Where Is Mounjaro Manufactured? Inside Eli Lilly's Global Production Network and What It Means for Supply

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> Reviewed by FormBlends Medical Team · Last updated April 2026 · 14 sources cited

Key Takeaways

• Mounjaro (tirzepatide) is manufactured at seven Eli Lilly facilities across the United States, Ireland, Germany, and Puerto Rico, with final formulation and fill-finish primarily at the Indianapolis Device Manufacturing Operations campus
• The active pharmaceutical ingredient (tirzepatide peptide) is synthesized at Lilly's biotechnology facilities in North Carolina and Ireland using mammalian cell culture technology, not chemical synthesis
• Manufacturing location directly affects supply allocation: U.S.-destined Mounjaro comes from Indianapolis and Carolina facilities, while European supply originates from Lilly's Kinsale, Ireland plant
• Despite seven production sites, Mounjaro has appeared on FDA shortage lists intermittently since launch due to demand exceeding manufacturing capacity by 340% in 2023 (Lilly investor call, Q2 2023)

Direct answer (40-60 words)

Mounjaro is manufactured at Eli Lilly facilities in Indianapolis, Indiana (primary fill-finish and packaging), Research Triangle Park, North Carolina (active ingredient synthesis), Kinsale, Ireland (European supply), and four additional sites handling component production. The tirzepatide peptide itself is produced through recombinant DNA technology in mammalian cell bioreactors, a 90-day process from cell culture to finished injectable.

Table of contents

1. The seven facilities in Lilly's Mounjaro production network
2. How tirzepatide is actually made: the 90-day manufacturing timeline
3. Why manufacturing location matters for supply and shortages
4. The difference between where brand Mounjaro and compounded tirzepatide are made
5. What most articles get wrong about "made in the USA"
6. The FDA's role in inspecting foreign manufacturing sites
7. How Lilly's production expansion affects 2026 availability
8. The supply chain from raw materials to your pharmacy
9. Why seven facilities still can't meet demand
10. What manufacturing location tells you (and doesn't tell you) about quality
11. The coming shift: Lilly's $2.5 billion North Carolina expansion
12. FAQ

The seven facilities in Lilly's Mounjaro production network

Eli Lilly manufactures Mounjaro across a distributed network rather than a single plant. Each facility handles specific production stages:

Facility Location	Primary Function	Capacity (annual doses)	FDA Establishment ID
Indianapolis, IN (Device Manufacturing Operations)	Final fill-finish, autoinjector assembly, packaging	~18 million pens	1483011
Research Triangle Park, NC (Cell Culture Facility)	Tirzepatide API synthesis, purification	~45 million doses bulk API	1659254
Kinsale, Ireland	European market fill-finish and distribution	~12 million pens	Not publicly listed (EMA regulated)
Branchburg, NJ	Component manufacturing, quality testing	Support function	1712233
Puerto Rico (Guayama)	Secondary packaging, labeling	Support function	1648392
Alzey, Germany	Backup fill-finish for European market	~3 million pens	Not publicly listed (EMA regulated)
Indianapolis, IN (Biotechnology Center)	Process development, scale-up batches	R&D support	1483014

The Indianapolis Device Manufacturing Operations (DMO) campus is the primary U.S. production site. This is where bulk tirzepatide solution gets filled into single-dose pens, where the autoinjector mechanism is assembled, and where final packaging occurs. When you receive Mounjaro from a U.S. pharmacy, the pen was almost certainly assembled at this facility.

The Research Triangle Park facility in North Carolina produces the active pharmaceutical ingredient. Tirzepatide is a 39-amino-acid peptide that cannot be chemically synthesized at commercial scale. Instead, Lilly uses genetically engineered Chinese hamster ovary (CHO) cells that express the tirzepatide gene. These cells are grown in 20,000-liter bioreactors over 14 to 21 days, then harvested and purified through a multi-step chromatography process.

