Mass and Purity Testing vs. Safety: The Noob Explainer I Wish I Had From The Beginning

Nathanologist

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If you’re new to peptides, like me, here’s the simple truth: purity and mass tests tell you about quality and quantity of the target substance, not total contents of the vial, or even safety beyond dosing errors. Too many of us see 99.xx% purity and think, “seriously how bad could the other 0.xx% be?!” But that % isn’t what you think; it doesn’t mean that 99.xx% of that white powdery stuff in the vial is your libido enhancing, skin glowing, hair growing fat melting magic elixir.

Purity testing shows how much of the material in the vial that should be the peptide is actually the peptide; it doesn’t measure the rest of the vial. For example, 10mg of Retatrutide at 99.89% purity means almost all of that 10mg is the correct molecule (the other 0.11% of that 10mg is usually benign stuff that is related to or responds like the peptide), but it says nothing about the rest of the vial’s contents.

Mass testing (like quantitative assays and mass spectrometry) tells you how much peptide is actually in the vial, which helps with dosing and confirming you got what you paid for. If the vial contains 10mg of peptide, the assay confirms that; if it actually contained 100mg, and you didn’t test it, you could administer a dose 10x higher than intended. So that is actually a safety concern addressed by the common testing.

Together, these tests answer: “Is this the peptide I expect?” and “Is it the amount that I expect?” They do not prove safety, per se. You could, hypothetically, have a vial with 10mg of 99.89% pure Retatrutide and 90mg of lyophilized plague infected rat semen and the purity testing would still look fine for the peptide portion, but most of the vial would not be something safe to inject or ingest.

Use mass and purity testing to avoid dosing mistakes and confirm the molecule, but don’t assume the product is completely safe. These tests will likely answer those “why does this new vendors product give me sick?” and “why isn’t this working even though I’ve titrated up to 10x the max dose used in the study?” Type questions. Incidentally the estimate I got for the panel of tests to find out what the rest of the junk in the vial is was over $1,000. Even after all that testing- you still cannot be sure what’s in the rest of your untested vials.

There are plenty of people more informed than I am who will tell you that any other testing is unnecessary because it’s unlikely to identify danger 95% of the time. Be careful with your confirmation bias. Hope is not a safety net. We are all playing at risk probabilities here and trying to find our acceptable tolerance.

…and now I invite you all to pick this post apart, tell me why I’m wrong, or uninformed or inexperienced …or defend me and tell me how brilliant it is with gratitude. I don’t actually care and am always glad to be educated or flattered. I just couldn’t easily find this info spelled out clearly and so I figured I’d write something up. This community of peppers is so much more than I deserve and have helped me more than hurt me. Trying to give back in a small way. Much love.
 
That's separate, that only test for dead bacteria, 120$ and 1 vial

Contamination is 170$ and doesn't require an extra vial.

Sterility is live bacteria for 240$ and 2 vials
 
If you’re new to peptides, like me, here’s the simple truth: purity and mass tests tell you about quality and quantity of the target substance, not total contents of the vial, or even safety beyond dosing errors. Too many of us see 99.xx% purity and think, “seriously how bad could the other 0.xx% be?!” But that % isn’t what you think; it doesn’t mean that 99.xx% of that white powdery stuff in the vial is your libido enhancing, skin glowing, hair growing fat melting magic elixir.

Purity testing shows how much of the material in the vial that should be the peptide is actually the peptide; it doesn’t measure the rest of the vial. For example, 10mg of Retatrutide at 99.89% purity means almost all of that 10mg is the correct molecule (the other 0.11% of that 10mg is usually benign stuff that is related to or responds like the peptide), but it says nothing about the rest of the vial’s contents.

Mass testing (like quantitative assays and mass spectrometry) tells you how much peptide is actually in the vial, which helps with dosing and confirming you got what you paid for. If the vial contains 10mg of peptide, the assay confirms that; if it actually contained 100mg, and you didn’t test it, you could administer a dose 10x higher than intended. So that is actually a safety concern addressed by the common testing.

