How is tirzepatide different from semaglutide?

Semaglutide acts on the GLP-1 receptor alone; tirzepatide acts on both GLP-1 and GIP. In trials the dual agonist has produced larger average weight reductions, though the two have different dosing scales and different side-effect profiles.

Why are tirzepatide vials sold in such large milligram sizes?

Doses are measured in milligrams rather than micrograms, so a vial covering several weeks holds substantially more compound than a typical research peptide vial. This is also why entering a tirzepatide dose in micrograms by mistake produces an obviously wrong result, and the calculator will flag it.

Tirzepatide

LY3298176GLP-2 TGLP-2

Approved

Evidence

Approved

Half-life

5 d

Typical vial

5 mg

Route

Subcut

What it is

A once-weekly dual agonist that activates both the GIP and GLP-1 receptors, approved for type 2 diabetes and for weight management.

Reviewed 12 Aug 2026

Tirzepatide activates two incretin receptors rather than one: GIP (glucose-dependent insulinotropic polypeptide) as well as GLP-1. It is a single 39-amino-acid peptide engineered to bind both, with a fatty-acid chain that extends its half-life to roughly five days.

In head-to-head and placebo-controlled trials it has produced larger average weight reductions than GLP-1 agonism alone. Why adding GIP activity helps is still debated, since the receptor's role in appetite regulation is not settled. The clinical effect has been replicated across large trials regardless.

How it works

GLP-1 receptor activity accounts for the familiar effects: insulin release when glucose is high, suppressed glucagon, slowed gastric emptying, and reduced appetite through receptors in the brain.

The GIP component adds activity at a second incretin receptor found in the pancreas, in fat tissue, and in the brain. Current thinking is that GIP agonism improves how fat tissue handles nutrients and may independently reduce food intake, though the mechanism is an active research question rather than a settled one.

What it is studied for

Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.

Weight management
Clinical trial
Approved for chronic weight management.
EvidenceRandomised placebo-controlled phase 3 trial in adults with obesity over 72 weeks.
Type 2 diabetes
Clinical trial
Approved for glycaemic control in type 2 diabetes.
EvidenceThe SURPASS phase 3 programme.

Regulatory status

Last reviewed 12 Aug 2026. Positions in this category change frequently, so we date the line.

United States

Approved by the FDA as a prescription medicine for type 2 diabetes and for chronic weight management. Material sold as a research chemical is not the approved product and is not legal to sell for human use.

Identity and clearance

What the molecule is, and how long a dose stays measurable.

Clinical trial

Molecule

Class: Dual GIP and GLP-1 receptor agonist
Molecular weight: 4813.5 Da
Length: 39 amino acids

A single engineered peptide, not two molecules combined. The C20 fatty diacid chain provides albumin binding and the long half-life.

Pharmacokinetics

Clinical trial

Peak2 d

Half-life5 d

Substantially cleared3.6 w

Modelled from the half-life above, assuming first-order elimination. Illustrative rather than measured — it shows the shape of clearance, not a prediction for any individual.

About five days, so steady state is reached after roughly four weeks of consistent weekly dosing.

Dose protocols reported in sources

Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.

A week-by-week progression is also reported for Tirzepatide. See it against a 5 mg vial, where the syringe units can be worked out.

Dose protocols reported in sources, with the source of each.
Goal	Dose	Frequency	Route	Units, 5 mg vial	Source	Start this protocol
Trial escalation, weeks 1–4	2.5 mg	Once weekly	Subcutaneous	50 u	Clinical trial	Start this
Trial escalation, thereafter	5 mg – 12.5 mg	Once weekly, raised by 2.5 mg every four weeks	Subcutaneous	from 100 u	Clinical trial	Start this
Trial maintenance doses	5 mg – 15 mg	Once weekly	SubcutaneousThe trial ran separate 5 mg, 10 mg and 15 mg maintenance arms, not a single target dose.	from 100 u	Clinical trial	Start this

The doses above in syringe units, for the vial you have:

2 more sizes

Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.

Work out what to draw

Pre-filled with a 10 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.

Tool

Draw to 50 units on a 1 mL U-100 syringe. That is 0.5 mL, containing 2.5 mg of Tirzepatide.

Concentration5mg / mL

Volume drawn0.5mL

Doses per vial4doses

Per unit50mcg / unit

50 units sits exactly on a printed line.

Get a shareable image Read the profile

BioAlmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.

