Qsymia is the strongest of the older non-GLP-1 weight-loss drugs on its own label, and it is the long-term form of phentermine. It pairs phentermine with topiramate, an anti-seizure drug, at lower doses of each than either uses alone. Its top strength took off about 10 to 11% of body weight over a year in its main trials and held it for two years in an extension. Its main constraint is pregnancy: topiramate can harm a fetus, so the drug is sold only through certified pharmacies with monthly pregnancy testing recommended.
This page reads the US Qsymia label (Vivus, effective 22 April 2026, read 3 November 2026), its trials and the maker's price page, and sets the GLP-1 figures this site already reports beside them, each with its population. It does not rank the medicines. The full list of non-GLP-1 options is on GLP-1 alternatives.
What Qsymia is
Each extended-release capsule contains phentermine (a sympathomimetic appetite suppressant; its own record is on phentermine) and topiramate (an anti-seizure and migraine drug that also reduces appetite; what its own label and its obesity trials record is on topiramate and weight loss). FDA approved it on 17 July 2012 (NDA 022580). The capsules come in four strengths — 3.75 mg/23 mg, 7.5 mg/46 mg, 11.25 mg/69 mg and 15 mg/92 mg — listed here as product facts.
The label covers long-term weight reduction and maintenance, with diet and physical activity, in:
- adults and children 12 and older with obesity, and
- adults with overweight plus at least one weight-related condition.
Its effect on cardiovascular illness and death "has not been established", and its safety with other weight-loss products has not been studied. Phentermine makes it a Schedule IV controlled substance.
The label's dosing section describes a stepped schedule with two checkpoints. After 12 weeks on 7.5 mg/46 mg, if an adult has not lost at least 3% of starting weight (or a child 3% of BMI), the strength is stepped up; after 12 weeks on 15 mg/92 mg, if an adult has not lost at least 5%, the label says Qsymia should be stopped, tapering it because abrupt withdrawal of topiramate can trigger seizures. These are the label's own decision points for prescribers.
The adult trials
Two one-year trials (four weeks of titration plus 52 weeks of treatment) underpin the label. Both recommended a diet about 500 calories a day below need, with lifestyle counselling, for every arm.
| Trial | Population | Placebo | 3.75/23 mg | 7.5/46 mg | 15/92 mg |
|---|---|---|---|---|---|
| Study 1 — EQUIP | BMI ≥35, no type 2 diabetes; mean 116 kg, BMI 42; 83% women | −1.6% | −5.1% | — | −10.9% |
| Study 2 — CONQUER | BMI 27–45 with two or more related conditions; mean 103 kg; 16% with type 2 diabetes | −1.2% | — | −7.8% | −9.8% |
| Lost ≥5% (EQUIP / CONQUER) | 17% / 21% | 45% / — | — / 62% | 67% / 70% | |
| Lost ≥10% (EQUIP / CONQUER) | 7% / 7% | 19% / — | — / 37% | 47% / 48% |
Source: Qsymia label Table 10 (intention-to-treat, last observation carried forward); EQUIP, Allison et al., Obesity 2012; CONQUER, Gadde et al., Lancet 2011. 40% of EQUIP and 31% of CONQUER participants withdrew before week 56.
Two years — SEQUEL. 676 CONQUER participants continued blinded treatment to week 108; 84% completed it. Weight change from baseline was −1.8% on placebo, −9.3% on 7.5 mg/46 mg and −10.5% on 15 mg/92 mg (Garvey et al., Am J Clin Nutr 2012). The people who chose to continue were a selected group, so SEQUEL shows the loss can hold, not how often it does.
Against its own parts. A 28-week trial compared the combination with phentermine alone, topiramate alone and placebo: 66.0% on 15 mg/92 mg lost at least 5%, against 46.2% on phentermine 15 mg alone, 48.6% on topiramate 92 mg alone and 15.5% on placebo; mean change on the combination was −9.2% against −1.7% (Aronne et al., Obesity 2013). The combination did better than either drug at the same dose, which is the reason it exists.
