The federal government has expressed concern over a study conducted by Dr. Michael Hoffer while on deployment in Iraq.

Hoffer, a captain the Naval Medical Corps and a well-respected doctor at the Naval Medical Center in Balboa Park, conducted a study of wounded troops suffering from mild forms of traumatic brain injury.

According to the Department of Defense, in a test involving 80 troops, Hoffer gave half of the troops a placebo and the other half an antioxidant called NEC -- a drug he reportedly holds two patents for.

"Financial interest is certainly a red flag to a conflict of interest in patient treatment and in a clinical trial involving human subjects," said Joy Delman, a professor of bio-ethics for the Thomas Jefferson School of Law.

The Pentagon is also looking to see if medical guidelines and protocols were followed in the study.

"When you have a double blind study where some patients are receiving treatment and some are getting a placebo, it's mandatory that the patients are aware of that and that they agree to participate," said Delman.

The study first came to light through a tip to the Inspector General in 2009.

The Navy said none of the participants were harmed in the study.

A representative at Naval Medical Center said Hoffer is not commenting pending the outcome of the investigation.