United States securities and exchange commission logo January 23, 2023 Michael Raab President & Chief Executive Officer Ardelyx, Inc. 400 Fifth Avenue, Suite 210 Waltham, MA 02451 Re: Ardelyx, Inc. Registration Statement on Form S-3 Filed January 19, 2023 File No. 333-269297 Dear Michael Raab: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Tyler Howes at 202-551-3370 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Mark V. Roeder, Esq.