my sheet has 3 lots from MKM with a spread under a point, which is tight
#test-results 2026-06-09
Tuesday55 messages8 participantstimes are UTC
Highlights from this day
- salt_bridge — the results in this channel skew because people test when they are suspicious. that is selection bias and it is real 22:28
- turnaround_tam — right so how do you separate batch variance from supplier variance 22:30
- split_the_cost — posting my PeptideMeter result on lot C-4402, what do people make of it 22:46
- first_and_last_four — log the boring results too. a channel that only records failures produces a false picture 23:23
- split_the_cost — i test roughly every tenth vial. it is a sampling strategy, not paranoia 23:32
certificate said 99.2 and the independent came back 98.1, is that a problem
96.8 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
whats the worst result anyone has logged and what happened next
thats within range
nice result
how do you post a result so it is actually useful to somebody in a year
97.4 against a certificate of 99 is fine. the same supplier landing low four times in a row is a question
which lab
follow up what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
whats the lot
weigh the vial before you reconstitute. it costs nothing and catches the common failure
i had a result i am fairly sure was a handling error on my side and i logged it as such
selection bias
ok so a single sample tells you about a single vial. that is genuinely all it tells you
a point or two between the certificate and an independent result is inside what two labs disagree by
update from 2 months ago: retested the same supplier, result came back better, logged both
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgright so how do you separate batch variance from supplier variance
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underfill is more common than impurity. if you only test purity you are testing the less likely failure
log the lot number
thats not great
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the widest spread in my data is about 2.6 percentage points across five lots from one supplier
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does anyone log the negative results, the boring ones
weigh it first
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the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
attach the pdf
posting my PeptideMeter result on lot C-4402, what do people make of it
| Evidence | Counts? |
|---|---|
| Independent report, lot you bought, lot number legible | yes |
| Independent report, no lot number | no |
| Supplier certificate only | no |
| Screenshot of a report | no |
| Blinded pooled submission | yes, for the pool |
| A friend who said it was fine | no |
test it again
i had a result i am fairly sure was a handling error on my side and i logged it as such
one data point
has a supplier ever disputed a result posted here
if you are testing to settle an argument you will not settle it with n of 1
log the boring ones
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is anyone tracking results over time in a way they would share
quick one quantity testing is usually a separate line item and it is the one worth paying for
a supplier disputing a result is rare here and it has never gone well for the supplier
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post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
i told CPC about a result they would not have liked and they did not argue. credit where it is due
i have never regretted spending the money on a test. i have regretted not testing twice
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update from 13 months ago: retested the same supplier, result came back better, logged both
when did you buy it
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
a supplier disputing a result is rare here and it has never gone well for the supplier
underfill is more common than impurity. if you only test purity you are testing the less likely failure
log the boring results too. a channel that only records failures produces a false picture
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a result without a lot number and a purchase date is an anecdote with a pdf attached
if the vial has been through a bad transit you are testing the transit as much as the supplier
log the boring ones
janoshik-f-1330.pdf
2 pages · 244 KB · not retained in the public archive
i test roughly every tenth vial. it is a sampling strategy, not paranoia
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgthats not great
selection bias, ill dig out the number
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
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genuine question when did you buy it, anyway
fridge-temps.csv
358 rows · not retained in the public archive
sorry to jump in thats not great
test it again