Exhibit 99.1

Stanley Higgins

Associate Vice President

Nasdaq Listing Qualifications

By Electronic Delivery to: karkus@prophaselabs.com

December 29, 2025

Ted Karkus

Principal Executive Officer

ProPhase Labs, Inc.

626 RXR Plaza

6th Floor

Uniondale, New York 11556

Dear Ted Karkus:

As you are aware, on December 26, 2024, Staff notified the Company that the bid price of its listed securities had closed at less than $1 per share over the previous 30 consecutive business days, and, as a result, did not comply with Listing Rule 5550(a)(2). Therefore, in accordance with Listing Rule 5810(c)(3)(A), the Company was provided 180 calendar days, or until June 24, 2025, to regain compliance with the Rule. Subsequently, on June 25, 2025, the Company was provided an additional 180 calendar day compliance period, or until December 22, 2025, to demonstrate compliance.

The Company has not regained compliance with Listing Rule 5550(a)(2). Accordingly, its securities will be delisted from the Capital Market. In that regard, trading of the Company’s common stock will be suspended at the opening of business on January 5, 2026, and a Form 25-NSE will be filed with the Securities and Exchange Commission (the “SEC”), which will remove the Company’s securities from listing and registration on The Nasdaq Stock Market.

The Company may appeal Staff’s determination to the Panel, pursuant to the procedures set forth in the Nasdaq Listing Rule 5800 Series.¹ Hearing requests should not contain arguments in support of the Company’s position. The Company may request either an oral hearing or a hearing based solely on written submissions. The fee for a hearing is $20,000.² Please submit your non-refundable Hearing Request fee in accordance with the instructions provided on the attached

¹ Pursuant to Listing Rule 5815(a)(1)(B)(ii)(d), a timely request for a hearing will not stay the trading suspension of the securities of a Company afforded the second 180-day compliance period described in Rule 5810(c)(3)(A)(ii) that failed to regain compliance with the minimum bid price requirement during such period.

² Nasdaq is not responsible for costs associated with the wire transfer of hearing fees. Please be sure to include a sufficient amount to cover any applicable bank fees.

Ted Karkus

December 29, 2025

Page 2

“Check Payment Form”.³ The request for a hearing and confirmation of payment should be submitted electronically through our Listing Center⁴ and must be received by the Hearings Department no later than 4:00 p.m. Eastern Time on January 5, 2026.⁵

The Company will be asked to provide a plan to regain compliance to the Panel. Accordingly, the Company may wish to consider presenting a plan that includes a discussion of the events that it believes will enable it to regain compliance in this time frame and a commitment to effect a reverse stock split, if necessary.

Listing Rule 5835 prohibits communications relevant to the merits of a proceeding under the Listing Rule 5800 Series between the Company and the Hearings Department unless Staff is provided notice and an opportunity to participate. In that regard, Staff waived its right to participate in any oral communications between the Company and the Hearings Department. Should Staff determine to revoke such waiver, the Company will be immediately notified, and the requirements of Listing Rule 5835 will be strictly enforced.

Our Rules require that the Company promptly disclose receipt of this letter by either filing a Form 8-K, where required by SEC rules, or by issuing a press release. The announcement needs to be made no later than four business days from the date of this letter and must include the continued listing criteria that the Company does not meet, and a description of each specific basis and concern identified by Nasdaq in reaching the determination.⁶ The Company must also submit the announcement to Nasdaq’s MarketWatch Department.⁷ If the public announcement is made between the hours of 7:00 AM and 8:00 PM Eastern Time, the Company must submit the announcement to Nasdaq’s MarketWatch Department at least ten minutes prior its public release. If the public announcement is made outside of these hours, the Company must submit the announcement prior to 6:50 A.M. Eastern Time. Please note that if you do not make the required announcement trading in your securities will be halted.⁸

While the suspension announcement will be included on the “Daily List,” which is posted and available to subscribers of www.Nasdaqtrader.com at approximately 2:00 p.m. on January 2, 2026, news of the suspension may not be deemed publicly disseminated until the Company makes an announcement through a Regulation FD compliant means of communication.

³ The Form also includes a “link” for payment by wire.

⁴ To utilize our electronic form process, please create a user account, if you have not already done so. Once you create a user account, you can begin completing the Hearing Request Form. At any time, you may save your work and complete it at a later time. Upon submission, you will receive a confirmation email. Please note that prior to starting you will need the following company information: current trading symbol, Central Index Key (CIK) code or CUSIP.

⁵ Listing Rule 5815(a)(3). Within seven calendar days of the date of the Staff Delisting Determination, Public Reprimand Letter, or written denial of an initial listing application, the Company must submit a non-refundable hearing fee of $20,000. No payment will be credited and applied towards the hearings fee unless the issuer has previously paid all applicable fees due to the Exchange.

⁶ Listing Rule 5810(b). See FAQ #428 available on the Nasdaq Listing Center.

⁷ The notice must be submitted to Nasdaq’s MarketWatch Department through the Electronic Disclosure submission system available at nasdaq.net/ED/IssuerEntry.

⁸ Listing IM-5810-1.

Ted Karkus

December 29, 2025

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If you have any questions, please contact Patryk Muter, Listing Analyst at, +1 301 532 6389.

Sincerely,

NASDAQ ONLINE RESOURCES

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