In this “Ask Me Anything” (AMA) episode, Peter and Bob discuss all things related to testosterone: what happens when testosterone levels are low, and the potential benefits and risks of testosterone replacement therapy (TRT). They explain the physiology of testosterone, how it works, and how its level changes over the course of a person's life. They have a detailed discussion about existing literature, which reveals vast potential structural, functional, and metabolic benefits of testosterone replacement therapy. They also take a very close look at potential risks of this therapy, with a focus on the controversial effects on cardiovascular disease and prostate cancer.

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We discuss:

• A primer on the hormone testosterone and how it influences gene expression [3:30];
  
• How the body naturally regulates testosterone levels [11:30];
  
• The defining threshold for "low testosterone," how low T impacts men, and why free testosterone is the most important metric [16:15];
  
• When it makes sense to treat low testosterone [26:00];
  
• The structural and metabolic benefits of testosterone replacement therapy [29:15];
  
• Body composition changes with TRT [45:30];
  
• Changes in bone mineral density with TRT [48:15];
  
• The metabolic impact of TRT: glucose, insulin, triglycerides, and more [52:30];
  
• A study investigating testosterone replacement therapy for prevention or reversal of type 2 diabetes [59:30];
  
• The impact of TRT on metabolic parameters and body composition—A study comparing results from continuous vs. interrupted treatment [1:07:15]
• The controversy over TRT and cardiovascular disease [1:21:45];
  
• Two flawed studies that shaped perceptions of risks associated with TRT [1:44:15];
  
• The controversy over TRT and prostate cancer [1:56:45];
  
• Other potential risks with testosterone replacement therapy [2:02:15]; and
  
• More