WARRANT TO PURCHASE COMMON STOCK OF LIPID SCIENCES, INC

Exhibit 4.1

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAW, AND MAY NOT BE OFFERED FOR SALE, SOLD OR TRANSFERRED UNLESS A REGISTRATION STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS SHALL BE EFFECTIVE WITH RESPECT THERETO, OR AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS IS AVAILABLE IN CONNECTION WITH SUCH OFFER, SALE OR TRANSFER. SUBJECT TO COMPLIANCE WITH THE REQUIREMENTS OF THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS, THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT MAY BE PLEDGED OR HYPOTHECATED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY THIS WARRANT OR ANY OF THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT.

WARRANT TO PURCHASE COMMON STOCK

OF

LIPID SCIENCES, INC.

Issue Date:  December 18, 2006                                                                                                                 Warrant No. 2006-   

THIS CERTIFIES that OPPENHEIMER & CO. INC. (the " Holder ") of this Warrant (this " Warrant "), has the right to purchase from LIPID SCIENCES, INC., a Delaware corporation (the " Company "), up to 183,703 fully paid and nonassessable shares of the Company’s common stock, par value $0.001 per share (the " Common Stock "), subject to adjustment as provided herein, at a price per share equal to the Exercise Price (as defined below), at any time during the period commencing on the first Business Day following the six month anniversary of the date on which this Warrant is issued (the " Issue Date ") and ending at 5:00 p.m., New York City time, on the date that is the fifth (5th) anniversary of such commencement date (the " Expiration Date ").  This Warrant is issued pursuant to a placement agent letter agreement, dated as of November 30, 2006 and in connection with the sale of shares of the Company’s Common Stock to various investors at a price of $1.35 per share (the " Offering Price ").  For purposes of this Warrant, a " Business Day " shall mean any day other than Saturday, a Sunday or a day on which the New York Stock Exchange is closed or on which the City of New York are required or authorized by law to be closed.

1.             Exercise .

(a)           Right to Exercise; Exercise Price .  Subject to the terms and conditions set forth herein, the Holder shall have the right to exercise this Warrant at any time and from time to time during the period commencing on the six month anniversary of the Issue Date and ending on the Expiration Date as to all or any part of the shares of Common Stock covered hereby (the " Warrant Shares ").  The " Exercise Price " for each Warrant Share purchased by the Holder upon the exercise of this Warrant shall be equal to $2.18 (subject to adjustment for the events specified in Section 4 of this Warrant).

(b)           Exercise Notice .  In order to exercise this Warrant, the Holder shall deliver, at any time prior to 5:00 p.m. New York City time on the Business Day on which the Holder wishes to effect such

exercise (the " Exercise Date "), to the Company an executed copy of the notice of exercise in the form attached hereto as Exhibit A (the " Exercise Notice ") and the Exercise Price (by delivery of immediately available funds).  The Exercise Notice shall also state the name or names (with address) in which the shares of Common Stock that are issuable on such exercise shall be issued.  After delivery of the Exercise Notice, the Holder shall promptly deliver the original warrant to the Company for cancellation.  In the case of a dispute as to the calculation of the Exercise Price or the number of Warrant Shares issuable hereunder (including, without limitation, the calculation of any adjustment pursuant to Section 4 of this Warrant), the Company shall promptly issue to the Holder the number of Warrant Shares that are not disputed and shall submit the disputed calculations to a certified public accounting firm of national recognition (other than the Company’s independent accountants) promptly following the date on which the Exercise Notice is delivered to the Company. The Company shall cause such accountant to calculate the Exercise Price and/or the number of Warrant Shares issuable hereunder and to notify the Company and the Holder of the results in writing no later than ten (10) Business Days following the day on which such accountant received the disputed calculations (the " Dispute Procedure "). Such accountant’s calculation shall be deemed conclusive absent manifest error.  The fees of any such accountant shall be borne by the party whose calculations were most at variance with those of such accountant.

