Testosterone plays an essential role in limiting inflammation throughout the body. Low testosterone can be the cause of joint pain. 

Effects of Testosterone on Joints and Inflammation

• Testosterone improves most forms of chronic joint pain.
• Testosterone improves most types of chronic muscle pain, including symptoms of osteoarthritis and fibromyalgia.
• Testosterone can lower inflammatory markers.
• Most autoimmune patients notice a decrease in symptoms and pain(including those with rheumatoid arthritis).

The Benefits of Testosterone for Chronic Pain Patients

• Necessary for opioid receptor bonding.
• Increases exercise tolerance.
• Maintains sexual drive and function. 
• Affects mood (decreases depression/anxiety.
• Maintains the blood-brain barrier.
• Maintains muscle and bone mass.
• Prevents opioid complications, such as osteoporosis.

Bianchi VE. The Anti-Inflammatory Effects of Testosterone. J Endocr Soc. 2018;3(1):91-107. Published 2018 Oct 22. doi:10.1210/js.2018-00186

Hillary D. White, Thomas D. Robinson, A novel use for testosterone to treat central sensitization of chronic pain in fibromyalgia patients, International Immunopharmacology, Volume 27, Issue 2, 2015, Pages 244-248, ISSN 1567-5769, https://doi.org/10.1016/j.intimp.2015.05.020.