An introduction into PTH analogs:
The most commonly mentioned PTH analogs are Teriparatide and Abaloparatide, both these drugs are classified as anabolic osteoporosis drugs, they stimulate new bone formation while also slowing bone breakdown and resorption.
-Mimics endogenous (natural) PTH signaling at the PTH1 receptor
-Also activates the same receptor but with different signaling bias
Differences in mechanisms:
-Abaloparatide activates PTH1R with stronger stimulation of Gs-cAMP and β-arrestin pathways which are directly associated with bone formation
-In animal models abaloparatide produced larger increases in cortical bone thickness and more bone formation than teriparatide
(water explanation) Abalo mogs Teri to the gandy shop
Dosing frequency
Studies have shown that continuous PTH exposure can cause bone resorption rather than formation
Intermitten exposure causes the bone formation that we aim to achieve
With this in mind its important to maintain once a day injections to benefit from the anabolic effect
Its not a compound where you can carelessly skip pins so keep that in mind
Clinical Trials
In recent and active clinical trials, it was found abaloparatide increase BMD in the spine and hip. Effect of Abaloparatide vs Placebo
The rate of hypercalcemia was 3.4% for abalo and 6.4% for teri, meaning abaloparatide has a lower risk profile and better results
Side Effects and risks
The two major concerns with using PTH analogs is the risk of hypercalcemia and osteosarcoma
The risk of hypercalcemia is very low as I mentioned before (3.4% & 6.4%)
In rat studies, researchers found a high risk of osteosarcoma (bone cancer)
Should the risks concern you?
Short answer, no.
Daily injections in rats for 2 years increased osteosarcoma incidence at 13.6 µg/kg/day
A lower dose (4.5 µg/kg/day) did not cause cancer
Risk depends on dose and duration
rats exposed to PTH analogs for most of their lifespan (8 weeks → 2 years) at 4–28× human exposure developed more bone cancer
Evidence found in humans:
Nearly 1000 humans treated with PTH analogs for up to 3 years showed no increased bone tumor incidence
1 million people have been treated worldwide with teriparatide and only 3 cases of osteosarcoma were found, but thats the normal rate of bone cancer founnd in people anyway
Osteoanabolic Agents for Osteoporosis
Key takeaways:
- If you're gonna hop on PTH analogs, abalo is better in every way
- Don't be scared of the fearmongering you see when people say it causes bone cancer
-Dosing for abaloparatide should be around 80-100µg a day
If you need a source, DM me and I can provide it but obv do more research
You might've noticed I didnt talk about romosozumab but its a more complicated compound, I'll write a thread about it soon
The most commonly mentioned PTH analogs are Teriparatide and Abaloparatide, both these drugs are classified as anabolic osteoporosis drugs, they stimulate new bone formation while also slowing bone breakdown and resorption.
Teriparatide;
-Recombinant human parathyroid hormone fragment PTH(1-34)-Mimics endogenous (natural) PTH signaling at the PTH1 receptor
Abaloparatide
-Synthetic analog of PTH-related peptide, (PTHrP)-Also activates the same receptor but with different signaling bias
Differences in mechanisms:
-Abaloparatide activates PTH1R with stronger stimulation of Gs-cAMP and β-arrestin pathways which are directly associated with bone formation
-In animal models abaloparatide produced larger increases in cortical bone thickness and more bone formation than teriparatide
(water explanation) Abalo mogs Teri to the gandy shop
Dosing frequency
Studies have shown that continuous PTH exposure can cause bone resorption rather than formation
Intermitten exposure causes the bone formation that we aim to achieve
With this in mind its important to maintain once a day injections to benefit from the anabolic effect
Its not a compound where you can carelessly skip pins so keep that in mind
Clinical Trials
In recent and active clinical trials, it was found abaloparatide increase BMD in the spine and hip. Effect of Abaloparatide vs Placebo
The rate of hypercalcemia was 3.4% for abalo and 6.4% for teri, meaning abaloparatide has a lower risk profile and better results
Side Effects and risks
The two major concerns with using PTH analogs is the risk of hypercalcemia and osteosarcoma
The risk of hypercalcemia is very low as I mentioned before (3.4% & 6.4%)
In rat studies, researchers found a high risk of osteosarcoma (bone cancer)
Should the risks concern you?
Short answer, no.
Daily injections in rats for 2 years increased osteosarcoma incidence at 13.6 µg/kg/day
A lower dose (4.5 µg/kg/day) did not cause cancer
Risk depends on dose and duration
rats exposed to PTH analogs for most of their lifespan (8 weeks → 2 years) at 4–28× human exposure developed more bone cancer
Evidence found in humans:
Nearly 1000 humans treated with PTH analogs for up to 3 years showed no increased bone tumor incidence
1 million people have been treated worldwide with teriparatide and only 3 cases of osteosarcoma were found, but thats the normal rate of bone cancer founnd in people anyway
Osteoanabolic Agents for Osteoporosis
Key takeaways:
- If you're gonna hop on PTH analogs, abalo is better in every way
- Don't be scared of the fearmongering you see when people say it causes bone cancer
-Dosing for abaloparatide should be around 80-100µg a day
If you need a source, DM me and I can provide it but obv do more research
You might've noticed I didnt talk about romosozumab but its a more complicated compound, I'll write a thread about it soon
