Tekla Life Sciences Investors : Proxy Statement

100 Federal Street, 19th Floor

Boston, Massachusetts 02110

[phone]

NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

To the Shareholders of TEKLA LIFE SCIENCES INVESTORS:

An Annual Meeting of Shareholders of Tekla Life Sciences Investors ("HQL"), (the"Fund") will be held on Thursday, June 9, 2022 at 11:30 a.m. at 100 Federal Street, 19th Floor, Boston, Massachusetts 02110, for the following purposes:

• (1) The election of Trustees the Fund;

• (2) The ratification or rejection of the selection of Deloitte & Touche LLP as the independent registered public accountants of the Fund for the fiscal year ending September 30, 2022;

• (3) Take action on a shareholder proposal requesting that the Fund take the steps necessary to reorganize the Board of Trustees into one class with each Trustee subject to election each year, if properly presented at the meeting; and

• (4) The transaction of such other business as may properly come before the Annual Meeting and any adjournment(s) or postponement(s) thereof.

If you have any questions about the proposals to be voted on, please call our solicitor, Okapi Partners, at [phone].

The Board of Trustees of the Fund recommends that shareholders vote FOR the election of all nominees for election as Trustees, FOR the selection of Deloitte & Touche LLP as the independent registered accountants of the Fund and AGAINST the shareholder proposal.

Shareholders of record at the close of business on April 13, 2022 will be entitled to vote at the Annual Meeting or at any adjournment(s) or postponement(s) thereof.

Due to COVID-19 and the related recommendations, protocols and orders issued by public health authorities and federal, state, and local governments, the date, time, location and/or means of conducting the Annual Meeting may change. The Fund plans to announce these changes, if any, atwww.teklacap.comand encourage you to check this website prior to the Annual Meeting if you plan to attend.

By Order of the Board of Trustees of the Fund,

Daniel R. Omstead, PhD

President

April 18, 2022

Please complete, date and sign the Proxy for the shares held by you and return the Proxy in the envelope provided so that your vote can be recorded. No postage is required if the envelope is mailed in the United States. It is important that you return your signed Proxy promptly, regardless of the size of your holdings, so that a quorum may be assured.

PROXY STATEMENT

This Proxy Statement is furnished in connection with the solicitation by the Board of Trustees (the "Board") of Tekla Life Sciences Investors ("HQL") (the "Fund") of proxies to be voted at the Annual Meeting of Shareholders of the Fund to be held on June 9, 2022 (the "Annual Meeting"), and any adjournment(s) or postponement(s) thereof, for the purposes set forth in the accompanying Notice of Annual Meeting, dated April 18, 2022. This Proxy Statement, the Notice of Annual Meeting and the Proxy Card(s) are first being mailed to shareholders on or about April 18, 2022.

Proposal 1 relates to the election of Trustees of the Fund, Proposal 2 relates to the ratification of the independent registered public accountants of the Fund and Proposal 3 relates to a shareholder proposal to be acted on, if properly presented at the meeting.

The Board of Trustees of the Fund recommends that shareholders vote FOR the election of all nominees for election as Trustees, FOR the selection of Deloitte & Touche LLP as the independent registered accountants of the Fund and AGAINST the shareholder proposal.

The Fund will furnish, without charge, a copy of its Annual Report, or the most recent Semi-Annual Report succeeding the Annual Report, if any, to a shareholder upon request. Requests may be sent to the Fund at 100 Federal Street, 19th Floor, Boston, MA 02110 or be made by calling [phone].

Proposal 1

ELECTION OF TRUSTEES

The Fund's Declaration of Trust, as amended to date (the "Declaration of Trust"), provides that its Board shall be divided into three classes with staggered terms. For HQL, the term of office of the Class C Trustees expires on the date of the 2022 Annual Meeting and the term of office of the Class A and Class B Trustees will expire one and two years, respectively, thereafter. Trustees chosen to succeed the Class C Trustees whose terms are expiring will be elected for a three-year term.

The Fund's Declaration of Trust provides that a majority of its Trustees shall fix the number of the entire Board of Trustees and that such number shall be at least three and no greater than fifteen. The Fund's Board has fixed the number of Trustees at seven. Proxies will be voted for the election of the following nominees for HQL. Each nominee has consented to serve as a Trustee if elected at the Annual Meeting. In the event that a nominee is unable to serve for any reason when the election occurs, the accompanying Proxy will be voted for such other person or persons as the applicable Fund's Board may recommend.

HQL Class C Nominees to Serve until 2025 Rakesh K. Jain, Ph.D. Thomas M. Kent, CPA

Each of the following persons, except for W. Mark Watson, is presently serving as a Trustee and has consented to so serve in the class and for the term specified below.

HQLClass A Trustees to Serve until 2023*Kathleen L. Goetz

Class B Trustees to Serve until 2024

Oleg M. Pohotsky, MBA, JD W. Mark Watson, CPA** Jeffrey A. Bailey

Daniel R. Omstead, Ph.D.

* William S. Reardon is also presently serving as a Trustee in this class but will retire from the Board effective as of the Annual Meeting. ** W. Mark Watson has been appointed as a Trustee, effective June 9, 2022.

