Peptide Dose Converter
Reviewed by the Rite Aid Health Team · Last updated July 6, 2026
Convert dose units for a peptide your licensed clinician prescribed and an appropriate pharmacy prepared. This tool does not choose a dose or verify whether a product is appropriate for you.
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Mass: 1 mg = 1,000 mcg. IU: product-specific biological activity.
How mcg, mg, and g relate
Micrograms, milligrams, and grams are mass units. They describe how much material is present by weight, not how much liquid is in the syringe and not how strong a biological effect will be. For peptide labels and prescribed doses, the two mass units people usually need are mcg and mg.
The base relationship is fixed: 1 mg equals 1,000 mcg. That means 0.25 mg is 250 mcg, 1.5 mg is 1,500 mcg, and a 5 mg vial contains 5,000 mcg total before any reconstitution math. A gram is much larger: 1 g equals 1,000 mg, or 1,000,000 mcg.
This page only converts the unit label. It does not tell you how many insulin syringe units to draw after a vial is mixed. For that, the missing information is concentration: how many mg are in the vial and how many mL of diluent were added. Use the peptide dosage calculator for concentration, reconstitution, and U-100 syringe unit math.
Why IU is different
IU means international unit. It is not a measure of mass. It is a measure of biological activity under a defined potency standard for a specific compound or drug product. That distinction matters because two products can have the same number of milligrams but different biological activity if the standard, molecule, or preparation is different.
An IU conversion is only valid when a recognized relationship exists for that specific substance. For somatropin, the common relationship is 3 IU = 1 mg. For HCG, vendor and clinical references often use an approximate relationship around 9,000 IU = 1 mg. Those are not interchangeable. The HCG relationship should not be applied to HGH, and the HGH relationship should not be applied to a different growth-hormone secretagogue or research peptide.
If a vial label shows only mg or mcg, the conservative assumption is that IU conversion does not apply. Use mass conversion for mcg and mg, then use clinician-provided directions and the pharmacy-prepared product labeling for anything involving volume, concentration, or administration.
What the presets mean
The generic preset is intentionally limited to mcg and mg. It is appropriate when you only need to translate a mass dose, such as 300 mcg to 0.3 mg, or 2 mg to 2,000 mcg.
The HGH/somatropin preset enables IU because somatropin has a commonly used potency relationship of 3 IU per 1 mg. This is useful for reading older or mixed unit references, but it still does not determine whether HGH is appropriate, lawful, or permitted in sport.
The HCG preset enables IU using an approximate 9,000 IU per 1 mg relationship. HCG is a prescription hormone with specific reproductive and endocrine uses. It is not a weight-loss peptide, and unit conversion does not replace product labeling or clinician instructions.
Common conversion examples
- 250 mcg = 0.25 mg.
- 500 mcg = 0.5 mg.
- 1 mg = 1,000 mcg.
- 3.21 mg = 3,210 mcg.
- With the HGH/somatropin preset, 3.21 mg = 9.63 IU.
- With the HCG preset, 3.21 mg is about 28,890 IU.
These examples are math examples, not suggested doses. A large-looking or small-looking number can be misleading when units change. Always compare the final unit to the unit your clinician and pharmacy used.
How this fits with reconstitution math
A dose converter and a reconstitution calculator answer different questions. The dose converter answers, "What is the same amount expressed in another unit?" The reconstitution calculator answers, "After this vial is mixed with this amount of liquid, how many syringe units contain my prescribed dose?"
For a peptide your licensed clinician prescribed and an appropriate pharmacy prepared, keep the workflow separate: confirm the prescribed dose, convert only if the prescription and label use different units, then calculate syringe units from the final concentration. Do not use unit math to create your own protocol or to reinterpret research-only products for human use.
Related guides
- Peptide dosage calculator for vial concentration, reconstitution, and insulin syringe units.
- Reconstitution guide for prescribed peptides prepared by an appropriate pharmacy.
- Insulin syringe units guide for U-100 volume math.
- Tesamorelin, weight-loss peptides, and the IU glossary entry.
- HCG and semaglutide pages for examples of why approved-product labeling and research-vial labels should not be treated as the same thing.
Almost done
We sent the first email to .
Confirm your email to secure 20% off your first compounded-peptide order. We'll notify you when consultations and ordering open.
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1
Confirm your email
Open the first email and click the confirmation link.
-
2
Only after step 1
Then your discount is reserved
Once you confirm, we reserve your discount and will notify you when peptide services launch.
The first email should arrive within a minute. Do not see it? Check spam or promotions.
Get 20% off your first compounded-peptide order
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For general education only — not medical advice or a treatment recommendation. Peptides are not a substitute for care from a licensed provider. Talk to a qualified healthcare professional before you start, stop, or change any peptide, medication, or supplement.
FAQ
No. IU only applies when that compound has a defined potency standard. Most peptide dose math uses mcg and mg, and an IU relationship from one medication should not be applied to a different peptide.
No. This tool only converts units for a dose already chosen by a licensed clinician. It does not choose a protocol, confirm that a product is appropriate, or make research-only products approved for human use.
IU measures biological activity, not weight. Somatropin and HCG are standardized around different biological assays, so the IU-per-mg relationship is different for each one.
Use the mass conversion only: 1 mg equals 1,000 mcg. If you need to know syringe units after reconstitution, use the peptide dosage calculator with the vial amount, diluent volume, and prescribed dose.
No. Unit conversion cannot verify identity, sterility, purity, potency, storage, or whether a product was lawfully dispensed. Those questions belong with the prescriber and pharmacy.