As filed with the Securities and Exchange Commission on October 8, 2013

Registration No. 333-          

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM S-1
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

KYTHERA BIOPHARMACEUTICALS, INC.
(Exact Name of Registrant as Specified in its Charter)

27200 West Agoura Road, Suite 200
Calabasas, CA 91301
(818) 587-4500
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant's Principal Executive Offices)

Keith R. Leonard, Jr.
President and Chief Executive Officer
KYTHERA Biopharmaceuticals, Inc.
27200 West Agoura Road, Suite 200
Calabasas, CA 91301
(818) 587-4500
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

         Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement becomes effective.

         If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.    o

         If this Form is filed to register additional securities for an offering pursuant Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    ý 333-191450

         If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

         If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

         Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):

CALCULATION OF REGISTRATION FEE

(1)

In accordance with Rule 462(b) promulgated under the Securities Act of 1933, as amended, an additional amount of securities having a proposed maximum offering price of no more than 20% of the maximum aggregate offering price of the securities eligible to be sold under the related Registration Statement on Form S-1, as amended (File No. 333-191450), is hereby registered.

(2)

Estimated solely for the purposes of computing the amount of the registration fee in accordance with Rule 457(o) promulgated under the Securities Act of 1933, as amended.

         The Registration Statement shall become effective upon filing in accordance with Rule 462(b) promulgated under the Securities Act of 1933, as amended.

EXPLANATORY NOTE AND INCORPORATION BY REFERENCE

        This registration statement is being filed with respect to the registration of additional shares of common stock, par value $0.00001 per share, of KYTHERA Biopharmaceuticals, Inc., a Delaware corporation, pursuant to Rule 462(b) promulgated under the Securities Act of 1933, as amended, representing an increase in the maximum aggregate offering price of $22,999,934.00. The contents of the earlier registration statement on Form S-1, as amended (File No. 333-191450), which was declared effective by the Securities and Exchange Commission on October 8, 2013, are incorporated in this registration statement by reference.

        The required opinion and consents are listed on an Exhibit Index attached hereto and filed herewith.

SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant has duly caused this Registration Statement on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized, in Calabasas, California, on October 8, 2013.

        Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

EXHIBIT INDEX

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