1. DHT in the Hippocampus . Researchers found that in rats, it was DHT (or a related metabolite) that actually was the cause of reduced anxiety.  Of course, DHT is converted from testosterone in the male and so this is why increasing testosterone lowers anxiety. The researchers noted that the rats with reduced anxiety were more "exploratory". In other words, as anxiety goes down, creativity can increase. This is going to be good for your career and relationships.
The manufacturers of certain testosterone products (., AndroGel and Striant) state that their products are contraindicated in patients with soybean, soy, or soya lecithin hypersensitivity because they are derived partially from soy plants. There is a risk of serious hypersensitivity reactions or anaphylaxis with the use of testosterone undecanoate (Aveed) oil for injection. These allergic reactions can occur after any injection of testosterone undecanoate during the course of therapy, including after the first dose. Observe patients in the healthcare setting for 30 minutes after an Aveed injection in order to provide appropriate medical treatment in the event of serious hypersensitivity reactions or anaphylaxis. The Aveed injection contains benzyl benzoate, the ester of benzyl alcohol and benzoic acid, and refined castor oil. Therefore, testosterone undecanoate use is contraindicated in patients with polyoxyethylated castor oil hypersensitivity, benzoic acid hypersensitivity, or benzyl alcohol hypersensitivity. Patients with suspected hypersensitivity reactions should not be re-treated with testosterone undecanoate injection.
Adverse effects of testosterone supplementation may include increased cardiovascular events (including strokes and heart attacks ) and deaths based on three peer-reviewed studies involving men taking testosterone replacement.  In addition, an increase of 30% in deaths and heart attacks in older men has been reported.  Due to an increased incidence of adverse cardiovascular events compared to a placebo group , a Testosterone in Older Men with Mobility Limitations (TOM) trial (a National Institute of Aging randomized trial) was halted early by the Data Safety and Monitoring Committee .  On January 31, 2014, reports of strokes , heart attacks , and deaths in men taking FDA-approved testosterone-replacement led the FDA to announce that it would be investigating the issue.  Later, in September 2014, the FDA announced, as a result of the "potential for adverse cardiovascular outcomes", a review of the appropriateness and safety of Testosterone Replacement Therapy (TRT).    The FDA now requires warnings in the drug labeling of all approved testosterone products regarding deep vein thrombosis and pulmonary embolism .