Initial Registration Statement (Form S-1)

PROSPECTUS SUMMARY

This summary contains basic information about us and this offering. Because it is a summary, it does not contain all of the information that you should consider before investing. Before you decide to invest in our Common Stock, you should read this entire prospectus carefully, including the section entitled "Risk Factors," and any documents incorporated by reference.

Our Business

Overview

We are a biopharmaceutical company focused on developing ABP-450 as a biosimilar to BOTOX® (onabotulinumtoxinA) for therapeutic indications. Our strategy is to pursue biosimilarity across all clinically relevant dimensions of the reference product, including label breadth, dosing and dilution, clinical performance and physician workflow, in order to enable seamless substitution and minimize switching friction for prescribers and payers, and to initially pursue regulatory approval in the United States through Section 351(k). We hold exclusive development and commercialization rights for ABP-450 in therapeutic indications across the United States, Canada, the European Union, the United Kingdom, and certain other international territories.

Building on this strategy, we are advancing ABP-450 through the 351(k) biosimilar pathway toward a potential BLA in the United States, targeting the therapeutic botulinum toxin market, which we estimate to be approximately $3.5 billion in 2026 and projected to grow at an annual growth rate of approximately 8%, according to Clarivate Therapeutic Botulinum Toxin Market Insights 2025. This large and continually growing market has historically been dominated by a single branded product, BOTOX®. We believe this market has remained highly concentrated in part due to the reference product's broad label covering all twelve FDA-approved therapeutic indications, which has limited the adoption of competing products with narrower labels. Based on qualitative interviews conducted by a third-party market research firm with a small number of neurologists and payers in late 2025, physicians reported operational complexity and economic constraints associated with existing therapeutic neurotoxins, including limited flexibility under buy-and-bill reimbursement dynamics and challenges associated with managing products with differing dosing, dilution and labeling requirements. These interviewees indicated that, despite these challenges, BOTOX® remains the predominant product due to its comprehensive label and established clinical workflows. We believe these dynamics may contribute to continued reliance on a single product and highlight the importance of a biosimilar approach designed for full-label alignment and workflow compatibility. ABP-450 is the same botulinum toxin complex that is currently approved as a biosimilar in Mexico, India and Philippines and, in the U.S., is approved to provide temporary improvement in the appearance of moderate to severe glabellar lines for certain adult patients and marketed by Evolus, Inc. under the name Jeuveau® in the U.S. and Nuceiva® in Canada and the European Union. We have established a highly experienced management team with specific experience in biopharmaceutical and botulinum toxin development and commercialization.

ABP-450 is manufactured by Daewoong Pharmaceutical Co., Ltd. ("Daewoong") pursuant to a license and supply agreement under which we hold exclusive development and commercialization rights to ABP-450 for therapeutic indications in the United States, Canada, the European Union, the United Kingdom, and certain other international territories. ABP-450 is manufactured by Daewoong in a facility designed to be compliant with current Good Manufacturing Practice ("cGMP") that has manufactured products approved by the FDA, Health Canada, and the European Commission. These facilities have been inspected by global regulatory authorities, including the FDA and EMA. The same botulinum toxin complex is commercially available in multiple international markets and is approved in the United States for aesthetic use under the brand name Jeuveau®. Our development program is focused exclusively on therapeutic indications, where we believe the biosimilar pathway may enable efficient development and broad label access, subject to regulatory review.

We believe the U.S. therapeutic neurotoxin market is characterized by a concentrated prescriber and payer base, which may enable an efficient commercialization approach. Based on third-party claims data analyses, a relatively small number of high-volume neurologists account for a significant portion of therapeutic neurotoxin utilization, and a limited number of payers cover a majority of treated patients. We believe this concentration may allow for targeted engagement strategies focused on key prescribers and payers.

We held an initial meeting with the FDA in the third quarter of 2024 during which we obtained feedback from the FDA on the next steps to develop a BOTOX® biosimilar. We commenced analytical studies in the fourth quarter of 2024 to prepare for a BPD Type 2a meeting with the FDA that was held in January 2026. During the meeting, the FDA reviewed the Company's proposed analytical similarity strategy under the 351(k) biosimilar pathway. The FDA acknowledged the scientific challenges associated with characterizing a 900 kDa botulinum neurotoxin complex, provided constructive feedback on our proposed development approach and analytical assessment plan, and noted that our analytical methodologies appeared reasonable to support advancement of the program toward a comprehensive analytical similarity package. We believe this feedback provides a framework for the remaining analytical components of our biosimilar development program and plan to complete the majority of our analytical comparability program in 2026. We are currently planning to hold a BPD Type 2b meeting with the FDA in the second half of 2026 to discuss the next phase of the development program to support approval of ABP-450 as a biosimilar to BOTOX® across all approved therapeutic indications.