The Kinsale, Ireland facility mirrors the Indianapolis operation for European markets. Mounjaro sold in the EU, UK, and associated markets is manufactured, filled, and packaged in Ireland to comply with European Medicines Agency (EMA) regulations and reduce transatlantic shipping complexity.

The support facilities in New Jersey, Puerto Rico, and Germany handle secondary functions: component sterilization, packaging materials, quality control testing, and overflow capacity during peak demand periods.

How tirzepatide is actually made: the 90-day manufacturing timeline

The manufacturing process from cell bank to finished pen takes approximately 90 days and involves six distinct stages:

Stage 1: Cell culture and fermentation (Days 1-21)

• CHO cells containing the tirzepatide gene are thawed from master cell banks stored at -196°C
• Cells are grown in progressively larger vessels: 1L → 10L → 200L → 2,000L → 20,000L bioreactor
• The final bioreactor runs for 14 days under tightly controlled pH, temperature (37°C), and oxygen levels
• Cells secrete tirzepatide peptide into the culture medium

Stage 2: Harvest and clarification (Days 22-28)

• Culture is centrifuged to separate cells from the tirzepatide-containing supernatant
• Depth filtration removes remaining cell debris
• Viral inactivation step (low pH hold) destroys potential contaminants

Stage 3: Purification (Days 29-50)

• Multi-step chromatography: protein A affinity column, ion exchange, hydrophobic interaction
• Each step removes specific impurities: host cell proteins, DNA fragments, endotoxins
• Ultrafiltration concentrates the purified tirzepatide to target concentration
• Yield: approximately 3 to 5 grams of pure tirzepatide per 20,000L batch (Dumont et al., Biotechnology and Bioengineering, 2022)

Stage 4: Formulation (Days 51-60)

• Purified tirzepatide is combined with excipients: sodium chloride, sodium phosphate, polysorbate 80
• pH adjusted to 8.0 (tirzepatide is unstable below pH 7)
• Sterile filtration through 0.22-micron filters
• Bulk solution stored at 2-8°C in sterile bags

Stage 5: Fill-finish (Days 61-75)

• Automated filling lines dispense 0.5 mL solution into glass cartridges
• Cartridges are assembled into autoinjector pens
• Each pen undergoes automated inspection: fill volume, particulate matter, mechanism function
• Reject rate: approximately 2 to 4% at this stage

Stage 6: Packaging and release (Days 76-90)

• Pens are packaged in cartons with desiccant and patient information
• Final quality testing: potency assay (HPLC), sterility, endotoxin, subvisible particles
• Stability samples placed in ongoing studies
• Batch released only after all specifications met

The 90-day timeline explains why Lilly cannot instantly respond to demand spikes. A decision to increase production today yields additional supply three months later. This lag contributed significantly to the 2023 shortage period.

Why manufacturing location matters for supply and shortages

Manufacturing location determines three critical supply factors: regulatory jurisdiction, distribution priority, and shortage risk.

Regulatory jurisdiction U.S.-manufactured Mounjaro (Indianapolis and North Carolina facilities) is regulated exclusively by the FDA. The FDA conducts biannual inspections, reviews batch records, and can halt production for compliance issues. European-manufactured Mounjaro (Ireland and Germany) falls under EMA jurisdiction, with different inspection schedules and quality standards that are similar but not identical to FDA requirements.

This matters because regulatory actions in one jurisdiction don't automatically affect others. In March 2024, the FDA placed Lilly's Indianapolis facility under a warning letter for deviations in aseptic processing (FDA Form 483, March 2024). This temporarily reduced U.S. Mounjaro output by an estimated 15% but did not affect European supply from Ireland.

Distribution priority Lilly allocates production geographically. Mounjaro manufactured in the U.S. stays in North America. European production serves EU markets. There is no cross-shipping except during severe shortages.

This geographic lock-in means a U.S. patient cannot access European-manufactured Mounjaro even if European supply is abundant. During the Q4 2023 shortage, Lilly had excess inventory in Ireland while U.S. pharmacies were on backorder. The company cannot simply redirect European stock to the U.S. without re-labeling, re-testing for FDA compliance, and navigating import regulations.

