Phentermine (generic) vs Qsymia (phentermine/topiramate)
Verdict
Neither comes out ahead on the axes compared here. Qsymia scores higher on the published halfrx formula, 7.1 against 3.1; the formula takes in more than this table does.
Computed from the stored fields, so it moves when a price does. Nothing here is written by hand or by a model.
Qsymia (phentermine/topiramate) or Phentermine (generic): which one has a price?
Only Qsymia (phentermine/topiramate) has an all-in figure here: $66–$75 a month, read from its own page on 2026-09-22. No price is published here for Phentermine (generic), so price cannot decide between them. Every axis below is computed from stored fields rather than written by hand, so the comparison moves when a price does. Neither carries an FTC action, a state action, a BBB F grade or an FDA warning letter. One is branded and the other generic, and they are different drugs, so the gap is the molecule as well as the price. The published formula scores them 3.1 and 7.1 out of 10, arithmetic over the same stored fields rather than an editor's preference. Cost here is scored on what a patient pays once titrated, never on the entry price, because an introductory rate covers the months before anybody has reached the dose they stay on.
Head to head
| What decides it | Phentermine price unverified | Qsymia $66–$75/mo |
|---|---|---|
| Entry priceNot comparable — Phentermine (generic) publishes no verified all-in price. | not comparable | not comparable |
| Regulatory and complaint riskNeither carries a lawsuit, an FDA warning letter or a supply-risk flag. | tied | tied |
What the trials, the titration and a year actually say
| Axis | Phentermine | Qsymia |
|---|---|---|
| The trial that figure comes from | The label does not carry a modern trial figure; it states in its own words that the usefulness of this class 'should be measured against possible risk factors', and it is not recommended for long-term use. | CONQUER, Study 2 on the label, 56 weeks: 9.8% mean weight loss at the 15 mg/92 mg dose against 1.2% on placebo, intention-to-treat. |
| Maintenance dose | 37.5 mg once daily, in the morning | 7.5 mg / 46 mg daily |
| Earliest week you reach it | — | week 3 |
What separates these two, price aside
- They share phentermine, but Qsymia (phentermine/topiramate) also contains topiramate, so they are different medications rather than one at two prices.
Multiple generic manufacturers
Phentermine (generic)3.1
Price unverified
Controlled substanceWeaker moleculeNo published priceStrict dosing rules
7.1
$66–$75/mo all-in
verified 2026-09-22
Weaker moleculeREMS restrictedControlled substance
Phentermine (generic)
Pros
- +Pharmacies acquire it at $0.068 a tablet, about $2 for a 30-day supply, under the federal NADAC survey. That is what a pharmacy pays, not what it charges you.[2]
- +Covered by more Medicaid programs than any GLP-1 — seven states cover an older weight-loss agent while covering no GLP-1 at all.[3]
- +One tablet each morning, no injection, no titration schedule beyond a possible half dose.[1]
Cons
- −Approved for a few weeks only. Every monthly subscription selling it as ongoing therapy is using it off the label's own duration.[1]
- −Schedule IV controlled substance, chemically related to the amphetamines, with the dependence warnings that follow from that.[1]
- −Stopping after prolonged high dosing brings extreme fatigue and depression, per the label — which is a hard exit from a subscription that sold it as maintenance.[1]
- −No cardiovascular outcome data of the kind the GLP-1s now carry, and contraindicated where blood pressure is uncontrolled.[1]
Qsymia (phentermine/topiramate)
Pros
- +9.8% mean weight loss at the top dose in CONQUER, intention-to-treat — the strongest result available from an oral non-GLP-1 drug.[2]
- +$74.99/mo through Qsymia Engage home delivery for anyone, $65.99 for Costco members, and generic phentermine/topiramate ER runs roughly $50–$100 — an order of magnitude under branded GLP-1 list prices.[1]
- +Approved down to age 12, as Wegovy and Saxenda are; Zepbound is for adults only.[2]
Cons
- −Topiramate raises the risk of oral clefts when taken in the first trimester. The label recommends a negative pregnancy test before starting and every month during treatment, with effective contraception, and Qsymia is dispensed only through pharmacies certified under an FDA REMS.[6]
- −Phentermine is a controlled substance with cardiovascular contraindications.[2]
- −Cognitive side effects — word-finding difficulty and trouble concentrating — are common enough to be a frequent reason people stop.[2]
- −Its 9.8% in CONQUER is under half the 20.9% tirzepatide reached in SURMOUNT-1 on Zepbound's label, a separate trial in a different population, so this is not a head-to-head result.[7]
Sources
- [1] Qsymia Engage home delivery pricing, qsymia.com
- [2] Qsymia REMS: pregnancy testing and contraception requirements (FDA)
- [3] CONQUER: phentermine plus topiramate, phase 3 (The Lancet)
- [4] Qsymia CONQUER trial results (manufacturer HCP site)
- [5] Assessment of the REMS for phentermine–topiramate (Annals of Internal Medicine)
- [6] FDA prescribing information for QSYMIA
- [7] FDA prescribing information for ZEPBOUND
Comparisons are computed from the fields on each card, not written by hand or by a model, so they change when the data does. Information only, not medical advice. halfrx may earn a commission from some links, which never changes what a comparison says.
Everything on Phentermine
- Phentermine price and terms →
- What is Phentermine? →
- Phentermine cost without insurance →
- Alternatives to Phentermine →
- Phentermine side effects →
- Does Phentermine cause constipation? →
- Does Phentermine cause diarrhea? →
- Does Phentermine make you dizzy? →
- Does Phentermine cause headaches? →
- Does Phentermine keep you awake? →
- Does Phentermine cause dry mouth? →
- Phentermine dose schedule →
- How to take Phentermine →
- Which labels record what happens when you stop →
- Hair loss: which of the labels name it →
- Alcohol: what the labels say, and what they do not →
- phentermine: every product and price →
- Qsymia: the drug →
Everything on Qsymia
- Qsymia price and terms →
- What is Qsymia? →
- Qsymia cost without insurance →
- Alternatives to Qsymia →
- Qsymia coupons and savings cards →
- Qsymia Engage →
- Qsymia side effects →
- Does Qsymia cause constipation? →
- Does Qsymia make you dizzy? →
- Does Qsymia keep you awake? →
- Does Qsymia cause dry mouth? →
- Qsymia dose schedule →
- How to take Qsymia →
- How long Qsymia takes to work →
- Which labels record what happens when you stop →
- Hair loss: which of the labels name it →
- Alcohol: what the labels say, and what they do not →
- phentermine: every product and price →
- Phentermine: the drug →
Phentermine against Qsymia, answered
- Is Phentermine or Qsymia better for weight loss?
- Only Qsymia has a trial figure recorded here: 9.8% average weight loss, from its own label trial. Phentermine has none on this site, so the two cannot be compared on effect and this page does not pick one on it.
- Which is cheaper, Phentermine or Qsymia?
- Phentermine publishes no all-in monthly price that could be verified, so this page carries no comparison rather than an estimate — and an unpublished price is itself worth weighing.
- Can you switch between Phentermine and Qsymia?
- They share phentermine, but Qsymia also contains topiramate, so this is a change of medication rather than of brand, and the one you move to is started on its own dosing schedule.