The initial results from our analytical studies indicate a 100% amino acid sequence match confirmed between ABP-450 and BOTOX®, based on sequence coverage of 93% to 99% for the five proteins that comprise the 900 kDa botulinum toxin type A complex, using liquid chromatography/mass spectrometry ("LC/MS") analysis of more than 3,400 amino acids across multiple lots of ABP-450 and BOTOX®, without any sequence deviations observed. Additionally, ABP-450 also demonstrated highly similar potency across two distinct assays (LD50 - an in vivo biological activity assay and CBPA - a cell-based potency assay) to support clinical dose predictability, comparable vial-to-vial active ingredient composition using ELISA - further supporting dose similarity and reliability, and functional cleavage of SNAP-25, consistent with the mechanism of action. These results contribute to our assessment of analytical similarity by characterizing key structural attributes of ABP-450 relative to the reference product and are intended to reduce residual uncertainty and potentially limit the need for further clinical assessments. Additional analytical and functional studies are ongoing as part of our broader analytical similarity assessment. Based on an internal review of peer-reviewed literature, we have identified more than 230 reported or potential therapeutic uses across multiple therapeutic areas, including neurology, pain, urology, gastroenterology, ophthalmology, dermatology, autonomic disorders, and musculoskeletal conditions. ABP-450 has been previously evaluated in multiple clinical and preclinical programs, including Phase 2 studies in cervical dystonia and migraine and preclinical work in gastroparesis and neuropsychiatric models. The Phase 2 cervical dystonia program met its primary and key secondary endpoints and, together with its open-label safety extension, provides human clinical data supporting the potential safety and efficacy of ABP-450. We are not currently pursuing additional 351(a) indication-specific development programs, but we retain related intellectual property and know-how that could support future collaborations or lifecycle opportunities.

Prior to licensing the botulinum toxin complex to Evolus, Daewoong conducted a broad preclinical development program for ABP-450 and has received approval from over 69 regulatory authorities. Subsequently, Evolus completed a comprehensive clinical development program of the same botulinum toxin complex and has received approval in the United States, the European Union and Canada to market and sell Jeuveau® in the United States and Nuceiva® in Canada and the European Union for the temporary improvement in the appearance of moderate to severe glabellar, or frown lines in adults. Over 2,100 adult subjects with moderate to severe glabellar lines at maximum frown participated in Evolus' clinical development program, and each of Evolus' Phase 3 clinical studies successfully met their respective primary safety and efficacy endpoints. While none of these preclinical or clinical programs specifically contemplated any therapeutic use of ABP-450, given that the FDA's regulatory requirements are generally the same for the cosmetic or therapeutic use of a toxin, we believe that the positive data derived from these preclinical and clinical studies will support the clinical development and potential future safety labeling of ABP-450 for our 351(k) biosimilar program, across all labeled dose ranges.

We plan to pursue approval of ABP-450 by submitting a Section 351(k) BLA that exclusively contemplates therapeutic indications for ABP-450, which we believe could improve provider reimbursement for ABP-450, if approved. Existing botulinum toxins, including BOTOX®, are approved under a single BLA for both therapeutic and cosmetic indications. As a result of this and other factors, other botulinum toxins are required to include the sales prices of both therapeutic and cosmetic botulinum toxin sales when calculating the average selling price, or ASP, that is used to determine the reimbursement amount physicians receive for therapeutic usage. The inclusion of a lower cosmetic sales price in the calculation of ASP can, in some cases,

cause physicians that inject for therapeutic applications to lose money when treating patients with existing botulinum toxins and also creates a deterrent to providing payors and/or providers with rebates or other financial incentives. If we are successful in obtaining approval of a Section 351(k) BLA for therapeutic indications of ABP-450, we believe this could facilitate more consistent reimbursement economics for providers administering ABP-450 in therapeutic settings while also providing greater flexibility to support contracting strategies with payors. Subject to pricing, reimbursement and formulary decisions, these characteristics may create greater alignment between provider reimbursement incentives and payor objectives to manage treatment costs. We believe such alignment, if achieved, could support adoption of ABP-450 in therapeutic indications. This pricing approach would be unique within the current therapeutic neurotoxin market and, we believe, could provide flexibility to offer competitive net pricing to payers while maintaining favorable reimbursement dynamics for providers. In addition, under the Medicare Part B buy-and-bill framework, biosimilars are generally reimbursed at the biosimilar's own ASP plus an add-on payment equal to 6% of the reference product's ASP, which, because the reference product typically has a higher ASP than the biosimilar, can result in a larger per-unit margin for providers administering the biosimilar relative to the reference product. However, our expected pricing model has not been finalized and may differ from current expectations.

