Filed Pursuant to Rule 424(b)(3)

Registration No. 333-299150

794,972,289 Shares of Common Stock

This prospectus relates to the resale of up to 410,046,456 shares of our common stock, par value $0.001 per share (the “common stock”) and 384,925,833 shares of our common stock underlying certain warrants (collectively, the “Shares”) by the selling stockholders identified in this prospectus under “Selling Stockholders.” The selling stockholders may sell all or a portion of the Shares from time to time, in amounts, at prices and on terms determined at the time of sale. The Shares may be sold by any means described in the section of this prospectus entitled “Plan of Distribution” beginning on page 43.

We are not selling any shares of our common stock under this prospectus and will not receive any proceeds from the sale of these Shares by the selling stockholders. We will, however, receive proceeds from any warrants that are exercised through the payment of the exercise price in cash. We will bear all other costs, fees and expenses incurred in effecting the registration of the Shares covered by this prospectus. All selling and other expenses incurred by the selling stockholders will be borne by the selling stockholders.

We are registering the offer and sale of [a majority] of the Shares pursuant to certain registration rights granted to certain selling stockholders. The registration of the Shares does not necessarily mean that any of the Shares will be offered or sold by the selling stockholders. The timing and amount of any sale is within the sole discretion of the selling stockholders.

Our common stock is quoted on the OTCQB of OTC Markets Group, Inc. under the symbol “CYDY.” On October 6, 2026, the closing price of our common stock was $0.20 per share.

Investing in our securities involves risk. You should carefully consider the risks that we have described under the section captioned “Risk Factors” in this prospectus on page 7 before buying our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is October 7, 2026

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S‑3 (the “Registration Statement”) that we filed with the U.S. Securities and Exchange Commission (the “SEC”). You should read this prospectus and the information and documents incorporated by reference carefully. Such documents contain important information you should consider when making your investment decision. See “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” in this prospectus.

This prospectus may be supplemented from time to time to add, to update or change information in this prospectus. Any statement contained in this prospectus will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in such prospectus supplement modifies or supersedes such statement. Any statement so modified will be deemed to constitute a part of this prospectus only as so modified, and any statement so superseded will be deemed not to constitute a part of this prospectus. You may only rely on the information contained in this prospectus or that we have referred you to. We have not authorized anyone to provide you with different information. This prospectus does not constitute an offer to sell or a solicitation of an offer to buy any securities other than the securities offered by this prospectus. This prospectus and any future prospectus supplement do not constitute an offer to sell or a solicitation of an offer to buy any securities in any circumstances in which such offer or solicitation is unlawful. Neither the delivery of this prospectus or any prospectus supplement nor any sale made hereunder shall, under any circumstances, create any implication that there has been no change in our affairs since the date of this prospectus or such prospectus supplement or that the information contained by reference to this prospectus or any prospectus supplement is correct as of any time after its date.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed, or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under “Where You Can Find More Information.”

CytoDyn Inc. and its consolidated subsidiaries are referred to herein as “CytoDyn,” “the Company,” “we,” “us,” and “our,” unless the context indicates otherwise.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains certain forward-looking statements that involve risks, uncertainties, and assumptions that are difficult to predict. Words and expressions reflecting optimism, satisfaction, or disappointment with current prospects, as well as words such as “believes,” “hopes,” “intends,” “estimates,” “expects,” “projects,” “plans,” “anticipates,” and variations thereof, or the use of future tense, identify forward-looking statements, but their absence does not mean that a statement is not forward-looking. Our forward-looking statements are not guarantees of performance, and actual results could vary materially from those contained in or expressed by such statements. Our forward-looking statements reflect our current views with respect to future events and are based on currently available financial, economic, scientific, and competitive data and information on current business plans.

