Methotrexate dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
The best test we have of whether calming long-term inflammation makes you live longer. In a big heart trial in people, it did not cut heart attacks or strokes. In mice, it did not extend lifespan.
Evidence grade for Methotrexate: Strong. The rule: at least two finished studies in people, and at least 1,000 people who took it. The sum on this page: 2 completed trials, 5,022 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 5,022
- Human studies
- 2
- Found nothing
- 1
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
FDA-approved for rheumatoid arthritis, psoriasis and several cancers. Not approved to prevent heart and blood vessel disease, or for any ageing use.
4 effects reported, 3 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism, Ageing and longevity, Injury, healing and recovery, Immune system and inflammation, Bone and joints, Gut health
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.
Methotrexate is a prescription drug that calms the immune system. At low weekly doses it treats rheumatoid arthritis. At high doses it is a cancer drug. It was tested to see if calming inflammation helps you live longer.
What people take it for
- Calming long-term inflammation to slow ageing.
- Guarding the heart by lowering inflammation.
What studies in people showed
In 4,786 people with heart disease, low doses did not cut heart attacks or strokes over about two years. It did not lower the inflammation markers either. In 236 adults with joint pain, a year on it did not stop arthritis from coming. Pain and stiffness were a bit better. Now mice. It did not make either sex live longer.
What people report
Reports, not study results
The good
- It is the main drug for rheumatoid arthritis and calms the disease in many people.
The bad
- Liver enzyme rises and lower blood counts in the heart trial.
- More skin cancers of the less common kinds in the heart trial.
- Lung swelling and mouth sores are known risks. It needs regular blood tests.
Where these come from: The side effects are from the heart trial and drug notes on this page. We have no user reports.
My bottom line
It failed in people and in mice. It needs blood tests to use safely. Do not take it for ageing.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Methotrexate has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Inflammation5,022 people · 2 studies · 1 found nothing
- Liver fat and liver health4,786 people · 1 study · 1 found nothing
- Joint and knee pain236 people · 1 study
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. This is an approved medicine. So the missing study in people is for this use, not for the drug. Drug makers paid to test it for what it is approved for. The record on this one is set out below.
- Living longer1 animal or lab study
32 of the 36 indexed goals have no study of any kind behind Methotrexate
No study in people, animals or cells on this page reports a result for these. That does not prove Methotrexate does nothing for them. It does mean anything you have heard about Methotrexate and one of these did not come from a study cited here.
Show full evidence
What is Methotrexate?
The best test we have of whether calming long-term inflammation makes you live longer. In a big heart trial in people, it did not cut heart attacks or strokes. In mice, it did not extend lifespan.
"Inflammaging" is the idea that low-level, long-term inflammation drives the diseases of ageing. It is one of the most accepted ideas in ageing science. Methotrexate is the most-used long-term anti-inflammatory drug in medicine. So it is the natural way to test whether turning inflammation down gives people more healthy years.
It has been tested twice, in two species, and both answers were no. In people, the big CIRT trial gave low-dose methotrexate to patients who already had heart disease. It did not cut heart attacks or strokes. It also did not lower two main blood markers of inflammation, interleukin-6 and C-reactive protein (CRP). In mice, in the lifespan program's 2026 run, it did not make either sex live longer.
That detail about the markers matters. The drug did not fail even though it cut inflammation. It failed to cut those inflammation markers at all. That makes it a weaker test of the idea than it first looks.
How does Methotrexate work?
At high cancer doses, methotrexate blocks an enzyme (DHFR) that cells need to use folate. Without it, cells cannot copy their DNA, so fast-growing cells die. At the low weekly doses used for rheumatoid arthritis, it works a different way. It blocks another enzyme (ATIC), which lets adenosine build up, and adenosine calms inflammation. It also drains folate inside cells and affects how genes are tagged (methylation). The two dose ranges act like different drugs and should not be mixed up.
What have studies in people found about Methotrexate?
A very large record in inflammatory disease, plus one big heart trial in people that came up empty. Nothing on ageing.
