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Preliminary Proxy Statement

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Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

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Definitive Proxy Statement

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Definitive Additional Materials

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Soliciting Material under §240.14a-12

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No fee required.

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Fee paid previously with preliminary materials.

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Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

styleINA Scan QR for digital voting C/O TABULATOR, P.O. BOX 8016, CARY, NC 27512-9903 Your vote matters! LifeStance Health Group, Inc. Annual Meeting of Stockholders Monday, June 3, 2024 1:00 PM, Eastern Time Annual Meeting to be held live via the Internet - please visit www.proxydocs.com/LFST for more details. You must register to attend the meeting online and/or participate at www.proxydocs.com/LFST For a convenient way to view proxy materials, VOTE, and obtain directions to attend the meeting go to www.proxydocs.com/LFST To vote your proxy while visiting this site, you will need the 12 digit control number in the box below. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. This is not a ballot. You cannot use this notice to vote your shares. We encourage you to access and review all of the important information contained in the proxy materials before voting. Under United States Securities and Exchange Commission rules, proxy materials do not have to be delivered in paper. Proxy materials can be distributed by making them available on the internet. If you want to receive a paper or e-mail copy of the proxy material, you must request one. There is no charge to you for requesting a copy. In order to receive a paper package in time for this year's meeting, you must make this request on or before May 24, 2024. Meeting Materials: Notice of Meeting and Proxy Statement & Annual Report on Form 10-K Important Notice Regarding the Availability of Proxy Materials for the Stockholders Meeting To Be Held On June 3, 2024 For Stockholders of record as of April 12, 2024 To order paper materials, use one of the following methods. Internet: www.investorelections.com/LFST Call: 1-866-648-8133 Email: paper@investorelections.com * If requesting material by e-mail, please send a blank e-mail with the 12 digit control number (located below) in the subject line. No other requests, instructions OR other inquiries should be included with your e-mail requesting material. Your control number Have the 12 digit control number located in the box above available when you access the website and follow the instructions. SEE REVERSE FOR FULL AGENDA Copyright © 2024 BetaNXT, Inc. or its affiliates. All Rights Reserved

LifeStance Health Group, Inc. Annual Meeting of Stockholders THE BOARD OF DIRECTORS RECOMMENDS A VOTE: FOR ON PROPOSALS 1, 2, 3 AND 1 YEAR ON PROPOSAL 4 PROPOSAL 1. Election of the three director nominees named in the Proxy Statement to serve until the 2027 annual meeting of stockholders; 1.01 Kenneth Burdick 1.02 Jeffrey Rhodes 1.03 William Miller 2. Ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ended December 31, 2024; 3. Approval, on an advisory basis, of the compensation of the Company's named executive officers; 4. Approval, on an advisory basis, of the frequency of future advisory votes on the compensation paid to the Company's named executive officers; and 5. Transacting such other business as may properly come before the meeting or any adjournment thereof.