The adolescent trial
Study 3 enrolled 223 adolescents aged 12–17 with BMI at or above the 95th percentile (mean 106 kg, BMI 38; 81% severely obese), all offered a family lifestyle programme, for 56 weeks. The primary measure was BMI, not weight:
| Measure (label Table 13) | Placebo (n=56) | 7.5 mg/46 mg (n=54) | 15 mg/92 mg (n=113) |
|---|---|---|---|
| Mean BMI change | +3.3% | −4.8% | −7.1% |
| BMI fell ≥5% | 13.6% | 44.0% | 52.2% |
| BMI fell ≥10% | 4.5% | 33.5% | 44.4% |
38% of the adolescents withdrew before week 56. The label adds a warning on slowing of growth in height and lists depression, dizziness and joint pain among the most common adolescent side effects. The GLP-1 labels for teenagers are covered on GLP-1 for teens.
Beside the GLP-1 figures
No trial compares Qsymia with a GLP-1 medicine. These are separate trials with their populations:
| Medicine (trial) | Population | Weeks | Medicine | Placebo |
|---|---|---|---|---|
| Qsymia 15/92 mg (EQUIP) | BMI ≥35, no diabetes | 56 | −10.9% | −1.6% |
| Qsymia 15/92 mg (CONQUER) | Overweight/obesity with two related conditions, 16% diabetes | 56 | −9.8% | −1.2% |
| Semaglutide 2.4 mg (STEP 1) | Obesity or overweight with a related condition, no diabetes | 68 | −14.9% | −2.4% |
| Tirzepatide 15 mg (SURMOUNT-1) | Obesity or overweight with a related condition, no diabetes | 72 | −20.9% | −3.1% |
| Contrave (COR-I) | Obesity or overweight with a related condition | 56 | −5.4% | −1.3% |
Sources: Qsymia label; STEP 1; SURMOUNT-1; Contrave label. Lengths, eras and dropout handling differ, so the gaps are approximate. The detailed GLP-1 results are on Wegovy weight-loss results and Zepbound weight-loss results; Contrave's on Contrave.
Side effects, from the label
From the adult safety pool (2,318 people on Qsymia, mean exposure 298 days):
| Adverse reaction (label Table 1) | Placebo (N=1,561) | 3.75/23 mg (N=240) | 7.5/46 mg (N=498) | 15/92 mg (N=1,580) |
|---|---|---|---|---|
| Paraesthesia (tingling) | 2% | 4% | 14% | 20% |
| Dry mouth | 3% | 7% | 14% | 19% |
| Constipation | 6% | 8% | 15% | 16% |
| Dysgeusia (altered taste) | 1% | 1% | 7% | 9% |
| Insomnia | 5% | 5% | 6% | 9% |
| Dizziness | 3% | 3% | 7% | 9% |
| Headache | 9% | 10% | 7% | 11% |
| Nausea | 4% | 6% | 4% | 7% |
| Blurred vision | 4% | 6% | 4% | 5% |
| Depression | 2% | 3% | 3% | 4% |
Almost every rate rises with strength. Tingling, taste change and dry mouth come largely from topiramate; insomnia and dry mouth also from phentermine. Constipation is shared with the GLP-1 class (rates on GLP-1 constipation); tingling and taste change are not typical GLP-1 effects.
The label's warnings include embryo-fetal toxicity (below); suicidal thoughts (anti-seizure drugs as a class roughly doubled the risk in pooled trials, 0.43% vs 0.24%); acute myopia and angle-closure glaucoma; mood and sleep disorders; problems with attention, memory or word-finding; metabolic acidosis; reduced kidney function; seizures on abrupt withdrawal; kidney stones; reduced sweating and overheating; low potassium; and rare serious skin and hypersensitivity reactions. Heart rate rose 1.0 beat a minute on the top strength while blood pressure fell (EQUIP, label Table 11). Contraindicated in pregnancy, glaucoma, hyperthyroidism, with MAO inhibitors within 14 days, and with known hypersensitivity.
