Exhibit 99.1

Key Physician Advisors Email

Dear Miramar Key Physician Advisors:

As a key advisor to Miramar Labs^®, I want to keep you abreast of recent developments at the company. I am excited to announce this morning it was made public that Sientra, Inc. of Santa Barbara, California will acquire Miramar Labs. Sientra intends to retain Miramar Labs as a wholly-owned subsidiary and will maintain headquarters in Santa Clara, CA.

With this acquisition, I believe we now have the resources and backing to not only continue the high level of support and commitment to bringing miraDry^® patients into your practice, but to increase those activities. This transaction will also help accelerate our R&D programs to bring new applications and further increase the value of your investment in your miraDry system.

We expect the transaction to close within the next two months subject to completion of the tender offer. Until further notice, you should expect each company will continue business operations as before, with all points of contact remaining the same. We will continue to provide you updates on developments as they may affect you.

I would like to personally thank you for your guidance and advice in making miraDry a growing procedure and in shaping our future. We expect to maintain this relationship and will continue to lean on you for advice, support and guidance as we work with Sientra to make the miraDry business even stronger.

If you have any questions or need any additional information, please feel free to contact me or Rob Ellis.

Sincerely,

Mike Kleine

CEO, Miramar Labs

Cautionary Statement Regarding Forward-Looking Statements

Any statements made in this communication that are not statements of historical fact, including statements about the expected timetable for completing the transaction and the potential effects of the acquisition on both Sientra and Miramar Labs, are forward-looking statements that are based on management’s beliefs, certain assumptions and current expectations and should be evaluated as such. These statements may be identified by their use of forward-looking terminology such as the words “expects,” “projects,” “anticipates,” “intends” and other similar words. Forward-looking statements include statements that may relate to Sientra’s or Miramar Labs’ plans, objectives, strategies, goals, future events, future revenues or performance, and

other information that is not historical information. Such forward-looking statements involve risks and uncertainties that could cause actual results to differ materially from those projected. These risks and uncertainties include, but are not limited to, general economic, business and market conditions and the satisfaction of the conditions to closing of the proposed transaction. For a more complete discussion of certain of the risks and uncertainties that could cause actual results to differ from those contained in the forward-looking statements with respect to Miramar Labs, see the discussion of risks and uncertainties in Miramar Labs’ annual report on Form 10-K for the fiscal year ended December 31, 2016 filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 17, 2017 and other reports Miramar Labs files with the SEC, as well as the tender offer documents to be filed with the SEC by Sientra and its acquisition subsidiary and by Miramar Labs. The forward-looking statements contained in this document are made as of the date that the document is issued, and Miramar Labs undertakes no obligation to update any forward-looking statements, whether as a result of future events, new information or otherwise, except as required by law. All forward-looking statements in this communication are qualified in their entirety by this cautionary statement.

Additional Information and Where to Find It

In connection with the proposed acquisition, Sientra will commence a tender offer for all of the outstanding shares of Miramar Labs. The tender offer has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Miramar Labs, nor is it a substitute for the tender offer materials that Sientra and its acquisition subsidiary will file with the SEC upon commencement of the tender offer. At the time that the tender offer is commenced, Sientra and its acquisition subsidiary will file tender offer materials on Schedule TO with the SEC, and Miramar Labs will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the offer. THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE AND CERTAIN OTHER TENDER OFFER DOCUMENTS) AND THE SOLICITATION/ RECOMMENDATION STATEMENT WILL CONTAIN IMPORTANT INFORMATION THAT SHOULD BE READ CAREFULLY AND CONSIDERED BY MIRAMAR LABS’ STOCKHOLDERS BEFORE ANY DECISION IS MADE WITH RESPECT TO THE TENDER OFFER. Both the tender offer statement and the solicitation/recommendation statement will be made available to Miramar Labs’ stockholders free of charge. A free copy of the tender offer statement and the solicitation/recommendation statement will also be made available to all stockholders of Miramar Labs by phone at (408) 940-8700, or by visiting Miramar Labs’ website (www.miramarlabs.com). In addition, the tender offer statement and the solicitation/recommendation statement (and all other documents filed with the SEC) will be available at no charge on the SEC’s website (www.sec.gov) upon filing with the SEC. MIRAMAR LABS’ STOCKHOLDERS ARE ADVISED TO READ THE TENDER OFFER STATEMENT AND THE SOLICITATION/RECOMMENDATION STATEMENT, AS EACH MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC WHEN THEY BECOME AVAILABLE BEFORE THEY MAKE ANY DECISION WITH RESPECT TO THE TENDER OFFER BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND THE PARTIES TO THE TRANSACTION.