Open this calculation in the full calculator

Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.

Safety

Reported effects, the situations that need care, and the ones that mean stop.

Read before dosing

Reported effects

NauseaClinical trial
Very common in trials
Dose-related and worst after an increase.
Diarrhoea, constipation, vomitingClinical trial
Common in trials
Reduced appetiteClinical trial
Very common
Can be pronounced enough to make adequate protein and fluid intake difficult.
Gallbladder problemsClinical trial
Uncommon but documented
PancreatitisClinical trial
Rare
Loss of lean mass alongside fatClinical trial
Documented in trials

When to stop

Severe, persistent abdominal pain radiating to the back, with or without vomiting. Seek urgent medical care.
Persistent vomiting or inability to keep fluids down.
Upper right abdominal pain, fever, or yellowing of the skin or eyes.
A neck lump, hoarseness, or difficulty swallowing.
Any allergic response: rash, hives, facial swelling, or difficulty breathing. Seek urgent care.
If you become pregnant or are planning to.

Interactions and situations that need care

Personal or family history of medullary thyroid carcinoma, or MEN 2Avoid
The approved product carries a boxed warning on this basis, following rodent thyroid C-cell findings.
History of pancreatitisUse caution
Pancreatitis is a documented if uncommon adverse event.
Pregnancy and breastfeedingAvoid
Not recommended, and the long half-life means stopping well in advance.
Insulin or sulfonylurea therapyUse caution
Combined glucose-lowering raises hypoglycaemia risk and usually requires the other agent to be adjusted by its prescriber.
Planned surgery or general anaesthesiaUse caution
Delayed gastric emptying can leave food in the stomach despite standard fasting, which is an aspiration risk. Tell your anaesthetist.

What to expect

What the sources describe over time, and how confident anyone can be about it.

In SURMOUNT-1, mean weight reduction over 72 weeks was about 15% at 5 mg, 19.5% at 10 mg and 20.9% at 15 mg weekly, against 3.1% on placebo.
Escalation to a maintenance dose takes roughly five months under the trial schedule.
These are averages under supervised conditions with lifestyle support, not a prediction for an individual.
As with semaglutide, weight regain after discontinuation is documented.

Storage and combinations

How to keep it, and what it does and does not go with.

Printable one-pager →

Storage and handling

Freeze-dried powder: Refrigerated at 2–8 °C and protected from light. Keep the powder dry until you are ready to use it.
After mixing: Refrigerated at 2–8 °C. Do not freeze. Discard if cloudy or discoloured.
Long-term, frozen: Unopened lyophilised powder is stable at −20 °C or colder.

Printable one-pager How to reconstitute a vial, step by step

With other peptides

Semaglutideincompatible
Both act on the GLP-1 receptor. Running them together duplicates a mechanism rather than adding one, and compounds gastrointestinal effects.
Retatrutideincompatible
Overlapping GLP-1 and GIP agonism. These are alternatives, not a stack.
Liraglutideincompatible
Tirzepatide already includes full GLP-1 receptor agonism. Adding liraglutide stacks the same mechanism, with the same side effects and no additional benefit.
Cagrilintidecaution
Plausible on paper, since amylin signalling is separate from both GLP-1 and GIP. No trial has tested it, and stacking three appetite-suppressing mechanisms risks intake falling below what is safe.
Orforglipronincompatible
Tirzepatide already includes full GLP-1 agonism. Adding orforglipron stacks the same mechanism with the same side effects and no additional benefit.

Check this against a whole stack

Checking your vial

Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it.

Quality and COAs →

White cake, clear solution
Standard for a correctly lyophilised peptide of this class.
Collapsed cake or discoloured solution
Indicates heat damage or degradation. Do not use.

Vocabulary on this page

Titration: Raising a dose in planned steps rather than starting at the target, so side effects appear at a dose small enough to retreat from.
Lyophilised: Freeze-dried. The process used to turn a peptide solution into a stable dry powder for shipping and storage.
GLP-1 agonist: A drug acting on the receptor for glucagon-like peptide-1, a gut hormone that signals fullness and slows stomach emptying.
Reconstitution: Adding liquid to a freeze-dried peptide powder to turn it into a solution that can be drawn into a syringe.
Half-life: The time it takes for half of a compound to be cleared from the body.
Vial: The small sealed glass container a peptide is sold in, holding a stated mass of freeze-dried powder under a rubber stopper.