Forward-looking statements include, among others, statements about leronlimab, its ability to have positive health outcomes, the Company’s ability to implement a successful operating strategy for the development of leronlimab and thereby create shareholder value, the ability to obtain regulatory approval of the Company’s drug products for commercial sales, and the strength of the Company’s leadership team. The Company’s forward-looking statements are not guarantees of performance, and actual results may vary materially from those contained in or expressed by such statements due to risks and uncertainties, including: (i) the regulatory determinations of leronlimab’s safety and effectiveness to treat the disease and conditions for which we are studying the product by the U.S. Food and Drug Administration (the “FDA”) and, potentially, drug regulatory agencies in various other countries; (ii) the Company’s ability to raise additional capital to fund its operations; (iii) the Company’s ability to meet its debt and other payment obligations; (iv) the Company’s ability to recruit or retain key employees; (v) the Company’s ability to enter into or maintain partnership or licensing arrangements with third-parties; (vi) the timely and sufficient development, through internal resources or third-party consultants, of analyses of the data generated from the Company’s clinical trials required by the FDA or other regulatory agencies in connection with applications for approval of the Company’s drug product; (vii) the Company’s ability to achieve approval of a marketable product; (viii) the design, implementation, and conduct of clinical trials; (ix) the results of any such clinical trials, including the possibility of unfavorable clinical trial results; (x) the market for, and marketability of, any product that is approved; (xi) the existence or development of vaccines, drugs, or other treatments that are viewed by medical professionals or patients as superior to the Company’s products; (xii) regulatory initiatives, compliance with governmental regulations, and the regulatory approval process; (xiii) legal proceedings, investigations, or inquiries affecting the Company or its products, including the finalization of an agreement in principle to settle the class-action litigation filed against the Company in the state of Washington; (xiv) general economic and business conditions; (xv) changes in domestic and foreign political and social conditions; (xvi) stockholder actions or proposals with regard to the Company, its management, or its Board of Directors; and (xvii) various other matters, many of which are beyond the Company’s control.

We intend that all forward-looking statements made in this prospectus will be subject to the safe harbor protection of the federal securities laws and regulations pursuant to the Securities Act of 1933, as amended (the “Securities Act”), and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), to the extent applicable. Except as required by law, we do not undertake any responsibility to update these forward-looking statements to consider events or circumstances that occur after the date of this prospectus. Additionally, we do not undertake any responsibility to update you on the occurrence of any unanticipated events that may cause actual results to differ from those expressed or implied by these forward-looking statements.

PROSPECTUS SUMMARY

This summary highlights certain information about us, this offering, and information appearing elsewhere in this prospectus and in the documents we incorporate by reference. This summary is not complete and does not contain all of the information that you should consider before investing in our securities. To fully understand this offering and its consequences to you, you should read this entire prospectus carefully, including the information referred to under the heading “Risk Factors” in this prospectus on page 7, and the financial statements and other information incorporated by reference in this prospectus, when making an investment decision. This is only a summary and may not contain all the information that is important to you. You should carefully read both this prospectus and any accompanying prospectus supplement, including the information incorporated by reference therein, and any other offering materials, together with the additional information described under the heading “Where You Can Find More Information.”

About Us

The Company is a clinical-stage biotechnology company focused on the clinical development and potential commercialization of its product candidate, leronlimab, which is being studied for its potential in solid-tumor oncology. Leronlimab targets CCR5, a receptor increasingly recognized for its role in tumor progression, metastasis, and immune regulation, providing the Company with the opportunity to explore a potentially differentiated therapeutic approach across multiple solid tumor indications.

Our current business strategy is to continue the clinical development of leronlimab, which may include the following:

Corporate Information

CytoDyn Inc. is a Delaware corporation with its principal executive offices at 1111 Main Street, Suite 660, Vancouver, Washington 98660, telephone (360) 980-8524. Our website can be found at www.cytodyn.com. We do not intend to incorporate any contents from our website into this prospectus. Effective August 27, 2015, we completed a reincorporation from Colorado to Delaware. Effective November 16, 2018, we implemented a holding company reorganization, as a result of which we became the successor issuer and reporting company to the former CytoDyn Inc. (now our wholly owned subsidiary, CytoDyn Operations Inc.).

Smaller Reporting Company

We are a “smaller reporting company” as defined in rules adopted under the Exchange Act. As a result, we may take advantage of certain reduced disclosure obligations available to smaller reporting companies, including the exemption from compliance with the auditor attestation requirements pursuant to the Sarbanes-Oxley Act of 2002, reduced disclosure about our executive compensation arrangements and the requirements to provide only two years of audited financial statements in our annual reports and registration statements. As currently defined, we will continue to be a “smaller reporting company” as long as (1) we have a public float (i.e., the market value of our common stock held by non-affiliates) less than $250 million calculated as of the last business day of our most recently completed second fiscal quarter, or (2) our annual revenues are less than $100 million for our previous fiscal year and we have either no public float or a public float of less than $700 million as of the end of that fiscal year’s second fiscal quarter. Reduced disclosures in our SEC filings due to our status as a “smaller reporting company” may make it harder for investors to analyze our results of operations and financial prospects.

Summary of Transactions in which Shares of Common Stock and Warrants Held by Selling Stockholders Were Issued

The selling stockholders identified in this prospectus may sell shares of our common stock as shown under “Selling Stockholders” below. The transactions in which the shares of our common stock available for resale under this prospectus were or may be acquired by the selling stockholders, including shares underlying warrants to purchase our common stock, are described below.

