FOURTH AMENDMENT

TO

AMENDED AND RESTATED NOTE PURCHASE AGREEMENT

This FOURTH AMENDMENT TO AMENDED AND RESTATED NOTE PURCHASE AGREEMENT (the “Amendment”), dated and effective as of June 29, 2012, by and between INTERLEUKIN GENETICS, INC., a Delaware corporation (the “Company”), and PYXIS INNOVATIONS INC., a Delaware corporation (“Pyxis”).

WHEREAS, the Company and Pyxis are parties to an Amended and Restated Note Purchase Agreement dated as of March 10, 2009 and amended on August 10, 2009, February 1, 2010 and September 30, 2010 (the “Agreement”), pursuant to which Pyxis extended the Company a credit facility (the “Credit Facility”) in an amount (following applicable adjustments) not to exceed Fourteen Million Three Hundred Sixteen Thousand Two Hundred Fifty-Five Dollars and No/100 ($14,316,255.00) on which the Company may draw down until June 30, 2012 (the “Credit Facility Termination Date”);

WHEREAS, Pyxis purchased, and the Company sold and issued to Pyxis, (i) a promissory note in the principal amount of Four Million Dollars and No/100 ($4,000,000.00) on June 10, 2008, (ii) a promissory note in the principal amount of One Million Dollars and No/100 ($1,000,000.00) on May 29, 2009, (iii) a promissory note in the principal amount of Two Million Dollars and No/100 ($2,000,000.00) on November 9, 2009, (iv) a promissory note in the principal amount of Two Million Dollars and No/100 ($2,000,000.00) on February 1, 2010, (v) a promissory note in the principal amount of Two Million Dollars and No/100 ($2,000,000.00) on September 30, 2010, (vi) a promissory note in the principal amount of Two Million Dollars and No/100 ($2,000,000.00) on November 9, 2011 and (vii) a promissory note in the principal amount of One Million Three Hundred and Sixteen Thousand Two Hundred and Fifty-Five Dollars and No/100 ($1,316,255.00) on April 13, 2012, all under the terms of the Credit Facility;

WHEREAS, the Company has requested that Pyxis extend the Maturity Date of all Notes issued pursuant to the Credit Facility, and Pyxis is willing to grant such extension;

NOW, THEREFORE, in consideration of the foregoing premises and the representations, warranties, covenants and agreements contained in the Agreement and this Amendment, the parties hereto agree as follows:

IN WITNESS WHEREOF, the parties have executed this Fourth Amendment to Amended and Restated Note Purchase Agreement as of the date first written above.