Nandrolone and stanozolol damage bodybuilders' DNA A couple of days ago we wrote about an animal study in which a one-time injection of nandrolone decanoate caused genetic damage. Now mice are not men and genetic damage is nothing like cancer, but a 2010 Brazilian study has shown that humans can also damage their genes by using steroids. The researchers studied 15 young men who did weight training four times a week and used anabolic steroids. The men took a four-week course and in that period ? according to the researchers ? injected 50 mg nandrolone decanoate and took 18 mg stanozolol three times a week. [Yes, that's what it says. Maybe they recorded it incorrectly.] A control group of 15 bodybuilders took no steroids. Another control group of 20 young men did no training and took no steroids either. Two months after the steroids course the researchers took cheek swabs from each test subject, taking samples of 2000 cells. Then the researchers examined the samples under a microscope to determine how many of the cells showed signs of genetic damage. The Brazilians recorded the number of cells with pyknosis [genetic material in the cell condenses], karyolysis [genetic material dissolves] and karyorrhexis [genetic material fragments]. The researchers also counted the number of micronucleated cells: cells with an extra small nucleus. These nuclei contain 'too much' DNA and make extra nuclei out of this. The photo below shows a micronucleated cell. The more micronucleated cells in a sample, and the more cells with pyknosis, karyolysis or karyorrhexis, the greater the chance of cancer developing, scientists believe. If you look at the table above, it looks as though strength training lowers the likelihood of genetic damage, but that steroids raise the likelihood. And that's the conclusion the Brazilians draw too. "Chromosomal damage and cytotoxicity are induced by anabolic steroids after 2 months of administration in oral mucosa cells", they write. "Since DNA damage and cellular death are important steps in events leading to carcinogenesis, this study represents a relevant contribution to the correct evaluation of the potential health risks associated with the consumption of anabolic steroids." If you compare this with other studies, however, the research results look considerably less alarming. In 2009, for example, the same Brazilians published a study in which they compared cheek swabs of petrol station attendants with those of people who did not spend their days exposed to diesel and petrol fumes. [Environ Int. 2009 Oct; 35(7): 1062-5.] The table below comes from that study. If you just look at the 'other nuclear alterations', then it looks as though four weeks of low doses of stanozolol and nandrolone decanoate are safer than working in a petrol station?