Sales of Common Stock and Warrants in Private Offerings through Paulson Investment Company, LLC. During the period from December 2011 through August 2026, the Company engaged in a series of private offerings of common stock and warrants to purchase common stock to accredited investors through Paulson Investment Company, LLC, as placement agent. A total of 255,902,505 shares of our common stock sold in the offerings or issued upon the exercise of warrants sold in the offerings, as well as 277,093,497 shares of common stock underlying the warrants, are among those being offered for resale as shown under “Selling Stockholders”. The weighted average exercise price of the outstanding warrants is $0.28 per share.

Issuances of Shares of Common Stock in Settlement of Convertible Promissory Notes and Exercise of Warrants Sold in Private Offerings by Us. In August 2015 and early 2018, we issued shares of common stock in settlement of the principal amount of, plus accrued but unpaid interest on, convertible promissory notes previously sold by us in private offerings of the notes and warrants to purchase common stock to accredited investors. A total of 2,518,366 shares of our common stock issued in settlement of the convertible promissory notes and upon the exercise of related warrants are among those being offered for resale as shown under “Selling Stockholders”.

Issuances of Warrants and Shares Issued upon Exercise of Warrants Issued to Paulson Investment Company, LLC, as Compensation in Connection with Offerings of Common Stock and Warrants and Convertible Promissory Notes. A total of 4,863,182 shares of common stock issued upon the exercise of warrants to purchase our common stock issued to Paulson Investment Company, LLC, or to its designees, as well as 65,746,692 shares of common stock underlying warrants with a weighted average exercise price of $0.14 per share issued as compensation for its services in connection with private offerings and registered direct offerings of shares of our common stock, warrants, and convertible promissory notes that occurred during the period from December 2011 through August 2026, are among those being offered for resale as shown under “Selling Stockholders”.

Public Tender Offers. The Company conducted a total of four public tender offers during 2018, 2019, and 2024 pursuant to which the Company offered to exchange warrants held by the investors for warrants with a reduced exercise price, conditioned upon the immediate exercise of the warrants. A total of 82,496,090 shares of common stock issued pursuant to the exercise of the warrants issued in the tender offers are among those being offered for resale as shown under “Selling Stockholders”.

Private Warrant Exchanges. In May 2019, January 2020, June 2020, October 2020, March 2021, and December 2022, the Company entered into warrant exchange agreements with investors in which the Company offered to issue warrants to purchase shares of common stock with a reduced exercise price in exchange for warrants held by the investors, conditioned on the immediate exercise of the warrants issued in exchange. In some cases, additional shares of common stock were issued as an added inducement for the exercises. A total of 29,666,066 shares of common stock issued in connection with the private warrant exchanges are among those being offered for resale as shown under “Selling Stockholders”.

Legal Settlement Issuances. In August 2021, we settled a dispute with a placement agent in part through the issuance of warrants to purchase common stock. A total of 23,597 shares of common stock issued upon exercise of the warrants are among those being offered for resale as shown under “Selling Stockholders”.

Sales of Common Stock and Warrants in Private Sales Conducted by Us. During November 2021, the period from February 2022 through April 2022, and January, February, and August 2026, the Company entered into private sale transactions of common stock directly with accredited investors, as well as warrants to purchase common stock in

certain transactions. A total of 26,515,728 shares of common stock sold in the private sale transactions or issued upon the exercise of warrants sold in the private sale transactions, as well as 4,085,644 shares of common stock underlying warrants with a weighted average exercise price of $0.32, are among those being offered for resale as shown under “Selling Stockholders”.

Warrants Issued to 4-Good Ventures LLC. On February 14, 2022, we entered into a Surety Bond Backstop Agreement (the “Backstop Agreement”) with David F. Welch, Ph.D., both individually and in his capacity as trustee of a revocable trust, LRFA, LLC, a Delaware limited liability company, and certain other related parties (collectively, the “Indemnitors”). Pursuant to the Backstop Agreement, the Indemnitors agreed to assist the Company in obtaining a surety bond (the “Surety Bond”) for posting in connection with the Company’s ongoing litigation with Amarex Clinical Research, LLC, by, among other things, agreeing to indemnify the issuer of the Surety Bond with respect to the Company’s obligations under the Surety Bond. Under the Backstop Agreement, the Company issued to 4-Good Ventures LLC, an affiliate of the Indemnitors (“4-Good Ventures”), two warrants, each for the purchase of 15,000,000 shares of our common stock, as a backstop fee, each with a five-year term and, as amended in July 2022 and December 2022, an exercise price of $0.10 per share and an additional two warrants, each for the purchase of 7,500,000 shares of our common stock, each with a five-year term and an exercise price of $0.10 per share (the “Backstop Warrants”). The remaining 31,000,000 shares of common stock underlying the Backstop Warrants, as well as 8,060,922 shares of common stock received by the revocable trust upon exercise of a portion of one of the Backstop Warrants, are among those being offered for resale as shown under “Selling Stockholders”.

