There are studies that suggest a possible connection, but more research is needed to understand how TRT might affect tendon health in the long term. Some researchers believe that TRT could make tendons stiffer or more prone to injury, especially if the treatment is not carefully monitored. Tendonitis is a painful condition that affects the tendons, which are the tissues that connect muscles to bones. One area of concern that has been emerging is the possible link between TRT and tendonitis, which is the inflammation of the tendons. Future studies should focus on the long-term effects of TRT on tendon structure, strength, and the risk of tendon injuries. Regular exercise can help maintain tendon flexibility and strength, reducing the risk of injury. One way to balance TRT benefits with tendon health is through proper exercise and physical therapy. This is because testosterone can weaken the tendons, making them more susceptible to injury. As men age, their testosterone levels naturally decrease, leading to symptoms such as decreased muscle mass, fatigue, and low sex drive. Normalization of testosterone in men with deficiency does not increase tendon rupture risk and may even support long-term tendon maintenance. One underrecognized risk with high-dose TRT is the increased chance of tendon injuries, particularly tendon tears and ruptures. Systemic IGF-1 remained unchanged, but interstitial IGF-I increased in GH treated tendons compared with saline treated tendons. Another potential long-term effect of TRT on tendons is related to the balance between muscle growth and tendon adaptation. Stiffer tendons are more likely to suffer from injuries such as tendonitis, which is the inflammation of the tendons. While thicker tendons might seem beneficial, there is a risk that these tendons could become stiffer and less flexible. Testosterone plays a role in muscle growth and repair, but its effect on tendons is not as clear. Understanding how TRT might affect tendons over time is essential for anyone considering or currently undergoing this therapy. Testosterone Replacement Therapy (TRT) is often prescribed to men with low testosterone levels to improve their overall health and well-being. A control group was created, comprising patients aged years who had never filled a prescription for exogenous testosterone. Records between 2011 and 2018 were queried to identify patients aged years who filled a testosterone prescription for a minimum of 3 months. However, this potential bias should theoretically be equally applicable to both the testosterone supplementation cohort and the control cohorts, and therefore not materially influence the study conclusions. Patients on testosterone therapy who met diagnostic criteria were excluded from the study. However, the exact mechanism by which testosterone impacts the biomechanical properties of tendons and soft tissue is not well understood.28 It is possible that the impact of higher levels of relaxin on surrounding tissues may impact the stability of a tendon, making it more prone to injury. This is a one-to-one matched retrospective cohort study utilizing the PearlDiver database. If this is the case, then we have the potential opportunity to help decrease the risk of a debilitating injury. As such, many patients would be required, likely necessitating multicenter collaboration facilitated by a dedicated study group. The relatively low incidence of quadriceps rupture creates a practical obstacle to completing such a study. Is there an ideal exercise regimen to help prevent injury for a patient that we know is at risk? Anecdotally, I have noted in my practice that a patient sustaining a quadriceps injury under these circumstances tends to sustain the rupture as they are approaching the end of the activity they were performing, suggesting that there is an element of fatigue contributing to injury. There is a considerable knowledge deficit regarding the safe level of activity thresholds for patients with testosterone deficiency. However, the effect of estrogen on collagen synthesis in ligaments has yielded conflicting results in other systems. Further, Rahr-Wagner et al. found a 20% higher relative risk (RR) value of ACL injury in women who had never used OCs than in women who were long-term users (Rahr-Wagner et al., 2014). Since knee laxity changes with cycle phase, many active women want to know whether OCs could prevent the change in laxity and injury risk. By contrast, Carcia et al. (2004) found no change in knee displacement in relation to cycle; however, it is important to note that that these authors used self-reported cycle length to estimate menstrual phase, whereas the other studies directly measured estrogen levels in concert with knee laxity. When estrogen concentration increased during the menstrual cycle, knee laxity increased as well (Shultz et al., 2010, 2011, 2012a). For instance, if tendon pain began or worsened after initiating TRT, this information is vital for diagnosis. They should also check if the patient has any history of tendon problems or other musculoskeletal issues before starting TRT. Providers need to look at the whole picture, including the patient’s activity level, overall health, and how long they have been on TRT. It’s well-known for its effects on muscle growth, strength, and overall vitality. Tendons are the strong, fibrous tissues that connect muscles to bones, and they play a crucial role in movement. Therefore, novel strategies to prevent the negative effects of estrogen on joint laxity are desperately needed to decrease the risk of catastrophic injuries in active women. Shifting to the low progesterone OC in the specific preparation phase, or in season, would help increase stiffness within tendon and ligament while not preventing muscle repair following quality sessions or games. The low level of estrogen in the OC would decrease the negative effects of the ovulatory rise in estrogen on tendon and ligament mechanics (Lee C. A. et al., 2015), whereas the work of Hansen et al. (2011) showed that only high progesterone OCs decrease muscle protein synthesis. IGF-1 in turn can affect collagen content through an increase in protein synthesis through the production of the La-related protein (LARP) 6 (Blackstock et al., 2014). We have yet to determine whether the increase in collagen content was the result of a change in collagen synthesis or incorporation (Lee C. A. et al., 2015); however, the decrease in stiffness correlated with a decrease in LOX activity. Note that with ERT collagen incorporation is higher in the same women where collagen synthesis is repressed. Engaging in regular, low-impact exercises like swimming or cycling can help keep your muscles strong without putting too much strain on your tendons. They can help you monitor your tendon health and adjust your TRT dosage if necessary. One of the key challenges in managing tendonitis while on TRT is finding the right balance between the benefits of TRT and maintaining tendon health. When treating tendonitis in patients on TRT, doctors may need to take a more cautious approach. This means that while you are on TRT, your tendons might be more prone to strain and injury. Managing tendonitis while on TRT requires careful consideration to ensure that both the therapy and the treatment of tendonitis are effective. Diagnosing tendonitis in patients receiving TRT requires a comprehensive and detailed approach.