Exhibit 32.1
CERTIFICATIONPURSUANT TO
SECTION 1350, CHAPTER 63 OF TITLE 18, UNITED STATES CODE,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002
Pursuant to Section 1350, Chapter 63 of Title 18, United States Code, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned, as principal executive officer and principal financial officer of Sirtris Pharmaceuticals, Inc. (the “Company”), do hereby certify that to their knowledge:
1) the Company’s Form 10-Q for the fiscal quarter ended March 31, 2008 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
2) the information contained in the Company’s Form 10-Q for the fiscal quarter ended March 31, 2008 fairly presents, in all material respects, the financial condition and results of operations of the Company.
| /s/ Christoph Westphal |
| Christoph Westphal |
| President and Chief Executive Officer |
| (principal executive officer) |
| |
| |
| /s/ Garen Bohlin |
| Garen Bohlin |
| Chief Operating Officer |
| (principal financial officer) |
| |
| |
Dated: May 14, 2008 | |
