Hydralazine dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Hydralazine is an old blood pressure drug. In people, paired with a nitrate, it cut deaths in heart failure. It made worms live longer by switching on the same stress pathway as eating less. In mice it did nothing, in either sex.
Evidence grade for Hydralazine: Strong. The rule: at least two finished studies in people, and at least 1,000 people who took it. The sum on this page: 3 completed trials, 1,724 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 1,724
- Human studies
- 3
- 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 high blood pressure. It is also used for heart failure, together with another drug, isosorbide dinitrate. No ageing use.
4 effects reported, 3 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism, Brain, memory and mood, Ageing and longevity, Heart and circulation, Sleep
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.
Hydralazine is an old blood pressure pill that relaxes blood vessels. With a nitrate, it helps people with heart failure live longer. It made worms live longer, which got it tested for ageing.
What people take it for
- High blood pressure.
- Heart failure, paired with a nitrate.
- A longer life, after a worm study.
What studies in people showed
In 1,050 Black patients with advanced heart failure, a pill of hydralazine plus a nitrate cut deaths from 10.2 to 6.2 percent. In 642 men with heart failure, the same pair cut deaths at two years from 34.3 to 25.6 percent. On its own, in 32 people, it did no better than a dummy pill. Nobody has tested it for ageing. Now animals. It made worms live longer. In mice, it did nothing in either sex.
What people report
Reports, not study results
The good
- With a nitrate, it helped people with heart failure live longer in two trials.
The bad
- A fast heartbeat.
- Holding on to salt and water.
- Drug-induced lupus with long use, more often in people who clear it slowly.
Where these come from: The side effects are from the drug notes on this page. The death numbers are from the heart failure trials. We have no user reports.
My bottom line
A real heart drug when paired right. The longevity case is worms, and the mice said no. 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 Hydralazine 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.
- Heart attacks and strokes1,724 people · 3 studies · 1 found nothing
- Mood and anxiety1,050 people · 1 study
- Living longer642 people · 1 study
- Losing weight32 people · 1 study · 1 found nothing
32 of the 36 indexed goals have no study of any kind behind Hydralazine
No study in people, animals or cells on this page reports a result for these. That does not prove Hydralazine does nothing for them. It does mean anything you have heard about Hydralazine and one of these did not come from a study cited here.
Show full evidence
What is Hydralazine?
Hydralazine is an old blood pressure drug. In people, paired with a nitrate, it cut deaths in heart failure. It made worms live longer by switching on the same stress pathway as eating less. In mice it did nothing, in either sex.
Hydralazine is a blood pressure drug that directly relaxes blood vessels. It has been used since the 1950s. It came into ageing research from an odd direction. Screens in the worm C. elegans found it made worms live longer and cope better with stress. It worked through the worm's version of NRF2, an antioxidant switch that eating less also uses.
That is a real finding in a real lab animal, published in a strong journal. It is the reason the compound was worth testing further.
The NIA mouse lifespan program tested it in mice and found no clear effect on lifespan in either sex. The gap between a worm and a mouse is where most longevity compounds die, and this is a clean example.
How does Hydralazine work?
It does two separate things that should not be mixed up. As a medicine, it directly relaxes small arteries. That lowers the resistance the heart pumps against and lowers blood pressure. In response, the heart speeds up and the body holds on to fluid. That is why it is usually given with a beta blocker and a water pill. Its ageing case has nothing to do with that. In worms, it switches on the NRF2 and SKN-1 pathway, a stress response that looks like part of what eating less does. At higher amounts, it also blocks enzymes that tag DNA (DNA methyltransferases).
What have studies in people found about Hydralazine?
A long record as an approved drug for high blood pressure and heart failure, with one well-known immune risk. Nothing on ageing.
- In 1,050 Black patients with advanced heart failure (A-HeFT), a fixed pill of hydralazine plus a nitrate on top of standard treatment cut deaths: 6.2 percent against 10.2 percent on a dummy pill. The trial was stopped early. It was a two-drug pill.
- In 642 men with heart failure (V-HeFT), adding hydralazine plus a nitrate lowered deaths at two years: 25.6 percent against 34.3 percent on a dummy pill. Again, two drugs together.
- In 32 people with heart failure, hydralazine on its own did no better than a dummy pill over about 20 weeks.
- Approved and used for decades for high blood pressure, and with a nitrate (isosorbide dinitrate) in heart failure.
- A fast heartbeat and holding on to salt and water are expected results of relaxing blood vessels directly. That is why it is rarely used alone.
- Drug-induced lupus is a known risk with long use. It is more common in people whose bodies clear the drug slowly (slow acetylators). It is the reason long-term use without check-ups is a poor idea.
- No human study has looked at lifespan, healthy years or anything else about ageing.
What this does not tell you: The human record is about blood pressure and heart failure, not ageing. The longevity evidence is a worm result, and the mouse lifespan test that came after it was a no in both sexes. The drug-induced lupus risk is specific and real. That makes this one of the less sensible compounds to try on the strength of worm data.
The state of the research
This is the clearest worm-to-mouse failure in the batch, and it is worth being exact about what that means. The worm result is not junk science. It is in a strong journal, the way it works is clear, and the pathway is truly one that eating less uses. The problem is carrying it over. Worms live short lives, lack most of the biology of mammals, and react unusually strongly to stress-response tweaks. So longer life in worms has a poor record of carrying over.
