UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported): September 24, 2015

SIENTRA, INC.

(Exact Name of Registrant as Specified in Its Charter)

420 South Fairview Avenue, Suite 200

Santa Barbara, CA 93117

(Address of Principal Executive Offices and Zip Code)

(805) 562-3500

(Registrant’s Telephone Number, Including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o                 Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o                 Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                 Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                 Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01.                                        Other Events.

On September 24, 2015, Sientra, Inc. (the “Company”) issued a letter to its plastic surgeon customers regarding the suspension of the CE certificate for all medical devices made by Silimed, the Company’s contract manufacturer. A copy of the letter is filed as Exhibit 99.1 and is incorporated herein by reference.

Item 9.01.                                        Financial Statements and Exhibits.

(d)                                 Exhibits

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereto duly authorized.

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INDEX TO EXHIBITS

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