The whole glossary →

Questions

Reader questions

How is tirzepatide different from semaglutide?: Semaglutide acts on the GLP-1 receptor alone; tirzepatide acts on both GLP-1 and GIP. In trials the dual agonist has produced larger average weight reductions, though the two have different dosing scales and different side-effect profiles.
Why are tirzepatide vials sold in such large milligram sizes?: Doses are measured in milligrams rather than micrograms, so a vial covering several weeks holds substantially more compound than a typical research peptide vial. This is also why entering a tirzepatide dose in micrograms by mistake produces an obviously wrong result, and the calculator will flag it.

References

Everything on this page that came from a source, with the source.

Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)
New England Journal of Medicine, 2022 · Randomised, double-blind, placebo-controlled phase 3 trial
Adults with obesity, without diabetes · n = 2539 · 5 mg, 10 mg or 15 mg once weekly · 72 weeks
Mean weight change of −15.0%, −19.5% and −20.9% across the three dose arms against −3.1% on placebo. Gastrointestinal events were the most common adverse effects.
10.1056/NEJMoa2206038

Quick reference

Commonly described dose: 2.5 mg
How often: Once weekly
Route: Subcutaneous
Where: Abdomen, Thigh, Upper arm
Timing: Any time of day, with or without food, on the same day each week.
Half-life: About 5 days
Storage once mixed: Refrigerated, 30 days

These describe what sources report, not what you should do. Full detail and provenance in the dosing section below.

Price index

$1.00 – $15.00per mg

Across 33 vendors, normalised per milligram and confirmed by a person.

SizeIn stock only

Confirmed listings for this compound, cheapest per milligram first.
Vendor	Size
S1Research	140 mg	$140.00	$1.00
Crownwell Research	60 mg × 2 vial	$140.00	$1.17
S1Research	60 mg	$73.00	$1.22
Crownwell Research	30 mg × 10 vial	$372.00	$1.24
Alpha Peptides	60 mg	$89.24	$1.49

