare cover Mounjaro.
The question to ask before switching
If a prescriber suggests moving from one to the other, ask your plan whether the new drug is on its formulary and at which tier, and whether a prior authorization from the old drug carries over. Those two answers, not the self-pay gap, decide what an insured patient pays. Novo Nordisk’s rival is compared in Trulicity vs Ozempic and Mounjaro vs Ozempic.