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7.2k

4 months in and dead space is still the thing I get wrong

PSA Long Haul ×9 Well Actually ×1 Sourced ×2

Posting this because I searched for it and got nothing useful.

Setup: 5mg, week 19, constipation present but not ruining anything. I changed exactly one variable — units — and tracked it for 21 weeks.

Result: a difference, but a small one, and well inside what I would call noise if someone else posted it. So I am putting it here rather than presenting it as a finding. If two or three other people have done the same thing we might actually learn something.

Not medical advice, obviously. This is one person with a spreadsheet.

11,732 up / 4,494 down72% upvoted49 commentsid 9bh2mm3 Jan 2026

49 comments

30 in this archive, depth 6

best — the order this archive was captured in

u/ismael_nwosu794 points·6 months ago

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

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u/honest_syringe_2025OP544 points·6 months ago

Small correction: the trial was 13 weeks, not 35. Does not change your point but people will quote it.

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u/oskar_ibarra197 points·6 months ago

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

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u/units_not_mgsyringe math158 points·6 months ago

never post a calculation as advice without stating the concentration

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u/honest_syringe_2025OP86 points·6 months ago

This is correct. 2mL versus 21mL is the common mistake.

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u/alcohol_aversion69 points·6 months ago

i am begging people to write down the concentration

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u/ruben_cabrera27 points·6 months ago

This is correct.

Adding to this: insulin syringe is doing more work than the comment implies.

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u/rina_bergstrom48 points·6 months ago

the concentration on the vial in marker is the most important step

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u/honest_syringe_2025OP287 points·6 months ago

Small correction: the trial was 13 weeks, not 35.

Counter-anecdote: opposite result, same dose. Which mostly tells us the variance is huge.

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[removed]513 points·6 months ago

[removed by moderator]

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u/vito_beaulieu218 points·6 months ago

What was the vial size and how much bac water?

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u/hedda_ekstrom457 points·6 months ago

Mechanistically the bit that matters is units. It explains most of the early profile and a decent chunk of the outcome.

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u/janek_ferrari0 points·6 months ago

the concentration on the vial in marker is the most important step

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u/aleksi_lehtinen1 point·6 months ago

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

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u/reflux_report1 point·6 months ago

never post a calculation as advice without stating the concentration

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u/kavya_radich-14 points·6 months ago

What was the vial size and how much bac water?

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u/vial_math_veraMOD283 points·6 months ago

This is an urgent-care question wearing a forum question's clothes. Please contact a clinician rather than waiting for replies.

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u/batch_number_bertievetting86 points·6 months ago·edited

Mechanistically the bit that matters is concentration. It explains most of the early profile and a decent chunk of the outcome.

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u/priya_weiss56 points·6 months ago

never post a calculation as advice without stating the concentration

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u/elodie_grimaldi43 points·6 months ago

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

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u/escrow_evangelist30 points·6 months ago

swirl, do not shake, or you are courting oxidation

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u/piotr_bruun7 points·6 months ago

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

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u/britta_nakamura23 points·6 months ago

This is correct. 2mL versus 9mL is the common mistake.

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u/elin_ferrari185 points·6 months ago

The single most useful thing I did was write the concentration on the vial. Stopped all the confusion after that.

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u/tomas_kimani131 points·6 months ago

i am begging people to write down the concentration

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u/hedda_adeyemi119 points·6 months ago

swirl, do not shake, or you are courting oxidation

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u/nadia_kjaer65 points·6 months ago

the concentration on the vial in marker is the most important step

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u/mateusz_achebe53 points·6 months ago

Small correction: the trial was 23 weeks, not 38. Does not change your point but people will quote it.

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u/signe_grimaldi32 points·6 months ago

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

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u/declared_value_dv13 points·6 months ago

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

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