What is ratio-based dosing?
In a blended vial, each component has a fixed fraction of the total content. If you choose one component as the “driver,” the amounts of the others scale automatically by the same draw volume.
Driver peptide logic (math)
If a blend has:
- Peptide A total amount = Atotal
- Peptide B total amount = Btotal
- Chosen dose of A = Adose
Then B dose implied by ratio is:
Bdose = (Adose ÷ Atotal) × Btotal
Worked ratio example
Blend contains A = 10 mg and B = 5 mg total (2:1 ratio). If chosen A dose is 2 mg:
- Fraction of vial used = 2 / 10 = 0.2
- B dose = 0.2 × 5 = 1 mg
Why blends can be tricky
- You cannot independently change one component without changing all others (unless reformulated).
- Different half-lives and side-effect profiles can make fixed ratios less flexible.
- A ratio that looks convenient may not fit individual tolerance or goals.
Practical harm-minimizing checks
- Document exact vial composition and reconstitution volume.
- Run dose math for each component, not just the driver.
- Avoid ambiguous shorthand labels.
- Treat combined uncertainty as higher than single-agent uncertainty.
Common pitfalls
- Forgetting that reconstitution changes concentration but not component ratio.
- Reporting only one component dose and omitting the rest.
- Ignoring different evidence quality across components in the same blend.
Sources
- FDA: Drug combinations and fixed-dose products (regulatory framing) — https://www.fda.gov/drugs/development-approval-process-drugs
- ISMP medication safety principles (dose clarity and error prevention) — https://www.ismp.org/recommendations
- CDC Injection Safety basics — https://www.cdc.gov/injection-safety/hcp/clinical-guidance/index.html