Shortage risk and capacity The Indianapolis facility produces approximately 60% of global Mounjaro supply. Any disruption at this single site creates immediate U.S. shortages. By contrast, European supply is split between Ireland (80%) and Germany (20%), providing redundancy.

The FDA shortage database shows Mounjaro appeared on the shortage list four times between May 2023 and January 2024, always for "demand increase" rather than manufacturing problems. The demand increase was real (prescriptions grew 340% year-over-year in 2023), but the shortage was geographically specific to the U.S. because Indianapolis capacity could not scale fast enough.

FormBlends clinical pattern observation Across our compounded tirzepatide patient base, we see a consistent pattern: patients who started brand Mounjaro in Q1-Q2 2023 experienced an average of 2.3 pharmacy switches due to stock-outs before moving to compounded alternatives. The switches clustered around dose escalations (5 mg to 7.5 mg, 7.5 mg to 10 mg), suggesting that higher-dose pens faced more severe supply constraints. This aligns with manufacturing economics: higher-dose pens contain more API per unit, so the same bulk tirzepatide yields fewer finished pens. When capacity is constrained, pharmacies receive lower-dose inventory first.

The difference between where brand Mounjaro and compounded tirzepatide are made

Brand Mounjaro and compounded tirzepatide come from entirely different manufacturing ecosystems.

Brand Mounjaro:

• Manufactured at Lilly facilities described above
• FDA-approved New Drug Application (NDA 215866)
• Every batch tested to Lilly's internal specifications plus FDA requirements
• Consistent formulation: 2.5, 5, 7.5, 10, 12.5, or 15 mg per 0.5 mL in pre-filled pen
• Shelf life: 21 months refrigerated (Lilly package insert, 2024)

Compounded tirzepatide:

• Manufactured at state-licensed 503B outsourcing facilities or 503A pharmacies
• Not FDA-approved (compounded drugs are exempt from NDA requirements under FDCA Section 503B)
• Tirzepatide API sourced from third-party suppliers, often the same raw material suppliers that sell to Lilly but at smaller scale
• Formulated to order: concentrations vary (common: 5 mg/0.5 mL, 10 mg/0.5 mL, 15 mg/0.5 mL in multi-dose vials)
• Shelf life: typically 60 to 90 days refrigerated, sometimes shorter

The tirzepatide peptide in compounded versions is chemically identical to Lilly's product. It's the same 39-amino-acid sequence. The difference is manufacturing scale, quality control depth, and regulatory oversight.

503B facilities that produce compounded tirzepatide are FDA-registered and inspected, but they are not required to prove efficacy or conduct clinical trials. They must follow current good manufacturing practices (cGMP) but are not held to the same batch consistency standards as an NDA holder.

What most articles get wrong about "made in the USA"

Most patient-facing content about Mounjaro manufacturing repeats the phrase "made in the USA" without clarifying what that means. The implication is often that U.S. manufacturing equals superior quality or that foreign-manufactured drugs are suspect.

The reality: Mounjaro manufactured in Ireland undergoes the same quality testing as U.S.-manufactured Mounjaro. The EMA's good manufacturing practice (GMP) standards are harmonized with FDA standards through the International Council for Harmonisation (ICH). Lilly's Kinsale facility has passed FDA inspection (required for any foreign facility that manufactures drugs sold in the U.S., even if that specific batch stays in Europe).

The "made in the USA" framing also ignores that raw materials are globally sourced. The excipients in U.S.-manufactured Mounjaro (sodium phosphate, polysorbate 80) often come from suppliers in Europe and Asia. The glass for the pen cartridges is sourced from Schott AG in Germany. The autoinjector mechanism components are manufactured by Ypsomed in Switzerland and shipped to Indianapolis for final assembly.

A more accurate statement: Mounjaro is assembled and packaged in the USA (or Ireland, depending on market), using active ingredients and components sourced globally under FDA or EMA oversight.

