Apologies for the delay in responding. I wanted to provide a comprehensive response. Currently, I am under the care of the head of OB/GYN at Georgetown University Hospital for my overall health. Following their recommendation of Forteo, they also mentioned that I could continue with Hormone Replacement Therapy (HRT), which aids in preserving bone density. However, it's worth noting that while HRT helps maintain bone, it may not promote bone growth as rapidly as necessary for my current needs. Additionally, due to variations in the machines used for my recent scans, it's debatable whether I am experiencing bone loss or gain.

My regular gynecologist was initially hesitant to prescribe it back in 2018, citing my age of 68 as a factor. Despite presenting her with studies on transdermal Hormone Replacement Therapy (HRT) conducted on women a decade past menopause, she remained cautious but eventually acquiesced, prescribing the lowest feasible dosage. While HRT undoubtedly assists with various aspects such as hair, skin, and overall energy, and building and preserving bone, she declined to increase the dosage. I believe that had she done so, the extent of my bone loss might have been mitigated. Unfortunately, conducting a comprehensive review of all transdermal HRT studies is beyond my means at the moment. Nonetheless, here are a few noteworthy studies:

ACP Journal: https://www.acpjournals.org/doi/abs/10.7326/0003-4819-117-1-1

American College of Obstetricians and Gynecologists (2020):

https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2013/04/postmenopausal-estrogen-therapy-route-of-administration-and-risk-of-venous-thromboembolism which concludes:

The Estrogen and Thromboembolism Risk study, a multicenter case–control study of thromboembolism among postmenopausal women aged 45–70 years, demonstrated an odds ratio for venous thromboembolism in users of oral and transdermal estrogen to be 4.2 (95% CI, 1.5–11.6) and 0.9 (95% CI,0.4–2.1), respectively, when compared with nonusers 10. Transdermal estrogen had no increased risk compared with nonusers. Similar results were reported elsewhere 30 31 32 33 34 35 and of particular importance, in women who were stratified for weight 36 and the presence of prothrombotic mutations

BodyLogic/NAMS/University of Southern California references:
https://www.bodylogicmd.com/blog/should-you-use-hormone-replacement-therapy-after-65-why-attitudes-are-changing/#:~:text=For%20many%20women%2C%20the%20benefits,or%20duration%20of%20hormone%20therapy
“Hormone therapy does not need to be routinely discontinued in women aged older than 60 or 65 years and can be considered for continuation beyond age 65 years for persistent [vasomotor], [quality of life] issues, or prevention of osteoporosis after appropriate evaluation and counseling of benefits and risks.”

Convincing a doctor based solely on a handful of transdermal HRT studies is challenging, especially when the medical community doesn't seem to prioritize conducting its own thorough review. Consequently, the response from most doctors tends to be negative or some variation thereof. However, the doctor at Georgetown did acknowledge that remaining on the lowest dose was likely acceptable. Additionally, they suggested that after my two-year course of Forteo, it might reduce the necessity for a subsequent drug to prevent further bone loss. It's worth mentioning that I am adamantly opposed to taking bisphosphonates under any circumstances.

As previously mentioned, I began low-dose transdermal HRT around the age of 68 and I’m now 74. And yes, the primary reason for initiating this therapy was to mitigate bone loss. Until you brought it up, I hadn't been aware of CTX. Your observation regarding the necessity for a higher dose for bone preservation is valid. The physician at Georgetown advised against increasing the dosage for the time being while I'm on Forteo. However, she expressed a potential willingness to reconsider this decision in two years. Hopefully, by then, there will be increased efforts within the medical community to conduct comprehensive literature reviews and additional studies on the utilization of HRT for postmenopausal women.

Sorry this was so long!