Rusfertide dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Rusfertide is a lab-made peptide that copies hepcidin, the body's iron-control hormone.
Evidence grade for Rusfertide: Moderate. The rule: at least one finished study in people, and at least 100 people who took it. The sum on this page: 5 completed trials, 166 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 166
- Human studies
- 5
- 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 28 August 2026 (Mimrylo, NDA 220605, a brand-new drug molecule) to treat too many red blood cells in adults with polycythaemia vera, a rare blood disorder. A shot under the skin once a week, in 9.5 to 54 mg vials.
No first-hand reports gathered yet. That is a gap in what we have collected, not a finding that nothing has been reported.
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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.
Rusfertide is a weekly shot for polycythaemia vera, a blood cancer that makes too many red blood cells. It copies hepcidin, the body's own iron-control hormone. With less iron to use, the body makes fewer red cells. That means less need to have blood removed. The FDA approved it as Mimrylo in August 2026.
What people take it for
- Fewer trips to have blood removed.
- Keeping red cell levels in a safe range.
- Less tiredness.
What studies in people showed
The big study had 293 adults who still needed blood removed often. Between weeks 20 and 32, 76.9 percent on this drug never needed blood removed. On a dummy shot it was 32.9 percent. Over 32 weeks they averaged 0.53 blood removals, against 1.82. Tiredness got a little better. A 70 person study before it showed the same pattern. The drug makers paid for every study. No study has shown fewer blood clots or longer lives. It does not treat the faulty cells behind the disease. It manages the red cell count.
What people report
Reports, not study results
The good
- Far fewer blood removals in the studies on this page.
- Tiredness got a little better.
The bad
- Reactions where the needle went in hit 56 percent, against 33 percent on the dummy shot.
- Anaemia, too few red cells, hit 16 percent against 4.1 percent.
- Too many platelets hit 8 percent against 0.7 percent. The label warns about this.
Where these come from: These come from the FDA label and the studies on this page. We have not collected user reports on this one yet.
My bottom line
If you have this blood cancer and are tired of the needle, this is a real option to raise with your blood doctor. In my opinion, just know what it does and does not do. It controls a blood count. It has not been shown to prevent clots or change the disease.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Rusfertide 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.
- Tanning and pigmentationno headcount stated · 1 study
34 of the 36 indexed goals have no study of any kind behind Rusfertide
No study in people, animals or cells on this page reports a result for these. That does not prove Rusfertide does nothing for them. It does mean anything you have heard about Rusfertide and one of these did not come from a study cited here.
Show full evidence
What is Rusfertide?
Rusfertide is a lab-made peptide that copies hepcidin, the body's iron-control hormone. The FDA approved it on 28 August 2026 for adults with polycythaemia vera, a blood cancer that makes too many red blood cells. In the 293 person VERIFY study, 76.9 percent on rusfertide avoided needing blood removed between weeks 20 and 32, against 32.9 percent on a dummy injection.
Rusfertide is a lab-made peptide, 18 amino acids long, shaped into a ring and fitted with a fat tail. It copies hepcidin, the liver hormone that decides how much iron gets into the blood. In polycythaemia vera, the bone marrow makes too many red blood cells. The usual fix is to remove blood again and again (phlebotomy), which leaves people short of iron. Rusfertide limits the iron available to build red cells. So the share of the blood made of red cells (the haematocrit) falls without removing blood. Protagonist Therapeutics discovered it. Takeda sells it in the United States as Mimrylo, a shot once a week.
The main evidence is VERIFY (NCT05210790), a large final-stage study in 293 adults with polycythaemia vera. They still needed blood removed often despite standard care. People were assigned by chance to rusfertide or a dummy injection, and nobody knew which. The study had not appeared in a medical journal as of 11 September 2026, so the numbers below come from the FDA label. Between weeks 20 and 32, 113 of 147 people (76.9 percent) on rusfertide never reached the point of needing blood removed. On the dummy injection it was 48 of 146 (32.9 percent). The gap was 43.8 percentage points. Over 32 weeks, people on rusfertide averaged 0.53 blood removals, against 1.82 on the dummy injection. The haematocrit stayed below 45 percent the whole time in 62.6 percent, against 14.4 percent. Tiredness, the one thing patients rated themselves, improved by 1.98 points more than on the dummy injection. That is a real but small change on that scale. Earlier, the 70 person REVIVE study (New England Journal of Medicine, 2024) showed the same pattern. Blood removals fell from 8.7 a year to 0.6 during 28 weeks when everyone got the drug. Then some people were switched by chance to a dummy injection for 12 weeks. 60 percent of those who stayed on rusfertide kept responding, against 17 percent of those switched to the dummy.
