How many units of Tirzepatide should I draw?

It depends on your vial size, BAC water, and dose. For a 5mg vial with 2mL BAC water, a beginner dose of 2500mcg is typically 100 units on a U-100 syringe. Use the calculator above for your exact numbers.

How much BAC water should I add to Tirzepatide?

The standard amount is 2mL of bacteriostatic water for a 5mg vial. More water gives a more dilute solution — easier to measure small doses. Less water means fewer injections per vial. Adjust the BAC water slider in the calculator to see how it changes your syringe units.

How long does a Tirzepatide vial last?

At a beginner dose of 2500mcg weekly, a 5mg vial lasts about 2 doses. The calculator shows exact doses per vial for your selected tier.

What syringe should I use for Tirzepatide?

Most people use a U-100 insulin syringe (1mL / 100 units). For very small doses, a U-50 or U-30 syringe gives better precision. The calculator adjusts units automatically for whichever syringe you pick.

How should I store Tirzepatide after reconstitution?

Store reconstituted Tirzepatide at 2-8°C (36-46°F). Refrigerate at 2-8°C, use within 4 weeks. Before reconstitution: refrigerate at 2-8°c.

How does Tirzepatide compare to similar peptides?

Tirzepatide has 4 head-to-head comparisons available: Semaglutide, Retatrutide, Semaglutide. See the full comparison pages for dosing differences, mechanisms, and which one fits your goals.

What is the recommended tirzepatide dosage?

Start at 2.5 mg weekly for 4 weeks, then titrate to 5 mg. From there, increases of 2.5 mg every 4 weeks up to a maximum of 15 mg weekly. SURMOUNT-1 used the 5/10/15 mg doses. Most weight loss benefit hits a ceiling around 10-15 mg for most people.

Not medical advice. Talk to your provider before using any peptide.

Full disclaimer

Peptide Schedule Research TeamReviewed Apr 202613 Citations

Weight LossFDA ApprovedGrade A

GLP-1 AgonistWeight ManagementAppetite RegulationBlood Sugar Control

Tirzepatide Dosage Calculator

~5 days half-life·Injection

Tirzepatide targets both GIP and GLP-1 receptors, producing 20-22% body weight loss in important trials. FDA-approved as Zepbound (obesity) and Mounjaro (T2D). GI side effects during titration are the main limiting factor; a black box warning for thyroid tumors applies.

Used by Johnson, Williams

Hot1,865Very High

21 referencesVerified 2026-04-09

Vial Size

BAC Water (mL)

Dosing Level

2,500mcg · Weekly

Custom Dose (mcg) — optional

Syringe Type

100.0 units

100 units (1mL)

Concentration

2,500

mcg/mL

Draw Volume

1.000

Syringe Units

100.0

units

Doses / Vial

doses

Summary: Add 2mL BAC water to your 5mg vial. Draw to 100.0 units on a U-100 syringe for a 2,500mcg dose. This vial will last 2 doses.

Schedule This Protocol

2,500mcg weekly — draw 100.0 units on U-100 syringe

Subcutaneous. Typical beginner frequency: weekly.At beginner dose (2500mcg) with a 5mg/2mL vial: draw to the 100-unit mark on a U-100 syringe.

After reconstituting, store at 2-8°C (36-46°F) (refrigerate at 2-8°c, use within 4 weeks).

View side effects and safety warnings →

Quick-Start: Reconstitution

1Gather supplies: tirzepatide vial (or pre-filled pen), bacteriostatic water (if reconstituting a vial), alcohol swabs, insulin syringe (31-32 gauge, 4-6 mm needle for subcutaneous injection).
2If using a compounded vial: add 2 mL bacteriostatic water slowly down the side of the vial. Swirl gently until dissolved. Never shake. For a 10 mg vial, final concentration is 5 mg/mL. For a 15 mg vial, concentration is 7.5 mg/mL.
3Draw your dose. At 5 mg/mL concentration: 50 units on the syringe equals 2.5 mg. 100 units equals 5 mg. At 7.5 mg/mL concentration: 100 units equals 7.5 mg. 67 units equals approximately 5 mg. Calculate your dose carefully for each vial concentration.

