UNSECURED CONVERTIBLE PROMISSORY NOTE

Exhibit 4.3

THIS NOTE AND THE SECURITIES ISSUABLE UPON CONVERSION OF THIS NOTE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR THE SECURITIES LAWS OF ANY STATE.  THIS NOTE AND ANY OF SUCH SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT RELATING TO SUCH TRANSACTION UNDER THE ACT AND ALL OTHER APPLICABLE SECURITIES LAWS, OR PURSUANT TO AN EXEMPTION FROM THE REGISTRATION PROVISIONS OF THE ACT AND OTHER APPLICABLE SECURITIES LAWS.

THIS UNSECURED CONVERTIBLE PROMISSORY NOTE (AND ALL PAYMENT AND ENFORCEMENT PROVISIONS HEREIN) IS SUBJECT TO THE TERMS OF A SUBORDINATION AGREEMENT DATED AS OF [JANUARY 3, 2014] [MAY 21, 2014], BY AND AMONG THE HOLDER (AS DEFINED HEREIN), THE LENDERS THAT ARE PARTY TO THE AGREEMENT (AS DEFINED HEREIN), THE COMPANY (AS DEFINED HEREIN), AND OXFORD FINANCE LLC (THE “SUBORDINATION AGREEMENT”).  IN THE EVENT OF ANY INCONSISTENCY BETWEEN THIS NOTE AND THE SUBORDINATION AGREEMENT, THE TERMS OF THE SUBORDINATION AGREEMENT SHALL CONTROL.

UNSECURED CONVERTIBLE PROMISSORY NOTE

FOR VALUE RECEIVED, Clarus Therapeutics, Inc., a Delaware corporation (the “Company”), hereby promises to pay to the order of                      (the “Holder”) the sum of                                                  dollars ($                ) all as hereinafter provided with interest thereon from the date of issuance of this Unsecured Convertible Promissory Note (this “Note”) at the applicable rate set forth in Section 2 hereof.  All payments to be made by the Company in repayment of interest and principal or other amounts due hereunder shall be made in currency of the United States of America which at the time of payment shall be legal tender for the payment of public or private debts.

This Note is one of a series of notes (collectively, the “Notes”) being issued pursuant to, and is subject to the terms and conditions of, the Note and Warrant Purchase Agreement by and among the Company, the Holder and the other parties thereto, dated as of May 19, 2014 (the “Agreement”). For avoidance of doubt, the Notes, the Additional Notes and the New Notes (each as defined in the Agreement) shall be considered the Notes for all purposes of this Note.  Capitalized terms used but not otherwise defined herein shall have the meanings given to such terms in the Agreement.  This Note is subordinated to the obligations set forth in that certain Loan and Security Agreement, by and among Silicon Valley Bank, Oxford Finance LLC and the Company, dated as of April 9, 2013.

1.                                      PAYMENT.

1.1                               Maturity.  Subject to (i) conversion into the capital stock of the Company in accordance with Section 4 hereof, including mandatory conversion pursuant to Section 4.3, (ii)

acceleration of the maturity of this Note in connection with the occurrence of an Event of Default (as hereinafter defined), (iii) prepayment in accordance with Section 1.2 and (iv) repayment in an Acquisition Event in accordance with Section 1.4, the Holder of this Note shall have the right to demand repayment of the total amount of outstanding principal under this Note and all accrued and unpaid interest thereon in a single lump sum on or after July 31, 2015, or such later date as selected by the Holder, (such date, the “Maturity Date”), by giving the Company fifteen (15) days prior written notice of such demand for repayment.

1.2                               Prepayment.  The Company may not prepay this Note without the consent of C-Bridge, Draconis and any of their successors, assigns and transferees as holders of a Note (the “Requisite Holders”), and any such prepayment shall be pro-rata among the Purchasers based on the aggregate principal amount of the Notes then outstanding.  For as long as the Requisite Holders hold at least a majority of the principal of the Notes then outstanding, with the consent of the Requisite Holders, at any time prior to the Maturity Date, upon two (2) Business Days prior written notice and without penalty, the Company may prepay the then outstanding amounts under this Note in whole or in part.  Any such prepayment received with respect to this Note shall first be applied toward the repayment of the accrued but unpaid interest then outstanding, with the remainder, if any, applied toward the payment of the then outstanding principal.  At such time as the Requisite Holders do not hold a majority of the principal of the Notes then outstanding, the term of the “Requisite Holders” shall mean the Purchasers holding a majority of the principal of the Notes then outstanding.

1.3                               Form of Payment.  All payments of interest and principal or other amounts payable under this Note shall be payable in immediately available funds to the account of the Holder as the Holder may from time to time designate in writing to the Company.