The Board believes that each Trustee's experience, qualifications, attributes and skills on an individual basis and in combination with those of other Trustees lead to the conclusion that each Trustee should serve in such capacity. Among the attributes or skills common to all Trustees are their ability to review critically and to evaluate, question and discuss information provided to them, to interact effectively with the other Trustees, the Fund's investment adviser, the administrator and other service providers, counsel and independent registered public accounting firm, and to exercise effective and independent business judgment in the performance of their duties as Trustees. Each Trustee's ability to perform the duties of a trustee effectively has been attained and enhanced through the Trustee's education, professional training and other life experiences, such as business, consulting or public service positions and through experience from service as a member of the Fund's Board, public companies, or non-profit entities or other organizations.

Jeffrey A. Bailey: Mr. Bailey is a seasoned operational healthcare executive with over 30 years of leadership experience within the healthcare industry. Mr. Bailey has extensive business development and transactional expertise, with diverse leadership experiences in commercial and supply chain management, finance, business development and product development for various pharmaceutical medical device companies. He serves as Vice Chairman, on the Valuation Committee and on the Governance and Nominating Committee of the Fund. Most recently, Mr. Bailey served as chief executive officer and director of BioDelivery Sciences, a biotechnology company, from 2020-2022. He served as chief executive officer and director of IlluminOss Medical, Inc., a medical device company, from 2018 to 2020. From 2015 until 2017, Mr. Bailey served as chief executive officer of Neurovance, Inc., a biotechnology company. Previously, from 2013 through 2015, Mr. Bailey served as president and chief executive officer and as a director of Lantheus Medical Imaging, Inc., a public medical diagnostic company. Prior to 2013, Mr. Bailey held various leadership positions with several public and private pharmaceutical and medical device companies, including president and general manager at Novartis Pharmaceuticals, a multinational pharmaceutical company, and a 22-year career with Johnson & Johnson, a multinational medical devices, pharmaceutical and consumer packaged goods manufacturing company. Mr. Bailey also has extensive board member experience, having previously served on boards of directors for eight companies. Mr. Bailey currently serves as a director for Aileron Therapeutics Inc. and Madison Vaccines, Inc. Mr. Bailey holds a BA in business administration from Rutgers University.

Kathleen Goetz: Ms. Goetz was Vice President Head of Sales at Novartis Pharmaceuticals, a global healthcare company until 2019. Ms. Goetz serves on the Audit Committee and Valuation Committee of the Fund. Ms. Goetz brings to the Fund over 30 years of healthcare business and leadershipexperience, including experience working within a spectrum of diverse healthcare stakeholders and ecosystems. She brings extensive knowledge of the healthcare provider, a deep understanding of payor interests and the needs of the patient. During her 28 years with Novartis, Ms. Goetz held positions of increasing responsibility, leading marketing, sales and reimbursement teams through various stages of commercialization from pre-launch planning through to loss of exclusivity across diverse therapeutic areas. Other key roles during her time at Novartis also include National Executive Director of Strategic Accounts, Integrated Market Planning and Marketing Director, providing her with valuable experience leading organizational transformation, resourcing, forecasting, and analytics. Early in her career Ms. Goetz spent time working at Centocor Biologics. She continues to act as a mentor to future leaders and as a champion for diversity through her past work as an Executive Leadership Development mentor and a former Novartis Pharmaceuticals Women in Leadership Chair. Ms. Goetz has won numerous healthcare and business leadership awards and recognition throughout her career, including being recognized with the Healthcare Women's Business Association Rising Star Award. She continues to act as an independent consultant within the pharmaceutical and biotech industry. Ms. Goetz holds a Business Finance degree from Iowa State University.

Rakesh K. Jain, Ph.D.: Dr. Jain is the A. W. Cook Professor of Radiation Oncology (Tumor Biology) at Harvard Medical School and the Director of the E. L. Steele Laboratories of Tumor Biology at Massachusetts General Hospital, providing the Fund with a valuable perspective on emerging life sciences technologies. Dr. Jain co-founded XTuit Pharmaceuticals, Inc. in 2012, where he also served as a board member until 2018. He serves as the Chairman of the Governance and Nominating Committee of the Fund. Prior to joining Harvard, he was professor of chemical engineering at Columbia University and Carnegie Mellon University. Dr. Jain is regarded as a pioneer in the fields of tumor biology, drug delivery, in vivo imaging and bioengineering. Dr. Jain has authored more than 750 publications. He serves on advisory panels to government, industry and academia, and has served or continues to serve on editorial advisory boards of twenty journals, including Journal of Clinical Oncology and Nature Reviews Clinical Oncology. He has received more than 90 major awards and lectureships, including the United States National Medal of Science, a Guggenheim Fellowship, the Humboldt Senior Scientist Award, the National Cancer Institute's Research Career Development Award and Outstanding Investigator Grant, the Academic Scientist of the Year Award from the Pharmaceutical Achievements Awards, the Distinguished Service Award from Nature Biotechnology and the Innovator Award from the DoD Breast Cancer Program. He is a member of all three branches of U.S. National Academies - the Institute of Medicine, the National Academy of Engineering and the National Academy of Sciences and is a member of both the National Academy of Investors and the American Academy of Arts and Sciences. In May 2016, Dr. Jain received the National Medal of Science from President Obama at the White House.

