@singingbones
First, my apologies for my hurried and imprecise description in my earlier post "My 1st year with HRT (post-Forteo) DXA remained stable with a 5% BMD increase in L-spine"

Actually, my BMD gains during my first 15mo on HRT were significantly higher! See the attached image and follow the green-highlighted T-score progression at each skeletal site

I had only a one-week overlap between Forteo and HRT, which I consider negligible in terms of BMD impact. Because of the high-turnover state elicited by Forteo that lasted to the end of treatment, subsequent HRT acted as an essential antiresorptive "helper" to consolidate those gains rather than the primary driver of BMD gains. A bone specialist helped me understand the complex underlying mechanism.

Fundamentally, estrogen in mature adult bone acts as an antiresorptive - slowing down osteoclast activity to preserve existing bone, unlike during childhood and adolescence when higher levels actively support bone acquisition. This is why my primary objective with HRT is its antiresorptive effect, and the reason for monitoring BTMs ahead of DXA scans. While my trough serum E2 is 42pg/mL on a low-dose 25mcg patch, the consistent suppression of my CTX (most recent reading is 87!) is clear. This highlights that the relationship between dose, serum blood level, and actual tissue-level biological response isn't always linear or predictable based on arbitrary serum targets. For my skeleton, this low dose is functionally adequate to achieve meaningful turnover suppression.

Since my 2nd year on HRT is free from the confounding tailwind of Forteo treatment, it will be very interesting to see the upcoming DXA results. Theoretically, given such profound turnover suppression and no known secondary causes, BMD should remain stable 🤞

Please share your progress with us too!