MOTS-c test, NAD+ and other less-tested compounds: what a lab checks and how often samples fail

What a MOTS-c test shows

A MOTS-c test answers the same three questions as any peptide test. LC-MS shows whether the main compound has the right mass. HPLC shows how pure it is, as a share of UV peak area. A content assay against a reference standard gives the mg per vial. Endotoxin and sterility are separate tests, run on their own unopened vials.

MOTS-c is a 16-amino-acid peptide, sequence MRWQEMGYIFYPRKLR, formula C101H152N28O22S2. Its calculated monoisotopic mass is 2173.1077 Da. Methionine sits at positions 1 and 6, and methionine oxidation is a common chemical degradation pathway in peptides; each oxidised methionine adds about 16 Da. A useful MOTS-c identity result gives the observed mass, the error in ppm and any +16 Da species next to the main peak.

MOTS-c and NAD+ test results in published data

Finnrick, a US platform that sends community-submitted and purchased samples to third-party labs and publishes the results, holds the largest public set. It began publishing MOTS-c and NAD+ results in February 2026. Its public data summary, read on 4 October 2026 with the latest test dated 25 September, shows:

• MOTS-c: 77 tests from 20 vendors. 22 passed and 52 failed, so 70% of classifiable samples failed.
• NAD+: 61 tests from 19 vendors. 15 passed and 41 failed: 73%.
• Retatrutide, for scale: 4,367 tests, with 22% of classifiable samples failed.

Incomplete tests are left out of the fail shares. Even the highest-rated sellers score low: on the public leaderboards, the highest MOTS-c rating is 41% (8 tests) and the highest NAD+ rating 35% (2 tests). These ratings are recency-weighted pass shares, pulled toward the product’s average when a seller has few tests.

The sets are small and move fast: our snapshot of the same summary with data to 20 September 2026 listed 27 NAD+ tests, against 61 two weeks later. Finnrick’s default standard, Purity Focus, passes a sample only if purity is at least 99.5% and the fill is within ±35% of the label claim; overfill fails too. The counts do not say which requirement each sample missed. The guide to peptide fail rates has more caveats.

Less-tested compounds at a glance

Compound	What it is	Calculated monoisotopic mass	Finnrick tests	Failed of classifiable
MOTS-c	16-amino-acid peptide	2173.1077 Da	77	52 of 74 (70%)
NAD+	Coenzyme, not a peptide	663.1091 Da	61	41 of 56 (73%)
KPV	3 amino acids (Lys-Pro-Val)	342.2267 Da	17	13 of 15
SS-31 (elamipretide)	4 residues, two of them non-standard	639.3857 Da	20	5 of 17
Semax	7 amino acids (MEHFPGP)	813.3480 Da	5	1 of 3
Selank	7 amino acids (TKPRPGP)	751.4341 Da	1	None classifiable
PT-141 (bremelanotide)	Cyclic, 7 amino acids, acid end	1024.5243 Da	151	53 of 148 (36%)
Melanotan II	Same ring, amide end	1023.5403 Da	182	67 of 177 (38%)
Mazdutide	GLP-1 and glucagon receptor dual agonist	4473.2883 Da	29	11 of 29 (38%)
Survodutide	GLP-1 and glucagon receptor dual agonist	4229.0957 Da	27	13 of 26 (50%)
AOD-9604	Growth hormone fragment analogue	1813.8604 Da	Not listed	Not listed
IGF-1 LR3	Recombinant IGF-1 analogue, 83 amino acids	About 9.1 kDa (supplier figure)	Not listed	Not listed

Masses are PubChem’s calculated monoisotopic masses; the IGF-1 LR3 figure is a supplier’s approximate weight. Finnrick counts come from its summary read on 4 October 2026.

