WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 525665

CAS#: 328232-95-7

Description: MK-0557 is a highly selective, orally administered neuropeptide NPY5R antagonist, could limit weight regain after very-low-calorie diet (VLCD)-induced weight loss. Neuropeptide Y (NPY) is a potent orexigenic neuropeptide, and antagonism of NPY Y1 and NPY Y5 receptors (NPYxR) is considered a potentially important anti-obesity drug target.

Price and Availability

Size Price Shipping out time Quantity
100mg USD 1450 2 Weeks
200mg USD 2150 2 Weeks
500mg USD 2950 2 Weeks
1g USD 3950 2 Weeks
2g USD 6950 2 Weeks
5g USD 14650 2 Weeks
Inquire bulk and customized quantity

Pricing updated 2021-01-25. Prices are subject to change without notice.

MK-0557, purity > 98%, is in stock. Current shipping out time is about 2 weeks after order is received. CoA, QC data and MSDS documents are available in one week after order is received.

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 525665
Name: MK-0557
CAS#: 328232-95-7
Chemical Formula: C22H19FN4O3
Exact Mass: 406.14412
Molecular Weight: 406.4174
Elemental Analysis: C, 65.02; H, 4.71; F, 4.67; N, 13.79; O, 11.81

Synonym: MK0557; MK 0557; MK-0557

IUPAC/Chemical Name: (1s,4s)-N-(1-(2-fluorophenyl)-1H-pyrazol-3-yl)-1'-oxo-1'H-spiro[cyclohexane-1,3'-furo[3,4-c]pyridine]-4-carboxamide


InChi Code: InChI=1S/C22H19FN4O3/c23-17-3-1-2-4-18(17)27-12-8-19(26-27)25-20(28)14-5-9-22(10-6-14)16-13-24-11-7-15(16)21(29)30-22/h1-4,7-8,11-14H,5-6,9-10H2,(H,25,26,28)/t14-,22+

SMILES Code: O=C([C@H]1CC[C@@](C2=C3C=CN=C2)(OC3=O)CC1)NC4=NN(C5=CC=CC=C5F)C=C4

Technical Data

Solid powder

>98% (or refer to the Certificate of Analysis)

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO, not in water

Shelf Life:
>2 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code:


1: Fichtner M, Lee E, Tomlinson E, Scott D, Cornelius P, Patterson TA, Carpino PA. Discovery and evaluation of spirocyclic derivatives as antagonists of the neuropeptide Y5 receptor. Bioorg Med Chem Lett. 2012 Apr 15;22(8):2738-43. doi: 10.1016/j.bmcl.2012.02.098. Epub 2012 Mar 6. PubMed PMID: 22445286.
2: MacNeil DJ. NPY Y1 and Y5 receptor selective antagonists as anti-obesity drugs. Curr Top Med Chem. 2007;7(17):1721-33. Review. PubMed PMID: 17979781.
3: Mifflin SW, Strack A. Obesity and the central nervous system. J Physiol. 2007 Sep 1;583(Pt 2):423. PubMed PMID: 17766646; PubMed Central PMCID: PMC2277037.
4: Erondu N, Addy C, Lu K, Mallick M, Musser B, Gantz I, Proietto J, Astrup A, Toubro S, Rissannen AM, Tonstad S, Haynes WG, Gottesdiener KM, Kaufman KD, Amatruda JM, Heymsfield SB. NPY5R antagonism does not augment the weight loss efficacy of orlistat or sibutramine. Obesity (Silver Spring). 2007 Aug;15(8):2027-42. PubMed PMID: 17712121.
5: Erondu N, Wadden T, Gantz I, Musser B, Nguyen AM, Bays H, Bray G, O'Neil PM, Basdevant A, Kaufman KD, Heymsfield SB, Amatruda JM. Effect of NPY5R antagonist MK-0557 on weight regain after very-low-calorie diet-induced weight loss. Obesity (Silver Spring). 2007 Apr;15(4):895-905. PubMed PMID: 17426325.
6: Erondu N, Gantz I, Musser B, Suryawanshi S, Mallick M, Addy C, Cote J, Bray G, Fujioka K, Bays H, Hollander P, Sanabria-Bohórquez SM, Eng W, Långström B, Hargreaves RJ, Burns HD, Kanatani A, Fukami T, MacNeil DJ, Gottesdiener KM, Amatruda JM, Kaufman KD, Heymsfield SB. Neuropeptide Y5 receptor antagonism does not induce clinically meaningful weight loss in overweight and obese adults. Cell Metab. 2006 Oct;4(4):275-82. PubMed PMID: 17011500.