We have never been profitable from operations and, as of March 31, 2026, we had an accumulated deficit of $482.6 million. We have never generated revenue from ABP-450. We have concluded that we do not have sufficient cash to fund our operations through March 31, 2027 without additional financing, and as a result, there is substantial doubt about our ability to continue as a going concern. As of the date of this prospectus, we expect to have sufficient cash to fund our operating plan into the third quarter of 2026. Any further development of ABP-450 for any indication, including the biosimilar pathway and any additional studies, will require additional funding, which may not be available to us on reasonable terms, or at all.

We do not expect to receive any revenue from ABP-450 or any future product candidates that we develop unless and until we obtain regulatory approval and commercialize ABP-450 or any future product candidates. We expect to continue to incur significant expenses and increasing net operating losses for the foreseeable future as we seek regulatory approval, prepare for and, if approved, proceed to commercialization of ABP-450.

Recent Developments

Leerink ATM

On August 14, 2024, the Company entered into a sales agreement with Leerink Partners LLC ("Leerink Partners") relating to an at-the-market offering program (the "ATM"), pursuant to which the Company may offer and sell, from time to time at its sole discretion, shares of Common Stock, having aggregate gross proceeds of up to $50.0 million through Leerink Partners as sales agent subject to applicable limitations. Under the ATM, Leerink Partners is entitled to commission at a rate equal to 3.0% of the gross proceeds from sales of shares of Common Stock under the ATM. The Company may cancel its at-the-market program at any time upon prior notice, pursuant to its terms. As of May 26, 2026, we have issued and sold an aggregate of 2,661,939 shares of Common Stock under the ATM and received net proceeds of approximately $2.9 million, and approximately $47.0 million of Common Stock remains available to be sold under the ATM subject to applicable limitations.

NYSE Continued Listing

On March 31, 2026, we received written notice of non-compliance (the "Notice") from the NYSE American indicating that we are not in compliance with the continued listing standards set forth in Section 1003(a)(ii) of the NYSE American Company Guide. Section 1003(a)(ii) requires stockholders' equity of $4.0 million or more if a listed company has reported losses from continuing operations and/or net losses in three of its four most recent fiscal years. The Notice states that we reported a stockholders' deficit of approximately $55 million as of December 31, 2025 and have incurred losses from continuing operations and/or net losses in three of our four most recent fiscal years, as reflected in our Annual Report on Form 10-K for the year ended December 31, 2025 filed with the SEC on March 30, 2026.

As previously reported, on February 7, 2025, we received a prior notice from NYSE American that we were not in compliance with Section 1003(a)(i) of the NYSE American Company Guide, which requires stockholders' equity of $2.0 million or more if a listed company has reported losses from continuing operations and/or net losses in two of its three most recent fiscal years. NYSE American allows for an exemption to Section 1003(a) for companies that satisfy both (1) total market capitalization of at least $50 million, or total assets and revenue of $50 million each in its last fiscal year or in two of its last three fiscal years; and (2) at least 1,100,000 shares publicly held, market value of publicly held shares of at least $15 million, and 400 round lot holders. Pursuant to that prior notice, we submitted a plan to regain compliance by August 3, 2026 (the "Plan"). In April 2025, NYSE American accepted the Plan and granted us until August 3, 2026 (the "Plan Period") to regain compliance. We have been subject to periodic reviews by NYSE American and have been making progress consistent with the Plan.

The Notice relates to our previously disclosed compliance status following our year-end results and does not have immediate effect on the listing of Common Stock on NYSE American or the Plan Period. Our Common Stock will continue to be listed and traded on NYSE American during the Plan Period, subject to compliance with other applicable listing standards, and will continue to trade with a ".BC" indicator to denote that we are below compliance. We will also continue to be included in the NYSE American list of noncompliant issuers.

We intend to continue to execute the Plan to regain compliance with Sections 1003(a)(i) and 1003(a)(ii) by August 3, 2026. However, there can be no assurance that we will be able to regain compliance within the required timeframe. We have a right to appeal a staff delisting determination in accordance with Section 1010 and Part 12 of the NYSE American Company Guide. Our receipt of the Notice does not affect our business operations or our reporting obligations with the SEC.