Side effects from the label, weeks 0 to 32: reactions where the needle went in, 56 percent against 33 percent on the dummy injection. Anaemia (too few red cells), 16 percent against 4.1 percent. Too many platelets (thrombocytosis), 8 percent against 0.7 percent. Shortness of breath, 8 percent against 1.4 percent. 11 percent had their dose cut because of side effects, mostly anaemia. The label warns about new or worsening high platelets and about injection site reactions. Across the study, 285 people took the drug for a middle value of 61 weeks.
Where it stands: the FDA approved it on 28 August 2026 (NDA 220605) as a brand new drug, for too many red cells in adults with polycythaemia vera. The FDA lists it as prescription only. No UK, Australian or Canadian approval record was found.
How does Rusfertide work?
Hepcidin works by grabbing ferroportin, the only known door that lets iron out of cells. The door gets pulled inside the cell and broken down. That traps iron inside gut cells and certain immune cells, and lowers iron in the blood. So the bone marrow has less iron to build red cells. Rusfertide copies hepcidin at that door. The FDA label says it blocks ferroportin, which cuts the iron available for red cells and lowers the haematocrit. In VERIFY, average ferritin, a measure of stored iron, rose from 21 mcg per litre at the start to 124 at week 32 and 174 at week 52. That is the iron that would otherwise have gone into red cells. What it does not do: rusfertide does not touch the faulty JAK2 blood cells that drive polycythaemia vera. It manages the extra red cells the disease makes. A 2026 review in Blood Reviews makes the same point. It says the evidence rests on blood counts, and the effect on blood clots and on how the disease unfolds is unknown. How the body handles it, from the label: about 51 percent of a shot reaches the blood. Levels peak at a middle value of 24 hours. It takes an average of 28.6 hours (give or take 11.3) to clear half of it. More than 99 percent rides bound to blood proteins, and the body breaks it into smaller pieces. Levels settle after about 3 weekly doses. A careful heart rhythm study in 60 healthy volunteers found no meaningful effect.
What have studies in people found about Rusfertide?
One large final-stage study of 293 people against a dummy injection (VERIFY, 32 weeks, so far reported only on the FDA label). One 70 person study in the New England Journal of Medicine. A 20 person study where everyone got the drug. A 16 person study in a different iron disease. And early dosing studies in healthy volunteers. The makers paid for all of them. In the main study, 285 people took the drug for a middle value of 61 weeks.
- VERIFY (label data): 293 adults, average age 57, 73 percent men, 89 percent White. All still needed blood removed despite standard care. 45 percent were on blood removal alone, 39 percent also took hydroxyurea, and 13 percent also took interferon. Between weeks 20 and 32, 76.9 percent on rusfertide avoided needing blood removed, against 32.9 percent on the dummy injection. 91.2 percent made it to week 32.
- VERIFY, other results: 0.53 against 1.82 blood removals over 32 weeks. Haematocrit kept below 45 percent in 62.6 against 14.4 percent. Tiredness scores 1.98 points better on rusfertide, a real but small change.
- VERIFY side effects, weeks 0 to 32, 145 people on the drug against 146 on the dummy: injection site reactions 56 against 33 percent (severe in 0.7 percent). Anaemia 16 against 4.1 percent. High platelets 8 against 0.7 percent. Shortness of breath 8 against 1.4 percent. People stopped for good because of injection site reactions (2), high platelets (2) and anaemia (1).
- REVIVE: 70 people. Blood removals fell from 8.7 to 0.6 a year while everyone got the drug. Then 59 were split between staying on it and a dummy injection: 60 against 17 percent kept responding. Symptom scores fell in people who started with moderate or bad symptoms, but there was no comparison group for that.
- A 20 person study in people with a haematocrit above 48 percent, where everyone got the drug: 85 percent got below 45 percent by week 8. 7 of 20 stopped over 52 weeks.
- A 16 person study in haemochromatosis, an iron overload disease: 15 of 16 needed no blood removed over 24 weeks. Liver iron did not clearly fall. It is not approved for this.
- A careful heart rhythm study in 60 healthy volunteers found no meaningful effect.
