Erythropoietin (EPO) is a hormone made mainly by the kidneys that tells the bone marrow to make red blood cells. Drug versions such as Epogen, Procrit and the biosimilar Retacrit are FDA-approved to treat anemia from chronic kidney disease, the HIV drug zidovudine and cancer chemotherapy.[1][3] They carry a boxed warning: aiming for higher hemoglobin raises the risk of death, heart attack, stroke and blood clots.[1] EPO is also one of the best-known doping drugs in sport and is banned at all times by WADA.[18]

This profile covers what EPO is, what trials showed, dosing on the label, side effects, related drugs, doping history and the law.

What is erythropoietin (EPO)?

Epoetin alfa is a 165-amino-acid glycoprotein made with recombinant DNA technology. Its amino acid sequence matches natural erythropoietin.[1] Doctors call this drug group erythropoiesis-stimulating agents, or ESAs.

DrugWhat it isFDA approval
Epogen / ProcritEpoetin alfa; both made by AmgenJune 1, 1989[6][2]
AranespDarbepoetin alfa, longer actingSeptember 17, 2001[7]
MirceraMethoxy polyethylene glycol-epoetin beta (CERA)November 14, 2007[8]
RetacritEpoetin alfa-epbx, biosimilar to Epogen/ProcritMay 15, 2018[9][3]

Their half-lives differ: 4 to 13 hours for Epogen given into a vein in kidney disease, about 21 hours for Aranesp given into a vein in dialysis, and about 5 days for Mircera.[1][4][5] Mircera is approved only for kidney disease anemia and is not recommended for anemia from chemotherapy.[5]

EPO benefits: what the research shows

Approved uses

On the Epogen label, EPO is used to treat anemia from chronic kidney disease (on dialysis or not), from zidovudine in HIV, and from chemotherapy when at least two more months of chemotherapy are planned. It is also used to cut donor blood transfusions in some elective surgeries that are not heart or vascular operations.[1] The main benefit is fewer transfusions. The label states that EPO has not been shown to improve quality of life, fatigue or well-being.[1]

In a Russian study of 44 people with stage 3 to 4 kidney disease, epoetin beta reached the target hemoglobin faster than darbepoetin, but darbepoetin kept hemoglobin more stable once it was reached.[22]

Why higher hemoglobin targets backfired

Doctors once hoped that raising hemoglobin to normal would protect the heart. Three large trials showed the opposite:

  • Normal Hematocrit Study (1998): in 1,233 people on dialysis with heart disease, aiming for a normal hematocrit led to 183 deaths versus 150 in the lower-target group, and the study was stopped early.[10]
  • CHOIR (2006): in 1,432 people with kidney disease not on dialysis, a hemoglobin target of 13.5 g/dL led to more of the combined outcome of death, heart attack, heart failure admission or stroke than 11.3 g/dL (125 vs 97 events), with no better quality of life.[11]
  • TREAT (2009): in 4,038 people with type 2 diabetes and kidney disease, darbepoetin aimed at 13 g/dL did not reduce death, heart events or kidney failure, and strokes rose from 53 to 101.[12]

In cancer, a meta-analysis of 53 trials with 13,933 patients found ESAs raised the risk of death during treatment (hazard ratio 1.17) and slightly worsened overall survival.[13]

EPO dosage

Doses on the label are set in units per kilogram and adjusted by hemoglobin, checked weekly at first.[1] Iron levels are checked before and during treatment.[1]

Use (Epogen label)Usual adult starting dose
Chronic kidney disease50 to 100 Units/kg 3 times a week; start when hemoglobin is below 10 g/dL[1]
Zidovudine in HIV100 Units/kg 3 times a week[1]
Chemotherapy150 Units/kg 3 times a week or 40,000 Units weekly[1]
Surgery300 Units/kg daily for 15 days, or 600 Units/kg weekly for 4 doses[1]

On dialysis, the dose is reduced or paused if hemoglobin approaches or exceeds 11 g/dL; for people not on dialysis, the cut-off is 10 g/dL.[1] This page does not cover doping use, and there is no safe dose for that purpose.

EPO side effects

Boxed warning. ESAs increase the risk of death, heart attack, stroke, venous blood clots, clotting of dialysis access, and tumor progression or recurrence. In kidney disease, these risks rose when ESAs were used to aim for hemoglobin above 11 g/dL; in breast, lung, head and neck, lymphoid and cervical cancers, ESAs shortened survival and/or sped tumor progression in studies. No trial has found a hemoglobin target, dose or dosing strategy that avoids these risks in kidney disease. Clot prevention is recommended when EPO is used around surgery.[1]

In dialysis trials, these were more common with Epogen than placebo:[1]

Side effectEpogenPlacebo
High blood pressure27.7%12.5%
Joint pain16.2%3.1%
Fever10.1%8.3%
Vascular access clotting8.1%2.1%

Other label warnings:[1]

  • Blood pressure: about 25% of dialysis patients needed new or more blood pressure medicine. Uncontrolled high blood pressure rules EPO out.
  • Seizures: more likely in people with kidney disease.
  • Pure red cell aplasia: rarely, antibodies against EPO shut down red cell production, causing severe anemia.
  • Clots after spine surgery: in 680 people not given clot prevention, deep vein clots occurred in 4.7% on EPO versus 2.1% without it.
  • Serious allergic and skin reactions, including Stevens-Johnson syndrome.

EPO vs darbepoetin, CERA and ARA-290

Darbepoetin (Aranesp) and CERA (Mircera) act on the same receptor as epoetin but last longer, so they are given less often.[4][5] All share the same class warnings.[4] ARA-290 is different: an EPO-derived peptide engineered to avoid raising red cell counts, tested for nerve pain in diabetes. It acts on the tissue-protective innate repair receptor.[24] Like HGH, EPO sits in WADA’s S2 class. See all performance compounds and metabolic peptides.

EPO in sport: doping history and detection

  • 1998 Tour de France: the Festina doping scandal hit the race, and the fallout helped lead to the creation of WADA in 1999.[21] USADA later reported that before that scandal broke, EPO use was open among U.S. Postal Service riders who took it.[19]
  • Lance Armstrong: USADA’s 2012 reasoned decision concluded that Armstrong depended on EPO, testosterone and blood transfusions.[19] USADA said its evidence included sworn testimony from 26 people, including 15 riders, and described the U.S. Postal Service team as running “the most sophisticated, professionalized and successful doping program that sport has ever seen.”[20]
  • Detection: a 2000 Nature paper described a urine test that separates recombinant EPO from the body’s own.[15] When CERA became linked to abuse in endurance sport, labs built a blood test for it.[16] The Athlete Biological Passport tracks blood values over time and makes small-dose EPO use harder to hide.[17]
  • Health risks: pushing red cell counts up thickens the blood and raises the risk of high blood pressure, clots and other heart and blood vessel problems.[17]
  • Prescription only: EPO is approved for specific anemias, and the label limits its use.[1]
  • Not a compounded peptide: EPO is a licensed biological product. FDA says such products are not eligible for the compounding exemptions under sections 503A and 503B.[23]
  • Banned in sport: WADA’s 2026 list names erythropoietins, darbepoetins and CERA under S2.1.1, prohibited at all times. S2.1.5 also bans innate repair receptor agonists such as carbamylated EPO.[18] In our reading, ARA-290 would fall under that class, though it is not named.

This is general information, not legal advice. For more on drug rules, see our FDA and regulation hub.

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