NAD+ is a coenzyme, not a peptide

NAD+ (nicotinamide adenine dinucleotide) has the formula C21H27N7O14P2. It is sold next to peptides, so buyers search for an “NAD+ peptide test”, but a lab needs an NAD+ method. One published method, written for cell and tissue extracts, separates NAD+ by reversed-phase HPLC and reads it by UV absorbance at 261 nm, with the NAD+ peak clear of related metabolites (Yoshino and Imai, 2013). Janoshik files its NAD+ test under “Others”, not under peptides. The results you need do not change: identity by mass, purity as % area, and mg per vial against an NAD+ reference standard.

PT-141 and melanotan II are less than 1 Da apart

PT-141 (bremelanotide) and melanotan II share the same seven amino acids, cyclised the same way. PubChem records PT-141 with a free acid at the end and melanotan II with an amide. Their calculated masses differ by 0.98 Da. A mass check that accepts results within 1 Da cannot tell them apart. Ask for the observed monoisotopic mass with its ppm error, and the chromatogram.

Semax and Selank: acetylated and amidated forms

Semax and Selank carry the same trap. Janoshik lists N-acetyl and amidated versions of both as separate tests. An acetyl group adds 42.01 Da; an amide end lowers the mass by 0.98 Da. Tell the lab which form the label claims, and check that the report names it.

KPV, SS-31, AOD-9604 and IGF-1 LR3

• KPV is recorded in PubChem as MSH (11-13), the last three amino acids of α-MSH. The highest Finnrick rating for any KPV seller is 17%.
• SS-31 is D-arginine, 2’,6’-dimethyltyrosine, lysine and a phenylalanine amide. A version made with L-arginine would have exactly the same mass, so LC-MS cannot rule it out; that needs a chromatographic separation.
• AOD-9604 names are loose. PubChem holds an AOD-9604 record and a separate “HGH Fragment 176-191” record about 44 Da heavier. Janoshik lists “rHGH fragment or AOD-9604” as one test. Ask the lab to print the formula it tested for.
• IGF-1 LR3 is a small protein made recombinantly. Its intact mass is read from many charge states, as for hGH.

Mazdutide and survodutide

Their masses sit in the same range as semaglutide (4111.1154 Da) and retatrutide (4728.4718 Da), both listed in the guide to blind GLP-1 identification, yet differ from each by more than 100 Da. LC-MS tells them apart, but only if the lab looks for them. A blind GLP-1 identification checks a vial against a fixed candidate list, so ask whether mazdutide and survodutide are on it. Finnrick’s data here are thin and old: its latest mazdutide test is dated 25 November 2025.

Before you send a less-tested compound

1. Ask whether the lab holds a reference standard for that exact compound. Without a qualified standard, mg per vial is an estimate and should be labelled as one. See content per vial and the guide to net peptide content.
2. Ask which form it tests for: acetylated or not, amide or acid, which fragment.
3. Ask what the identity result shows: the observed mass and ppm error, not retention time alone.
4. Expect to pay more than for a common peptide at some labs. Janoshik, Krause Analytical, BTLabs and TrustPointe each list MOTS-c, NAD+, KPV and SS-31 as named tests. At Janoshik and TrustPointe, each of the four is listed at about twice the price of a BPC-157 test at the same lab (checked September 2026).
5. Share the cost. A group test splits one lab fee across buyers of the same batch; the guide to running a peptide group test covers the steps.

A test shows what was in the vial the lab received. It cannot say whether a product is safe to use.

What HK Analytical does for less-tested compounds

MOTS-c, NAD+ and the other compounds here are not on our list of peptides we test. Name the compound in your quote request and ask which of our tests apply: identity (LC-MS), purity (HPLC), content per vial, endotoxin (LAL) and Sterility (USP <71>, 14 days), in any mix, per sample. Where no qualified reference standard exists, the report marks content as estimated. We do not offer sequence confirmation or per-component blend analysis. Results within days of receipt. Sterility (USP <71>, 14 days) is the one test that takes 14 days, because the method incubates for 14 days. Every number comes with its raw data, in a signed record you can check at hkanalytical.com/verify. See the example report.