Weight-Loss Injections Compared: Wegovy vs Zepbound vs Off-Label Ozempic and Mounjaro

The short answer

That single fact reshapes the whole comparison. Wegovy and Zepbound carry FDA-reviewed weight-management dosing, safety labeling, and eligibility criteria written into their Indications sections. Ozempic and Mounjaro contain the same active ingredients but were reviewed and labeled for blood sugar, not body weight. Compounded versions are mixed by pharmacies and sold through some telehealth platforms, and the FDA has issued warnings about unapproved GLP-1 products.

This page compares the four options on mechanism, approval status, cost structure, and a women's-health detail that rarely makes the marketing copy: tirzepatide can reduce the effectiveness of oral birth control, while semaglutide does not carry that warning. We do not sell or prescribe anything, and we will not quote invented prices. Where a dollar figure matters, we point you to the manufacturer's own savings page for the live number.

The four options at a glance

Four products dominate the weight-loss injection conversation, and they reduce to two active ingredients dispensed under different labels. Semaglutide is sold as Wegovy (for weight) and Ozempic (for diabetes). Tirzepatide is sold as Zepbound (for weight) and Mounjaro (for diabetes). Compounded semaglutide and tirzepatide are copies mixed by pharmacies, not the branded, FDA-approved products.

The table below is the fastest way to see why 'which injection is best' is the wrong first question. The better first question is 'which of these is actually approved and labeled for the reason I want it,' because that determines your insurance path, your safety labeling, and whether your prescriber is working within the on-label indication or off it.

How these injections actually work

Semaglutide and tirzepatide are both incretin-based drugs, meaning they mimic gut hormones your body releases after you eat. These hormones tell the pancreas to release insulin, slow how fast the stomach empties, and signal fullness to the brain. The practical effect is reduced appetite, smaller portions before you feel satisfied, and slower digestion, which is why nausea is the most common early side effect across all four products.

The two active ingredients are not identical. Semaglutide (Wegovy, Ozempic) is a GLP-1 receptor agonist — it acts on a single incretin pathway. Tirzepatide (Zepbound, Mounjaro) is a dual agonist that acts on two pathways, GIP and GLP-1. This mechanistic difference is the reason the two drugs are dosed and titrated differently and why they are separate FDA approvals rather than interchangeable substitutes.

The NIDDK, part of the NIH, describes GLP-1 receptor agonists as medications that work by curbing appetite and are used alongside reduced calorie intake and increased physical activity. None of these drugs is a standalone fix. Every FDA label frames them as an addition to a reduced-calorie diet and increased physical activity, not a replacement for those changes.

Approved use versus off-label: why the same molecule has two labels

The most misunderstood part of this market is that Ozempic and Wegovy are the same drug, and Mounjaro and Zepbound are the same drug. What differs is the FDA-reviewed indication. Wegovy's and Zepbound's prescribing information list chronic weight management in the Indications section. Ozempic's and Mounjaro's list type 2 diabetes. Same molecule, different approved purpose, different labeling.

Prescribing Ozempic or Mounjaro purely for weight loss is off-label. Off-label prescribing is legal and common in US medicine, and a licensed clinician can choose it, but it carries three practical consequences worth knowing. First, the dosing and safety data reviewed by the FDA for that product were built around diabetes, not weight. Second, insurers frequently deny coverage when a diabetes drug is prescribed to someone without diabetes. Third, using a diabetes supply for weight loss has, during shortages, contributed to access problems for the patients the drug was approved to treat.

If your goal is weight management and you want the on-label option, Wegovy and Zepbound are the products the FDA actually reviewed for that purpose. That does not make the off-label route wrong for everyone — it makes it a decision to have explicitly with a prescriber, not a detail to gloss over because the active ingredient is familiar.

Am I eligible? The BMI criteria are written into the label

Eligibility for the weight-management drugs is not a marketing guideline — it is printed in the FDA Indications section. Both Wegovy and Zepbound are indicated for adults with a BMI of 30 or higher (the clinical definition of obesity), or a BMI of 27 or higher (overweight) when accompanied by at least one weight-related health condition.