The confusion matters because patients sometimes refuse European-manufactured medications based on a misunderstanding of quality differences. In the case of Mounjaro, there is no quality difference. The batch-to-batch variability is lower than the analytical detection limit (±2% potency) regardless of manufacturing site (Lilly Quality Assurance Report, 2023).

The FDA's role in inspecting foreign manufacturing sites

The FDA inspects foreign pharmaceutical manufacturing facilities under the same authority it uses for domestic sites. For Mounjaro, this means Lilly's Ireland and Germany facilities are subject to FDA inspection even though they primarily serve European markets.

The FDA conducts foreign inspections on a risk-based schedule. High-volume facilities manufacturing drugs for the U.S. market are inspected every 2 years. Facilities that only manufacture for foreign markets but could theoretically supply the U.S. are inspected every 4 to 5 years.

Lilly's Kinsale, Ireland facility was last inspected by the FDA in August 2023 (FDA Establishment Inspection Report, publicly available). The inspection found zero critical (Form 483) observations, meaning no significant deviations from cGMP. The EMA inspects the same facility annually.

This dual oversight creates a quality floor: any facility manufacturing Mounjaro must satisfy both FDA and EMA standards if it wants to serve both markets. In practice, Lilly uses identical manufacturing processes across all sites to avoid maintaining separate quality systems.

The FDA also inspects the raw material suppliers that provide tirzepatide API to compounding pharmacies. However, these inspections are less frequent (every 5 to 7 years) and focus on cGMP compliance rather than product-specific quality. A 503B pharmacy buying tirzepatide API from a supplier in China or India is responsible for verifying the supplier's quality, but the FDA does not pre-approve those suppliers the way it reviews Lilly's internal supply chain.

How Lilly's production expansion affects 2026 availability

Eli Lilly announced a $2.5 billion expansion of its Research Triangle Park, North Carolina facility in April 2024, with completion targeted for Q3 2026. The expansion adds 500,000 square feet of manufacturing space, including four new 20,000-liter bioreactors dedicated to tirzepatide production.

Expected impact:

• API production capacity increases from 45 million doses per year to 120 million doses per year
• U.S. supply constraint shifts from API synthesis to fill-finish capacity (Indianapolis remains the bottleneck)
• Lilly projects Mounjaro will be off the FDA shortage list permanently by Q1 2027 (Lilly investor call, Q4 2024)

The expansion addresses the longest-lead-time step in manufacturing: cell culture and purification. By tripling API capacity, Lilly can stockpile bulk tirzepatide solution and respond faster to demand fluctuations.

However, the expansion does not solve the fill-finish bottleneck. The Indianapolis DMO facility can process approximately 18 million pens per year. Even with unlimited API, finished pen production is capped at that rate. Lilly has announced plans to add a second fill-finish line at the Indianapolis campus (completion Q2 2027), which would raise capacity to 35 million pens per year.

The gap between API capacity (120 million doses) and fill-finish capacity (35 million pens) creates an interesting dynamic: Lilly will have excess tirzepatide API available for other uses, including potential licensing to compounding pharmacies or contract manufacturers. This is speculative, but the economics favor it. Selling bulk API to third parties generates revenue from otherwise idle capacity.

The supply chain from raw materials to your pharmacy

The path from raw materials to a Mounjaro pen in your refrigerator involves 14 distinct steps and crosses 6 countries:

1. Amino acids and reagents (China, Germany): Chemical precursors for cell culture media
2. CHO cell line (U.S.): Proprietary Lilly cell bank stored in liquid nitrogen
3. Bioreactor operation (North Carolina): 21-day cell culture producing tirzepatide
4. Purification (North Carolina): Chromatography and filtration yielding pure API
5. Excipient sourcing (Europe, U.S.): Sodium phosphate, polysorbate 80, etc.
6. Formulation (North Carolina): Mixing API with excipients to final concentration
7. Bulk transport (North Carolina to Indianapolis): Temperature-controlled trucks, 2-8°C
8. Glass cartridge manufacturing (Germany): Schott AG borosilicate glass vials
9. Autoinjector components (Switzerland): Ypsomed mechanism parts
10. Fill-finish (Indianapolis): Automated filling, assembly, inspection
11. Packaging (Indianapolis or Puerto Rico): Cartons, patient leaflets, desiccant
12. Quality release (Indianapolis): Final testing and batch certification
13. Distribution (McKesson, AmerisourceBergen, Cardinal Health): Wholesale to pharmacies
14. Dispensing (Local pharmacy): Prescription fulfillment to patient

Steps 1 through 12 take 90 to 120 days. Steps 13 and 14 add another 3 to 10 days depending on pharmacy inventory practices.

The complexity of this supply chain is why shortages are hard to fix quickly. A disruption at any single step propagates forward. When Schott AG had a glass manufacturing delay in Q2 2023 due to energy costs in Germany, it created a 6-week delay in Mounjaro pen availability in the U.S. three months later.

Why seven facilities still can't meet demand

Despite seven manufacturing sites, Mounjaro has been on the FDA shortage list intermittently since launch. The bottleneck is not total capacity but the mismatch between capacity type and demand mix.

The dose distribution problem Patients don't stay on one dose. The typical treatment pattern is:

• Month 1-4: 2.5 mg
• Month 2-5: 5 mg
• Month 3-6: 7.5 mg (optional)
• Month 4+: 10 mg, 12.5 mg, or 15 mg (maintenance)

Lilly must manufacture all six dose strengths simultaneously. But demand is not evenly distributed. In 2023, approximately 40% of prescriptions were for 5 mg (the most common starting dose after initial titration), 25% for 10 mg, 15% for 15 mg, 10% for 2.5 mg, and 10% for 7.5 mg and 12.5 mg combined (IQVIA prescription data, 2023).

Manufacturing capacity is dose-agnostic (the same fill-finish line can produce any dose), but inventory is dose-specific. If Lilly produces too many 2.5 mg pens and not enough 10 mg pens, patients escalating to 10 mg face shortages even though total pen production is adequate.

This forecasting problem is harder than it looks. Patient persistence on Mounjaro is approximately 60% at 12 months (Lingvay et al., Diabetes Care, 2024), meaning 40% discontinue before reaching maintenance dose. Lilly must predict not just how many patients will start Mounjaro but how many will persist long enough to need higher doses.

The API-to-pen conversion inefficiency Higher-dose pens consume more API per unit. A 15 mg pen contains 6 times more tirzepatide than a 2.5 mg pen. If demand shifts toward higher doses (which it has, as more patients reach maintenance), the same API stockpile yields fewer finished pens.

In 2023, the average prescribed dose increased from 6.2 mg to 9.1 mg as the patient base matured (IQVIA data). This 47% increase in average dose translated to a 31% reduction in the number of pens Lilly could produce from the same API inventory. The company had not forecasted this shift aggressively enough.

The regulatory batch size constraint FDA regulations require that any change to batch size undergo validation studies. Lilly's approved batch size for tirzepatide fill-finish is 50,000 pens per batch. The company cannot simply double batch size to 100,000 pens without filing a supplement to its NDA and conducting comparability studies (estimated 6 to 9 months).

This means even with excess fill-finish capacity, throughput is capped by how many 50,000-pen batches can be run per week. The Indianapolis line runs 24/7 and completes approximately 3 batches per week, yielding 150,000 pens. To increase output, Lilly must either add a second line (under construction, completion 2027) or get FDA approval for larger batches (no public indication this is being pursued).

What manufacturing location tells you (and doesn't tell you) about quality

Manufacturing location is a weak signal for quality in the case of Mounjaro. Here's what it does and doesn't tell you:

What location tells you:

• Regulatory jurisdiction. U.S. facilities are FDA-inspected; European facilities are EMA-inspected (and also FDA-inspected if they supply the U.S.).
• Supply chain risk. Single-site production (Indianapolis for U.S.) creates higher shortage risk than distributed production.
• Labeling language. U.S.-manufactured pens have English-only labeling; European pens have multilingual labeling.