Show 131 more vendors

The remaining listings, continuing from cheapest.
IDUN Peptides	30 mg	$49.99	$1.67
Evolve BioPep	60 mg	$100.00	$1.67
Genpeptide	30 mg	$50.00	$1.67
Alpha Peptides	30 mg	$58.02	$1.93
OneDay Compounds	60 mg	$118.99	$1.98
Legendary Peptides	60 mg	$120.00	$2.00
S1Research	30 mg	$63.00	$2.10
Glacier Aminos	60 mg	$126.74	$2.11
Genpeptide	60 mg	$130.00	$2.17
Longevity Pro Labs	63 mg	$150.00	$2.38
S1Research	10 mg	$24.00	$2.40
Glacier Aminos	30 mg	$73.49	$2.45
Nationwide Peptides	60 mg	$149.00	$2.48
OneDay Compounds	30 mg	$76.99	$2.57
Ameano Peptides	60 mg	$155.00	$2.58
BulkGLP	1000 mg	$2,599.00	$2.60
BulkGLP	1000 mg	$2,599.00	$2.60
Sentinel Valor	30 mg	$79.99	$2.67
Evolve BioPep	30 mg	$80.00	$2.67
Nationwide Peptides	50 mg	$140.00	$2.80
Glacier Aminos	20 mg	$56.99	$2.85
Glacier Aminos	45 mg	$131.99	$2.93
Peak Lab Peptides	60 mg	$177.60	$2.96
IDUN Peptides	10 mg	$29.99	$3.00
Sentinel Valorout of stock	20 mg	$59.99	$3.00
Royal Peptidesout of stock	100 mg	$300.00	$3.00
Genpeptide	30 mg	$90.00	$3.00
Ameano Peptides	30 mg	$90.00	$3.00
Nationwide Peptides	40 mg	$123.00	$3.08
Sentinel Valor	10 mg	$30.99	$3.10
OneDay Compounds	20 mg	$62.99	$3.15
Nura Peptide	60 mg	$190.00	$3.17
Royal Peptides	60 mg	$196.00	$3.27
Prime Lab Peptides	30 mg × 10 vial	$980.00	$3.27
Royal Peptides	40 mg	$132.00	$3.30
Nationwide Peptides	20 mg	$66.00	$3.30
Peptira	60 mg	$199.00	$3.32
PSPeptides	60 mg	$199.99	$3.33
Peak Lab Peptides	50 mg	$173.20	$3.46
Royal Peptides	30 mg	$104.00	$3.47
OneDay Compounds	10 mg	$34.99	$3.50
PSPeptides	50 mg	$174.99	$3.50
BulkGLP	40 mg	$140.00	$3.50
BulkGLP	40 mg	$140.00	$3.50
BulkGLP	40 mg	$140.00	$3.50
Royal Peptides	20 mg	$72.00	$3.60
PSPeptides	40 mg	$144.99	$3.62
Longevity Pro Labs	33 mg	$120.00	$3.64
Royal Peptides	15 mg	$56.00	$3.73
Peak Lab Peptides	40 mg	$149.60	$3.74
NuScience Peptides	60 mg	$225.00	$3.75
Nationwide Peptides	30 mg	$113.00	$3.77
Xeno Peptides	60 mg	$228.00	$3.80
Glacier Aminos	10 mg	$38.24	$3.82
PSPeptides	30 mg	$114.99	$3.83
NuScience Peptides	100 mg	$399.00	$3.99
PSPeptidesout of stock	20 mg	$79.99	$4.00
Royal Peptides	10 mg	$40.00	$4.00
Genpeptide	20 mg	$80.00	$4.00
Nura Peptide	30 mg	$120.00	$4.00
Ameano Peptides	20 mg	$84.00	$4.20
PSPeptides	15 mg	$64.99	$4.33
Apollo Peptide Sciences	60 mg	$259.99	$4.33
Prime Peptides	60 mg	$260.00	$4.33
Reserve Research	30 mg	$130.00	$4.33
Evolve BioPep	15 mg	$65.00	$4.33
Peak Lab Peptides	30 mg	$130.70	$4.36
Genpeptide	10 mg	$45.00	$4.50
Xeno Peptides	30 mg	$135.00	$4.50
Ameano Peptides	15 mg	$68.00	$4.53
Nexus Peptides	5 mg × 10 vial	$239.99	$4.80
Ameano Peptides	10 mg	$48.00	$4.80
NuScience Peptides	30 mg	$149.00	$4.97
Apollo Peptide Sciences	30 mg	$150.99	$5.03
Nationwide Peptides	10 mg	$51.00	$5.10
Polaris Peptides	60 mg	$309.00	$5.15
Peptira	30 mg	$159.00	$5.30
Prime Peptides	30 mg	$160.00	$5.33
Polaris Peptides	50 mg	$270.00	$5.40
PSPeptides	10 mg	$54.99	$5.50
Prime Lab Peptides	30 mg	$170.00	$5.67
Royal Peptides	5 mg	$28.80	$5.76
Crownwell Research	10 mg × 5 vial	$289.00	$5.78
Peak Lab Peptides	20 mg	$116.20	$5.81
Evolve BioPep	5 mg	$30.00	$6.00
Nura Peptide	10 mg	$60.00	$6.00
Nationwide Peptides	5 mg	$31.00	$6.20
Xeno Peptides	10 mg	$62.00	$6.20
Apollo Peptide Sciences	20 mg	$125.99	$6.30
Peak Lab Peptides	15 mg	$94.80	$6.32
Peptira	20 mg	$129.00	$6.45
NuScience Peptides	15 mg	$99.00	$6.60
Protide Health	60 mg	$400.00	$6.67
Prime Lab Peptides	10 mg × 10 vial	$695.00	$6.95
Longevity Pro Labs	10 mg	$70.00	$7.00
Blank Peptides	30 mg	$219.00	$7.30
Apollo Peptide Sciences	15 mg	$109.99	$7.33
Peak Lab Peptides	10 mg	$74.40	$7.44
Polaris Peptides	30 mg	$225.00	$7.50
Life Link Research	30 mg	$233.00	$7.77
Koi Peptides	30 mg	$239.95	$8.00
Kylo Peptides	30 mg	$249.95	$8.33
Protide Health	30 mg	$250.00	$8.33
Reserve Research	10 mg	$85.00	$8.50
Royal Peptides	100 mg	$875.00	$8.75
Polaris Peptides	10 mg	$89.00	$8.90
Blank Peptides	10 mg	$89.00	$8.90
Peptira	10 mg	$89.00	$8.90
Koi Peptidesout of stock	10 mg	$89.95	$8.99
Protide Health	15 mg	$139.00	$9.27
Life Link Research	15 mg	$139.00	$9.27
Kylo Peptides	10 mg	$99.95	$9.99
NuScience Peptides	5 mg	$49.99	$10.00
Prime Peptides	10 mg	$100.00	$10.00
Prime Lab Peptides	10 mg	$100.00	$10.00
Royal Peptides	60 mg	$650.00	$10.83
Protide Health	10 mg	$110.00	$11.00
Polaris Peptides	5 mg	$55.00	$11.00
Peak Lab Peptides	5 mg	$57.60	$11.52
Royal Peptides	50 mg	$600.00	$12.00
Royal Peptides	40 mg	$550.00	$13.75
Prime Lab Peptides	5 mg	$70.00	$14.00
Pure Bio Labs	10 mg	$149.99	$15.00
Royal Peptides	30 mg	$450.00	$15.00
Legendary Peptides	60 mg	$1,000.00	$16.67
Pure Bio Labs	5 mg	$89.99	$18.00
Royal Peptides	20 mg	$380.00	$19.00
Royal Peptides	15 mg	$320.00	$21.33
Royal Peptides	10 mg	$265.00	$26.50
Royal Peptides	5 mg	$250.00	$50.00
NuScience Peptides	10 mg	$699.00	$69.90

