Every figure here is checkable at the laboratory that produced it
Verification / Europe

A Vial Can Be 99.7% Pure and Still Be Half Empty

The report looks perfect the whole way down. There is a second number on it, one row up, and most sellers never put it on a product page at all.

Two lines in the results box

Purity

99.744%

the figure every seller

puts on the page

Amount

22.43mg

the figure that says what

is actually in the vial

Crystal Peptides, batch RT6423CP, analysed 25 May 2026

The report is one page. A logo at the top. A batch number. A small box of results in the middle.

You know where you are going before the page finishes loading. The thumb moves. The eye drops into the box and lands on the bold percentage.

99.744%.

New to this? This page assumes you already know what research peptides are. If you do not, start with this one instead. It covers what this market is, why it exists, and what lab testing has found in it.

That is the number. The one we print on the product page. The one people screenshot. The one that ends the argument in a group chat.

Now go back up one row.

Directly above the purity line, in the same box, on the same page, sits a second result. It is one short line, and it is easy to read straight past on the way down.

On the Crystal Peptides report for Retatrutide 20mg, batch RT6423CP, that line reads:

Retatrutide 22.43 mg.

The vial is labelled 20 mg. The laboratory measured 22.43 mg. About twelve percent over what the label promises.

On the American Peptides certificate for the same compound at the same size, lot RETA20-0803, the same row reads 20.22 mg against a 20 mg label. One percent over.

Both clear the bar. They are nowhere near each other, and that spread is the whole reason to read the row.

Here is why that row is the one you wanted.

Purity is a percent, and a percent is a ratio. Take powder that is 99.6% pure and pour half of it away. What is left is still 99.6% pure. Pour half of that away too. Still 99.6%.

The number does not move. It cannot move. It has nothing to measure itself against except the powder already in the glass.

So the same clean figure survives all the way down. That is not an accusation about anyone. It is arithmetic.

And you cannot settle it by looking. Inside the vial is a small amount of freeze dried white powder. You cannot weigh it by eye. Nobody can.

Two questions

What each row can prove, and what it cannot

There are two things you might want to know about a vial, and people tend to collapse them into one.

Row one

Retatrutide 22.43 mg

How much is in the glass. An amount, in milligrams, that can be compared against the number printed on the label.

Row two

Purity 99.744%

What the material is, as a proportion of itself. A quality score for the powder that is present. It says nothing about how much is present.

Both are on the same certificate. Both came from the same sample. They answer different questions, and only one of them is ever quoted in marketing.

A seller can be entirely honest and still only ever show you the second one, because the second one is the number the whole market learned to ask for. That is why the row above it goes unread even when it is printed right there.

Be clear about this

The amount is never missing from the laboratory. It is missing from the page. It sits on the certificate one row above the figure everybody quotes, and almost nobody puts it in the copy.

The trap

The one number you cannot check yourself

Janoshik price list / 73 peptide tests

Almost every other claim a seller makes can be tested by a careful reader for free.

Is a laboratory named on the certificate? Look. Does the batch code on the report match the one on the product page? Compare them. Is there a verification code you can type on the lab's own website? Type it.

The amount is different. To check it you need an instrument, and the instrument is not something anyone has at home.

“So aside from paying a fortune to test them, how do i know if its good?”

r/Peptides

He has a point, and the numbers are worth knowing. Janoshik publishes its price list: 73 peptide tests, and the cheapest of them is 215 dollars.

Retatrutide starts at 105 dollars at one of the sellers on this site. So the cheapest test on the list costs about twice the product, a full panel costs several times it, and you would be paying either one after your money has already gone.

Which means the amount gets settled on somebody else's paperwork or it does not get settled at all.

The standard

Buyers already wrote the rule. Two lines, not one.

Peptide forum / group buy thread

The informed end of this market did not wait for sellers to sort this out.

