EX-5.1

Exhibit 5.1

LOGO

Thomas A. Coll

+1 858 550 6013

collta@cooley.com

June 29, 2023

Regulus Therapeutics Inc.

4224 Campus Point Court, Suite 210

San Diego, CA 92121

Ladies and Gentlemen:

We have represented Regulus Therapeutics Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission (the “Commission”), covering the offering of up to 5,000,000 shares of the Company’s Common Stock, $0.001 par value (the “Shares”), issuable pursuant to the Company’s 2019 Equity Incentive Plan (the “Plan”).

In connection with this opinion, we have examined and relied upon the Registration Statement and the related prospectus, the Plan, the Company’s certificate of incorporation and bylaws, each as currently in effect, and such other documents, records, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies, the accuracy, completeness and authenticity of certificates of public officials, and the due authorization, execution and delivery of all documents by all persons other than the Company where authorization, execution and delivery prerequisites to the effectiveness thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plan and the Registration Statement and related prospectus, will be validly issued, fully paid, and nonassessable (except as to Shares issued pursuant to deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

Cooley LLP 10265 Science Center Drive San Diego, CA 92121

t: (858) 550-6000 f: (858) 550-6420 cooley.com


Sincerely,

COOLEY LLP

By:		/s/ Thomas A. Coll
		Thomas A. Coll