QuickLinks -- Click here to rapidly navigate through this document


Exhibit 5.1

May 10, 2004

(310) 552-8500

C 38208-00018

(310) 552-7030

WH Holdings (Cayman Islands) Ltd.
WH Capital Corporation
c/o Herbalife International, Inc.
1800 Century Park East
Los Angeles, California 90067

Re:   WH Holdings (Cayman Islands) Ltd./WH Capital Corporation
Registration Statement on Form S-4

Ladies and Gentlemen:

        We have acted as United States special counsel to WH Holdings (Cayman Islands) Ltd., a Cayman Islands exempted limited liability company, and WH Capital Corporation, a Nevada corporation (the "Issuers"), in connection with the Issuers' registration, on a Registration Statement on Form S-4 (the "Registration Statement"), under the Securities Act of 1933, as amended, of $275,000,000 aggregate principal amount of 9.50% Notes due 2011 (the "New Notes").

        The New Notes will be offered in exchange for like principal amounts of the Issuers' outstanding 9.50% Notes due 2011 (the "Outstanding Notes") pursuant to the Registration Rights Agreement, dated as of March 8, 2004 (the "Registration Rights Agreement"), by and between the Issuers and UBS Securities LLC (the "Initial Purchaser"). The Registration Rights Agreement was executed in connection with the private placement of the Outstanding Notes.

        The New Notes will be issued pursuant to the Indenture, dated as of March 8, 2004 (the "Indenture"), by and between the Issuers and The Bank of New York, as Trustee. The New Notes and the Indenture are each governed under the internal laws of the State of New York, and are sometimes collectively referred to herein as the "Documents."

        In rendering this opinion, we have examined the Documents, and have also made such inquiries and examined, among other things, originals or copies, certified or otherwise identified to our satisfaction, of such records, agreements, certificates, instruments and other documents, as we have considered necessary or appropriate for purposes of this opinion.

        In rendering this opinion, we have assumed:


        Based upon the foregoing and in reliance thereon, and subject to the assumptions, exceptions, qualifications and limitations contained herein, we are of the opinion that when issued in exchange for the Outstanding Notes pursuant to the terms of the Indenture and the exchange offer described in the Registration Statement, the New Notes will be legally issued and will constitute binding obligations of the Issuers.

        The foregoing opinions are subject to the following exceptions, qualifications and limitations:

        We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to this firm under the heading "Legal Matters" contained in the prospectus that forms a part of the Registration Statement. In giving this consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations promulgated thereunder.

JKL/BDK/MBM/FEM




QuickLinks