Is this price moving? →Every compound we price →

Average per mg

30 daysAll

We started tracking more vendors during this window, so part of this line is who we track rather than what they charge.

Lowest ever: $1.00 4 Oct 2026
Highest ever: $50.00 14 Sept 2026
Change: 17 → 22 vendors 13 Sept to 13 Oct

We started tracking more vendors during this window, so part of this line is who we track rather than what they charge.

Lowest ever: $1.00 4 Oct 2026
Highest ever: $50.00 14 Sept 2026
Change: 1 → 22 vendors 28 Aug to 13 Oct

Mean of each vendor’s cheapest vial listing, US dollars only. Full chart

Email me when Tirzepatide gets cheaper

Ranked on price alone. We sell nothing, take no payment for placement, and use no affiliate links — listing a price is not a recommendation to buy. Prices are what the vendor listed when we last looked, not a live quote.

Cold chain

Freeze-dried: Refrigerated at 2–8 °C and protected from light. Keep the powder dry until you are ready to use it.
After mixing: Refrigerated at 2–8 °C. Do not freeze. Discard if cloudy or discoloured.
Long-term, frozen: Unopened lyophilised powder is stable at −20 °C or colder.

How to reconstitute a vial

Stop and seek advice

Severe, persistent abdominal pain radiating to the back, with or without vomiting. Seek urgent medical care.
Persistent vomiting or inability to keep fluids down.
Upper right abdominal pain, fever, or yellowing of the skin or eyes.
A neck lump, hoarseness, or difficulty swallowing.
Any allergic response: rash, hives, facial swelling, or difficulty breathing. Seek urgent care.
If you become pregnant or are planning to.

The full safety section carries the sources for these.

Tirzepatide compared with

Tirzepatide vs survodutide

Two dual agonists that picked different second receptors, GIP in one case and glucagon in the other, and that sit at very different stages of evidence.

Semaglutide vs tirzepatide

Both are once-weekly incretin agonists approved for weight management. The difference is how many receptors each one acts on, and what that does to the dosing scale.

Tirzepatide vs retatrutide

Two and three receptors respectively. Retatrutide reported the larger weight reduction; tirzepatide has a completed phase 3 programme and an approval. This is a different kind of claim.

Mazdutide vs tirzepatide

Two dual agonists that picked different second receptors. Tirzepatide added GIP; mazdutide added glucagon, which does something GIP does not.

Also compared with Liraglutide, Cagrilintide, Orforglipron, Eloralintide, Tesofensine, 5-Amino-1MQ.

Related compounds

Semaglutide

A long-acting GLP-1 receptor agonist approved for type 2 diabetes and for weight management, dosed once weekly.

Retatrutide

An investigational once-weekly triple agonist acting on the GLP-1, GIP and glucagon receptors. Not approved anywhere.

Liraglutide

The first GLP-1 analogue approved for weight loss. A daily injection, superseded by weekly semaglutide but still the best-documented compound in the class.

Cagrilintide

A long-acting amylin analogue in late-stage trials. It works on a different satiety pathway from the GLP-1 drugs. Which is why it is being developed alongside semaglutide rather than against it.

Keep this page honest

If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.

Suggest a correction

This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on BioAlmanac is medical advice. No clinician reviews these pages.

Page last updated 12 Aug 2026