What FDA approval actually means, and what it does not
FDA approval usually rests on a few thousand people studied for months to a few years. The agency says so itself.
We have not finished checking this source. No judgement either way. how we score evidence
Caveat on this rating: The trial-duration count quoted here is our own audit of this library, not an independent finding: the denominator is the 72 randomised trials in this corpus, not the psychiatric literature as a whole. The FDA's phase participant numbers and durations are descriptive ranges the agency publishes about its own process, not measured averages across approvals.
Approval means one thing precisely. For one use, in one population, over one defined period, a drug's benefit outweighed its known risks on the evidence that existed that day.
Every one of those qualifiers is load-bearing.
Significant findings
The FDA describes Phase 3 - the stage approval usually rests on - as 300 to 3,000 volunteers over 1 to 4 years.
It names the limit itself: "Phase 3 studies provide most of the safety data. In previous studies, it is possible that less common side effects might have gone undetected."
Short trials are the norm, not the exception. Of the 72 randomised trials in this library, 57 report how long they ran. Of those 57, 47 measured their headline result at three months or sooner.
Worth asking
None of this makes approval worthless; most drug candidates never clear it. It means nobody can honestly say that long-term use is supported by the approval evidence.
Ask your prescriber how long the trials behind your medication ran. Then compare that with how long you are expected to take it. Never change a medication on your own.
Source
Step 5: FDA Post-Market Drug Safety Monitoring — US Food and Drug Administration (2026)
How this was scored
- Study design
- not recorded
- Funding
- not recorded
- Published in
- not recorded
- Sample size
- not recorded
- Preregistered
- not recorded
- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
We have not finished checking this source, so there is no scoring to show yet. “We have not checked this yet” and “this is disputed” are different statements, so no scored band is shown rather than a low one.
Read the full scoring rubric, including what it can't tell you.
Published August 31, 2026.
Questions
How strong is the evidence behind this?
Resolv rates this source "not yet assessed". We have not finished checking this source. No judgement either way. One caveat travels with that badge: The trial-duration count quoted here is our own audit of this library, not an independent finding: the denominator is the 72 randomised trials in this corpus, not the psychiatric literature as a whole. The FDA's phase participant numbers and durations are descriptive ranges the agency publishes about its own process, not measured averages across approvals. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Step 5: FDA Post-Market Drug Safety Monitoring — US Food and Drug Administration (2026). The full source is linked on this page so you can read it yourself.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.