- Heart disease (CIRT), 4,786 people with a past heart attack or blocked heart arteries plus diabetes or metabolic syndrome: low-dose methotrexate did not cut heart attacks or strokes over about 2.3 years (201 against 207 people). It did not lower interleukin-6, interleukin-1 beta or CRP. All took folate too.
- That result is different from canakinumab, a drug that did lower the inflammation markers and did cut heart events. That is why the inflammation idea survived the methotrexate result.
- Before arthritis (TREAT EARLIER), 236 adults with joint pain and hidden joint inflammation on MRI: a year of methotrexate did not stop arthritis from arriving (19 against 18 percent). Pain, stiffness and function were a little better. They also got one steroid shot at the start.
- The main drug for rheumatoid arthritis, with decades of trials showing it calms the disease and slows joint damage.
- The harms are real and need blood tests: liver damage, low blood counts, lung inflammation and mouth sores. Folic acid helps lower them.
- No human trial has looked at lifespan, healthy years or anything else about ageing.
What this does not tell you: The honest reading of the heart trial is that it tested the drug, not the idea, because the inflammation markers did not move. The mouse lifespan result is a cleaner test of the drug. It still says nothing about whether a different anti-inflammatory would work. Nothing here supports using methotrexate for ageing, and its harms make casual use a bad idea anyway.
The state of the research
This compound was one of eleven in the program's run reported in 2026. None of the eleven clearly made male or female mice live longer. The run is worth seeing as a whole. It deliberately retested astaxanthin, mitoglitazone and meclizine. The same program had earlier found all three made mice live longer. This time they were given at different doses or started at older ages, and all three failed. In females, pooling all three labs, astaxanthin, late-start mitoglitazone and pioglitazone were linked to clearly shorter lives. A closer look found that untreated females at one lab lived unusually long. With that lab left out, the harm held for mitoglitazone and pioglitazone only. The authors conclude that timing and dose matter a great deal, and that results from one lab or one run need careful reading.
Methotrexate is the best example in this batch of why a failed test needs a closer look at how the drug worked. Read quickly, the heart trial says calming inflammation does not prevent heart attacks. Read carefully, it says this drug did not lower the inflammation markers it was expected to lower. So the idea was never really put to the test. A different drug, canakinumab, did lower those markers and did cut heart events. The mouse lifespan failure says more about methotrexate, and less about the inflammation idea.
The National Institute on Aging runs the Interventions Testing Program at three separate labs: The Jackson Laboratory, the University of Michigan and the University of Texas Health Science Center at San Antonio. It uses UM-HET3 mice, a mixed breed made by crossing four strains, so a result cannot be a quirk of one strain. Compounds go in the food. Both sexes are tested. Each group is big enough to spot about a 10 percent change in lifespan. Results are checked with one test for typical lifespan and another for the longest-lived mice. The failures are published next to the wins. No other ageing research has all of that together. That is why a no from this program means much more than a no from one lab.
The evidence, in charts
Fig. 1a · how many people
5,022people, across 2 studies in people cited here
| Study | People | Share |
|---|---|---|
| The New England Journal of Medicine 2019 | 4,786 | 95% |
| The Lancet 2022 | 236 | 5% |
One study holds 95% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 3 sources here are studies in people. The rest is not.
- Study in people · done in people267%
- Animal study · done in animals133%
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 3 different years, 2019 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Approved
UK
Approved
AU
Approved
CA
Approved
Approved in all 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. 5 · what the molecule is
- Kind of compound
- Small molecule
- Molecule weight
- 454.4 Da. A small molecule, not a peptide.
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Three to ten hours at low doses, longer at high doses and in renal impairment, which is the main determinant of its toxicity.
No amino acid sequence is on file for Methotrexate, which is expected: a small molecule is not built from amino acids.
The studies we cite
- Study in people2019Low-Dose Methotrexate for the Prevention of Atherosclerotic Events.
