ISRIB dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
ISRIB is not an approved medicine anywhere. No person has taken it in a registered study. In mice, it brought back lost memory in old mice and in mice after a brain injury. That is the whole case.
Evidence grade for ISRIB: Animal or lab only. The rule: only animal or lab studies on this page. No study in people yet. The sum on this page: 3 animal studies, 1 lab study, no human study. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
3 animal studies, 1 lab study, no human study
4 effects reported, 3 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Brain, memory and mood, Ageing and longevity, Immune system and inflammation
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
ISRIB is a lab chemical, not a medicine. When cells are stressed, they put a brake on making new proteins. ISRIB takes that brake off. It is not approved anywhere. No person has taken it in a registered study, and it is sold online as a research chemical.
What people take it for
- Sharper memory and thinking.
- Undoing memory loss with age.
- Healing after a brain injury.
What studies in people showed
Nobody has tested this in people. There is no registered study of it, more than ten years after the first paper. Everything is in mice. In old mice, it undid memory loss. In mice after a brain injury, it undid memory problems, even when given weeks later. The first paper also found that cells under long-term stress survived less well on it. A newer cousin is being tested in people with a rare brain disease. Two of its studies ended early.
What people report
Reports, not study results
The good
- Brain-boosting forum users describe clearer thinking and easier speech.
The bad
- Most use untested powder of unknown purity, mixed at home.
- Doses are guessed from mouse doses by body weight. That math does not work, and there is no human data to check it against.
- There is no real user safety record. Too few people take it, and nobody checks on them.
Where these come from: Brain-boosting forums and Reddit, as collected on this page. These are uncontrolled self-reports on a research chemical.
My bottom line
Great mouse science, zero human data. If you take it, you are the experiment. I would not.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
What people using it report
Real people telling you what happened to them. Nobody checked it, and the people who post are not a fair sample, so it cannot prove anything works. It is still the best guide on this page to what people actually do with ISRIB, what they expect, and what goes wrong. The full account, including the negative reports, is below.
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none. The record on this one is set out below.
- Memory and thinking2 animal or lab studies
- Immune function1 animal or lab study
- Living longer1 animal or lab study
32 of the 36 indexed goals have no study of any kind behind ISRIB
No study in people, animals or cells on this page reports a result for these. That does not prove ISRIB does nothing for them. It does mean anything you have heard about ISRIB and one of these did not come from a study cited here.
Show full evidence
What is ISRIB?
ISRIB is not an approved medicine anywhere. No person has taken it in a registered study. In mice, it brought back lost memory in old mice and in mice after a brain injury. That is the whole case.
ISRIB sits on this page as the odd one out. The other five drugs here are licensed medicines with years of safety data in people. People take them for ageing even though they are not approved for that. ISRIB is different. It has no approval in any country and no registered study in people. Nobody has even published how the human body handles it. Anyone taking it is the experiment.
In cells and rodents, what it does is well understood. When a cell is under stress, it hits a brake on making new proteins. Many kinds of stress all pull the same brake. ISRIB takes the brake off.
Its fame comes from memory results in mice. The first report in 2013 found treated mice got better at learning places and fear cues. In 2017 the same team found it undid memory problems in mice after two kinds of brain injury, even when given weeks later. In 2020 it undid memory loss in old mice. Their brain cells worked more like young ones again, and signs of immune activity in the brain went down.
Every one of those is a mouse. The ageing claim is just one of them.
How does ISRIB work?
ISRIB works on a switch inside cells called eIF2B. That switch helps start the making of new proteins. When the cell is stressed, a signal jams the switch and protein making slows down. ISRIB holds the switch together and keeps it on, so protein making carries on. Four different kinds of stress all use this one brake, so ISRIB blocks all four at once. That is the appeal. It is also the reason to be careful. The brake is there to protect the cell. The first ISRIB paper found that cells under long-term stress survived less well on the drug.
What do people who took ISRIB report?
This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.
- Brain-boosting forum users describe clearer thinking and easier speech. They usually use untested powder of unknown purity, dissolved at home.
- The doses they discuss are scaled up from mouse doses by body weight. That math is wrong in principle, and there is no human data to check it against.
- There is no real safety record from users. Too few people take it, nobody checks on them, and it is all self-reported.
Sources: Nootropic forums and Reddit. Uncontrolled self-report on an unapproved research chemical with no human trial. Included so readers know what circulates, not as evidence of anything.
The state of the research
There is no evidence in people about ISRIB at all. That is why this page has no human evidence section. Not weak evidence, not blood-marker evidence. None. As of September 2026, there is no registered study of ISRIB in people. That is more than ten years after the first paper. That is odd for something this talked about, and it tells you something. ISRIB does not dissolve well in water, and the companies moved on to newer cousins instead.
The newer cousin is worth knowing about, because it is the closest thing to a human result. It is called fosigotifator. It works on the same switch and was licensed from the same university team. It is being tested in people with vanishing white matter disease, a rare brain disease. Two of its studies are listed as ended early. One was an early safety study and one was in depression. None of that tells you anything about ISRIB, or about ageing.
One more thing belongs here. The stress brake exists because it protects cells. The first ISRIB paper found cells under long-term stress survived less well on the drug. Take the brake off, and a drug can look like a memory booster in a maze test. In a body part that needed the brake, it could do harm. No study in any mammal has run long enough to tell which wins over years.
