Is Anyone Else Tracking Your P1NP to CTX Ratio, While Taking Tymlos?

Honestly I was lucky... it was nausea and feeling sickish for about a week. And I think my fear about taking it (I put it off for years) compounded my perception of the side effects. I do get spine pain once in awhile when my spine hits against something but hard to know what that is attributed to. If it doesn't get any better will you maybe try Forteo? Some say that was easier for them. I hope it's getting better!

So my blood test results:
6 months of Tymlos, ratio is 201. I guess that is good, but I don't have a baseline PNP1 to compare it to.
I had a baseline CTX which was 270- now it is 521. That seems high. However, I guess with that ratio I am still building, and the CTX is raised because of the active breakdown along with the rebuild. That's what I've read anyway ... waiting for dr. to weigh in. It does feel a bit pointless since he didn't do the PNP1 when I started, only CTX.

@lp30, I started to see a new endocrinologist who preferred Forteo. I was only on a half dose of Tymlos due to side effects. I was unable to tolerate more because of dizziness and nausea. I had also had too much calcium in my urine with Tymlos. I had fewer side effects with Forteo, but I didn't like the fatigue and brain fog. Of course, I had to take a full dose of Forteo, which the endocrinologist liked since that was what was studied.

The ratio was 310/1440 after 6 months of a half dose of Tymlos. The 1440 is divided by 1000 so the ratio is 219. This is considerably better than 150 so is a very good result.

I just received bone marker results back. I stopped Tymlos after 2 years of a half dose, was off it for 2 months, then went back on it for a month at my endocrinologist's request. I increased my estrogen from 14 mcg to 25 mcg 2 months ago. My P1NP is now only 37 and my CTX is 171. 37/.171=216 which is still a good ratio. I think the Tymlos may not be doing anything anymore since my P1NP is basically the same as it was 3 months ago when I was not on it. I think the CTX has dropped in response to the increase in estrogen.

I also got my DEXA results back and they have improved since a year ago:

Lumbar Spine: TBS 1.377, T-score -1.1, Z-score 1.1

Left Femoral Neck: T-score -1.4, Z-score 0.5

Right Femoral Neck: T-score-1.8, Z-score 0.2

Left Total Hip: T-score -1.2, Z-score 0.6

Right Total Hip: T-score -1.5, Z-score 0.3

"Since May 16, 2025, there has been a 1/9% increase in the bone mineral density of the lumbar spine, a 9.3% increase in the BMD of the left total hip, and a 10.8% increase in the bone mineral density of the right total hip. I am very pleased with the results. I would like to just stay on estrogen, but my endocrinologist wants me to continue Tymlos. I will see another endocrinologist next week to hear her opinion.

I got my P1NP back.
5/14/26 33
8/19/25. 98
5/6/25. 102
8/9/24. 90
6/14/24 49
the CTX I posted above:
May 14, 2026 131pg/mL
Aug 19, 2025 338pg/mL
May 6, 2025 643pg/mL (I don't think this is correct, I will look into it)
Aug 16, 2024 366pg/mL
Jun 14, 2024 322pg/mL+

So IF I wasn't taking Tymlos (had one Reclast before starting will do two more when I finish Tymlos this fall - the numbers ARE GREAT IF I wasn't on the medicine! The decrease is wonderful. But it is terrible since I am on the medicine. The numbers are supposed to increase.
I am not going to stress about it until I do my next Dexa with TBS this summer and will see the doctor in the fall. The Dexa is the gold standard not the blood plasma tests. If you have any input, I'd welcome it!!!

AI is cool. So I asked:
if my ctx is currently 131 (two years ago it was 322) and my Pinp is currently 33 (two years ago it was 49) what does that mean if I am on Tymlos for two years?
Its reply:
"Your current bone marker readings indicate that your bone turnover rate has significantly slowed compared to two years ago. This suggests that your bone breakdown (CTX) has decreased, and your bone formation (P1NP) is now within the typical, premenopausal range for adults.Here is a more detailed breakdown of what these numbers mean as you approach the two-year mark on Tymlos (abaloparatide):1. Bone Resorption (CTX) of \(131 \text{ pg/mL}\)What it means: A reading of \(131\) is on the lower side, reflecting a decrease in osteoclast activity (the cells responsible for breaking down bone).Tymlos Context: While Tymlos is an anabolic (bone-building) medication, it generally causes a milder or minimal increase in CTX compared to other drugs like Forteo. Your drop from \(322\) to \(131\) is significant, indicating much less bone dismantling is occurring.2. Bone Formation (P1NP) of \(33 \text{ mcg/L}\)What it means: A P1NP level of \(33\) indicates stable, ongoing bone formation, as it falls comfortably within the typical reference range (roughly 15–75 mcg/L for adult women).Tymlos Context: During the first few months of taking Tymlos, P1NP typically spikes or doubles as the medication rapidly builds new bone. After two years of continuous treatment, bone formation often slows down and trends back toward baseline as the initial intense building phase completes.The Overall PictureOn Tymlos, it is the ratio of building to breaking that matters most. In your case, you have strong, low bone turnover. However, the exact effectiveness of the medication cannot be measured by blood markers alone. These drugs work by stimulating an "anabolic window," meaning they build new bone faster than it is being broken down.Next Steps: The definitive measure of your treatment's success will be your next DEXA Scan, which your doctor will likely use to compare your bone mineral density to your baseline scans.Continuation of Therapy: The FDA Prescribing Information for Tymlos limits the use of the drug to a cumulative 2-year duration. Because of this, it is standard practice for endocrinologists to transition patients to an antiresorptive medication (such as Fosamax, Evenity, or Prolia) following the two-year period to protect and maintain the new bone you have built."
How cool is that?!

@loriesco As mentioned in the original post and according to the linked video, one result or the other by itself is useless (like knowing one team's score, but not being given the other team's.....no clue if you're winning or losing). So, according to that video if your RATIO is 150 or higher, you are likely BUILDING bone (aka anabolic), which is the desired goal. We know it is a slow process, with many variables, so the annual DEXA is what will have to give a better insight as to what his actually grown. I do not see that you calculated your P1NP:(CTX/1000) RATIO in order for you to see if you are theoretically growing bone or losing bone. Per your numbers listed above, your status at those given times:

Currently (33/.131) = 252 (indicating a strong response to treatment & building bone status)

2 Yrs Ago (49/.322) = 152 (indicating bone is still being built at a slower rate & closer to a "maintaining mode," with bone resporption and building at simikar rates.

I am not a doctor, simply sharing what the videos data crunching established. Without the ratio, you really have little indication of what's happening. Both markers are going to move together. The question is is one outpacing the other, per the ratio. And yes, that's why it is so important to be put on an anti-resorptive medication to lock in the bone growth that has occurred over those two years on Tymlos. Otherwise, you will become in balance and lose more bone at a higher rate than you are capable of building without medication.

And per the video and other infoI've seen, it appears that the rate of bone grows peaks at the 1-3 month mark and is expected to slow moving forward, but still continues to prompt bone growth..... until it evidently drops off at the 18-month mark, per their clinical trials.

@drsuefowler Thank you for sharing. Best wishes!!

My bone density growth was great in the first year on Tymlos, and much less in the second. That is in line with expectations. Both my P1NP and CTX have fallen now that I am on alendronate; also expected.