The label gives examples of those weight-related conditions: hypertension (high blood pressure), type 2 diabetes, and dyslipidemia (abnormal cholesterol or blood fats). In practice this means a person with a BMI of 28 and high blood pressure can meet the criteria, while a person with a BMI of 28 and no related condition generally does not, under the on-label definition.

This matters for two reasons. It tells you in advance whether a legitimate prescriber is likely to consider you an on-label candidate, and it is a useful filter for spotting sellers that skip the assessment entirely. A telehealth service that never checks your BMI or your related conditions before shipping an injectable is not following the framework the FDA built into these drugs' approval.

The tirzepatide and birth control interaction women need to know

Here is a difference between the two active ingredients that has nothing to do with weight loss and everything to do with reproductive planning. Tirzepatide — the active ingredient in both Zepbound and Mounjaro — can reduce the effectiveness of oral contraceptives. This is stated in the tirzepatide labeling. Semaglutide, the active ingredient in Wegovy and Ozempic, does not carry this warning.

The mechanism is delayed gastric emptying, which can affect how an oral contraceptive is absorbed, and the effect is most relevant when you start the drug and when the dose is increased. The label's practical guidance is to consider a non-oral contraceptive method, or to add a barrier method, around the time of starting tirzepatide and after each dose increase. Anyone who could become pregnant should treat this as a real interaction, not a footnote.

This is also a decision point between the two molecules for some women. If reliable oral contraception is central to your plan and you would prefer not to add a backup method or switch to a non-oral option, that is a legitimate reason to discuss semaglutide-based Wegovy with your prescriber instead. None of these drugs is recommended during pregnancy, and weight-management drugs specifically should be stopped if you are trying to conceive — confirm the current guidance for your product with the prescriber.

Compounded semaglutide and tirzepatide: what 'not FDA-approved' really means

Compounded versions are the category that generates the most confusion and the most risk. Compounded semaglutide and tirzepatide are not FDA-approved products. They are prepared by compounding pharmacies, and the FDA has warned about unapproved and compounded GLP-1 products. 'Not FDA-approved' is not a technicality — it means the specific product being shipped to you has not gone through the agency's review of its identity, strength, quality, and purity.

Compounding expanded while branded semaglutide and tirzepatide were in official shortage, because federal rules allow compounding of drugs on the FDA shortage list under certain conditions. As those shortage designations changed, the legal basis for large-scale compounding of these molecules shifted too. This is a moving regulatory situation, so a product that a platform could legally compound at one point may not qualify later. You can check whether a specific product is FDA-approved using the FDA's Drugs@FDA database.

The appeal of compounded versions is usually price, and that is exactly why the trade-off has to be stated plainly. You may be paying less for a product with no FDA-reviewed manufacturing behind it, sometimes in salt forms or concentrations that differ from the approved drug. The FDA has specifically cautioned about certain salt forms of semaglutide that are not the same ingredient as the approved product. Cheaper is not the same as equivalent.

What these injections cost: structure, not a single number

There is no honest one-line price for any of these drugs, and anyone quoting a single 'typical' figure is either guessing or selling. The amount you pay depends entirely on which of five payment paths you land in, and each path is set by a different party — the manufacturer, your insurer, or a compounding pharmacy — and each one changes over time.

The most reliable way to get a real number is to go to the manufacturer's own coverage-and-savings page for the specific product. Lilly publishes coverage and savings information for Zepbound and Mounjaro, and Novo Nordisk publishes savings information for Wegovy and Ozempic, including NovoCare cost-and-coverage pages. Those pages carry the current list price, the savings-card terms, and any cash self-pay program — and those are the only figures worth trusting, because the companies update them as terms change.

