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What Is HemAssist and HBOCs?

What is the Drug HemAssist and What Does It Have To Do with Lance Armstrong?


Updated March 12, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

HemAssist, or Diaspirin Cross-Linked Hemoglobin (DCLHb), is a class of drug called a Hemoglobin-based Oxygen Carrier (HBOC). HBOCs are experimental drugs that re-engineer hemoglobin molecules to carry oxygen in the blood for a short period of time. They are designed to act as a blood substitute for trauma patients. HemAssist was in the final stages of clinical trials in 1998, when Baxter Pharmaceuticals pulled it from further research due to safety concerns.

HemAssist In the News

Although HemAssist never reached the marketplace, it made headlines in January 2011 when Sports Illustrated published The Case Against Lance Armstrong, in which authors Selena Roberts and David Epstein link Lance Armstrong with HemAssist, as well as EPO, during his reign as Tour de France champion. Listen to NPR's Story about the article.

HemAssist and other experimental Hemoglobin-based blood substitutes (HBBSs), including the PFC class of drugs, have not been approved for human use in the United States or Europe. However, there is speculation that athletes, particularly cyclists, have been trying to use them to boost endurance.

Reported Benefits of HBOCs

In theory, HBOCs such as HemAssist have twice the hemoglobin concentration and can carry nearly four times the oxygen as human blood. This means they can presumably deliver more oxygen to the working muscles than normally possible in even the most well-trained athlete. HBOCs also have a very short half-life and clear quickly from the body, which, in theory, makes them attractive to athletes who want to go undetected. Despite claims and speculation that HemAssist could possibly improve sports performance, there have been no research studies done to assess the drug's affect on physical endurance or sports performance, so such claims are still unproven.

Reported Dangers of HBOCs

Considering that all clinical trials on these drugs were stopped due to medical complications and safety concerns, use of these drugs clearly comes with substantial risks. The adverse events discovered during clinical trials included a substantial increase in cardiac events, myocardial infarction, and death.

Artificial blood substitutes are considered performance-enhancing drugs, and are on the "Banned Substance Lists" of the majority of organized and professional sports organizations, including the International Olympic Committee and the World Anti-Doping Agency.


Natanson, et al. Cell-Free Hemoglobin-Based Blood Substitutes and Risk of Myocardial Infarction and Death. JAMA. 2008;299(19):2304-2312. Published online April 28, 2008. [http://jama.ama-assn.org/content/299/19/2304.full]

The World Anti-Doping Agency, The 2011 Prohibited List International Standard [pdf]

International Cycling Union (UCI). Prohibited substances and methods. http://www.uci.ch/templates/UCI/UCI5/layout.asp?MenuId=MjI0NQ&LangId=1

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