(c)           Holder of Record .  The Holder shall, for all purposes, be deemed to have become the holder of record of the Warrant Shares specified in an Exercise Notice as of 5:00 p.m. New York City time on the Exercise Date, irrespective of the date of delivery of such Warrant Shares.  Except as specifically provided herein, nothing in this Warrant shall be construed as conferring upon the Holder hereof any rights as a stockholder of the Company prior to the Exercise Date.

(d)           Cancellation of Warrant .  This Warrant shall be canceled upon its exercise and, if this Warrant is exercised in part, the Company shall, at the time that it delivers Warrant Shares to the Holder pursuant to such exercise as provided herein, issue a new warrant, and deliver to the Holder a certificate representing such new warrant, with terms identical in all respects to this Warrant (except that such new warrant shall be exercisable into the number of shares of Common Stock with respect to which this Warrant shall remain unexercised); provided , however , that the Holder shall be entitled to exercise all or any portion of such new warrant at any time following the time at which this Warrant is exercised, regardless of whether the Company has actually issued such new warrant or delivered to the Holder a certificate therefor.

(e)           Redemption Right .  Should the Company’s Common Stock trade at $3.64 or greater per share (as appropriately adjusted for stock splits, stock dividends, combinations, recapitalizations and the like) for thirty (30) consecutive Trading Days (the " Redemption Threshold "), on the basis of closing prices of the Common Stock quoted on the Principal Market as reported by the Wall Street Journal (or, if the Wall Street Journal is not then representing such prices, by a comparable reporting service of national reputation selected by the Company), the Company may, at its sole option, redeem the Warrant by repurchasing it from the Holder for a purchase price of $0.01 per Warrant Share (as appropriately adjusted for stock splits, stock dividends, combinations, recapitalizations and the like).  The Company shall exercise its redemption right at any time after the Redemption Threshold has been met by delivery of thirty (30) days’ prior written notice to Holder (the " Redemption Exercise Period ").  Notwithstanding the foregoing, if the Redemption Threshold is met prior to this Warrant becoming exercisable by Holder, the Company may provide notice of its intention to redeem the Warrant and the Redemption Exercise Period shall commence upon the date the Warrant first becomes exercisable.  Holder shall have the right to exercise the Warrant in accordance with Section 1(b) above prior to expiration of the Redemption Exercise Period.

2.             Delivery of Warrant Shares Upon Exercise .  Upon exercise pursuant to Section 1 of this Warrant, the Company shall issue and deliver or caused to be delivered to the Holder the number of

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Warrant Shares as shall be determined as provided herein within a reasonable time, not exceeding (A) the close of business on the third (3rd) Business Day following the Exercise Date and (B) with respect to Warrant Shares that are the subject of a Dispute Procedure, the close of business on the third (3rd) Business Day following the determination made pursuant to Section 1(b) of this Warrant (each of the dates specified in (A) and (B) being referred to as a " Delivery Date ").  The Company shall effect delivery of Warrant Shares to the Holder by delivering to the Holder or its nominee physical certificates representing such Warrant Shares, no later than the close of business on such Delivery Date.  The certificates representing the Warrant Shares may bear legends in accordance with the legend set forth on the face of this Warrant or applicable law.

3.             Failure to Deliver Warrant Shares .

(a)           In the event that the Company fails for any reason to deliver to the Holder the number of Warrant Shares specified in the applicable Exercise Notice on or before the Delivery Date therefor (an " Exercise Default "), the Company shall pay to the Holder payments (" Exercise Default Payments ") in the amount of (i) (N/365) multiplied by (ii) the aggregate Exercise Price of the Warrant Shares which are the subject of such Exercise Default multiplied by (iii) the lower of twelve percent (12%) per annum and the maximum rate permitted by applicable law (the " Default Interest Rate "), where "N" equals the number of days elapsed between the original Delivery Date of such Warrant Shares and the date on which all of such Warrant Shares are issued and delivered to the Holder.  Cash amounts payable hereunder shall be paid on or before the fifth (5th) Business Day of each calendar month following the calendar month in which such amount has accrued.

