Testosterone may increase your metabolic risk profile – that is, the risk for conditions such as heart disease, diabetes, high cholesterol or blood pressure. The risk for heart disease is higher for people who smoke cigarettes, are overweight or have a family history of heart disease.
Testosterone causes hematocrit, the proportion of red blood cells in a volume of blood, to increase. This blood thickening, at high levels, can be life-threatening, causing stroke or a heart attack.
Testosterone can also cause increased appetite, headaches and acne.