Full injection guide →

Tirzepatide Dosing Protocol

FDA LabelZepbound FDA Prescribing Information (2023) (n=2,539 (SURMOUNT-1))

Level	Dose / Injection	Frequency
Beginner	2,500mcg	Weekly
Moderate	5mg	Weekly
Aggressive	10mg	Weekly

Note:

Tirzepatide comes in pre-filled pens (brand Zepbound/Mounjaro) and compounded vials (very limited availability since March 2025). For compounded vials: Reconstitution math for a 10 mg vial with 2 mL bacteriostatic water gives you 5 mg/mL. A 2.5 mg dose is 0.5 mL (50 units on an insulin syringe). A 5 mg dose is 1.0 mL (100 units, a full syringe). For a 15 mg vial with 2 mL BAC water, concentration is 7.5 mg/mL. A 7.5 mg dose is 1.0 mL (100 units). A 10 mg dose runs about 1.33 mL, which exceeds a standard 1 mL syringe; either use a 3 mL syringe or reconstitute with 3 mL instead (giving 5 mg/mL, then 2.0 mL per 10 mg dose). The thing most beginners miss: 2.5 mg is not a therapeutic dose for weight loss. It's a tolerability test. Don't judge whether tirzepatide "works" until you've been at 5 mg for at least 4 weeks. Evening injections help most people sleep through the nausea window (4 to 8 hours post-dose).

Dosing based on Zepbound FDA Prescribing Information (2023) — 21 published references.View all sources →

Verify your calculation

Cross-check your Tirzepatide reconstitution math with AI

Who Uses Tirzepatide?

Bryan Johnson

Entrepreneur & Longevity Pioneer

Raised RHR +3bpm, lowered HRV -7pts, sleep quality -10%. Halted after 3 weeks.

500mcg weekly · subcutaneous

Bryan Johnson, Hunter Williams

have published Tirzepatide protocols with dosing

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Tirzepatide Cost

Brand Price

Zepbound brand pens: ~$1,079–$1,086/month list price (without insurance, April 2026). With commercial insurance savings card: as low as $25/fill (max savings $1,300/year). Mounjaro (T2D indication): similar list price. Medicare/Medicaid ineligible for savings cards per federal law.

Generic / Research

No generic available. Tirzepatide is under active Eli Lilly patent protection.

Compounded

Compounded tirzepatide largely unavailable since March 19, 2025. FDA ended enforcement discretion for 503B outsourcing facilities (March 19, 2025) and 503A pharmacies (Feb 18, 2025). Federal court upheld FDA decision May 2025. Historical compounded price: $150–$400/month. As of April 2026, tirzepatide remains on FDA shortage list, allowing very limited 503A compounding only for individual patients with documented medical necessity (specific dose requirements or inactive ingredient allergy). LillyDirect self-pay vial program (brand Zepbound vials: NOT compounded): $299/month (2.5 mg) to $499/month (7.5–15 mg), available since Feb 2026.

Pricing updated 2026-04-09

Prices are estimates and vary by source, location, and prescription status.Full pricing breakdown →

Tirzepatide Pharmacokinetics

Pharmacokinetics — Active Dose Over Time

t½ = ~5 days

After 1 half-life (5d): 50% remainsAfter 2 half-lives (10d): 25% remainsAfter 3 half-lives (15d): 12.5% remains

At a 5mg dose: 50% = 2.5mg remaining after 5d. Recommended frequency: Weekly.

Disclaimer: This curve is a simplified first-order exponential decay model. Actual pharmacokinetics vary based on injection site, individual metabolism, body composition, and other factors. Half-life values are approximate and based on available preclinical and clinical literature. Many research peptides lack formal human pharmacokinetic studies. This is for educational purposes only — not medical advice.