(b)           In the event that the Holder has not received certificates representing the Warrant Shares on or before the Delivery Date, the Holder may, upon written notice to the Company (an " Exercise Default Notice "), regain on the date of such notice the rights of the Holder under the exercised portion of this Warrant that is the subject of such Exercise Default.  In such event, the Holder shall retain all of the Holder’s rights and remedies with respect to the Company’s failure to deliver such Warrant Shares (including without limitation the right to receive the cash payments specified in Section 3(a) of this Warrant).

(c)           The Holder’s rights and remedies hereunder are cumulative, and no right or remedy is exclusive of any other.  In addition to the amounts specified herein, the Holder shall have the right to pursue all other remedies available to it at law or in equity (including, without limitation, a decree of specific performance and/or injunctive relief).  Nothing herein shall limit the Holder’s right to pursue actual damages for the Company’s failure to issue and deliver Warrant Shares on the applicable Delivery Date.

4.             Anti-Dilution Adjustments; Distributions; Other Events .  The Exercise Price and the number of Warrant Shares issuable hereunder shall be subject to adjustment from time to time as provided in this Section 4 .

(a)           Subdivision or Combination of Common Stock .  If the Company, at any time after the Issue Date, subdivides (by any stock split, stock dividend, recapitalization, reorganization, reclassification or otherwise) its outstanding shares of Common Stock into a greater number of shares, then after the date of record for effecting such subdivision, the Exercise Price in effect immediately prior to such subdivision will be proportionately reduced.  If the Company, at any time after the Issue Date, combines (by reverse stock split, recapitalization, reorganization, reclassification or otherwise) its shares of Common Stock into a smaller number of shares, then, after the date of record for effecting such combination, the Exercise Price in effect immediately prior to such combination will be proportionally increased.

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(b)           Distributions .  If the Company shall declare or make any distribution of its assets (or rights to acquire its assets) to holders of Common Stock as a partial liquidating dividend or otherwise (including any dividend or distribution to the Company’s stockholders in cash or shares (or rights to acquire shares) of capital stock of a subsidiary) (a " Distribution "), the Company shall deliver written notice of such Distribution (a " Distribution Notice ") to the Holder at least twenty (20) Business Days prior to the earlier to occur of (i) the record date for determining stockholders entitled to such Distribution (the " Record Date ") and (ii) the date on which such Distribution is made (the " Distribution Date ").  The Holder shall be entitled to a reduction in the Exercise Price as of the Record Date therefor, such reduction to be effected by reducing the Exercise Price in effect on the Business Day immediately preceding the Record Date by an amount equal to the fair market value of the assets to be distributed divided by the number of shares of Common Stock as to which such Distribution is to be made, such fair market value to be reasonably determined in good faith by the independent members of the Company’s Board of Directors.

(c)           Dilutive Issuances .

(i)            Adjustment Upon Dilutive Issuance .  If, at any time after the Issue Date, the Company issues or sells, or in accordance with Section 4(c)(ii) of this Warrant, is deemed to have issued or sold, any shares of Common Stock for no consideration or for a consideration per share less than the lesser of (x) the Offering Price or (y) the Exercise Price on the date of such issuance or sale (or deemed issuance or sale) (a " Dilutive Issuance "), then the Exercise Price shall be adjusted so as to equal an amount determined by multiplying such Exercise Price by the following fraction:

• • • • • • N 0  + N 1

            N 0  + N 2

    where:

    • • • • • • N 0  =                         the number of shares of Common Stock outstanding immediately prior to the issuance, sale or deemed issuance or sale of such additional shares of Common Stock in such Dilutive Issuance (without taking into account any shares of Common Stock issuable upon conversion, exchange or exercise of any securities or other instruments which are convertible into or exercisable or exchangeable for Common Stock (" Convertible Securities ") or options, warrants or other rights to purchase or subscribe for Common Stock or Convertible Securities (" Purchase Rights "), including, without limitation, the Warrants);

                N 1  =                         the number of shares of Common Stock which the aggregate consideration, if any, received or receivable by the Company for the total number of such additional shares of Common Stock so issued, sold or deemed issued or sold in such Dilutive Issuance (which, in the case of a deemed issuance or sale, shall