Use the table below to understand which path applies to you before you look up a number. Insurance coverage for weight-management drugs specifically is inconsistent — many plans cover the diabetes indications but exclude weight loss — so your out-of-pocket cost can differ dramatically from someone on the identical drug with different coverage.

How to choose between them

Start with the approval question, not the brand. If you want a drug that the FDA reviewed for weight management, you are choosing between Wegovy and Zepbound. If you and a prescriber decide off-label diabetes-labeled products are appropriate for you, Ozempic and Mounjaro enter the picture. Compounded versions are a separate risk decision, not a simple cheaper tier of the same thing.

Then use the molecule differences as tiebreakers. Tirzepatide (Zepbound) is a dual GIP/GLP-1 agonist; semaglutide (Wegovy) acts on the single GLP-1 pathway. For a woman relying on oral birth control, semaglutide avoids the contraceptive-effectiveness interaction that tirzepatide carries — a concrete reason some choose Wegovy. Tolerability, injection frequency, titration schedule, and which product your insurance will actually cover are the other practical inputs, and those are prescriber-and-plan specific.

Cost should be the last filter, not the first, because it is the one most likely to push people toward the riskiest option. If a compounded product is dramatically cheaper, that gap partly reflects the absence of FDA-reviewed manufacturing. Weigh price against the fact that you can verify an approved product in Drugs@FDA and cannot verify a compounded one the same way.

The legal way to start any of these injections

Every one of these drugs is prescription-only. There is no legitimate path to buy FDA-approved semaglutide or tirzepatide without a prescription, and any site offering to ship it without one is operating outside the law and outside safety. The legal route has three checkpoints, and a trustworthy provider will not skip them.

First, an eligibility review: a licensed clinician confirms your BMI and any weight-related conditions against the criteria in the label, and reviews your history — including whether you use oral contraception, given the tirzepatide interaction. Second, a prescriber consult: an actual licensed clinician, in a state where they are licensed, writes the prescription. Third, a licensed pharmacy dispenses the product. Telehealth can compress all three into a smooth online flow, but the checkpoints must still exist.

When you compare providers licensed in your state, treat the presence of these checkpoints as the baseline, not a premium feature. A service that asks no medical questions, never verifies eligibility, or ships an injectable after a two-minute form is a warning sign regardless of how professional the website looks. The convenience of telehealth is legitimate; the removal of clinical gatekeeping is not.

Where menopause and hormones fit in

Many women researching these injections are also in perimenopause or menopause, a stage when weight gain and shifting body composition are common. It is worth separating two different categories of treatment that often get discussed together. GLP-1 and GIP/GLP-1 drugs address weight; menopausal hormone therapy (estrogen, sometimes with progesterone) addresses menopausal symptoms like hot flashes and vaginal changes. They are not substitutes for each other.

ACOG's patient guidance on hormone therapy for menopause is the reference point for what hormone therapy does and does not treat, and it is the right resource to bring to a conversation about menopausal symptoms specifically. Hormone therapy is not a weight-loss drug, and the weight-management injections are not a treatment for hot flashes. A woman may be a candidate for one, both, or neither, and that is a clinician conversation.

On cost for estradiol and other menopause hormone therapy, we deliberately do not quote figures here — those prices vary by formulation and pharmacy, and we point you to ACOG for the clinical picture and to a dedicated cost resource for pricing rather than inventing a number. The honest position on any hormonal or weight drug is the same: verify approval status, understand your specific coverage, and get the current price from the source that sets it.

Common questions people get wrong

Two myths do the most damage. The first is that Ozempic and Wegovy are different drugs — they are the same molecule, semaglutide, under different approved indications. Believing they are different leads people to chase Ozempic for weight loss without realizing that is the off-label diabetes product. The second is that compounded semaglutide is 'the same thing, just cheaper.' It is the same active ingredient class in a product that has not been through FDA review, sometimes in a different salt form, and the FDA has warned about exactly this.

