Does Qsymia cause constipation?
Bottom line
Yes. Constipation is listed among the common adverse reactions on Qsymia's own FDA label, published 2026-04-24. It clusters in the days after each dose increase. Qsymia steps up on a published schedule that reaches the maintenance dose at week 3, so the pattern most people see is a few rough days after each step and a settling in between — not one long stretch. Once you are at 7.5 mg / 46 mg daily and no longer stepping up, the trigger stops recurring.
Last updated 2026-04-24 — the FDA label this page quotes
Does Qsymia cause constipation?
Yes, and it is on the label rather than only in reports: constipation appears among the common adverse reactions in Qsymia's FDA prescribing information, published 2026-04-24. Listed means it was seen often enough in the trials to be printed, not that everyone gets it. The same slowed gut transit that produces the fullness produces constipation at the other end. Eating much less compounds it: less food means less fibre and less fluid, and both are what keep things moving. It clusters in the days after each dose increase. Qsymia steps up on a published schedule that reaches the maintenance dose at week 3, so the pattern most people see is a few rough days after each step and a settling in between — not one long stretch. Once you are at 7.5 mg / 46 mg daily and no longer stepping up, the trigger stops recurring. What helps, in the order worth trying: fluid first. It is the most common deficit and the easiest to fix; fibre added gradually rather than all at once, which otherwise trades constipation for bloating; movement, which does more for gut transit than most supplements; asking the prescriber about a stool softener or an osmotic laxative before reaching for a stimulant one. It stops being ordinary at a specific line: no bowel movement for several days with abdominal pain, distension or vomiting. That combination needs assessment rather than another laxative.
Why Qsymia does this
The same slowed gut transit that produces the fullness produces constipation at the other end. Eating much less compounds it: less food means less fibre and less fluid, and both are what keep things moving.
When it happens, against Qsymia's own schedule
One capsule each morning. Each row is a step up, and the days after each one are when this tends to arrive.
| Weeks | Dose |
|---|---|
| Days 1–14 | 3.75 mg / 23 mg |
| Day 15 and on | 7.5 mg / 46 mg |
| Higher steps | 11.25 mg / 69 mg then 15 mg / 92 mg |
What actually helps
- 1Fluid first. It is the most common deficit and the easiest to fix.
- 2Fibre added gradually rather than all at once, which otherwise trades constipation for bloating.
- 3Movement, which does more for gut transit than most supplements.
- 4Asking the prescriber about a stool softener or an osmotic laxative before reaching for a stimulant one.
A negative pregnancy test is required before starting and every month afterwards, under an FDA REMS. The top dose must be tapered rather than stopped, because stopping it abruptly can cause a seizure.
When to stop reading and call someone
No bowel movement for several days with abdominal pain, distension or vomiting. That combination needs assessment rather than another laxative.
If you are thinking of switching
Constipation is on the label of most drugs in this class, so a switch is not a reliable way out of it. What a switch does change is what you pay, and Qsymia is $98 a month at the maintenance dose here.
Every alternative to Qsymia, with each one's verified price and the date it was read →
Qsymia and constipation, answered
- Does Qsymia cause constipation?
- Yes — constipation is listed among the common adverse reactions on Qsymia's FDA prescribing information, published 2026-04-24. Listed means it was seen often enough in the trials to be printed, not that it happens to everyone.
- How long does Qsymia constipation last?
- It clusters in the days after each dose increase. Qsymia steps up on a published schedule that reaches the maintenance dose at week 3, so the pattern most people see is a few rough days after each step and a settling in between — not one long stretch. Once you are at 7.5 mg / 46 mg daily and no longer stepping up, the trigger stops recurring.
- What helps with constipation on Qsymia?
- Fluid first. It is the most common deficit and the easiest to fix. Fibre added gradually rather than all at once, which otherwise trades constipation for bloating. Movement, which does more for gut transit than most supplements. Asking the prescriber about a stool softener or an osmotic laxative before reaching for a stimulant one.
- When is constipation on Qsymia serious?
- No bowel movement for several days with abdominal pain, distension or vomiting. That combination needs assessment rather than another laxative.
- Would switching drugs help?
- constipation is listed on the labels of most drugs in this class, so switching is not a reliable way out of it. What a switch does change is the price, and every verified route is listed here with the date it was read.
Everything above is read from FDA prescribing information for QSYMIA, published 2026-04-24. Information only, not medical advice — a symptom that worries you is a call to your prescriber, not a search result.