High Turnover Help - Understanding my CTX/P1NP Ratio

@yogagirl57 I had baseline CTX and P1NP and then 3 months into Forteo, which like Tymlos is a PTH analog. I relied on AI to explain the meaning of my bone markers after 3 months of Forteo. Since this is an AI generated answer, you may want to take it with a grain of salt, but what it said was that increased CTX is normal in the early stages of treatment with teriparatide. A higher CTX number after 3 months on teriparatide is expected because this medication primarily stimulates bone formation, which initially leads to a temporary increase in bone resorption (as measured by CTX) as the body starts the remodeling process to build new bone, even though the net effect is a gain in bone density over time; essentially, teriparatide "primes" the bone to rebuild itself by increasing bone turnover, resulting in a higher CTX level early in treatment. When monitoring P1NP levels while on Forteo (teriparatide), a significant increase of more than 10 µg/L from your baseline level after 3 months is generally considered a positive response, indicating that the medication is effectively stimulating new bone formation; this is often used as a benchmark to assess treatment efficacy.

@mayblin Thank you for your response. In 2020 (baseline) my CTX was 350. My last one in 2024 was 254. I do not have a baseline for the P1NP. Thank you, also, for the comment to avoid collagen prior to test. I didn't know that.

@yogagirl57 thanks for sharing. One quick thought is that even without a baseline, P1Np likely increased along with CTX on Tymlos as part of increased bone remodeling.

@yogagirl57 thanks for sharing. One quick thought is that even without a baseline, P1Np likely increased along with CTX on Tymlos as part of increased bone remodeling.

@mayblin My wife started Tymlos three months ago. Before she started, her P1NP was around 90 and her CTX 700. Now, her CTX has doubled to 1400, but her P1NP has more than tripled to 300. That is a good sign that the medication is working. The ratio is much better.

These numbers have to be considered in context, and in comparison with each other. CTX alone doesn't really tell you anything, as you know, and the level can vary from person to person and from hour to hour.

By the way, she was also diagnosed with thyroid nodules that were causing her hormone levels to be high. I'm sure that was a contributing factor. She had surgery, so between that and Tymlos, her body chemistry has changed a lot.

@njx58 thanks for sharing - that's very helpful. It looks like your wife has had a very nice response to Tymlos. Agree that it's important to look at both markers together and in context. Good that the thyroid issue was addressed too, since it can be a contributing factor to bone loss as you pointed out.

@mayblin It's definitely important to get a competent endo to scan the thyroid. The first doctor she saw said that the nodules were small, and she would just monitor them. I didn't trust her, so we went to the endo who treated my osteoporosis. He did his own scan and said "That looks suspicious - let's biopsy it right now." The result was that the nodule was a category 4 which essentially means "likely to become cancerous." My wife had half her thyroid removed. The other doctor would have done nothing, and in fact didn't notice anything of concern.

I want to add that my wife's only symptom was a slightly elevated hormone level. Otherwise she never would have known.