Recently saw a thread where people discussed the efficacy of spreading out erda dose since the half life is rather long. If you dnr the entire thing here is the result: there is not much of a point its like pinning a weeks worth of tren e rather than spreading out your dose with tren ace.
Firstly, the mean effective half life is around 59 hours and it takes around 2 weeks to reach a steady state.
At 9 mg, predicted target inhibition stays flat, fluctuating only around 93.6–95.1% across the day with the long half-life keeps troughs high
At 4 mg/day: proportionally halved concentrations (~700 ng/mL peak / ~470 ng/mL trough total; ~0.9–1.4 ng/mL free)—still in the efficacious window which is ≈ 0.5–2.4 ng/mL, but toward the lower middle, below doses (6–9 mg) confirmed to reliably engage target
At 4 mg every other day: average exposure drops by roughly half again, and the 48 hour interval, which is closer to a full half life causes much bigger peak to trough swings where troughs likely dip below the efficacious threshold for stretches of each cycle, letting FGFR/FGFR3 signaling partially recover between doses.
In conclusion, theres not much of a point since you would probably want a more stable serum concentration rather than having it be like a roller coaster. This is also why you don't want to pin all of your compounds like once a week because the fluctuation is what causes lots of side effects.
IMPORTANT:
This is extrapolated from population PK parameters, not a regimen that's been directly studied in trials. The published intermittent schedule was 7-days-on/7-days-off at 10–12 mg, not QOD dosing. The referenced efficacious serum levels refer to tumor efficacy, not receptor occupancy.
My opinion:
I tried not being dogmatic in the post even though I state that "theres no point" but at the end of the day, yall are taking erda for height and any evidence is very limited. Take a lower dose to start off with every day and titrate up until the sides get to you lol. Ofc everybody responds differently, I wish everyone luck.
sources:
https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/212018s011lbl.pdf
https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2a8aa5c0-6c92-4566-8c45-e8f4d1fc20ee
https://ascpt.onlinelibrary.wiley.com/doi/10.1002/psp4.12727 full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC9124353/
https://www.annalsofoncology.org/article/S0923-7534(19)44417-7/fulltext
https://pmc.ncbi.nlm.nih.gov/articles/PMC9522481/
https://cdn.clinicaltrials.gov/large-docs/14/NCT03210714/Prot_SAP_000.pdf
https://cdn.clinicaltrials.gov/large-docs/48/NCT02393248/Prot_000.pdf
Firstly, the mean effective half life is around 59 hours and it takes around 2 weeks to reach a steady state.
At 9 mg, predicted target inhibition stays flat, fluctuating only around 93.6–95.1% across the day with the long half-life keeps troughs high
At 4 mg/day: proportionally halved concentrations (~700 ng/mL peak / ~470 ng/mL trough total; ~0.9–1.4 ng/mL free)—still in the efficacious window which is ≈ 0.5–2.4 ng/mL, but toward the lower middle, below doses (6–9 mg) confirmed to reliably engage target
At 4 mg every other day: average exposure drops by roughly half again, and the 48 hour interval, which is closer to a full half life causes much bigger peak to trough swings where troughs likely dip below the efficacious threshold for stretches of each cycle, letting FGFR/FGFR3 signaling partially recover between doses.
In conclusion, theres not much of a point since you would probably want a more stable serum concentration rather than having it be like a roller coaster. This is also why you don't want to pin all of your compounds like once a week because the fluctuation is what causes lots of side effects.
IMPORTANT:
This is extrapolated from population PK parameters, not a regimen that's been directly studied in trials. The published intermittent schedule was 7-days-on/7-days-off at 10–12 mg, not QOD dosing. The referenced efficacious serum levels refer to tumor efficacy, not receptor occupancy.
My opinion:
I tried not being dogmatic in the post even though I state that "theres no point" but at the end of the day, yall are taking erda for height and any evidence is very limited. Take a lower dose to start off with every day and titrate up until the sides get to you lol. Ofc everybody responds differently, I wish everyone luck.
sources:
https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/212018s011lbl.pdf
https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2a8aa5c0-6c92-4566-8c45-e8f4d1fc20ee
https://ascpt.onlinelibrary.wiley.com/doi/10.1002/psp4.12727 full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC9124353/
https://www.annalsofoncology.org/article/S0923-7534(19)44417-7/fulltext
https://pmc.ncbi.nlm.nih.gov/articles/PMC9522481/
https://cdn.clinicaltrials.gov/large-docs/14/NCT03210714/Prot_SAP_000.pdf
https://cdn.clinicaltrials.gov/large-docs/48/NCT02393248/Prot_000.pdf
