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c/reconstitution·posted 9 months ago by u/units_not_mg

mg/mL — 18 things I got wrong before I got it right

Correction Receipts ×9 Long Haul ×1

I have had 8 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 34 days on nominally the same lane, which matters more in summer than in February.

The independent number came back 96.8% against a claimed 97.2%, 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.

1,708 up / 518 down77% upvoted26 commentsid 193wg09 Oct 2025

26 comments

9 in this archive, depth 4

best — the order this archive was captured in

u/karl_fischer_kev-3 points·9 months ago

stopper coring on the 21th draw because you keep using the same entry point. rotate.

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u/cesar_ivaturi1 point·9 months ago·edited

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

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u/niels_roos1 point·9 months ago

That is net peptide content, not purity. Different number, different meaning.

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u/sock_puppet_spotter132 points·9 months ago

Disagree. What you are describing is consistent with concentration, not with what you concluded.

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u/units_not_mgOPsyringe math57 points·9 months ago

Yeah, showing the arithmetic is the fastest way for someone to spot the error.

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u/units_not_mgOPsyringe math36 points·9 months ago

Dead space ate 20 units on a low-volume draw. Tiny impact at 1.0mg, massive impact at 15mg.

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u/ruben_cabrera38 points·9 months ago

Yeah, showing the arithmetic is the fastest way for someone to spot the error.

Yes, exactly this, and it is the bit that took me 16 weeks to accept.

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u/quiet_reader_9926 points·9 months ago

show your working or it is unhelpful

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u/escrow_evangelist62 points·9 months ago

The confident tone is doing a lot of work that the evidence is not.

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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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