About 3 in 10 feel nauseous at some point, mostly while the dose is still going up.
Nausea
31%
Diarrhea
23%
Vomiting
12.2%
Constipation
11.7%
Out of 100 people assigned 15 mg, at any point over 72 weeks. Mostly mild to moderate;
6 in 100 stopped over side effects, against 3 in 100 on placebo.
For average weight loss, yes. In a head-to-head trial, people lost more weight with tirzepatide than with semaglutide.
Tirzepatide10–15 mg
−20.2%
Semaglutide1.7–2.4 mg
−13.7%
72 weeks, both titrated to the highest dose each person tolerated. Neither
side was blinded.
That trial compared weight loss, not protection from heart attacks or strokes.
Semaglutide has direct evidence and an FDA indication for reducing cardiovascular risk
in certain adults with obesity and established cardiovascular disease.
Tirzepatide acts on a second gut receptor that semaglutide does not.
Semaglutide
Ozempic, Wegovy
GLP-1GIP
vs
Tirzepatide
Zepbound, Mounjaro
GLP-1GIP
GIP fully on, GLP-1 only partway
Each molecule is sold under two names: one licensed for weight, one for
type 2 diabetes. Wegovy and Ozempic are the same semaglutide; Zepbound and Mounjaro are
the same tirzepatide.
It can cause temporary hair shedding in some people, especially during rapid weight loss.
7 in 100womenunder 1 in 100men
Both on tirzepatide. On placebo it was 1.3% of women. Shedding often settles three to six months after weight stabilises; no trial participant stopped treatment because of it. Patchy hair loss is not typical and warrants medical evaluation.
Do not take it if you have a personal or family history of medullary thyroid cancer or MEN2, or if you have had a serious allergic reaction to tirzepatide or its ingredients.
Medullary thyroid cancer, or MEN2personal or family history — this is the boxed warning
Previous pancreatitisnot an FDA contraindication; a history of pancreatitis requires individual medical review
Severe gastroparesisnot recommended in the FDA label because tirzepatide slows stomach emptying
Type 1 diabetestirzepatide may be used for weight loss, but insulin adjustments require specialist diabetes management
A serious allergic reaction to tirzepatideor to any ingredient in the formulation — an FDA contraindication
Pregnant, trying, or breastfeedingdo not use during pregnancy; discuss when to stop before trying, or whether to use while breastfeeding
Already taking another GLP-1 medicinethe FDA label does not recommend using them together
Unstable or severe mental illnessneeds individual review to confirm that treatment and medication use can be managed safely
Yes, some of the weight lost is lean mass, but most of the measured loss is fat.
Fat masson tirzepatide
−33.9%
Lean massmuscle, organs, water
−10.9%
Fat masson placebo
−8.2%
Lean masson placebo
−2.6%
Lean mass is not the same as muscle: it also includes organs, water and other tissue. Each bar is the change within that compartment, not its share of the weight lost.
Randomised trials provide three years of follow-up in obesity and four years in type 2 diabetes. Evidence beyond that is not yet available.
In obesityblinded throughout
3 years
In diabetesvs another drug
4 years
0123456
No new common side-effect pattern appeared through three years. The four-year evidence
is in people with type 2 diabetes, measured against another drug rather than placebo.
Tirzepatide strengthens signals between your gut and brain that reduce appetite and help you feel satisfied with less food.
Some patients feel less hungry. Others say the constant thoughts about food become quieter. It feels different for everyone, and it does not always happen right away.
Tirzepatide caused thyroid C-cell tumours in rats. It is unknown whether it causes them in people.
In rats
thyroid C-cell tumours, more at higher doses and longer use
?human risk
In people
the risk is unknown
The label says it is not known whether this happens in people. A personal or
family history of medullary thyroid cancer, or MEN2, rules you out. Report a lump in the
neck, hoarseness, or trouble swallowing.
The dispensing pharmacy uses an independent US lab to test every batch for sterility and endotoxins before shipment.
The pharmacyUS, state-licensed in 48 states and DC, NABP-accredited and LegitScript-certified
Every batchsterility and endotoxins, by an accredited US lab independent of the pharmacy
The active ingredientbase form, 99.4% pure on the supplier’s certificate. Compounded in the US; the ingredient itself is made abroad, at FDA-registered plants
Every trial on this page studied the branded drug. What we dispense is compounded
under Section 503A: not FDA-approved, and never trialled on its own.
Pharmacy licences, accreditation records, and batch certificates are held on file and available on request.
Yes. A licensed compounding pharmacy may prepare a patient-specific prescription when federal and state requirements are met.
One named patientmade on a prescription, for you, not for stock
Not a routine copy of the brandthe prescriber must document a patient-specific clinical difference when required
The exact requirements depend on the prescription and applicable federal and
state law. Compounded medicines are not FDA-approved, and the FDA does not review them
for safety, effectiveness or quality before they are dispensed.
Compounding lets me prescribe the dose a patient needs instead of limiting them to the fixed strengths available in single-dose brand pens. That flexibility can matter when someone needs to increase more slowly or stay at a lower dose.
Every vial contains tirzepatide plus either glycine or hydroxocobalamin, a form of vitamin B12. Neither additive has been shown to improve weight loss or reduce tirzepatide’s side effects.
Tirzepatidein every vial
plus one of these, depending on the prescription
Glycinean inactive ingredient
Vitamin B12an approved medicine for other uses
Neither combination was studied in the major tirzepatide trials. Glycine appears in FDA-approved injectable products. Hydroxocobalamin is approved separately for other uses.
The supplier’s certificate reports 99.4% purity for the tirzepatide starting material. Each finished lot is tested for sterility and endotoxins.
The additives are not what makes tirzepatide work. Glycine is used in approved injectable medicines, and hydroxocobalamin is a form of vitamin B12. I go through the exact formulation with each patient so they know what is in their vial and why.
Reviewed by James Simmons, MD. Medical Director, board-certified
in emergency medicine. July 2026. Educational only, not medical advice: talk to a clinician about your own
history before starting or stopping anything. Every trial cited here studied the branded drug, not the compounded
medication we dispense, which is not FDA-approved and has never been trialled
on its own.