Confused about reconstitution volume vs concentration for GH peptides

Posted by busy_mom in Beginner Questions - 1 points, 2 comments.

I have a pharmacology background so I understand the math in theory but I am second guessing myself on the practical side. Say a vial has 5 mg of peptide and I add 2 ml of bacteriostatic water. That gives 2.5 mg per ml or 2500 mcg per ml. If I want a 250 mcg dose I draw to the 10 unit mark on an insulin syringe. That part seems straightforward. Where I get stuck is when people talk about "reconstituting to 1 mg per ml" or "using 1 ml water per 1 mg peptide." Is that just a convention to make dosing easier or does the actual concentration affect stability or degradation? I have seen protocols that say use 1 ml for a 2 mg vial and others that say use 2 ml for the same vial. The final dose is the same if you adjust the draw volume so why does the starting concentration matter? Also when a protocol says "100 mcg three times daily" is that based on half-life data or just tradition? For GH peptides with a short half-life it makes sense but I want to understand the reasoning not just follow a template. Appreciate any clarification.

Comments

• biohacker_sarah: concentration mainly changes convenience and shelf life, higher conc means less volume per dose but can degrade faster once reconstituted, i usually do 1 mg per ml for gh peptides, easier math and less water activity, noticed less clumping that way too, half life drives the multiple daily doses for ghrp and mod grf, cjc no dac is longer so some run it once daily, but most protocols just copy each other without pk data, i stick to 100 mcg three times for ghrp 2 and mod grf 1 29, seems to match th
• busy_mom: That tracks with what I have seen in stability studies - water activity definitely accelerates hydrolysis and aggregation, especially at higher peptide concentrations where you get more molecular crowding. The clumping observation is interesting, I have noticed the same with higher concentration vials after a week or two in the fridge. On the dosing frequency, do you know if anyone has actually measured GH pulse amplitude comparing three times daily versus twice daily for the GHRP-2 plus Mod GRF

Community discussion - research and educational context only. Not medical advice.