Corporate Information

We were initially incorporated in the State of Delaware on November 17, 2020 under the name Priveterra Acquisition Corp. Upon the closing of the business combination on July 21, 2023, we changed our name to AEON Biopharma, Inc. Our principal executive offices are located at 5 Park Plaza, Suite 1750, Irvine, California 92614 and our telephone number is (949) 354-6499.

THE OFFERING

Shares of our Common Stock to be Offered

17,479,373 shares of Common Stock, based on an assumed public offering price of $0.7151 per share of Common Stock, which is equal to the last sale price of our Common Stock as reported on the NYSE American on July 2, 2026.

Pre-funded Warrants to be Offered

We are also offering to those purchasers, if any, whose purchase of the Common Stock in this offering would result in the purchaser, together with its affiliates and certain related parties, beneficially owning more than 4.99% (or at the election of the purchaser, 9.99%) of our outstanding Common Stock immediately following the consummation of this offering, the opportunity to purchase, if they so choose, Pre-Funded Warrants in lieu of the Common Stock that would otherwise result in ownership in excess of 4.99% (or 9.99%, as applicable) of our outstanding Common Stock.

The purchase price of each Pre-Funded Warrants will equal the price per share of Common Stock being sold to the public in this offering, minus $0.0001, and the exercise price of each Pre-Funded Warrant will be $0.0001 per share.

For each Pre-Funded Warrant we sell, the number of shares of Common Stock we are offering will be decreased on a one-for-one basis.

Each Pre-Funded Warrant will be immediately exercisable and may be exercised at any time until exercised in full. There is no expiration date for the Pre-Funded Warrants. To better understand the terms of the Pre-Funded Warrants, you should carefully read the "Description of Securities We are Offering" section of this prospectus. You should also read the form of Pre-Funded Warrant, which is filed as an exhibit to the registration statement that includes this prospectus.

Milestone Warrants to be Offered

Together with each share of Common Stock (or Pre-Funded Warrant) offered in this offering, we are also offering (i) one Two-Year Milestone Warrant to purchase one share of Common Stock or one Pre-Funded Warrant and (ii) one Five-Year Milestone Warrant to purchase one share of Common Stock or one Pre-Funded Warrant, representing 200% aggregate warrant coverage (100% coverage in the form of Two-Year Milestone Warrants and 100% coverage in the form of Five-Year Milestone Warrants). The Two-Year Milestone Warrant will be immediately exercisable upon issuance at an assumed exercise price of $0.7151 per share or $0.7150 per Pre-Funded Warrant (representing 100% of the assumed public offering price of $0.7151 per share, the last reported sale price of our common stock as reported on the NYSE American on July 2, 2026 (less the $0.0001 per share exercise price in the case of the Pre-Funded Warrant)) and the Five-Year Milestone Warrant will be immediately exercisable upon issuance at an assumed exercise price of $0.8224 per share (representing 115% of the assumed public offering price). Each Two-Year Milestone Warrant will expire on the earliest of (x) the second anniversary of the date of issuance and (y) 45 days after our public announcement that we have received Type 2B meeting minutes from the FDA that do not preclude advancement of ABP-450 toward a Biologics License Application under the Section 351(k) biosimilar pathway. Each Five-Year Milestone Warrant will expire on the earliest of (x) the fifth anniversary of the date of issuance and (y) 45 days following our public announcement of the initiation of a Phase 3 clinical equivalence trial of ABP-450 as a biosimilar to BOTOX®. At the option of the holder, each Milestone Warrant may be exercised for either one share of Common Stock or one Pre-Funded Warrant. To better understand the terms of the Milestone Warrants, you should carefully read the "Description of the Securities We are Offering" section of this prospectus. You should also read the form of each Milestone Warrant, which is filed as an exhibit to the registration statement that includes this prospectus. The Milestone Warrants and the Pre-Funded Warrants will be issued in accordance with pursuant to, and subject to the terms of the Warrant Agency Agreement to be entered into with Continental Stock Transfer & Trust Company, as warrant agent. See "Description of the Securities We Are Offering" for additional information.

Lock-Up Agreements

In connection with this offering, we and all of our executive officers and directors and certain of our stockholders will agree not to, without the prior written approval of the Representative, offer, sell, contract to sell or otherwise dispose of or hedge

Common Stock or securities convertible into or exchangeable for Common Stock, subject to certain exceptions. For more information, see "Underwriting."