Together, these tests answer: “Is this the peptide I expect?” and “Is it the amount that I expect?” They do not prove safety, per se. You could, hypothetically, have a vial with 10mg of 99.89% pure Retatrutide and 90mg of lyophilized plague infected rat semen and the purity testing would still look fine for the peptide portion, but most of the vial would not be something safe to inject or ingest.

Use mass and purity testing to avoid dosing mistakes and confirm the molecule, but don’t assume the product is completely safe. These tests will likely answer those “why does this new vendors product give me sick?” and “why isn’t this working even though I’ve titrated up to 10x the max dose used in the study?” Type questions. Incidentally the estimate I got for the panel of tests to find out what the rest of the junk in the vial is was over $1,000. Even after all that testing- you still cannot be sure what’s in the rest of your untested vials.

There are plenty of people more informed than I am who will tell you that any other testing is unnecessary because it’s unlikely to identify danger 95% of the time. Be careful with your confirmation bias. Hope is not a safety net. We are all playing at risk probabilities here and trying to find our acceptable tolerance.

…and now I invite you all to pick this post apart, tell me why I’m wrong, or uninformed or inexperienced …or defend me and tell me how brilliant it is with gratitude. I don’t actually care and am always glad to be educated or flattered. I just couldn’t easily find this info spelled out clearly and so I figured I’d write something up. This community of peppers is so much more than I deserve and have helped me more than hurt me. Trying to give back in a small way. Much love.

This is a great post. I think you 1,000% nailed the reality if it. From my understanding, regular purity testing basically says, 'what's on the label is what's in the bottle' but says nothing about what else might be in the bottle.

Beyond that, even if you do a test of excipients, they'll only find what they test for. If you don't test for mycotoxins, you won't find it. If you don't test for metals, you won't find them. Same with pesticide residues, solvent residues, etc.

I personally think this is a great and important discussion, and appreciate @Nathanologist for starting it and @juGGaKNot for adding to it.
 
that's why you do the contamination add-on that is 170$ and tells you all of the chemicals in the vial.
I NEVER knew that. Nobody's ever said "the contamination tells you all the chemicals in the vial" in a place where I was reading, and god that's useful to know.

Edit: Just in case that looked like sarcasm--it is not.
 
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that's why you do the contamination add-on that is 170$ and tells you all of the chemicals in the vial.

It’s true, further testing can eliminate some risk. I appreciate your perspective and engagement. But, that’s the type of overstatement of fact that makes this topic so confusing to us noobs. The “contamination add-on” is a GC-MS screen with a basic NIST library according to their site details. It will probably flag some additional volatile or unexpected compounds, but it’s not a full chemical breakdown, it won’t tell you “all of the chemicals in the vial.” You’ll never find what you don’t test for.

A broader panel, as discussed -plus a few extras, could include heavy metal screening (As, Cd, Pb, Hg), LC-MS and LC-HRMS, HPLC-DAD, ¹H NMR, endotoxin, and sterility testing. It covers 4 metals, organics, peptide purity, structural confirmation, and microbial/endotoxin contamination. Usually 1–2 vials are needed, plus shipping, and the cost is probably $1,500–$1,600 depending on sample complexity.

Even this panel only shows what each test can see. It can’t catch everything, guarantee batch consistency, or track post-test degradation. It would still probably not tell us about the plague ridden rat semen, at least not in ways we would overtly recognize. Testing reduces uncertainty, but doesn’t eliminate it.

We must clearly and accurately describe the inherent risks, and what the testing does and doesn’t mitigate. Speaking in blanket absolutes is a heuristic bias that oversimplifies fact so that we can find a false sense of security in areas where the facts don’t mitigate our fears to the level of our personal tolerance.
 
I will add this, probably the single most useful add-on any lab could offer and any client could purchase is full raw data. In my personal opinion. That is after all what we are intending to begin with. I would argue that it should not be an add-on, it should be included by default.
 
The “contamination add-on” is a GC-MS screen with a basic NIST library according to their site details. It will probably flag some additional volatile or unexpected compounds, but it’s not a full chemical breakdown
It wont tell you what there is, you need further testing for that, but it will tell you there is something else.

You want manitol, peptide and peptide degradation only, no ?
 

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