What this does not tell you: The main goal was avoiding the need for blood removal. That is a stand-in for how the disease is managed. VERIFY was not built to show, and did not show, fewer blood clots, less turning into myelofibrosis (scarred bone marrow) or leukaemia, or fewer deaths. Those are what matter most in polycythaemia vera. The comparison with a dummy injection ran 32 weeks. The people studied were 89 percent White and 73 percent men. The tiredness result is real but only about 2 points. The big study has not yet appeared in a medical journal, so the label is the only detailed source. The maker wrote it and the FDA reviewed it, rather than outside experts. Anaemia in 16 percent shows that a drug that holds back iron can overshoot.
The state of the research
Rusfertide reached approval on a clean, standard path. A small startup (Protagonist) ran the early and late studies, and a large company (Takeda) holds the US application. One of them paid for every study on this page. Protagonist staff are authors on the Leukemia Research and Clinical Therapeutics papers. All of that is disclosed in the papers. That is how new drugs get made, and it is not a criticism. But it means there is no independent study of rusfertide anywhere.
The bigger thing to keep in mind is what kind of drug this is. Polycythaemia vera is a blood cancer, almost always driven by a faulty JAK2 gene in one line of cells. Interferon and ruxolitinib act on those faulty cells. Blood removal and rusfertide act on the red cell count. A 2023 review called rusfertide a chemical phlebotomy. It does what the needle does, without the needle and without the iron shortage. The 2026 Blood Reviews assessment states the limit exactly. The evidence rests on blood counts, and the effect on blood clots and on how the disease unfolds is unknown. A page that suggested it changes the disease would be wrong. The label's warning about new or worsening high platelets is the other side of the same coin. Holding back red cells does not hold back the faulty cells' platelet output. 8 percent of people on the drug developed high platelets, against 0.7 percent on the dummy injection.
The evidence, in charts
Fig. 1a · how many people
166people, across 4 studies in people cited here
| Study | People | Share |
|---|---|---|
| New England Journal of Medicine 2024 | 70 | 42% |
| Clinical Therapeutics 2025 | 60 | 36% |
| Leukemia Research 2025 | 20 | 12% |
| Lancet Gastroenterology and Hepatology 2023 | 16 | 10% |
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. 3 more studies in people give no headcount and are not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
7 of 9 sources here are studies in people. The rest are not.
- Study in people · done in people778%
- Review of studies · sums up other studies222%
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, 2023 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Approved
UK
Not approved
AU
Not approved
CA
Not approved
Approved in 1 of 4, by prescription in 0, not approved in 3. 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
- Peptide
- Molecule weight
- 2,442.0 Da (free base, C114H181N27O28S2)
- Half-life
- About 28.6 hoursLong, 1 to 7 days
- Chain length
- Written out, not as plain letters
Half-life as stated on file: 28.6 hours (mean, plus or minus 11.3 hours, from the FDA label)
The chain as written
S6,S16-cyclo[N-isovaleryl-Asp-Thr-His-Phe-Pro-Cys-Ile-Lys(N-epsilon-(N-palmitoyl-gamma-Glu))-Phe-Glu-Pro-Arg-Ser-Lys-Gly-Cys-Lys-NH2], from the FDA label
Written the way the source writes it, so we do not count the amino acids. Two chains, changed amino acids or three-letter codes are all reasons it can look like this.
The studies we cite
- Study in people2025A Phase 3 Study of Rusfertide in Patients With Polycythemia Vera (VERIFY)
This is the registry entry for VERIFY, the big 293 person study. Its main measurement point passed in February 2025. The study goes on with everyone on the drug up to week 156, and it is no longer taking new people. As of 11 September 2026, no results were posted on the registry. The VERIFY numbers on this page come from the FDA label instead.
Phase 3, 293 participants, sponsor Protagonist Therapeutics. Primary completion 21 February 2025; status active, not recruiting, with open-label treatment continuing to week 156. No results posted on the registry as of 11 September 2026.
- Study in people2024Rusfertide, a Hepcidin Mimetic, for Control of Erythrocytosis in Polycythemia Vera
Rusfertide sharply cut the need for blood draws, in a small early trial. 70 people with polycythaemia vera first took the drug openly for about seven months. Then 59 of them were split by chance to continue or to switch to a dummy. Blood draws fell from nearly nine a year before treatment to well under one during it. Six in ten kept responding on the drug against fewer than two in ten on the dummy. Serious side effects hit about one in eight. Protagonist funded it.
REVIVE phase 2: 70 enrolled in a 28 week open-label dose-finding part, then 59 randomised 1:1 to rusfertide (30) or placebo (29) for a 12 week withdrawal period. Estimated phlebotomies fell from 8.7 per year before treatment to 0.6 during part 1; response in the withdrawal period 60 percent against 17 percent (P equals 0.002). Grade 3 adverse events in 13 percent, no grade 4 or 5; grade 1 to 2 injection site reactions common. Funded by Protagonist Therapeutics.