That is why the mouse lifespan program exists, and why a no from it outweighs a yes from a simpler animal. The drug also carries a specific immune risk with long use. So the balance of risk and benefit here is negative, not just unproven.
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
1,724people, across 3 studies in people cited here
| Study | People | Share |
|---|---|---|
| The New England Journal of Medicine 2004 | 1,050 | 61% |
| The New England Journal of Medicine 1986 | 642 | 37% |
| American Heart Journal 1982 | 32 | 2% |
One study holds 61% 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
3 of 4 sources here are studies in people. The rest is not.
- Study in people · done in people375%
- Animal study · done in animals125%
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, 1982 to 2017, counted from the list of sources on this page. The newest source on file is from 2017, more than five years ago. Research on it may have gone quiet.
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
- 160.2 Da as the free base. 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: Roughly three to seven hours, and it varies substantially with acetylator genotype, so slow acetylators get much higher exposure from the same dose.
No amino acid sequence is on file for Hydralazine, which is expected: a small molecule is not built from amino acids.
The studies we cite
- Study in people1986Effect of vasodilator therapy on mortality in chronic congestive heart failure. Results of a Veterans Administration Cooperative Study.
Adding hydralazine plus a nitrate to standard heart failure treatment lowered deaths over two years in 642 men. At two years, 25.6% had died on the pair against 34.3% on a dummy pill. It was the first trial of a blood vessel relaxing drug to show people living longer. It is a two-drug result, not hydralazine alone.
642 men with chronic heart failure on digoxin and a diuretic randomised double-blind to placebo, prazosin 20 mg daily, or hydralazine 300 mg plus isosorbide dinitrate 160 mg daily, mean follow-up 2.3 years. Two-year mortality 25.6% on hydralazine-nitrate versus 34.3% on placebo, a 34% risk reduction (p<0.028); 36.2% versus 46.9% at three years. Prazosin no different from placebo. Ejection fraction rose at 8 weeks and 1 year on the combination only.
- Study in people2004Combination of isosorbide dinitrate and hydralazine in blacks with heart failure.
In 1,050 Black patients with advanced heart failure, a fixed-dose pill of hydralazine and a nitrate, on top of modern treatment, cut deaths so clearly the trial was stopped early. 6.2% died on the pill against 10.2% on a dummy pill. Again a two-drug pill, in one specific group of people.
1,050 Black patients with NYHA class III or IV heart failure and dilated ventricles randomised to fixed-dose isosorbide dinitrate plus hydralazine or placebo on standard therapy, stopped early. Death from any cause 6.2% versus 10.2% (HR 0.57, a 43% reduction, p=0.01); first heart failure hospitalisation 16.4% versus 22.4% (p=0.001); quality of life score better (p=0.02).
- Study in people1982Hydralazine in the long-term treatment of chronic heart failure: lack of difference from placebo.
Hydralazine on its own did not beat a dummy pill in heart failure. Exercise time improved in both groups, which is what a dummy pill can do, and nothing else moved. Thirty-two people, so a small no.
32 patients with class III or IV heart failure on digitalis and diuretics randomised double-blind to hydralazine 200 mg daily or placebo, average follow-up 20 weeks. Exercise duration rose in both groups (259 to 421 seconds on hydralazine, 271 to 339 on placebo) with no significant difference between groups. No change in weight, clinical class, heart size or ejection fraction in either group; clinical events 8 versus 13, not significant.
- Animal study2017Hydralazine induces stress resistance and extends C. elegans lifespan by activating the NRF2/SKN-1 signalling pathway
In worms. Hydralazine made the worm C. elegans live longer and cope better with stress, by switching on the NRF2 and SKN-1 pathway. This is where the compound's longevity reputation comes from, and it is a worm result.
Nematode work. Hydralazine extended lifespan and induced stress resistance through the NRF2 and SKN-1 pathway. This is the origin of the compound's longevity reputation and it is an invertebrate result.
Common questions
Has Hydralazine been tested in people?
Yes. 1,724 people given it across 3 completed trials cited here, 1 of which found nothing. Hydralazine is an old blood pressure drug. In people, paired with a nitrate, it cut deaths in heart failure. It made worms live longer by switching on the same stress pathway as eating less. In mice it did nothing, in either sex.
What is the Hydralazine 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 high blood pressure. It is also used for heart failure, together with another drug, isosorbide dinitrate. No ageing use.
Is Hydralazine FDA-approved?
FDA-approved for high blood pressure. It is also used for heart failure, together with another drug, isosorbide dinitrate. No ageing use.
Did hydralazine extend lifespan?
In worms, yes, through the NRF2 and SKN-1 stress pathway. In mice, tested by the National Institute on Aging at three labs, it had no effect in either sex. The mouse result is the one that should guide any decision about a person.
Why did the worm result not carry over?
It usually does not. Worms live short lives, lack most mammal biology, and react strongly to stress-response tweaks. So longer life in worms rarely carries over. That is exactly why testing in mammals at several labs exists.
Is it safe to take for longevity?
No. It speeds up the heart and makes the body hold fluid. Long use carries a known risk of drug-induced lupus, especially in people who clear it slowly. There is no lifespan benefit in mammals to weigh against that.