Question 1

Which loses more weight, Zepbound or Qsymia?

Accepted Answer

Zepbound averaged about 20.9% body-weight loss at 72 weeks in SURMOUNT-1 at the 15 mg dose, while Qsymia averaged about 10.9% at 56 weeks in EQUIP at the top 15/92 mg dose. Zepbound is roughly twice as effective head-to-head on average, though no direct comparison trial exists.

Question 2

Is Qsymia really REMS-restricted? What does that mean?

Accepted Answer

Yes. Qsymia is dispensed only through a certified pharmacy network under a Risk Evaluation and Mitigation Strategy (REMS) program because topiramate causes oral clefts when taken during pregnancy. Patients who can become pregnant must use effective contraception and complete a monthly pregnancy test before each refill.

Question 3

Can I take Qsymia if I cannot tolerate Zepbound injections or nausea?

Accepted Answer

Yes, Qsymia is a reasonable alternative for patients who refuse injections or stop Zepbound due to GI side effects. Qsymia has its own side-effect profile (paresthesia, dry mouth, cognitive fogginess, insomnia from phentermine) but no injection burden and no GLP-1-style nausea.

Question 4

Is Qsymia cheaper than Zepbound?

Accepted Answer

Yes. Qsymia Advantage runs about $100-$200/mo cash, and clinicians can prescribe generic phentermine plus generic topiramate ER separately for roughly $50/mo total. Zepbound runs $349-$499/mo via LillyDirect Self Pay if insurance does not cover it.

Question 5

Who should not take Qsymia?

Accepted Answer

Qsymia is contraindicated in pregnancy, glaucoma, hyperthyroidism, MAOI use within 14 days, and known hypersensitivity to sympathomimetic amines. It should be used cautiously in patients with cardiovascular disease, history of kidney stones, or mood disorders.

Question 6

Can I switch from Qsymia to Zepbound?

Accepted Answer

Yes. There is no required washout period because the mechanisms do not overlap. Most clinicians taper Qsymia (especially topiramate, to avoid rebound headache or paresthesia) over 1-2 weeks, then start Zepbound at 2.5 mg weekly and titrate monthly per the standard label schedule.

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: Weekly Injection vs Oral Daily Pill for Weight Loss

The verdict

Side-by-side comparison

Frequently asked questions