- Study in people2025Rusfertide rapidly decreases hematocrit in patients with suboptimally controlled polycythemia vera
In a small open study, rusfertide brought a high blood thickness down fast. 20 patients whose disease was poorly controlled took it twice weekly, then weekly. By eight weeks, 17 of them had reached the target level, taking about five weeks on average, and none needed a blood draw. Seven of the twenty stopped the drug before the end. Nearly everyone had some side effect, mostly mild. Everybody got the drug, so there is nothing to compare against. Several authors work for the company.
Open-label phase 2 in 20 patients with baseline haematocrit above 48 percent, dosed 40 mg twice weekly then weekly. By week 8, 17 (85 percent) reached haematocrit below 45 percent, median time 4.9 weeks; no phlebotomies during treatment. 7 of 20 discontinued; 85 percent had treatment-emergent adverse events, mostly grade 1 to 2. Several authors are Protagonist employees and the investigators received Protagonist funding.
- Study in people2023Rusfertide for the treatment of iron overload in HFE-related haemochromatosis: an open-label, multicentre, proof-of-concept phase 2 trial
In an iron overload disease, rusfertide almost stopped the need for blood draws, but left the iron in the liver untouched. 16 adults took it for about six months and 12 finished. Blood draws fell from more than two in the previous six months to almost none, and 15 of the 16 needed none at all. Iron stored in the liver did not meaningfully change. Everybody got the drug, with nothing to compare against, and no single main measure was chosen in advance. The sponsor paid.
16 adults with hereditary haemochromatosis on maintenance phlebotomy received 24 weeks of rusfertide; 12 completed. Phlebotomies fell from 2.31 in the 24 weeks before to 0.06 during treatment (P below 0.0001), 15 of 16 were phlebotomy-free. Liver iron concentration did not change significantly (1.4 to 1.1 mg per g, P equals 0.068). No primary endpoint was prespecified. Sponsor funded; a different disease from the approved indication.
- Study in people2025Evaluation of Rusfertide, a Hepcidin Mimetic, on Cardiac Repolarization: A Randomized, Placebo- and Positive-Controlled Crossover Thorough QT Study in Healthy Participants
Rusfertide did not disturb the heart's electrical rhythm. 60 healthy adults took a high dose of the drug, a dummy, and a drug known to shift the rhythm, each in turn. The measure of the heart's electrical recovery barely moved on rusfertide, in either direction. A meaningful shift was ruled out across the whole range of blood levels reached. Four in ten had mild side effects. This was healthy volunteers taking one dose, not patients taking it for years. Protagonist paid for it.
60 healthy adults, 90 mg rusfertide against placebo and moxifloxacin. Placebo-corrected QTc change ranged minus 2.0 to 1.8 ms and an effect above 10 ms was excluded up to about 2,130 ng per mL. 40 percent had mild treatment-emergent adverse events. Sponsored and funded by Protagonist.
- Study in people2024Pharmacokinetics and Pharmacodynamics of Rusfertide, a Hepcidin Mimetic, Following Subcutaneous Administration of a Lyophilized Powder Formulation in Healthy Volunteers
This study measured what the body does with rusfertide, not whether it helps anyone. Healthy adults took a range of doses, each person trying more than one, and everybody knew what they were getting. Peak levels arrived a day after the smaller doses and within hours after the larger ones. The body took anywhere from under a day to over two days to clear half of it. Iron in the blood fell in step with the dose. Redness and itching at the injection site were common.
Randomised open-label crossover in healthy adults, 10 to 60 mg. Median time to peak 24 hours at 10 to 30 mg and 2 to 4 hours at 45 to 60 mg; mean terminal half-life 19.6 to 57.1 hours; dose-related falls in serum iron and transferrin saturation. Injection site erythema and pruritus were the treatment-related adverse events in 10 percent or more.
- Study in people2026Study to Evaluate the Long-term Safety of Rusfertide (PTG-300) in Subjects With Polycythemia Vera
The long-term safety study has produced nothing public. 46 people who had already been on rusfertide in earlier studies rolled over into it. Enrolment is closed, the main measurement point was April 2026, and no results have been posted. Two further early studies are registered, one in Japan with nine people and one in China with twenty-four. Nobody has yet watched anyone take this drug for years and published what happened.
Open-label phase 3 extension for 46 people rolling over from phase 2 studies; active, not recruiting; primary completion April 2026; no results posted. Further phase 2 trials in Japan (NCT07648030, 9 participants, recruiting) and China (NCT07765602, 24, not yet recruiting) are registered.