Over-allotment Option

We have granted the Representative a 30-day option to purchase from us up to an additional 2,621,905 shares of Common Stock and/or Pre-Funded Warrants to purchase up to 2,621,905 shares of Common Stock (or any combination thereof), representing 15% of the total number of shares of Common Stock and Pre-Funded Warrants sold in this offering, solely to cover over-allotments, if any. The Representative may exercise the over-allotment option with respect to shares of Common Stock only, Pre-Funded Warrants only, or any combination thereof. Any Common Stock or Pre-Funded Warrants purchased pursuant to the over-allotment option will be accompanied by the corresponding Two-Year Milestone Warrants and Five-Year Milestone Warrants on the same 100% coverage basis as the Common Stock and Pre-Funded Warrants sold at closing. The purchase price to be paid per additional share of Common Stock or per additional Pre-Funded Warrant will be equal to the public offering price per share of Common Stock or per Pre-Funded Warrant, as applicable, less the underwriting discounts and commissions. If the Representative exercises the option in full for shares of Common Stock only, the additional underwriting discounts and commissions payable by us related to such exercise will be $131,249, and the additional proceeds to us related to such exercise, before expenses, will be $1,743,735.

Shares of our Common Stock outstanding prior to this offering

26,307,211 shares of our Common Stock.

Shares of our Common Stock to be outstanding after this offering

43,786,584 Shares of our Common Stock (assuming we sell only shares of Common Stock and no Pre-Funded Warrants).

Use of proceeds

We expect to receive net proceeds of approximately $11.0 million from the issuance and sale of the securities in this offering, or approximately $12.8 million if the Representative exercises its over-allotment option in full for Common Stock only, assuming a price of $0.7151 per share of Common Stock, after deducting underwriting discounts and commissions and estimated offering expenses payable by us. We intend to use the net proceeds from this offering for working capital and general corporate purposes, including conducting comparative analytical testing on ABP-450 to support biosimilarity with BOTOX®. See "Use of Proceeds."

NYSE American symbol for our Common Stock

"AEON"

Risk Factors

This investment involves a high degree of risk. See "Risk Factors" beginning on page 9 of this prospectus for a discussion of factors you should carefully consider before deciding to invest in our securities.

Unless otherwise noted, the number of shares of Common Stock to be outstanding is based on 26,307,211 shares of Common Stock outstanding as of July 2, 2026 and excludes as of July 2, 2026:

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158,005 shares of Common Stock issuable upon the exercise of options, with a weighted-average exercise price of $296.85 per share;

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11,377,317 shares of Common Stock issuable upon the vesting and settlement of restricted stock units ("RSUs");

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2,352,070 shares of Common Stock issuable for vested RSUs that have not been issued, of which 357,638 shares of Common Stock will be withheld to satisfy tax obligations;

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6,084,111 shares of Common Stock that were reserved for future issuance under our 2023 Incentive Award Plan (the "2023 Plan") and 2025 Employment Inducement Incentive Award Plan (the "2025 EIP"), as well as any automatic increases in the number of shares of our Common Stock reserved for future issuance under the 2023 Plan;

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149,036 shares of Common Stock that were reserved for future issuance under our 2023 Employee Stock Purchase Plan ("ESPP"), as well as any automatic increases in the number of shares of our Common Stock reserved for future issuance under the ESPP;

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an aggregate of 18,389,740 shares of Common Stock issuable upon the exercise of private placement warrants, at a weighted average exercise price of $4.97 per share, and an aggregate of 24,400,289 shares of Common Stock issuable upon the exercise of pre-funded warrants, at a weighted average exercise price of $0.0001 per share, in each case to purchase shares of our Common Stock;

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3,268,860 shares of Common Stock issuable upon conversion of certain senior secured convertible note (the "Convertible Note"), assuming at a conversion price of $1.00 per share and the maximum accrued interest prior to the maturity date of the Convertible Note); and

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208,657 shares of Common Stock (the "Contingent Consideration Shares") issuable subject to achievement of certain milestone provisions set forth in our Business Combination Agreement, dated as of December 12, 2022 (as amended, the "Business Combination Agreement").

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Except as otherwise indicated, all information in this prospectus assumes:

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no exercise of outstanding options or settlement of outstanding RSUs;

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no conversion of the Convertible Note;

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no settlement of the Contingent Consideration Shares;

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no sale of Pre-Funded Warrants; and

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no exercise of the Representative's over-allotment option.

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