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ForumsDosing & ProtocolsReconstitution math — dilution calculator for compounded peptides Page 2

Reconstitution math — dilution calculator for compounded peptides

CarlaRPh_TPA Fri, Feb 27, 2026 at 9:42 PM 10 replies 500 viewsPage 2 of 2
amy_econ_NJ
Member
567
2,567
May 2024
Princeton, NJ
Feb 28, 2026 at 12:32 AM#6

Wait I'm confused. My vial says 3mg not 5mg. Do I just use the same formula?

Last edited: Feb 28, 2026 at 3:32 AM
5 2Dr.SportsMedIN, amy_econ_NJ, bbq_ray_KC and 2 others
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LondonLisa
Member
912
3,456
Mar 2024
London, UK
Feb 28, 2026 at 12:49 AM#7
Previously posted:
My vial says 3mg not 5mg. Do I just use the same formula?

Same exact formula, just different numbers. The universal formula is:

Volume to inject (mL) = Desired dose (mg) ÷ Concentration (mg/mL)

And concentration = Total mg in vial ÷ mL of BAC water added

So for your 3mg vial, if you add 1.5mL BAC water:

  • Concentration = 3mg / 1.5mL = 2mg/mL
  • 0.25mg dose = 0.25 / 2 = 0.125mL = 12.5 units (draw to halfway between 10 and 15)
  • 0.5mg dose = 0.5 / 2 = 0.25mL = 25 units

Or if you want easier numbers, add 1.2mL BAC water to get 2.5mg/mL, then 0.25mg = 10 units. Same as the 5mg vial example. The total number of doses per vial will be different of course (3mg total instead of 5mg).

34 1Dr.MetabolicMD, RetaRick_CA, JenPlateau and 31 others
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KristenIndy
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623
2,678
May 2024
Indianapolis, IN
Feb 28, 2026 at 1:06 AM#8

you are an absolute angel. I just did my first reconstitution and injection — 10 units, right in the belly, barely felt it. This community is the best. Thank you all so much!! 🙏🥹

40 2Dr.GutHealth, amsterdam_pete, LondonLisa and 37 others
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carlos_SATX
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245
1,123
Oct 2024
San Antonio, TX
Feb 28, 2026 at 1:23 AM#9

Pinning this thread. We get this question at least twice a week. Excellent explanations as always from our knowledgeable members. For anyone reading this in the future, we also have a reconstitution calculator in the Tools section of the wiki.

And a reminder: always verify your math before injecting. If something seems off, ask here or call your provider. It's never a dumb question when it comes to dosing.

Last edited: Feb 28, 2026 at 3:23 AM
23 14LindaRN_retired, tommy_boulder, hyun_seoul and 20 others
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