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ForumsCompounding & FormulationNeedle gauge and dead space — March 2026 Page 2

Needle gauge and dead space — March 2026

TirzTom Wed, Jun 4, 2025 at 6:46 PM 49 replies 2,557 viewsPage 2 of 10
Dr.ObesityLA
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Jun 4, 2025 at 11:16 PM#6
TrialTracker_MD said:
Concentration choice is a precision decision, not a preference.

I am going to disagree with reconstituting low as a general rule. More diluent, more punctures, more in-use days at room temperature, and the stability trade-off is real. Precision is not the only variable being optimised.

44 22zoe_NC, Dr.ObesityLA, NurseKim_ATL and 41 others
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Dr.GutHealth
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Jun 5, 2025 at 1:01 AM#7
TirzTom said:
Two of us with identical vials and identical diluent arrived at different unit counts, which means one of us has a conceptual error rather than a…

Comparison of compounded dosing arithmetic delivery formats I've tried:

FormatProsCons
Lyophilized vialLongest shelf life, lowest costRequires reconstitution
Pre-mixed vialReady to draw upShorter shelf life (28-45 days)
Pre-filled syringesMost convenientHigher cost, shorter shelf life
Sublingual dropsNo needlesLower bioavailability, less data

I use lyophilized vials for cost and stability. The reconstitution takes 30 seconds once you've done it a few times.

45 23tyler_CSCS, VanRx_Mike, steve_okc and 42 others
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carl_compliance
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Jun 5, 2025 at 2:46 AM#8
Dr.ObesityLA said:
I am going to disagree with reconstituting low as a general rule.

For anyone reconstituting dosing arithmetic peptides: the water-to-powder ratio determines your concentration. Here's my reference:

Vial SizeBAC WaterConcentration0.25mg Dose
5mg2mL2.5mg/mL10 units
5mg2.5mL2mg/mL12.5 units
10mg2mL5mg/mL5 units
10mg3mL3.33mg/mL7.5 units

More water = easier to measure small doses but vial runs out faster. Find the balance that works for your dose.

46 24ricardo_MIA, BrianDallas92, labquiet_amy and 43 others
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SleepDoc_PDX
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Portland, OR
Jun 5, 2025 at 4:31 AM#9

Following on from SkepticalSean — and this may be the naive question:

How to check the arithmetic without trusting a website calculator, since three calculators gave me three answers?

Last edited: Jun 5, 2025 at 7:31 AM
47 0sophie_paris, mel_PDX, Dr.AddMedPHL and 44 others
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TirzTom
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Jun 5, 2025 at 12:54 PM#10

Reporting back.

Follow-up: it was dead space. Switching to a low-dead-space fixed-needle syringe gave me the tenth dose back.

5 5DeniseRN_TPA, SandraNC_45, Dr.EndoIndy and 2 others
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