Low-dose methotrexate did not prevent heart attacks or strokes in people who already had heart disease, and it did not lower the inflammation markers it was supposed to. 4,786 people took it or a dummy pill for about two years, and all took folate too. This is the trial that separates methotrexate from the inflammation story it was borrowed for. It was stopped early. It carried real side effects, including liver enzyme rises, lower blood counts and more skin cancers.
4,786 patients with previous myocardial infarction or multivessel coronary disease plus type 2 diabetes or metabolic syndrome, randomised double-blind to methotrexate 15 to 20 mg weekly or placebo, all on 1 mg folate daily, median follow-up 2.3 years, stopped early. Methotrexate did not reduce cardiovascular events: primary endpoint in 201 versus 207 patients (4.13 versus 4.31 per 100 person-years, HR 0.96, 95% CI 0.79 to 1.16), and it did not reduce IL-1 beta, IL-6 or CRP. More liver enzyme elevations, lower leukocyte counts and haematocrit, and more non-basal-cell skin cancers on methotrexate.
- Study in people2022Intervention with methotrexate in patients with arthralgia at risk of rheumatoid arthritis to reduce the development of persistent arthritis and its disease burden (TREAT EARLIER): a randomised, double-blind, placebo-controlled, proof-of-concept trial.
A year of methotrexate given before rheumatoid arthritis was diagnosed did not stop the arthritis from arriving. 236 adults with joint pain took part. They also got one steroid shot at the start. They did have less pain, stiffness and joint inflammation two years on. One region, and an early test of the idea.
236 adults with arthralgia and MRI-detected subclinical joint inflammation randomised double-blind to a single 120 mg intramuscular glucocorticoid injection plus 1 year of oral methotrexate up to 25 mg weekly, or placebo, followed for 2 years. Persistent clinical arthritis in 19% versus 18% (HR 0.81, 95% CI 0.45 to 1.48). Physical functioning (HAQ difference -0.09), pain (-8 on a 0 to 100 scale), morning stiffness (-12) and MRI-detected inflammation (-1.4 points) better on methotrexate; serious adverse events equal.
- Animal study2026Astaxanthin, meclizine, mitoglitazone, pioglitazone, alpha-ketoglutarate, mifepristone, methotrexate, and atorvastatin-telmisartan do not increase lifespan
In mice. The NIA mouse lifespan program tested eleven compounds in mixed-breed mice at three labs. Methotrexate did not clearly make male or female mice live longer.
Interventions Testing Program, eleven compounds in UM-HET3 mice at three sites. Methotrexate did not significantly increase lifespan in male or female mice.
Common questions
Has Methotrexate been tested in people?
Yes. 5,022 people given it across 2 completed trials cited here, 1 of which found nothing. The best test we have of whether calming long-term inflammation makes you live longer. In a big heart trial in people, it did not cut heart attacks or strokes. In mice, it did not extend lifespan.
What is the Methotrexate dosage?
Approved medicine. No human dose established for unlabelled uses. Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose. FDA-approved for rheumatoid arthritis, psoriasis and several cancers. Not approved to prevent heart and blood vessel disease, or for any ageing use.
Is Methotrexate FDA-approved?
FDA-approved for rheumatoid arthritis, psoriasis and several cancers. Not approved to prevent heart and blood vessel disease, or for any ageing use.
Does reducing inflammation extend life?
Still open, and methotrexate does not settle it. In mice it did not extend lifespan. In people it did not cut heart attacks or strokes. But it also did not lower interleukin-6 or CRP, so it did not test the idea it seemed to test. A drug that did lower those markers, canakinumab, did cut heart events.
Would low-dose methotrexate be worth taking for ageing?
No. There is no sign of benefit in either species. The drug needs regular blood count and liver tests, and it carries risks of liver damage, low blood counts and lung inflammation. That is a real cost against a measured lack of benefit.
Why do the low and high doses matter?
Because they work in different ways. High cancer doses block the DHFR enzyme and kill fast-growing cells. Low weekly doses work mainly by letting adenosine build up, which calms inflammation. Evidence from one dose range does not carry over to the other.
Latest reading on Methotrexate
Blog posts about Methotrexate, newest first.