Question 1

Which works better for weight loss, Zepbound or Qsymia?

Accepted Answer

Zepbound recorded ~20.9% at 72 weeks (15 mg, SURMOUNT-1); Qsymia recorded ~10.9% at 56 weeks (15/92 mg, EQUIP); ~9.8% (CONQUER). ⚠ These come from separate trials with different protocols and populations, so the gap between two numbers from two studies is weaker evidence than it looks. No head-to-head trial of this pair is on record here.

Question 2

Are Zepbound and Qsymia the same drug?

Accepted Answer

No. Zepbound is tirzepatide and Qsymia is phentermine-topiramate — different molecules. Results with one do not predict results with the other.

Question 3

Is Zepbound or Qsymia cheaper?

Accepted Answer

On the manufacturers' own cash pricing: Zepbound at $349-$499/mo via LillyDirect Self Pay (vials, all doses), Qsymia at ~$100-$200/mo via Qsymia Advantage; separate generic phentermine + topiramate ~$50/mo. ⚠ That is the list-price comparison, and it is not what most people pay. What you actually pay depends on whether your plan covers it, which formulary tier it sits in, and whether you have met your deductible — and for many people the honest comparison is between an insured copay and a cash-pay compounded alternative rather than between these two figures.

Question 4

Which has worse side effects, Zepbound or Qsymia?

Accepted Answer

The most common adverse event reported was Nausea (~29%), diarrhea, constipation, injection-site reactions for Zepbound and Paresthesia, dry mouth, constipation, dysgeusia, insomnia, dizziness for Qsymia. ⚠ Rates come from separate trial populations and are not a like-for-like comparison. In practice how fast the dose is escalated affects tolerability at least as much as which drug it is, which is one reason a slower titration is worth asking for.

Question 5

What does a compounded version of each actually cost?

Accepted Answer

Across the 556 sellers in this register, the cheapest standing monthly cash prices we hold are tirzepatide from $99 a month. ⛔ A compounded preparation is not the approved product: no agency has reviewed that specific preparation for safety, effectiveness or manufacturing quality, and the legal ground under compounding these molecules narrowed once the shortages closed. The price gap is real and so is the difference in oversight.

Question 6

Can I switch from Zepbound to Qsymia?

Accepted Answer

Yes, with a prescriber. Expect to re-titrate from the bottom of the new drug's ladder rather than starting where you left off: these are different molecules and tolerance to one does not transfer to the other. Both the old drug's washout and the new drug's schedule apply.

Question 7

Which one should I ask for?

Accepted Answer

That is a prescriber's call, and anyone answering it from a table is guessing. What a page like this can do is tell you what the trials measured, what the manufacturers charge, and where the evidence is still missing, so the conversation starts from the record rather than from an advertisement.

Field	Zepbound	Qsymia
Route and frequency	Subcutaneous injection, once weekly	Oral capsule, once daily in the morning
Drug class	Dual GIP/GLP-1 receptor agonist	Sympathomimetic amine (phentermine) plus anticonvulsant (topiramate ER)
Approved doses	2.5, 5, 7.5, 10, 12.5, 15 mg weekly (titrate monthly)	3.75/23, 7.5/46, 11.25/69, 15/92 mg phentermine/topiramate
Average weight loss	~20.9% at 72 weeks (15 mg, SURMOUNT-1)	~10.9% at 56 weeks (15/92 mg, EQUIP); ~9.8% (CONQUER)
FDA approval for obesity	November 2023; added OSA indication December 2024	July 2012 (first oral combo approved for chronic weight management)
Common side effects	Nausea (~29%), diarrhea, constipation, injection-site reactions	Paresthesia, dry mouth, constipation, dysgeusia, insomnia, dizziness
Boxed warning / REMS	Boxed warning: thyroid C-cell tumor risk (rodent data); contraindicated in MTC or MEN 2	REMS program required; topiramate is teratogenic (oral cleft risk); monthly pregnancy testing in patients who can become pregnant
Cash price (US, 2026)	$349-$499/mo via LillyDirect Self Pay (vials, all doses)	~$100-$200/mo via Qsymia Advantage; separate generic phentermine + topiramate ~$50/mo
Insurance and Medicare	Often denied for obesity alone; OSA indication may unlock coverage	Rarely covered for obesity; Medicare excludes anti-obesity drugs
Best fit	Patients prioritizing maximum weight loss who tolerate weekly injections	Patients who refuse injections, need a lower-cost oral option, and can comply with REMS pregnancy precautions

Zepbound vs Qsymia: The Strongest Injection Against the Cheapest Oral

The verdict

Side-by-side comparison

What each one costs in the compounded market

Frequently asked questions