Molarity Calculator
Convert a mass concentration to a molar concentration for any of 50 catalog compounds. Each molar mass is the value published against that compound's PubChem record, not one we computed.
RESEARCH USE ONLY — LABORATORY REFERENCEConvert
Pick a catalog compound or enter a molar mass directly. 5 compound(s) carry a form warning that appears with the result when you pick them ‡ — their published mass is for a different form than the material as supplied.
Formula: molarity (mM) = concentration (mg/mL) ÷ molar mass (g/mol) × 1000. Molar masses are the published values on each compound's PubChem record, carried with its CID rather than derived here; verify against the lot's certificate of analysis for the exact salt or form mass.
Why the conversion is the easy part
Dividing a mass concentration by a molar mass is arithmetic. The part that goes wrong is deciding which molar mass belongs in the denominator, and the answer is usually not the one printed on a supplier's page.
Three different masses get called "the molar mass" of a peptide, and they are not interchangeable. The first is the free-base mass computed from the molecular formula — that is what this tool computes, and what a formula on a product record refers to. The second is the salt mass: most synthetic peptides are supplied as trifluoroacetate or acetate salts, and a counterion attached to every basic residue can add a real percentage to the formula weight. The third is what the vial actually contains, which is neither, because the powder is peptide plus counterion plus residual water.
The practical consequence: a solution prepared from the label mass and converted with the free-base molar mass overstates molarity, sometimes by more than a rounding error. A record that needs to be accurate takes net peptide content from the lot's certificate of analysis rather than from the label, and states which mass it used. That is a sentence worth writing into the record, because a molarity with no stated basis cannot be reproduced by anyone else.
Net content, purity and identity are reported as separate measurements per lot on the certificate of analysis. Where a field is unverified it is shown as pending rather than filled with a representative figure.
Catalog molar masses
Published molecular weights, carried with the PubChem CID they came from. A row marked ‡ is a mass for a different form than the material as supplied.
| Compound | Formula | Molar mass | Source |
|---|---|---|---|
| 5-AMINO-1MQ ‡ | C10H11N2+ | 159.21 g/mol | CID 950107 |
| Adipotide (FTPP) | C111H206N36O28S2 | 2,557.2 g/mol | CID 163360068 |
| AHK-Cu ‡ | C15H26N6O4 | 354.41 g/mol | CID 7408502 |
| AOD9604 | C78H123N23O23S2 | 1,815.1 g/mol | CID 71300630 |
| ARA-290 | C51H84N16O21 | 1,257.3 g/mol | CID 91810664 |
| BPC 157 | C62H98N16O22 | 1,419.5 g/mol | CID 9941957 |
| Bronchogen | C18H30N4O9 | 446.5 g/mol | CID 11690869 |
| Cagrilintide | C194H312N54O59S2 | 4,409 g/mol | CID 171397054 |
| Cartalax | C12H19N3O8 | 333.29 g/mol | CID 87815447 |
| CJC-1295 (no DAC) | C152H252N44O42 | 3,367.9 g/mol | — |
| CJC-1295 (with DAC) | C165H269N47O46 | 3,647.2 g/mol | CID 91971820 |
| Cortagen | C17H26N4O9 | 430.4 g/mol | CID 18439621 |
| DSIP | C35H48N10O15 | 848.8 g/mol | CID 68816 |
| Epithalon | C14H22N4O9 | 390.35 g/mol | CID 219042 |
| FOXO4-DRI | C228H388N86O64 | 5,358 g/mol | CID 167312269 |
| GHK-Cu ‡ | C14H24N6O4 | 340.38 g/mol | CID 73587 |
| GHRP-2 | C45H55N9O6 | 818 g/mol | CID 6918245 |
| GHRP-6 | C46H56N12O6 | 873 g/mol | CID 4345065 |
| Glutathione | C10H17N3O6S | 307.33 g/mol | CID 124886 |
| Gonadorelin Acetate | C57H79N17O15 | 1,242.3 g/mol | CID 11980076 |
| Ipamorelin | C38H49N9O5 | 711.9 g/mol | CID 9831659 |
| Kisspeptin-10 | C63H83N17O14 | 1,302.4 g/mol | CID 25240297 |
| KPV | C16H30N4O4 | 342.43 g/mol | CID 125672 |
| LL-37 | C205H340N60O53 | 4,493 g/mol | CID 16198951 |
| Matrixyl | C39H75N7O10 | 802.1 g/mol | CID 9897237 |
| Mazdutide | C207H317N45O65 | 4,476 g/mol | CID 167312357 |
| Melanotan I | C78H111N21O19 | 1,646.8 g/mol | CID 16197727 |
| Melanotan II | C50H69N15O9 | 1,024.2 g/mol | CID 92432 |
| MOTS-c (Human) | C101H152N28O22S2 | 2,174.6 g/mol | CID 146675088 |
| NAD+ | C21H27N7O14P2 | 663.4 g/mol | CID 5892 |
| Oxytocin Acetate ‡ | C43H66N12O12S2 | 1,007.2 g/mol | CID 439302 |
| PE-22-28 | C35H55N11O9 | 773.9 g/mol | CID 165437303 |
| Pinealon | C15H26N6O8 | 418.4 g/mol | CID 10273502 |
| PT-141 | C50H68N14O10 | 1,025.2 g/mol | CID 9941379 |
| PTD-DBM | C124H225N61O28S2 | 3,082.6 g/mol | CID 176453931 |
| Retatrutide | C221H342N46O68 | 4,731.3 g/mol | — |
| Selank | C33H57N11O9 | 751.9 g/mol | CID 11765600 |
| Semaglutide | C187H291N45O59 | 4,114 g/mol | CID 56843331 |
| Semax | C37H51N9O10S | 813.9 g/mol | CID 9811102 |
| Sermorelin Acetate ‡ | C149H246N44O42S | 3,357.9 g/mol | CID 16132413 |
| SNAP-8 | C41H70N16O16S | 1,075.2 g/mol | CID 76283482 |
| SS-31 | C32H49N9O5 | 639.8 g/mol | CID 11764719 |
| Survodutide | C192H289N47O61 | 4,232 g/mol | CID 171378821 |
| TB-500 | C38H68N10O14 | 889 g/mol | CID 62707662 |
| Tesamorelin | C221H366N72O67S | 5,136 g/mol | CID 16137828 |
| Thymalin/Thymulin | C33H54N12O15 | 858.9 g/mol | CID 71300623 |
| Thymosin Alpha-1 | C129H215N33O55 | 3,108.3 g/mol | CID 16130571 |
| Tirzepatide | C225H348N48O68 | 4,813 g/mol | CID 166567236 |
| Vesugen | C15H26N4O8 | 390.39 g/mol | CID 87571363 |
| VIP | C147H237N43O43S | 3,326.8 g/mol | CID 53314964 |
Last reviewed · first published . Sizes and prices update from the live catalog.
