Lock-Up Agreement

June 5, 2013

William Blair & Company, L.L.C.

222 W. Adams Street

Chicago, IL 60606

Re: Private Placement of Securities

Ladies and Gentlemen:

The undersigned understands that William Blair & Company, L.L.C. proposes to act as the exclusive placement agent (the “Placement Agent”), for Bacterin International Holdings, Inc., a Delaware corporation (the “Company”), in connection with the proposed private placement (the “Offering”) of shares (the “Shares”) of common stock, par value $0.000001 per share (“Common Stock”), and warrants to purchase Common Stock (the “Warrants” and together with the Shares, the “Securities”), of the Company.

In order to induce the Placement Agent to continue its efforts in connection with the Offering, the undersigned hereby agrees that for a period (the “Lock-Up Period) beginning on the date hereof and ending [30] days following the date of effectiveness of the registration statement registering the resale of the Shares and shares of Common Stock issuable upon exercise of the Warrants filed by the Company with the Securities and Exchange Commission in connection with such Offering, the undersigned will not, without the prior written consent of the Placement Agent, directly or indirectly, (1) offer, sell, contract to sell, pledge, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of any shares of Common Stock, or any securities convertible into or exercisable or exchangeable for the Common Stock (including, without limitation, shares of Common Stock or any such securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933, as the same may be amended or supplemented from time to time (such shares of securities, the “Beneficially Owned Shares”)); (2) enter into any sap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Beneficially Owned Shares, Common Stock, or any securities convertible into or exchangeable for the Common Stock, regardless of whether any such transaction described herein is to be settled by delivery of the Common Stock or such other securities, or by delivery of cash or otherwise; (3) make any demand for, or exercise any right with respect to, the registration of any shares of the Beneficially Owned Shares, Common Stock or any security convertible into or exercisable or exchangeable for the Common Stock; or (4) publicly announce any intention to do any of the foregoing; provided, however, that the obligations under this letter agreement (the “Lock-Up Agreement”) shall not apply to any Securities acquired in connection with the Offering.

Notwithstanding the foregoing, the restrictions set forth in clause (1) and (2) above shall not apply to (a) transfers (i) as a bona fide gift or gifts, or by will or intestate succession, provided that the donee or donees or transferee or transferees thereof agree to be bound in writing by the restrictions set forth herein, (ii) to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value, (iii) with the prior written consent of the Placement Agent or (iv) effected pursuant to any exchange of “underwater” options with the Company; provided that in the case of any transfer or distribution pursuant to clause (i), (ii), (iii) or (iv), no filing under Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) shall be required or shall be voluntarily made during the Lock-Up Period; (b) the acquisition or exercise of an option or warrant to purchase shares of Common Stock (or any securities convertible into or exercisable or exchangeable for Common Stock), including the sale of a portion of stock to be issued in connection with such exercise to finance a “cashless” exercise, provided that any such shares issued upon exercise of such option or warrant (or any securities convertible into or exercisable or exchangeable for Common Stock) shall continue to be subject to the applicable provisions of this Lock-Up Agreement; (c) the purchase or sale of the Company’s securities pursuant to a plan, contract or instruction that satisfies all the requirements of Rule 10b5-1(c)(1)(i) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that was in effect prior to the date hereof; or (d) the disposition of shares of Common Stock to satisfy any tax withholding obligations upon the vesting of shares of restricted Common Stock held by the undersigned. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin. None of the restrictions set forth in the Lock-Up Agreement shall apply to Common Stock acquired after the date hereof in open market transactions, provided that no filing under Section 16(a) of the Exchange Act shall be required or shall be voluntarily made in connection with subsequent sales of Common Stock acquired in such open market transactions. In addition, the undersigned may at any time after the date hereof enter into a trading plan or modify an existing trading plan that satisfies all of the requirements of Rule 10b5-1(c)(1)(i)(B) under the Exchange Act if then permitted by the Company and applicable law, provided that the Common Stock or other securities subject to a new trading plan may not be sold during the Lock-Up Period. Moreover, if the undersigned is a partnership, limited liability company, trust, corporation or similar entity, it may distribute the Common Stock or Beneficially Owned Shares to its partners, members or stockholders, or to affiliates under the control of the undersigned, provided, however, that in each such case, prior to any such transfer, each transferee shall execute a duplicate form of this Lock-Up Agreement or execute an agreement, reasonably satisfactory to the Placement Agent, pursuant to which each transferee shall agree to receive and hold such Common Stock or Beneficially Owned Shares subject to the provisions hereof, and there shall be no further transfer except in accordance with the provisions hereof.

The foregoing restrictions are expressly agreed to preclude the undersigned from engaging in any hedging or other transaction which is designed to or reasonably expected to lead to or result in a sale or disposition of the Beneficially Owned Shares or Common Stock even in such Beneficially Owned Shares or Common Stock would be disposed of by someone other than the undersigned. Such prohibited hedging or other transactions would include, without limitation, any short sale or any purchase, sale or grant of any right (including, without limitation, any put option or put equivalent position or call option or call equivalent position) with respect to any of the Beneficially Owned Shares or Common Stock or with respect to any security that includes, relates to, or derives any significant part of its value from such Beneficially Owned Shares of Common Stock.

The undersigned hereby agrees and consent to the entry of stop transfer instructions with the Company’s transfer agent against the transfer of securities of the Company held by the undersigned during the Lock-Up Period (as may have been extended pursuant hereto), except in compliance with this Lock-Up Agreement.

The undersigned understands that, if the Company notifies the Placement Agent in writing that it does not intend to proceed with the Offering, or if the Securities Purchase Agreement executed by Purchasers in connection with the Offering does not become effective, or if the Offering shall terminate or be terminated prior to payment for and delivery of the Securities to be sold thereunder, or if the Purchase Agreement has not been executed within 30 days of the date hereof, this Lock-Up Agreement shall be terminated and the undersigned shall be released from all obligations under this Lock-Up Agreement.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. This Lock-Up Agreement is irrevocable and all authority herein conferred or agreed to be conferred shall survive the death or incapacity of the undersigned and any obligations of the undersigned shall be binding upon the heirs, personal representatives, successors and assigns or the undersigned. The undersigned agrees that Purchasers of the Securities in the Offering shall be intended third-party beneficiaries of the undersigned’s obligations under this Lock-Up Agreement.

This Lock-Up Agreement shall be governed by and construed in accordance with the laws of the State of New York, without regard to conflict of laws principles thereof.

[Signature page follows.]