Both semaglutide and tirzepatide are prescription medications used for weight management. Both are given as a once-weekly injection you do yourself at home. They are not the same drug, they do not work in quite the same way, and they are not the same price.
This page lays out the differences plainly. Which one is appropriate for you is a clinical decision, made by a licensed physician after reviewing your health history — not something to settle from a comparison table. But it helps to know what you are choosing between.
| Semaglutide | Tirzepatide | |
|---|---|---|
| How it works | GLP-1 receptor agonist — acts on one incretin pathway | Dual GIP and GLP-1 receptor agonist — acts on two |
| How it is taken | Once-weekly injection, self-administered | Once-weekly injection, self-administered |
| Starting dose | Lowest dose first, adjusted over time by your physician | Lowest dose first, adjusted over time by your physician |
| Most common side effects | Nausea, constipation, diarrhoea, reflux — usually early and dose-related | Nausea, constipation, diarrhoea, reflux — usually early and dose-related |
| Month to month | $190 / month | $239 / month |
| On the 12-month plan | $99 / month | $149 / month |
| Consultation fee | None | None |
| Insurance | Not required, not billed | Not required, not billed |
| Who prescribes | A licensed physician, after reviewing your intake | A licensed physician, after reviewing your intake |
| Source | Compounded by an FDA-registered 503A pharmacy | Compounded by an FDA-registered 503A pharmacy |
What is the actual difference between semaglutide and tirzepatide?
The difference is how many pathways each one acts on.
Your gut releases hormones called incretins after you eat. They signal fullness, slow how quickly the stomach empties, and help regulate blood sugar. Semaglutide imitates one of them — GLP-1. Tirzepatide imitates two — GLP-1 and GIP.
That is the whole structural difference, and the rest follows from it. Tirzepatide is a newer molecule acting on a broader set of receptors. Semaglutide has been in wider clinical use for longer, which means a longer real-world track record.
Neither of those facts tells you which is right for you. People respond differently to each, tolerate each differently, and have different medical histories that make one more or less appropriate. That is what the physician review is for.
Do the side effects differ?
Both are in the same drug class and share the same side effect profile. The common ones are digestive: nausea, constipation, diarrhoea, stomach discomfort, and reflux. They tend to appear early, tend to be related to dose, and tend to settle as your body adjusts — which is exactly why both start at the lowest dose and step up slowly rather than starting where you will finish.
Less common but more serious effects are possible with both, including inflammation of the pancreas and gallbladder problems. Before prescribing either medication, your physician reviews your personal and family medical history — including any history of medullary thyroid carcinoma, multiple endocrine neoplasia syndrome type 2, pancreatitis, or gallbladder disease. Some histories make these medications inappropriate.
If you experience severe or persistent abdominal pain at any point, stop and contact a clinician.
Anyone who tells you one of these has no side effects is not describing a medication.
How is the dose decided?
By your physician, based on how you respond — not by a chart.
Both medications start at the lowest dose. Your physician reviews how you are tolerating it and whether it is working before adjusting. Some people stay at a lower dose for a long time because it is doing the job. Some move up. Some need to come back down.
This is the part of treatment that is genuinely individual, and it is the reason a prescription weight-loss programme is a relationship rather than a purchase. Changing your own dose — up or down — without telling your prescriber is how side effects become problems.
Can I switch from semaglutide to tirzepatide?
Yes, and people do. It is a clinical decision made with your physician, not a change you make on your own.
The two are not interchangeable at equivalent doses. They act on different receptors, and the amount of one you have been taking does not translate directly into an amount of the other. Switching means your physician sets a new starting point and adjusts from there — which usually means starting lower than you might expect and stepping up again.
The usual reasons to consider switching are tolerance, response, or cost. All three are worth raising. If you are already a patient, message your care team. If you are coming from another provider, note your current medication and dose in your intake so the physician reviewing it has the full picture.
Which one costs less?
Semaglutide, at every plan length. Month to month it is $190 against $239. On the 12-month plan it is $99 a month against $149.
That is the full cost. There is no consultation fee, no membership fee, and no separate charge for the physician review. Insurance is not required and is not billed — the price is the price, whatever your coverage is or is not.
The longer plans cost less per month because they are paid up front. Worth being clear about the trade: a 12-month plan is a 12-month commitment, and it is the cheaper option only if you intend to be treated for a year. Month to month costs more and commits to nothing. Neither is the right answer for everyone.
Which one is right for me?
Honestly: that is what the physician review is for, and any page that answers it for you without knowing your medical history is selling something.
What we can tell you is how the decision gets made. You complete an intake covering your health history, current medications, and what you are trying to achieve. A licensed physician reviews it — a person, not an algorithm — and either prescribes, asks follow-up questions, or tells you this is not appropriate for you. That last outcome is a real one and it happens.
If a medication is prescribed, it ships to you from an FDA-registered 503A compounding pharmacy, and your care team stays available for dose adjustments and questions.
Compounded semaglutide and tirzepatide are prepared for you by a licensed FDA-registered 503A compounding pharmacy. They contain the same active ingredients as the branded medications, but they are not branded medications and they are not FDA-approved products. Prescriptions are issued only after a medical intake is reviewed by a licensed physician, who may determine that treatment is not appropriate.