The evidence, in charts
Fig. 1a · how many people
0people have taken this in any study cited here
0 people · 0 studies in people
What this page cites instead is 3 animal studies and 1 lab study in a dish. None of them gave the compound to a person.
Counted from the list of sources on this page. We draw this chart only when a study in people is cited. An empty one is the answer, not a gap in the page.
Fig. 1b · evidence mix
None of the 4 sources here are studies in people.
- Animal study · done in animals375%
- Lab (cells in a dish) · cells or tissue125%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2013 to 2020, counted from the list of sources on this page. The newest source on file is from 2020, more than five years ago. Research on it may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Small molecule
- Molecule weight
- 451.3 Da
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Not established in humans. Reported in mice as a matter of hours after a single dose.
No amino acid sequence is on file for ISRIB, which is expected: a small molecule is not built from amino acids.
The studies we cite
- Animal study2013Pharmacological brake-release of mRNA translation enhances cognitive memory
In mice and in a dish. This is the paper that introduced ISRIB. In cells, a tiny dose undid the stress brake on protein making. Treated mice got better at learning places and fear cues. The same paper found that cells under long-term stress survived less well on it. That is the warning sign hidden in the first result.
The paper that introduced ISRIB, from a cell-based screen for PERK signalling inhibitors. It reverses the effects of eIF2 alpha phosphorylation with an IC50 of 5 nM, and treated mice showed significant enhancement in spatial and fear-associated learning. The same paper reports that ISRIB reduces the viability of cells under chronic endoplasmic reticulum stress, which is the harm signal hiding in the founding result.
- Animal study2017Inhibition of the integrated stress response reverses cognitive deficits after traumatic brain injury
In mice. A brain injury left the stress brake stuck on in mice. ISRIB undid their memory problems after two kinds of injury, a bruise-type injury and a concussion-type injury. It worked even when given weeks after the injury, and the benefit lasted after the drug stopped. One author holds the patent application, licensed to the company Calico.
Traumatic brain injury persistently activated the integrated stress response in mice, and ISRIB reversed hippocampal-dependent cognitive deficits in two injury models, focal contusion and diffuse concussive injury, including when given weeks after the injury, with the benefit persisting after treatment stopped. Suppressed hippocampal long-term potentiation was fully restored. One author holds the ISRIB patent application, licensed to Calico.
- Animal study2020Small molecule cognitive enhancer reverses age-related memory decline in mice
In mice. This is the only ageing result. In old mice, ISRIB undid memory loss for places and improved short-term memory. In the memory part of the brain, nerve cells worked more like young ones and regrew contact points. Signs of immune activity in the brain went down. It measured memory, not lifespan. Several authors have business interests in this type of drug.
The ageing result, and the only one. ISRIB reversed integrated stress response activation in the aged mouse brain, reversed spatial memory deficits and improved working memory in old mice, and in hippocampus restored intrinsic neuronal electrophysiological properties and spine density while reducing interferon and T cell mediated immune profiles. Memory endpoints, not lifespan or healthspan. Several authors disclose commercial interests in the compound class.
- Lab (cells in a dish)2015Pharmacological dimerization and activation of the exchange factor eIF2B antagonizes the integrated stress response
In a dish. This lab work showed how ISRIB works. It joins two halves of the eIF2B switch and turns it on. It does not act on the stress sensors further up the chain. That is why it blocks all four kinds of stress signal at once.
The mechanistic paper establishing that ISRIB works by dimerising and activating eIF2B rather than by acting on the kinases upstream. This is why it blocks all four branches of the integrated stress response at once.
Common questions
Has ISRIB been tested in people?
Not in any study cited here. ISRIB is not an approved medicine anywhere. No person has taken it in a registered study. In mice, it brought back lost memory in old mice and in mice after a brain injury. That is the whole case.
What is the ISRIB dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 3 animal studies, 1 lab study, no human study
Is ISRIB FDA-approved?
Not approved for any use in any country. No registered human trial of ISRIB itself exists. A separate drug that works on the same target (eIF2B), fosigotifator, is being tested in people with vanishing white matter disease, a rare brain disease. Two of its trials were stopped early.
Is ISRIB approved anywhere?
No. It is not approved in any country for anything. As of September 2026, there is no registered study of ISRIB in people. Every other drug in this group is a licensed medicine. This one is a research chemical.
Does ISRIB reverse age-related memory loss?
In old mice, one 2020 study found it undid memory loss for places and helped short-term memory. Their brain cells also worked more like young ones. That is the entire ageing case. No person has been tested.
Why has nobody run a human trial after more than ten years?
ISRIB does not dissolve well in water, which makes it hard to turn into a medicine. Companies put their money into newer cousins instead. One of those, fosigotifator, is being tested in a rare brain disease called vanishing white matter disease. An early safety study and a depression study of it are both listed as ended early.
Is it safe?
Nobody knows. That is the true answer, not a cautious one. There is no safety data in people. The stress brake it blocks is there to protect cells. The first paper found cells under long-term stress survived less well on ISRIB.
How does it compare to the other drugs in this group?
It does not compare, and that is why it is here. Empagliflozin, lamivudine, danazol, ambroxol and rilmenidine all have safety records in people from their approved uses. None of them has ageing evidence in people. ISRIB has neither.