On group buys, where a set of buyers order a batch together and pay for testing between them, the terms get written down before anyone sends money. One poster set out what theirs required:

“The guidelines I'm referring to on this GB was purity of at least 99% and it was. The quantity was to be at least 90% of 10 mg, and it was (I think 9.4 but not positive).”

Peptide forum, group buy thread

Read what that person asked for. Not one pass mark. Two.

A purity floor, at 99 percent. And an amount floor, at 90 percent of the labelled 10 mg. Their batch came in around 9.4 mg, so it cleared the second bar with a little room.

That is the whole idea, written by somebody spending their own money. Two questions, two numbers, and a pass mark for each.

Set both reports against the same two bars. Crystal Peptides: purity 99.744%, so it clears the first, and 22.43 mg against a 20 mg label, so it clears the second one going the other way. American Peptides: purity 99.79%, and 20.22 mg against a 20 mg label. Two passes, eleven percentage points apart on the row nobody reads.

The document

Both rows, on the real thing

Janoshik 163572 / 25 May 2026

These are two published certificates for two real batches, from two sellers and two laboratories. Not examples and not templates.

Read both rows, not one

The results box holds two lines, and the amount sits directly above the percentage.

Crystal Peptides. Retatrutide 22.43 mg above Purity 99.744%. Batch RT6423CP, task #163572, analysed 25 May 2026 by Janoshik. The tests-requested field reads “Common GLP-1 peptide blind test”, so the laboratory was not told what it had.

American Peptides. Content 20.22 mg and Overall purity 99.79% on adjacent rows, each with its method named. Lot RETA20-0803, issued 17 August 2026 by Bioviridian Inc., signed by a named principal chemist.

Both reports carry a photograph or a verification code that the seller cannot edit after the fact.

Look at the label in that photograph. It reads Retatrutide, 10 mg, 99% Purity.

Both of those numbers were printed before anything went into the glass. A label is a statement of intent. The report is the measurement.

Do this

Sixty seconds, on any seller

You can run this on us, and on whoever else you are looking at, before you type an email address.

  1. Open a lab report on their site. If there is no report at all, you are already finished.
  2. Find the results box. It is usually in the middle of the page, under the sample details.
  3. Count the rows. Is there a line with a weight on it, in milligrams, as well as a line with a percentage?
  4. If there is, compare that weight against the number on the product label. That is the check almost nobody runs.
  5. If the only figure anywhere is a percentage, then the amount has not been answered. That is not proof of anything bad. It is just a question still open.
Worth knowing

Plenty of sellers order tests that measure the amount without ever mentioning it, in exactly the way we did. If you find the weight on their report, that seller can answer the question. Ask them to put it on the page.

The limits

What this does not prove

RT6423CP / RETA20-0803

If we only told you what our report covers, we would be doing the thing this page is complaining about.

What we can say is narrow and checkable: on this batch, both rows were measured, and both are printed above.

Where to go from here

Run the five steps on whoever you are considering, then run them on us. The certificate is on the product page with the batch number and the verification code on it.

What happens if it goes wrong

Every seller looks the same on the good day. Four things decide what happens on the bad one, and all four are published before you order if you go and read them.

  • How long you have to report it. Windows we found in September 2026 ran from 48 hours to seven days from delivery. Two days is easy to miss if a parcel arrives while you are away.
  • What proof they demand. Some accept photographs. At least one accepts nothing but a full continuous unboxing video, which means the moment to protect yourself is before you open the parcel, not after you find the problem.
  • Whether customs seizure is covered. Some terms name it and cover it once. Others are silent, and silence is not cover.
  • What happens the second time. Look for whether a replacement that also fails gets refunded, or whether that is where the terms stop. Customs duties are yours everywhere. Your statutory rights as an EU consumer are unaffected by any seller's terms.

Read the seller's own published pages, not their marketing, and none of these terms were written by us.

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We will send the checking steps as a one page sheet, in plain language, so you can run them on any seller in any country, including the ones this site links to.

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Amount measured Batch matched Verify code included Outside lab Both rows published