DOSEGUY

Roxadustat

weak data

Also seen as: FG-4592

The Dose Guy’s verdict
Sep 1, 2026
4 sources

A real drug that does what it promises: roxadustat raises hemoglobin reliably, across thousands of patients, without injecting EPO. Approved in the EU, China, and Japan for kidney-disease anemia, rejected by the FDA over cardiovascular safety signals that have only sharpened since. The meta-analysis is blunt: higher odds of all-cause mortality and thrombosis versus comparators. If you are eyeing it for endurance, understand that you are borrowing a drug designed for sick kidneys, and the cardiovascular signal is not theoretical.

Would I take it?Real drug, real CV risk. Not a casual play.

What it is

An oral pill that inhibits HIF prolyl hydroxylase, the enzyme that tags hypoxia-inducible factor for destruction when oxygen is plentiful. Block that enzyme and your body acts as if it is at altitude: erythropoietin rises, iron mobilization increases, hemoglobin climbs. The same physiology that altitude tents and EPO injections exploit, in a capsule. For kidney patients who cannot make enough EPO on their own, roxadustat fills the gap without needles and with better iron handling than injectable EPO.

For endurance athletes, the appeal is obvious, which is why WADA prohibits the entire HIF-stabilizer class. Roxadustat is not a supplement or a gray-area peptide. It is a prescription pharmaceutical with a serious safety profile and a large trial program behind it.

What the research shows

Massive trial program, clear efficacy, and a cardiovascular safety signal the FDA found too large to approve through:

In nondialysis kidney-disease anemia, hemoglobin rose 2.00 g/dL with roxadustat versus 0.16 g/dL with placebo through weeks 28 to 52. 86.0% achieved hemoglobin response versus 6.6% on placebo, p<0.0001.ANDES · phase 3 · n=922
In dialysis patients, roxadustat was noninferior to epoetin alfa for hemoglobin response, with mean changes of 0.77 and 0.68 g/dL through weeks 28 to 52.ROCKIES · phase 3 · n=2133
Across 20 randomized comparisons: all-cause mortality OR 1.14, 95% CI 1.06 to 1.22. Vascular access thrombosis OR 1.50, 95% CI 1.06 to 2.12. Adverse-event discontinuations OR 1.76, 95% CI 1.48 to 2.10.Meta-analysis 2026 · 20 RCTs · n=11,418
Thyroid-function suppression was more common with roxadustat than ESA, OR 6.45, 95% CI 3.39 to 12.27. In a 51-patient hemodialysis cohort, median TSH fell from 2.46 to 1.36 during treatment and recovered to 2.56 after stopping.Thyroid meta-analysis 2024 · 2 studies

Realistic protocols

Roxadustat is prescribed at 70 mg three times per week for kidney-disease anemia, adjusted every 4 weeks by hemoglobin response. Take it on an empty stomach, separated from phosphate binders and calcium supplements by at least an hour, because those block absorption. Doses are taken on non-consecutive days.

No performance trial in healthy athletes exists, so if you are running it off-label for endurance, you are guessing at dose and accepting cardiovascular risk that was quantified in sick patients, not healthy ones. Before reaching for a HIF stabilizer, check your ferritin and iron saturation. Low iron is the most common fixable drag on hemoglobin, and correcting it with supplementation carries none of this risk. Altitude training and altitude tents work the same HIF pathway without the pill. If you still want to try roxadustat, start at the lowest clinical dose, monitor hematocrit every two weeks, and set a ceiling you will not push past. The hemoglobin response begins within weeks, which is also why it is detectable: the hemoglobin curve and reticulocyte shift are visible on standard blood work, and WADA tests for the drug directly.

Clinical start70 mg 3x/wkOral, empty stomach, non-consecutive days.
AdjustBy Hb responseEvery 4 weeks. Target is a hemoglobin range, not a ceiling.
SpacingAvoid calciumPhosphate binders and supplements block absorption. Separate by an hour.
MonitoringRegular bloodworkHemoglobin, thyroid, potassium. The drug moves all three.

Side effects

This is a drug with a real safety profile studied across thousands of patients:

commonNausea, diarrhea, and peripheral edema, the standard profile in the trials.
monitorThe mortality and thrombosis signals from the meta-analysis are the reason the FDA said no. If you are running this off-label, set a hemoglobin ceiling with your doctor and stop if cardiovascular symptoms appear.
monitorThyroid suppression: TSH and free T4 drop during treatment. Reversible when you stop, but get thyroid labs before and during any course.
monitorHematocrit and blood viscosity. A healthy athlete pushing hemoglobin past the normal ceiling risks the same clotting problems the kidney trials flagged. Monitor hematocrit, not just hemoglobin.
monitorHyperkalemia, especially relevant in kidney patients. Check potassium regularly.

Where to buy

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