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c/reconstitution·posted 11 months ago by u/rasmus_kuipers

does dead space actually matter or is it forum lore at this point

PSA Clean Column ×7 Slow Clap ×3 Long Haul ×2

I have had 19 orders now and I keep a table, so here is the honest summary rather than a vibe.

Material has been consistent. Communication has not. Shipping has varied by about 24 days on nominally the same lane, which matters more in summer than in February.

The independent number came back 93.7% against a claimed 98.6%, which I read as agreement rather than a discrepancy — inter-lab variance on this assay is a point or two either way and treating one lab as ground truth is how people end up in pointless arguments with vendors.

Batch number is in the comments. Ask if you want the method.

4,838 up / 721 down87% upvoted45 commentsid 175w2n9 Aug 2025

45 comments

30 in this archive, depth 5

best — the order this archive was captured in

u/aleksi_lehtinen344 points·11 months ago

The evidence standard in c/vendorvetting gets called too strict about once a month, and every time, the thread ends with the complainant agreeing.

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u/rasmus_kuipersOP138 points·11 months ago

You have restated the marketing copy. What is the actual substance here.

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u/rasmus_kuipersOP79 points·11 months ago

Not convinced. The evidence does not support that reading.

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u/wanjiru_varga62 points·11 months ago

more water means more units for the same dose, which means finer resolution

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u/rasmus_kuipersOP43 points·11 months ago

Show the arithmetic. Where did the units come from?

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u/arto_falk32 points·11 months ago·edited

30mg vial, 1mL water, concentration is 30/1 — write it on the vial afterwards

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u/vial_math_verasyringe math220 points·11 months ago·edited

You have restated the marketing copy. What is the actual substance here.

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u/tuva_kirchner76 points·11 months ago

u-100 syringe, not u-40, or your math is off by factor of 10

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u/reflux_report257 points·11 months ago
this should be in the wiki
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u/anjali_tamm192 points·11 months ago

Spent 22 weeks confused about concentration math until someone showed me the table. 30mg, 2mL, concentration is 30/2.

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u/emil_wojcik51 points·11 months ago

15mg vial, 2mL water, concentration is 15/2 — write it on the vial afterwards

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u/gradient_goblin58 points·11 months ago

Spent 22 weeks confused about concentration math until someone showed me the table.

Adding to this: mg/mL is doing more work than the comment implies.

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u/santiago_ndiaye27 points·11 months ago

bacteriostatic and sterile water are not interchangeable, do not use them that way

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u/escrow_evangelist88 points·11 months ago

u-100 syringe, not u-40, or your math is off by factor of 22

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u/ismael_nwosu61 points·11 months ago

u-100 syringe, not u-40, or your math is off by factor of 22

Yes, exactly this, and it is the bit that took me 84 weeks to accept.

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u/sigrid_kaufmann18 points·11 months ago

u-100 syringe, not u-40, or your math is off by factor of 22 Yes, exactly this, and it is the bit that took me 84 weeks to accept.

Disagree on that part. 98.4% and 98.3% on the same vial is normal.

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u/signe_grimaldi36 points·11 months ago

Sceptical. If this were true we would see it reflected in the data and we do not.

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[removed]26 points·11 months ago

[removed by moderator]

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u/nabila_espinoza9 points·11 months ago·edited

This is the "correlation is mechanism" thing again. You changed three variables at once.

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u/rina_bergstrom28 points·11 months ago

u-100 syringe, not u-40, or your math is off by factor of 20

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u/britta_nakamura97 points·11 months ago

The evidence standard in c/vendorvetting gets called too strict about once a month, and every time, the thread ends with the complainant agreeing.

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u/aurel_boateng25 points·11 months ago

No. This is the kind of confident post that gets copied into a screenshot and repeated for years. Where is the evidence.

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u/britta_nakamura21 points·11 months ago

i am begging people to write down the concentration

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u/ahmed_rasmussen10 points·11 months ago

Sceptical. If this were true we would see it reflected in the data and we do not.

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u/freya_onwuka-33 points·11 months ago

dead space is real and the syringe matters

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u/karl_fischer_kev1 point·11 months ago

dosing errors come from people reconstituting two vials differently and forgetting which is which

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u/elodie_grimaldi31 points·11 months ago

15mg vial, 2mL water, concentration is 15/2 — write it on the vial afterwards

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u/soren_zamora16 points·11 months ago

swirl, do not shake, or you are courting oxidation

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u/ledger_modmod · vetting29 points·11 months ago·edited

This is correct. 2mL versus 7mL is the common mistake.

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u/hub_opssite staff9 points·11 months ago

Cosigning. The concentration on the vial in marker is load-bearing.

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About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

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