- Review of studies2026MIMRYLO (rusfertide) for injection, prescribing information, section 14 Clinical Studies
The official US label, which is where the VERIFY results appear. 293 adults got rusfertide or a dummy injection. Between weeks 20 and 32, 76.9 percent on rusfertide avoided needing blood removed, against 32.9 percent on the dummy. They averaged 0.53 blood removals against 1.82. Side effects: injection site reactions 56 against 33 percent, anaemia 16 against 4.1 percent, high platelets 8 against 0.7 percent. The full VERIFY paper could not be found in PubMed on 11 September 2026.
VERIFY: 293 adults randomised 1:1. Response (no phlebotomy eligibility, weeks 20 to 32) in 113 of 147 (76.9 percent) against 48 of 146 (32.9 percent), risk difference 43.8 percentage points (95 percent CI 33.5 to 54.2), P below 0.0001. Mean phlebotomies 0.53 against 1.82. Haematocrit kept below 45 percent in 62.6 against 14.4 percent. PROMIS fatigue difference minus 1.98 (95 percent CI minus 3.71 to minus 0.25). Injection site reactions 56 against 33 percent, anaemia 16 against 4.1 percent, thrombocytosis 8 against 0.7 percent. The peer-reviewed VERIFY paper was not locatable in PubMed on 11 September 2026.
- Review of studies2026Targeting the hepcidin-ferroportin axis in polycythemia vera: a complementary approach to clone-directed therapies
A 2026 review of drugs that work on the body's iron control system in polycythaemia vera. It says the evidence for rusfertide rests mostly on blood counts. Whether it cuts blood clots or changes how the disease unfolds is still unknown.
States that current evidence for rusfertide is largely based on surrogate haematological endpoints and that whether iron-directed strategies reduce thrombotic risk or modify disease trajectory remains undefined.
Where to buy Rusfertide
Rusfertide is an approved medicine. The approved product comes from a pharmacy, with a prescription. The vials below are sold “for research” and are not the approved drug.
No seller we track lists Rusfertide yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has Rusfertide been tested in people?
Yes. 166 people given it across 5 completed trials cited here, 1 of which found nothing. Rusfertide is a lab-made peptide that copies hepcidin, the body's iron-control hormone.
What is the Rusfertide 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 28 August 2026 (Mimrylo, NDA 220605, a brand-new drug molecule) to treat too many red blood cells in adults with polycythaemia vera, a rare blood disorder. A shot under the skin once a week, in 9.5 to 54 mg vials.
Is Rusfertide FDA-approved?
FDA approved 28 August 2026 (Mimrylo, NDA 220605, a brand-new drug molecule) to treat too many red blood cells in adults with polycythaemia vera, a rare blood disorder. A shot under the skin once a week, in 9.5 to 54 mg vials.
What is rusfertide and what is it approved for?
A lab-made, ring-shaped peptide of 18 amino acids that copies hepcidin, the hormone that controls how much iron gets into the blood. The FDA approved it on 28 August 2026 as Mimrylo. It treats too many red blood cells (erythrocytosis) in adults with polycythaemia vera. It is a shot under the skin once a week.
How well did it work in the phase 3 trial?
In VERIFY, 293 people who still needed blood removed often despite standard care got rusfertide or a dummy injection. Between weeks 20 and 32, 76.9 percent on rusfertide avoided needing blood removed, against 32.9 percent on the dummy. Over 32 weeks, they averaged 0.53 blood removals against 1.82. The maker paid for the study, and so far the results appear only on the FDA label.
Does it reduce blood clots or change the course of the disease?
That has not been shown. VERIFY measured red cell levels and the need for blood removal. It did not measure blood clots, turning into myelofibrosis, or survival, and it was not built to. Rusfertide does not act on the faulty JAK2 cells that drive polycythaemia vera. It controls the red cell count.
What are the side effects?
Over 32 weeks: reactions where the needle went in, 56 percent against 33 percent on the dummy injection. Anaemia, 16 percent against 4 percent. Raised platelets, 8 percent against under 1 percent. Shortness of breath, 8 percent against 1.4 percent. About 11 percent needed a lower dose, mostly for anaemia. The label warns about new or worsening high platelets.
Can it treat iron overload or haemochromatosis?
In a 16 person study in hereditary haemochromatosis, everyone got the drug and there was no comparison group. 15 of 16 went 24 weeks without needing blood removed. But liver iron did not clearly fall. It is not approved for that use anywhere.