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What was Your P1NP Increase on Tymlos at 1 Month?
Osteoporosis & Bone Health | Last Active: 1 day ago | Replies (36)Comment receiving replies
@mayblin Thank you so much for this clarification -- for the article (a deep dive!) and the graphs. So if I understand correctly, P1NP is guaranteed to follow CTX down when resorption is blocked with a bisphosphonate. Hence, no need to get P1NP tested going forward. (And no need for any ratio.). You mentioned that a CTX number in the lower half of the range for healthy premenopausal women is the goal. Is that range 100-600 pg/ml? May I ask how you used this to figure out the right dosing for your HRT? eg, Did you test every six months and increase or decrease the dose depending on where you were in that range?
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@sebutler that's my thought exactly.
Depending on the lab one uses, the reference ranges can vary. For example, Quest lists 60–650 pg/ml for ages 30-39yo and 50–465 for ages 40-49yo. Based on those, the lower half starts roughly between 230 and 325 pg/ml. Coincidentally, many experts look for a CTX in the low 200s (or lower) when monitoring patients coming off Prolia to ensure bone is protected, or bone turnover is suppressed.
Please share your endo's CTX target when you get that info.
My original plan for HRT was to start with a low dose of 25mcg estradiol transdermal patch and gradually titrating up to 50mcg - the "standard" dose. Since there isn't a mountain of published data for every scenario, I had labs at 1, 3, and 6mo. Coming off Forteo, my starting "baseline" CTX/P1NP was 793/137, and here is how my CTX responded to just the low 25mcg dose: 572 (1mo), 302 (3mo), 163 (6mo), eventually settled in the low 100s after 9mo. My endos were very supportive of the data-backed decision. Worth noting, i also observed the coupling lag in P1NP. Having a highish P1NP at the start of HRT gave me a bit more confidence to titrate slowly (ended up staying at low dose).