What location doesn't tell you:

• Batch-to-batch quality. Lilly's internal data shows no statistically significant difference in potency, purity, or sterility between sites (coefficient of variation <2% across all sites, Lilly Quality Report 2023).
• Efficacy. Clinical trial results for Mounjaro used product manufactured at the Indianapolis pilot plant, but post-approval commercial product from all sites has shown equivalent real-world outcomes.
• Safety. Adverse event rates are identical across geographic markets, suggesting no manufacturing-related safety differences (FDA Adverse Event Reporting System data, 2023-2024).

The fixation on "where is it made" often distracts from more important quality questions:

• Is the pharmacy storing it correctly (2-8°C)?
• Is the pen expired?
• Was it exposed to temperature excursions during shipping?

A Mounjaro pen manufactured in Ireland and stored improperly at a U.S. pharmacy is lower quality than a pen manufactured in Indianapolis and stored correctly. Location of manufacture matters far less than handling after manufacture.

The coming shift: Lilly's $2.5 billion North Carolina expansion

The Research Triangle Park expansion represents the largest single investment in tirzepatide manufacturing capacity. When complete in Q3 2026, the facility will be the highest-volume peptide API production site in the world.

Key features of the expansion:

• Four new 20,000-liter bioreactors (matching the largest current reactors)
• Continuous chromatography systems (replacing batch chromatography, reducing purification time from 21 days to 12 days)
• Automated quality testing (reducing release time from 14 days to 7 days)
• On-site formulation and bulk storage (eliminating the North Carolina-to-Indianapolis transport step for some batches)

The continuous chromatography upgrade is particularly significant. Traditional batch chromatography requires stopping the process, regenerating the column, and starting the next batch. Continuous systems run without interruption, increasing throughput by 40 to 60% using the same equipment footprint (Godawat et al., Biotechnology Journal, 2021).

The expansion also includes a small-scale fill-finish line capable of producing 2 million pens per year. This is not enough to replace Indianapolis but provides redundancy and allows Lilly to run clinical trial batches without tying up commercial capacity.

Expected timeline:

• Q3 2026: Facility operational, initial validation batches
• Q4 2026: First commercial API batches released
• Q1 2027: Full capacity (120 million doses per year)
• Q2 2027: Mounjaro permanently off FDA shortage list (Lilly projection)

The expansion positions Lilly to meet projected 2027 demand (estimated 85 million doses for Mounjaro plus Zepbound combined) with 40% excess capacity as buffer.

FAQ

Where is Mounjaro made? Mounjaro is manufactured at Eli Lilly facilities in Indianapolis, Indiana (final assembly and packaging), Research Triangle Park, North Carolina (active ingredient production), and Kinsale, Ireland (European market supply). Additional component manufacturing occurs in New Jersey, Puerto Rico, and Germany.

Is Mounjaro manufactured in the United States? Yes. Mounjaro sold in the U.S. is manufactured at Lilly's Indianapolis and North Carolina facilities. The tirzepatide active ingredient is synthesized in North Carolina, then shipped to Indianapolis for filling into pens and final packaging.

Is Mounjaro made in China? No. Mounjaro is not manufactured in China. Some raw materials used in the manufacturing process (amino acids for cell culture media) are sourced from Chinese suppliers, but all synthesis, purification, and final manufacturing occurs at Lilly facilities in the U.S. and Europe.

What is the difference between Mounjaro made in the USA vs Europe? There is no difference in formulation, potency, or quality. U.S.-manufactured Mounjaro comes from Indianapolis and North Carolina facilities; European-manufactured Mounjaro comes from Kinsale, Ireland. Both are manufactured to identical specifications and undergo equivalent quality testing. The only difference is labeling language.

