Dr Mark Hyman girlfriend Brianna Lee Welsh is the co-founder and CEO of Reneum Institute. 

Reneum Institute is an energy company that vets, monitors, and measures the environmental benefits of clean energy produced. They aim to fund climate solutions and begin the energy transition journey to a cleaner form of energy.

Brianna co-founded the company with Assaad Razzouk in May 2020. It is a graduate of Outlier Ventures' Polygon MATIC Basecamp accelerator. It is also a member of the Creative Destruction Lab's Blockchain track.

She is also involved with various other companies aside from Reneum Institute. She is a partner of the Filecoin Foundation, of which Reneum is a grantee.

The foundation helps to support climate-positive Regenerative Finance initiatives or ReFi, by using blockchains as their vehicle for climate solutions.

She is also a Venture Member of Top Tier Impact, a members-only ecosystem of entrepreneurs, investors, and professionals focused on solving critical global issues.

Welsh's professional career has been active since the late 2000s. Her professional career began in August 2009 when she started working at RBC Capital Markets. From early on, her job was focused on energy systems and the energy markets.

She then moved from Ontario, Canada, to New York, where she worked for the Clinton Global Initiative in 2014. Here she worked on presenting market trends for the initiative and another analysis and reports based on global issues.

Continuing her stay in New York, Welsh then started working for KPMG US, first in Private Equity and then Post-Merger Integration. In the first position, she led and advised in private equity deals amongst clients of the company in developing markets. She managed consulting teams, revenue delivery, and client relationships in the second position.

Welsh then moved to London in 2016 to work for Horizn Studios as the Director and Head of EMEA. Horizn is a travel tech venture with headquarters in Berlin, and Welsh was hired to head the company's expansion into the London market. 

She moved back to America, this time to Los Angeles, California, and worked as a strategic advisor to NANA, a comprehensive integrative therapy solution that combines tech, coaching, and lifestyle modifications in psychoactive medicine. 

Before she became active at Reneum Institute, her last job was as a Managing Director at Sindicatum Renewable Energy Company. The company, like Reneum, also focuses on financing renewable assets and clean energy.

Dr. Mark Hyman and his girlfriend Brianna Lee Welsh relationship may be out in the open now, but it began long ago.

Given Hyman's statement on the Instagram post where he revealed his relationship with Welsh, they have been dating for nine months. As the post was made on the first of December, one can assume that they started dating in February or March this past year.

Since her Instagram is private, one cannot go through her photos to see if she had already revealed her relationship with Hyman to her friends and followers, so there are only good doctor's words to take into account.

Regardless of the specifics of the beginnings of their relationship, the ten snapshots Hyman has publicized of their love story are filled with smiles, travel, adventure, and love. 

One of the more curious aspects about Hyman's caption is that he talked about how people's childhood programming corrupts their ability to love securely and hints that being with Welsh helped him in that aspect. 

He doubled down on the concept, paraphrasing a quote from the German poet Rainer Maria Rilke which talks about love consisting of two solitudes that protect each other, stating that is the case in their relationship. Finally, he ends the caption with a hashtag that says love heals.

He has let the world into his love life with this recent Instagram post and introduced many fans to the accomplished individual Brianna Lee Welsh.