Thomas M. Kent, CPA: Mr. Kent was a Partner at PricewaterhouseCoopers LLP, where he served the Investment Management Industry for over 30 years, 24 years as a Partner. In so doing, he worked with and for more than 20 different and distinct Investment Company Boards, and along side several of those Boards' service providers, including Advisors, Custodians, Accounting Agents, Transfer Agents, Security Pricing Providers, Tax advisors and others. His clients included both large and small fund groups, with both open-end and closed-end fund structures. Therefore, he provides the Fund with deep expertise in audit, valuation, operational and governance matters. He serves on the Governance and Nominating Committee and as Chairman of the Audit Committee of the Fund. Mr. Kent also serves as a Director of Principal Global Investors Trust Co., and a Director of the New England Canada Business Council. Mr. Kent is a member of the American Institute of CPA's and the MassachusettsSociety of CPA's where he serves on the Registered Investment Company Committee. He received his AB cum laude from Harvard College, where he majored in Economics and his MS in Accountancy from the Stern School of Business at NewYork University.

Daniel R. Omstead, Ph.D.: Dr. Omstead is President and Chief Executive Officer of Tekla Capital Management LLC (the "Adviser"), a registered investment adviser that serves as investment adviser to the Fund. Dr. Omstead is also President of the Fund and serves on its Valuation Committee. Dr. Omstead is portfolio manager for the public and restricted/venture portfolios within the Fund. Prior to joining the Adviser, Dr. Omstead was President and CEO of Reprogenesis, Inc., a private development stage biotech company which developed therapies in the field of tissue engineering and regenerative medicine. Before joining Reprogenesis, Dr. Omstead was Senior Vice President, Research and Development, at Cytotherapeutics, Inc, a public biotech company. Prior to entering the biotech industry, Dr. Omstead was employed for fourteen years in positions of increasing responsibility within the pharmaceutical industry at Ortho Pharmaceutical Corporation and at the R.W. Johnson Pharmaceutical Research Institute, both divisions of Johnson & Johnson, and at Merck, Sharp and Dohme Research Laboratories, a division of Merck & Co., Inc. Dr. Omstead provides the Fund with insights into both pharmaceutical and biotech companies. Dr. Omstead holds Ph.D. and Master's Degrees in Chemical Engineering and Applied Chemistry from Columbia University and a B.S. degree in Civil Engineering from Lehigh University. He is an emeritus member of the Board of Directors of a non-profit agency that provides emergency shelter, housing and supportive services to homeless and low-income individuals and families in the Boston area. Dr. Omstead was also a member of the Board of Trustees at the Joslin Diabetes Center.

Oleg M. Pohotsky, MBA, JD: Mr. Pohotsky is a corporate finance and investment professional with over fifty years of diversified experience gained both in industry and in financial markets. Mr. Pohotsky serves as Chairman of the Board of Trustees of the Fund and also serves on the Fund's Governance and Nominating Committee. He has over 45 years of cumulative board experience in the full range of organization types: publicly-traded, privately-held, venture-backed and non-profit. He has also served as a director of a healthcare services company listed on the Nasdaq NMS where he was a member of the audit committee. In his various directorships he has also served on investment, compensation, personnel and executive committees. His career spanned over twenty years in the investment industry, both as an investment banker and as a venture capital and private equity investor, and included serving as chairman of the valuation and fairness opinion committee of a NYSE-member firm. Mr. Pohotsky also currently serves on the Board of Directors of Avangardco Investments Holdings, an LSE-listed agribusiness enterprise based in Ukraine, on the board of directors of the New America High Income Fund, Inc., a closed end fund investing in high yield securities on a leveraged basis and on the Board of Advisors of Kaufman & Co., LLC, a Boston-based boutique investment banking firm, and was affiliated with GovernanceMetrics International, Inc. as a Senior Advisor. He provides the Fund with valuable experience in valuation and the financial industry. Mr. Pohotsky holds a BSChE degree from Clarkson University, a JD degree from the University of Miami and MBA from the Harvard Business School. He has also been awarded an honorary doctorate by Clarkson University.

W. Mark Watson, CPA (appointed March 17, 2022 to be a Trustee effective June 9, 2022): Mr. Watson is a Certified Public Accountant with over 40 years of experience in public accounting and auditing, having spent his entire career from January 1973 to June 2013 at Deloitte Touche Tohmatsu, the multinational professional services network, and its predecessor, most recently as Central Florida Marketplace Leader. Mr. Watson provides the Funds with a particular expertise in the health and life sciences sector, having played a significant role in the development of Deloitte's audit approach for health and life sciences companies and leading its national healthcare regulatory and compliance practice. He has served as lead audit partner and advisory partner on the accounts of many public companies ranging from middle market firms to Fortune 500 enterprises. Mr. Watson is a member of the American Institute of Certified