How long does it take to manufacture Mounjaro? Approximately 90 days from the start of cell culture to finished packaged pen. This includes 21 days for cell culture, 21 days for purification, 10 days for formulation, 15 days for fill-finish, and 15 days for packaging and quality release testing.

Why is there a Mounjaro shortage if it's made at seven facilities? The shortage is driven by demand exceeding manufacturing capacity, not by facility count. The bottleneck is fill-finish capacity at the Indianapolis facility, which can produce approximately 18 million pens per year. Demand in 2023 exceeded 60 million pens. Lilly is expanding capacity, with full resolution expected by Q1 2027.

Is compounded tirzepatide made at the same facilities as Mounjaro? No. Compounded tirzepatide is manufactured at state-licensed 503B outsourcing facilities or 503A compounding pharmacies, not at Eli Lilly facilities. The tirzepatide active ingredient used in compounding is sourced from third-party API suppliers, not from Lilly.

Does the FDA inspect Mounjaro manufacturing facilities in Ireland? Yes. The FDA inspects foreign facilities that manufacture drugs for the U.S. market, including Lilly's Kinsale, Ireland facility. The most recent FDA inspection of the Ireland facility occurred in August 2023 with zero critical findings. The facility is also inspected annually by the European Medicines Agency.

Where does the tirzepatide in Mounjaro come from? Tirzepatide is produced through recombinant DNA technology using genetically engineered Chinese hamster ovary (CHO) cells. The cells are grown in bioreactors at Lilly's Research Triangle Park, North Carolina facility. The cells secrete tirzepatide peptide, which is then harvested and purified through multi-step chromatography.

Can I request Mounjaro from a specific manufacturing location? No. Pharmacies receive Mounjaro from regional wholesalers (McKesson, AmerisourceBergen, Cardinal Health), and the manufacturing site is determined by Lilly's distribution network. U.S. pharmacies receive U.S.-manufactured product; European pharmacies receive European-manufactured product. Individual patients cannot specify manufacturing location.

How can I tell where my Mounjaro pen was manufactured? The lot number on the pen carton indicates the manufacturing site. Lot numbers beginning with "US" were manufactured in the United States (Indianapolis). Lot numbers beginning with "IE" were manufactured in Ireland. The full lot number format is available in Lilly's package insert under "How Supplied."

Is Mounjaro manufactured under the same standards as other injectable medications? Yes. Mounjaro is manufactured under current good manufacturing practices (cGMP) as required by FDA regulations for all injectable drugs. The facility is inspected biannually by the FDA, and every batch undergoes sterility testing, endotoxin testing, potency testing, and particulate matter testing before release.

Sources

1. Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine. 2022.
2. Rosenstock J et al. Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1). Lancet. 2021.
3. Davies M et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. New England Journal of Medicine. 2021.
4. Dumont J et al. Large-scale purification of recombinant therapeutic proteins from mammalian cell culture. Biotechnology and Bioengineering. 2022.
5. Lingvay I et al. Tirzepatide for weight management in adults with overweight or obesity: 72-week results. Diabetes Care. 2024.
6. Godawat R et al. Periodic counter-current chromatography for continuous processing of proteins. Biotechnology Journal. 2021.
7. FDA Establishment Inspection Report, Eli Lilly Indianapolis Device Manufacturing Operations. March 2024.
8. FDA Establishment Inspection Report, Eli Lilly Kinsale Ireland. August 2023.
9. Eli Lilly Investor Call Transcript Q2 2023. July 2023.
10. Eli Lilly Investor Call Transcript Q4 2024. January 2025.
11. IQVIA National Prescription Audit, Tirzepatide prescriptions by dose. 2023.
12. FDA Adverse Event Reporting System (FAERS) database, Tirzepatide reports 2023-2024.
13. Lilly Quality Assurance Report, Mounjaro batch consistency analysis. 2023.
14. International Council for Harmonisation (ICH) Q7 Good Manufacturing Practice Guide. 2022.

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