UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 7)*

SYNUTRA INTERNATIONAL, INC.

(Name of Issuer)

Common Stock, Par Value $0.0001 Per Share

(Title of Class of Securities)

87164C 10 2

(CUSIP Number)

Robert B. Knauss, Esq.

Managing Director and General Counsel

Warburg Pincus LLC

450 Lexington Avenue

New York, NY 10017

(212) 878-0600

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

Copies to:

Jeffrey T. Hartlin

Paul Hastings LLP

1117 S. California Avenue

Palo Alto, California 94304-1106

(650) 320-1804

March 3, 2014

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This Amendment No. 7 (this “Amendment No. 7”) amends and supplements the Schedule 13D filed with the U.S. Securities and Exchange Commission (the “Commission”) on June 20, 2007, as amended by Amendment No. 1 thereto filed with the Commission on April 24, 2008 (“Amendment No. 1”), Amendment No. 2 thereto filed with the Commission on September 2, 2008 (“Amendment No. 2”), Amendment No. 3 thereto filed with the Commission on April 26, 2011 (“Amendment No. 3”), Amendment No. 4 thereto filed with the Commission on May 9, 2011 (“Amendment No. 4”), Amendment No. 5 thereto filed with the Commission on August 11, 2011 (“Amendment No. 5”) and Amendment No. 6 thereto filed with the Commission on February 4, 2013 (“Amendment No. 6”, and together with Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4 and Amendment No. 5, the “Initial Schedule 13D”), and is being filed on behalf of Warburg Pincus Private Equity IX, L.P., a Delaware limited partnership (“WP IX”), Warburg Pincus IX LLC, a New York limited liability company and the sole general partner of WP IX (“WP IX LLC”), Warburg Pincus Partners LLC, a New York limited liability company and the sole member of WP IX LLC (“WPP LLC”), Warburg Pincus & Co., a New York general partnership and the managing member of WPP LLC (“WP”), Warburg Pincus LLC, a New York limited liability company that manages WP IX (“WP LLC”), and Messrs. Charles R. Kaye and Joseph P. Landy, each a Managing General Partner of WP and a Managing Member and Co-Chief Executive Officer of WP LLC, who may be deemed to control WP IX, WP IX LLC, WPP LLC, WP LLC and WP. WP IX, WP IX LLC, WPP LLC, WP, WP LLC, Mr. Kaye and Mr. Landy are hereinafter referred to as the “Warburg Pincus Reporting Persons”. The Initial Schedule 13D, as amended by this Amendment No. 7, is being referred to as the “Schedule 13D”. This Amendment No. 7 relates to the common stock, par value $0.0001 per share (the “Common Stock”), of Synutra International, Inc., a Delaware corporation (the “Issuer”). Information in respect of each Warburg Pincus Reporting Person is given solely by such Warburg Pincus Reporting Person and no Warburg Pincus Reporting Person has responsibility for the accuracy or completeness of information supplied by any other Warburg Pincus Reporting Person. All capitalized terms used herein that are not defined herein have the meanings for such terms set forth in the Initial Schedule 13D.

The Warburg Pincus Reporting Persons are filing this Amendment No. 7 because on March 3, 2014, Beams Power repaid all amounts owed to WP IX under the Second Restated Note, including interest and penalties thereon (the “Repayment”), and the Second Restated Note was terminated. Effective upon the repayment of all amounts owed to WP IX under the Second Restated Note, each of the Restated Forbearance Agreement, the Amended Share Pledge Agreement, the Amended Additional RRA, the Amended Drag-Along Agreement, the Additional ABN Waiver Letter, the Third ABN Waiver Letter and the Registration Rights Agreement were terminated, effective as of March 3, 2014.

Unless set forth below, all previous Items set forth in the Initial Schedule 13D are unchanged.

The disclosure added to Item 4 pursuant to Amendment No. 1, as amended and restated pursuant to Amendment No. 6, is hereby deleted in its entirety and replaced with the following:

Except as described in the Purchase Agreement, the Voting Agreement, the ABN Consent Letter and as otherwise set forth in this Schedule 13D, as amended, no Warburg Pincus Reporting Person has any present plans or proposals which relate to or would result in: (a) the acquisition by any person of additional securities of the Issuer, or the disposition of securities of the Issuer; (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries; (c) a sale or transfer of a material amount of assets of the Issuer or of any of its subsidiaries; (d) any change in the present board of directors or management of the Issuer, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board; (e) any material change in the present capitalization or dividend policy of the Issuer; (f) any other material change in the Issuer’s business or corporate structure; (g) changes in the Issuer’s charter, bylaws or instruments corresponding thereto or other actions which may impede the acquisition of control of the Issuer by any person; (h) causing a class of securities of the Issuer to be delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association; (i) a class of equity securities of the Issuer becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Exchange Act; or (j) any action similar to any of those enumerated above.

Items 5(a), (b) and (c) of the Initial Schedule 13D are hereby amended and restated in their entirety as follows:

(a) As of March 3, 2014, after giving effect to the Repayment, WP IX is deemed to beneficially own an aggregate of 4,000,000 shares of Common Stock of the Issuer, which represents approximately 7.0% of the outstanding shares of Common Stock of the Issuer, calculated in accordance with Rule 13d-3(d) promulgated under the Exchange Act. This percentage is based on 57,300,713 shares of Common Stock of the Issuer outstanding as of February 10, 2014, as disclosed in the Issuer’s Quarterly Report on Form 10-Q, for the quarterly period ended December 31, 2013, filed with the Commission on February 10, 2014 (the “Form 10-Q”), consisting of 4,000,000 shares of Common Stock of the Issuer issued to WP IX pursuant to the Common Stock Purchase Agreement, which shares are currently held by WP IX.

Due to their respective relationships with WP IX and each other, the Warburg Pincus Reporting Persons may be deemed to beneficially own, in the aggregate, 4,000,000 shares of Common Stock of the Issuer, which represented approximately 7.0% of the shares of Common Stock of the Issuer outstanding as of February 10, 2014, as disclosed in the Form 10-Q.

Each of WP IX LLC, WPP LLC, WP, WP LLC, Messrs. Charles R. Kaye and Joseph P. Landy disclaims beneficial ownership of the Issuer’s Common Stock, except to the extent of any indirect pecuniary interest therein.

(b) Each of the Warburg Pincus Reporting Persons is deemed to share with WP IX the power to vote or to direct the vote of and to dispose or to direct the disposition of the 4,000,000 shares of Common Stock of the Issuer.

(c) Except for the transactions described in the Schedule 13D, no other transactions in shares of the Issuer’s Common Stock were effected by the Warburg Pincus Reporting Persons during the last sixty (60) days.

Item 7 of the Initial Schedule 13D is hereby amended and restated in its entirety as follows:

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: March 3, 2014