Methotrexate
Methotrexate, folate antimetabolite and anti-inflammatory
Written by Aaron CuhaReviewed Sep 2026
Also known as: MTX, Amethopterin, Trexall, Otrexup
The best available test of whether suppressing chronic inflammation extends life. In a large human cardiovascular trial it did not reduce events, and in mouse lifespan testing it did not extend lifespan.
Overview
Inflammaging, the idea that low-grade chronic inflammation drives age-related disease, is one of the most widely accepted frameworks in geroscience. Methotrexate is the most-used disease-modifying anti-inflammatory drug in medicine, so it is the natural way to test whether turning inflammation down extends healthy life.
It has been tested twice, in two species, and both answers were negative. In the mouse lifespan programme's 2026 cohort it did not increase lifespan in either sex. In humans, the large CIRT trial gave low-dose methotrexate to patients with established cardiovascular disease and did not reduce cardiovascular events, and notably did not lower interleukin-6 or C-reactive protein either.
That second detail matters. The drug did not fail to help despite reducing inflammation. It failed to reduce the inflammatory markers in question at all, which makes it a weaker test of the hypothesis than it first appears.
Mechanism of action
At high oncology doses it inhibits dihydrofolate reductase, starving cells of reduced folate needed for DNA synthesis, which is a cytotoxic effect. At the low weekly doses used in rheumatoid arthritis the mechanism is different and centres on inhibition of aminoimidazole carboxamide ribonucleotide transformylase, causing adenosine accumulation, which is anti-inflammatory. It also promotes intracellular folate depletion and affects methylation. The two dose ranges are effectively different drugs and should not be conflated.
Human evidence
A very large clinical record in inflammatory disease, plus one major randomised cardiovascular outcome trial that was negative. No ageing endpoints.
- The anchor drug of rheumatoid arthritis treatment, with decades of randomised evidence for disease activity and joint damage.
- In cardiovascular prevention, low-dose methotrexate did not reduce events in patients with established disease, and did not lower interleukin-6, interleukin-1 beta or C-reactive protein.
- That null contrasts with canakinumab, which did lower inflammatory markers and did reduce cardiovascular events, which is why the inflammation hypothesis survived the methotrexate result.
- Toxicity is real and requires monitoring: hepatotoxicity, myelosuppression, pneumonitis and mucositis, mitigated by folic acid supplementation.
- No human trial has examined lifespan, healthspan or any geroscience endpoint.
What this does not tell you: The honest reading of the human cardiovascular null is that it tested the drug rather than the hypothesis, because the inflammatory markers did not move. The mouse lifespan null is a cleaner test of the drug and still says nothing about whether a different anti-inflammatory would work. Nothing here supports using methotrexate for ageing, and its toxicity profile makes casual use a bad idea regardless.
Reading the research record
This compound was one of eleven in the Interventions Testing Program cohort reported in 2026, and none of the eleven significantly increased lifespan in either sex. The cohort is worth understanding as a whole. It deliberately retested astaxanthin, mitoglitazone and meclizine, three compounds the same programme had previously found to extend lifespan, at different doses or starting at later ages. All three showed no benefit the second time. In females, pooling all three sites, astaxanthin, late-start mitoglitazone and pioglitazone were associated with significantly reduced lifespan; site-specific reanalysis found unusually long-lived control females at one site, and excluding it left the negative effect for mitoglitazone and pioglitazone only. The authors' own conclusion is that timing and dosage are critical variables and that single-site or single-cohort findings need cautious interpretation.
Methotrexate is the best illustration in this batch of why a null needs its mechanism checked. Read quickly, the human cardiovascular trial says suppressing inflammation does not prevent heart attacks. Read carefully, it says this drug did not lower the inflammatory markers it was expected to lower, so the hypothesis was never really put at risk. A different drug, canakinumab, did lower those markers and did reduce events. The mouse lifespan null is a stronger statement about methotrexate and a weaker one about inflammaging.
The Interventions Testing Program is run by the National Institute on Aging at three independent sites, The Jackson Laboratory, the University of Michigan and the University of Texas Health Science Center at San Antonio. It uses UM-HET3 mice, a genetically heterogeneous four-way cross, so a result cannot be an artefact of one inbred strain. Compounds are fed in the diet, both sexes are tested, cohorts are large enough to detect roughly a 10 percent lifespan change, and results are analysed by log-rank for median survival and by the Wang-Allison test for maximum lifespan. Its nulls are published alongside its positives. That combination of features does not exist anywhere else in ageing research, which is why a null here means considerably more than a null from a single laboratory.
The evidence, charted
Fig. 1 · evidence composition
0of 1 citation (0%) is in people
Every citation cited here is Animal work; no other study type is cited on this page. This count is of our own citation list and understates any literature larger than the sources we cite.
Fig. 2 · evidence over time
Every citation here was published in 2026.
Too few distinct publication years on this page to plot as a timeline.
Fig. 3 · legal status at a glance
US
Approved
UK
Approved
AU
Approved
CA
Approved
Approved in all four jurisdictions shown. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Fig. 4 · dose response
No human dose response curve exists
We draw this figure where the data supports it. For this compound in humans it does not, so the panel stays empty rather than borrowing an animal curve and implying it transfers.
Key studies & citations
- Animal2026
Astaxanthin, meclizine, mitoglitazone, pioglitazone, alpha-ketoglutarate, mifepristone, methotrexate, and atorvastatin-telmisartan do not increase lifespan
Interventions Testing Program, eleven compounds in UM-HET3 mice at three sites. Methotrexate did not significantly increase lifespan in male or female mice.
GeroScience
Frequently asked questions
Does reducing inflammation extend life?
Still open, and methotrexate does not settle it. In mice it did not extend lifespan. In humans it did not reduce cardiovascular events, but it also did not lower interleukin-6 or C-reactive protein, so it did not test the hypothesis it appeared to test. A drug that did lower those markers, canakinumab, did reduce events.
Would low-dose methotrexate be worth taking for ageing?
No. There is no benefit signal in either species, and the drug requires blood count and liver monitoring and carries hepatotoxicity, marrow suppression and pneumonitis risks. That is a real cost against a measured absence of benefit.
Why do the low and high doses matter?
Because they work through different mechanisms. High oncology doses block dihydrofolate reductase and are cytotoxic. Low weekly doses act mainly through adenosine accumulation and are anti-inflammatory. Evidence from one dose range does not transfer to the other.