1.4                               Repayment.  In the event of an Acquisition Event (as defined herein), if this Note has not previously been converted, then (i) 1.5 times the outstanding principal balance of this Note and (ii) any interest accrued and unpaid to date, shall be due and payable to the Holder upon the closing of the Acquisition Event.  “Acquisition Event” means (i) a consolidation or merger of the Company with or into one or more other corporations or other business organizations, (ii) the sale, lease, exclusive license, transfer or other disposition of all or substantially all of the assets of the Company, or (iii) any other form of corporate reorganization in which outstanding shares of the Company are exchanged for or converted into cash, securities of another corporation or business organization, or other property (including the issuance and sale of a controlling interest in the Company), unless, in each case, the Company’s stockholders of record immediately prior to such event shall (by virtue of the securities issued as a part of such event) hold at least 50% of the voting power of the surviving or acquiring entity immediately following such event.  The Company shall give the Holder notice of a proposed Acquisition Event no less than fifteen (15) days prior to the closing of the Acquisition Event.

2.                                      INTEREST.

This Note shall accrue interest from the date hereof on the unpaid outstanding principal balance hereof at a rate (the “Base Rate”) per annum equal to eight percent (8%), compounded daily, calculated on the basis of a 365-day year and the actual days elapsed in the period in which such interest is payable hereunder; provided, however, that upon and at all times during the

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continuation of any Event of Default, such Base Rate of interest shall be increased by two percent (2%) (the Base Rate, as so increased, the “Default Rate”); provided, further, that in the event any interest is paid on this Note which is deemed to be in excess of the then legal maximum rate, then that portion of the interest payment representing an amount in excess of the then legal maximum rate shall be deemed a payment toward and applied against the then outstanding principal under this Note.

3.                                      EXPENSES.

The Company shall pay to the Holder all reasonable out-of-pocket costs and expenses incurred by such Holder in any effort to collect any amounts due under this Note, including, without limitation, all reasonable attorneys’ fees and expenses for services rendered in connection therewith, and shall pay interest on such costs and expenses to the extent not paid when due hereunder demanded at the Default Rate.

4.                                      CONVERSION OF NOTE.

4.1                               Mandatory Conversion of Note upon Financing.  If this Note has not been repaid in accordance with Section 1 above or previously converted in accordance with this Section 4, upon the closing of a Financing (as defined below), the total outstanding amount of principal and accrued and unpaid interest of this Note shall automatically be converted into the number of fully paid and non-assessable shares of Financing Stock (as defined below) as is equal to (x) the aggregate amount of such principal and accrued and unpaid interest then outstanding under this Note, divided by (y) the Financing Purchase Price (as defined below).  For purposes of this Note, the term “Financing” shall mean (i) a firmly underwritten public offering of shares of Common Stock registered pursuant to the Securities Act of 1933, as amended, involving aggregate net proceeds to the Company of at least $30,000,000 in connection with which the Company’s Common Stock is listed on a nationally recognized securities exchange or trading system, provided that the Company shall not reserve more than 40% of the securities offered in such public offering for sale to the Company’s directors, officers, employees and business associates and other parties related to the Company pursuant to a directed share program or any similar arrangement, or (ii) the Company’s issuance and sale of shares of Preferred Stock to one or more investors in one or more related private transactions following the date hereof in connection with which the Company receives aggregate gross proceeds in all such related financings of at least $10,000,000 (excluding the Notes), the term “Financing Stock” shall mean the shares of Common Stock or Preferred Stock issued in the Financing, and the term “Financing Purchase Price” shall mean (a) in the case of a Financing described in Section 4.1(i) above, seventy percent (70%) of the per share initial public offering price of the Financing Stock in the Financing or (b) in the case of a Financing described in Section 4.1(ii) above, eighty-five percent (85%) of the per share purchase price paid for the Financing Stock in the Financing.

4.2                               Optional Conversion.  If this Note has not been repaid in accordance with Section 1 above or previously converted in accordance with this Section 4, at any time following July 31, 2014 up to but not including the Maturity Date, at the option of the Holder, the total outstanding amount of principal and accrued and unpaid interest of this Note shall be converted

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into the number of fully paid and non-assessable shares of the Company’s Series D-1 Convertible Preferred Stock, par value $0.001 per share (the “Series D-1 Preferred Stock”) equal to (i) the aggregate amount of such principal and accrued and unpaid interest to be so converted by the Holder, divided by (ii) the Series D-1 Purchase Price.  Such Series D-1 Preferred Stock shall have the same rights, powers and privileges as the Series D Preferred Stock (as defined below) except that the Liquidation Amount and Conversion Price (each as defined in the Company’s certificate of incorporation) shall be based on the Series D-1 Purchase Price for the Series D-1 Preferred Stock. For purposes of this Note, the term “Series D-1 Purchase Price” shall mean (i) $185 million, divided by (ii) the Fully Diluted Shares (as defined in the Warrants issued pursuant to the Agreement) immediately prior to the conversion of the Note pursuant to this Section 4.2.  Immediately prior to the conversion of the Note in accordance with this Section 4.2, the Company’s certificate of incorporation shall be amended to give effect to the rights, powers and privileges of Series D-1 Preferred Stock.