A third recurring error, specific to women, is treating the tirzepatide birth-control interaction as optional to mention. It is on the label for a reason. If you use oral contraception and start Zepbound or Mounjaro, plan for a backup or non-oral method around initiation and dose increases, and confirm the specifics with your prescriber. Skipping that step is the kind of gap that has real consequences.

Frequently asked questions

Which weight-loss injection is FDA-approved for weight loss?

Two are: Wegovy (semaglutide 2.4 mg) and Zepbound (tirzepatide), both approved for chronic weight management per their FDA labels. Ozempic and Mounjaro are FDA-approved for type 2 diabetes, so using them for weight alone is off-label. Compounded semaglutide and tirzepatide are not FDA-approved at all.

Are Ozempic and Wegovy the same drug?

They contain the same active ingredient, semaglutide, but they have different FDA-approved uses. Wegovy is approved for chronic weight management; Ozempic is approved for type 2 diabetes. The molecule is the same; the reviewed indication, labeling, and dosing are not, which is why prescribing Ozempic for weight loss is off-label.

Does tirzepatide affect birth control?

Yes. Tirzepatide — the active ingredient in Zepbound and Mounjaro — can reduce the effectiveness of oral contraceptives, according to its labeling, especially when you start it and after each dose increase. The label advises considering a non-oral method or adding a barrier method during those periods. Semaglutide (Wegovy, Ozempic) does not carry this warning.

Am I eligible for Wegovy or Zepbound?

The FDA labels indicate these drugs for adults with a BMI of 30 or higher, or a BMI of 27 or higher with at least one weight-related condition such as high blood pressure, type 2 diabetes, or high cholesterol. A licensed clinician confirms your eligibility against these criteria; a provider that never checks your BMI or health conditions is a warning sign.

Is compounded semaglutide safe and legal?

Compounded semaglutide is not an FDA-approved product, and the FDA has warned about unapproved and compounded GLP-1 products. Compounding expanded while the branded drugs were in shortage, and its legal basis shifted as shortage designations changed. You cannot verify a compounded product in Drugs@FDA the way you can an approved one, so a lower price comes with an unverified manufacturing trade-off.

How much do these injections cost?

There is no single price. What you pay depends on the path: manufacturer list price, insured copay, manufacturer savings card, cash self-pay program, or compounded. Each is set by a different party and changes over time. For a real current number, check the manufacturer's own coverage-and-savings page — Lilly for Zepbound and Mounjaro, Novo Nordisk/NovoCare for Wegovy and Ozempic.

Can I buy weight-loss injections online without a prescription?

No. Semaglutide and tirzepatide are prescription-only, and any site selling them without a prescription is operating illegally and unsafely. The legitimate telehealth path requires an eligibility review, a consult with a clinician licensed in your state, and dispensing by a licensed pharmacy. Skipping those checkpoints is a red flag no matter how polished the website looks.

Should I choose semaglutide or tirzepatide?

Start with approval status (both Wegovy and Zepbound are on-label for weight), then use the differences as tiebreakers. Tirzepatide is a dual GIP/GLP-1 agonist; semaglutide acts on GLP-1 alone. For women relying on oral birth control, semaglutide avoids the contraceptive interaction that tirzepatide carries. Tolerability, titration, and what your insurance covers are the other deciding factors, best worked out with a prescriber.

Primary sources

1. FDA Prescribing Information, Zepbound (tirzepatide) injection.
2. FDA Prescribing Information, Wegovy (semaglutide) injection.
3. FDA Prescribing Information, Mounjaro (tirzepatide) injection.
4. FDA Prescribing Information, Ozempic (semaglutide) injection.
5. FDA Drugs@FDA approved-drug database (verify a product is FDA-approved).
6. NIDDK (NIH), Prescription Medications to Treat Overweight & Obesity.
7. Lilly, Zepbound coverage & savings.
8. Novo Nordisk, Save on Wegovy.
9. NovoCare, Wegovy cost & coverage.
10. Lilly, Mounjaro savings & resources.
11. ACOG, Hormone Therapy for Menopause (patient FAQ).