Warrants Issued to Richard G. Pestell, M.D., Ph.D. In May 2022, we issued to Richard G. Pestell, M.D., Ph.D., warrants with a three-year term to purchase 7,000,000 shares of common stock with an exercise price of $0.37 per share in connection with the settlement of a lawsuit related to Dr. Pestell’s former employment as our Chief Medical Officer. The shares of common stock are among those being offered for resale as shown under “Selling Stockholders”.

THIS OFFERING

We are registering for resale by the selling stockholders named herein an aggregate of 794,972,289 shares of our common stock as described below.

RISK FACTORS

Investing in our securities involves risks. You should carefully consider the risks, uncertainties, and other factors described in our most recent Annual Report on Form 10‑K, as supplemented and updated by subsequent Quarterly Reports on Form 10‑Q and Current Reports on Form 8‑K that we have filed or will file with the SEC, and in other documents that are incorporated by reference into this prospectus, as well as the risk factors and other information contained in or incorporated by reference into any accompanying prospectus supplement, before investing in any of our securities. Our financial condition, results of operations, and cash flows could be materially adversely affected by any of these risks. The risks and uncertainties described in the documents incorporated by reference herein are not the only risks and uncertainties that you may face.

For more information about our SEC filings, please see “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

USE OF PROCEEDS

We will not receive any proceeds from the sale of shares of our common stock by the selling stockholders. A portion of the shares of common stock covered by this prospectus are issuable upon exercise of warrants issued to the selling stockholders. The exercise price of such warrants ranges from $0.09387 to $0.50 per share. The exercise price and number of shares of common stock issuable upon exercise of the warrants may be adjusted in certain circumstances, including stock splits or dividends, mergers, reclassifications, or similar events. Upon any exercise of warrants for cash, the selling stockholders will pay us the exercise price. The warrants issued to our placement agent include a cashless exercise feature, while all other warrants do not. To the extent we receive proceeds from the cash exercise of our outstanding warrants, we intend to use the proceeds for working capital and other general corporate purposes. We will bear all other costs, fees, and expenses incurred in effecting the registration of the shares covered by this prospectus. All selling and other expenses incurred by the selling stockholders will be borne by the selling stockholders. See “Selling Stockholders” and “Plan of Distribution” described below.

SELLING STOCKHOLDERS

When we refer to the “selling stockholders” in this prospectus, we mean the persons or entities specifically identified in the table below, as well as the permitted transferees, pledgees, donees, assignees, successors, and other successors-in-interest who may subsequently hold any of the selling stockholders’ interests other than through a public sale.

The table below sets forth information concerning the resale of our shares by the selling stockholders. The total number of common shares sold under this prospectus may be adjusted to reflect adjustments due to stock dividends, stock distributions, splits, combinations or recapitalizations with regard to the common stock. Unless otherwise stated below in the footnotes, to our knowledge, neither the selling stockholders, nor any affiliate of such stockholders, has held any position or office with us during the three years prior to the date of this prospectus.

We have registered 410,046,456 shares of our common stock and 384,925,833 shares underlying warrants to purchase our common stock for resale by the selling stockholders named below. We will not receive any of the proceeds of sales by the selling stockholders of any of the shares of common stock covered by this prospectus. However, if all of the warrants covered by this prospectus are exercised for cash, we may receive proceeds of up to approximately $94.6 million, as further described in “Use of Proceeds.”

Set forth below are the names of the selling stockholders and the amount and percentage of common stock beneficially owned by each of the selling stockholders (including shares that the stockholders have the right to acquire within 60 days of September 24, 2026) prior to the offering, the shares registered for sale in the offering (including shares underlying warrants), and the amount and percentage of common stock to be beneficially owned by each after the offering (including shares not included in the offering that the stockholders have the right to acquire within 60 days of September

24, 2026) assuming all shares are sold. The footnotes provide information about persons who have voting and dispositive power with respect to shares held by the selling stockholders.

The amounts and information set forth below are based upon information the Company received from the selling stockholders, as well as Company records. The selling stockholders may sell all or some of the shares of common stock they are offering, and may sell, unless indicated otherwise in the footnotes below, shares of our common stock otherwise than pursuant to this prospectus. The table below assumes that the selling stockholders sell all of the shares offered by them in offerings pursuant to this prospectus and do not acquire any additional shares. We are unable to determine the exact number of shares that will actually be sold or when or if these sales will occur.