The pregnancy programme
The label states that data from pregnancy registries and epidemiological studies show a fetus exposed to topiramate in the first trimester has an increased risk of major birth defects, including cleft lip and/or cleft palate, and of being small for gestational age. For that reason:
- Qsymia is contraindicated in pregnancy;
- the label recommends a negative pregnancy test before starting and monthly during treatment, with effective contraception;
- it is sold under a REMS: only certified pharmacies may dispense it.
This is the main practical difference from the GLP-1 class. The GLP-1 labels' own pregnancy guidance (every semaglutide label instructs stopping at least two months before a planned pregnancy) is on GLP-1 and pregnancy.
What it costs
The maker's site, read 3 November 2026, lists:
| Route | Price stated |
|---|---|
| Qsymia Engage home-delivery pharmacy, 30 days | $74.99 ($2.50 a day) |
| Same, 90-day supply where allowed | $70 a month ($2.33 a day) |
| Retail pharmacy with the manufacturer discount, 30 days | $75 |
| Costco pharmacy, members, 30 days | $65.99 |
| Maker's telehealth route | $65 doctor consultation charge |
Generic phentermine/topiramate ER exists: Drugs@FDA lists approvals on 25 June 2024 (ANDA 204982, Actavis) and 12 June 2025 (ANDA 208175, Dr. Reddy's). The pharmacy acquisition cost survey (NADAC, CMS) for the week of 21 October 2026 listed generic capsules at $2.99 (3.75/23 mg), $3.06 (7.5/46 mg), $3.02 (11.25/69 mg) and $2.70 (15/92 mg) each — about $81 to $92 for 30, more than the brand's own home-delivery price. Our arithmetic from NADAC unit costs; counter prices differ. GLP-1 cash prices are on GLP-1 cost.
What the record does not show
- Whether Qsymia changes heart attacks, strokes or deaths. No outcome trial is on the label.
- Results beyond two years in a placebo-controlled trial.
- Any comparison with, or combination with, a GLP-1 medicine. None is on either label.
Qsymia is a controlled prescription medicine with a pregnancy programme. Whether it, a GLP-1 medicine or neither suits a person is a decision for their prescriber.
Sources
- QSYMIA (phentermine and topiramate extended-release capsules), US prescribing information, Vivus, effective 22 April 2026, set ID 40dd5602-53da-45ac-bb4b-15789aba40f9 (openFDA drug label record), read 3 November 2026 — sections 1, 2, 4, 5, 6.1, 14 (Tables 1, 10, 11, 13).
- Drugs@FDA (openFDA): NDA 022580 (QSYMIA, approved 17 July 2012); ANDA 204982 (Actavis, approved 25 June 2024); ANDA 208175 (Dr. Reddy's, approved 12 June 2025). Read 3 November 2026.
- Allison DB et al. "Controlled-release phentermine/topiramate in severely obese adults (EQUIP)." Obesity 2012;20(2):330–42, doi:10.1038/oby.2011.330, PMID 22051941.
- Gadde KM et al. "Effects of low-dose, controlled-release, phentermine plus topiramate combination on weight and associated comorbidities (CONQUER)." Lancet 2011;377:1341–52, doi:10.1016/S0140-6736(11)60205-5, PMID 21481449.
- Garvey WT et al. "Two-year sustained weight loss and metabolic benefits with controlled-release phentermine/topiramate (SEQUEL)." Am J Clin Nutr 2012;95(2):297–308, doi:10.3945/ajcn.111.024927, PMID 22158731.
- Aronne LJ et al. "Evaluation of phentermine and topiramate versus phentermine/topiramate extended-release in obese adults." Obesity 2013;21(11):2163–71, PMID 24136928.
- qsymia.com, home and savings terms, read 3 November 2026.
- NADAC (National Average Drug Acquisition Cost) 2026, CMS, data.medicaid.gov, as-of date 21 October 2026, read 3 November 2026.
- Wilding JPH et al., NEJM 2021, PMID 33567185 (STEP 1). Jastreboff AM et al., NEJM 2022, PMID 35658024 (SURMOUNT-1). CONTRAVE prescribing information, effective 10 November 2025 — section 14.