Dr. Ellen Siobhan Mitchell
Ellen Siobhan Mitchell, PhD, known professionally as Siobhan Mitchell, is the Chief Scientific Officer at MitoQ Limited, the Auckland-based cellular health company behind MitoQ, a mitochondria-targeted antioxidant built on the molecule mitoquinol mesylate.
A neuroscientist by training, she has spent more than two decades studying how nutrition shapes brain aging, cognition, and mood, holding research leadership roles at Unilever, the Nestlé Institute of Health Sciences, PepsiCo, and Noom Inc. before joining MitoQ in November 2022.
At MitoQ, whose molecule was created by Professor Mike Murphy of the University of Cambridge and Professor Robin Smith of the University of Otago, and which was led between 2013 and 2019 by our Greg Macpherson, Siobhan directs science strategy, sets the evidence standards behind product claims, and leads university partnerships. The company reports more than $60 million invested in research and 25 clinical trials on its ingredient.
She was first author of the 2024 safety study Oral subchronic toxicity study and genetic toxicity evaluation of mitoquinone mesylate in the Journal of Applied Toxicology. In 2023, MitoQ formed a Science Expert Panel of Mike Murphy, our Richard Siow of King's College London, Marcia Haigis of Harvard Medical School, and Doug Seals of the University of Colorado Boulder, which she credits with helping build a broader portfolio of cell health molecules. Read Meet the MitoQ Science Expert Panel, Meet our new CSO: Siobhan Mitchell, and MitoQ Hires New CSO: Siobhan Mitchell.
Her partnership work spans a University of Colorado trial in postmenopausal women, MitoQ Supplementation for Restoring Aerobic Exercise Training Effects on Endothelial Function in Postmenopausal Women led by Kerrie L. Moreau, and a memorandum of understanding signed in May 2026 with the NUS Yong Loo Lin School of Medicine in Singapore.
Working with our Jan Gruber of NUS Medicine's Department of Biochemistry, the two-phase program applies the LinAge3 biological aging clock to 150 existing study participants before a controlled trial of roughly 100 participants, with completion targeted for December 2027. Read NUS Medicine partners MitoQ New Zealand to deepen mitochondria-targeted research for healthy ageing and Mitochondria for healthy aging: MitoQ New Zealand deepens Asia research with NUS.
From 2020 to 2022, Siobhan was Senior Director of Academic Research at Noom Inc., leading a team of clinical researchers investigating digital health interventions for weight loss, diabetes prevention and support, stress and anxiety management, and cancer support.
She was first author of Psychosocial Characteristics by Weight Loss and Engagement in a Digital Intervention Supporting Self-Management of Weight and The Impact of a Digital Weight Loss Intervention on Health Care Resource Utilization and Costs Compared Between Users and Nonusers With Overweight and Obesity.
Siobhan coauthored Cross-National Outcomes of a Digital Weight Loss Intervention in the United States, Canada, United Kingdom and Ireland, and Australia and New Zealand, which analyzed 18,459 participants, and the pilot randomized controlled trial Executive Function-Related Improvements on a Commercial CBT-Based Weight Management Intervention.
Between 2016 and 2020, she was Senior Principal Scientist at PepsiCo, where she planned nutrition strategies for beverages, snacks, and cereals, evaluated novel ingredients and health claims, and steered portfolio renovation toward healthier products. Her PepsiCo-era publications include Water intake reverses dehydration associated impaired executive function in healthy young women and More than just caffeine: psychopharmacology of methylxanthine interactions with plant-derived phytochemicals.
From 2011 to 2015, Siobhan was a project manager and scientist at the Nestlé Institute of Health Sciences on the EPFL campus in Lausanne, Switzerland, where she established the institute's neuroscience program, built its team of neuroscientists, and designed preclinical and clinical studies of micronutrients, probiotics, polyphenols, and ketogenic diets for aging, eating behavior, brain development, and mood.
That work produced the PLOS ONE paper Cognition and Synaptic-Plasticity Related Changes in Aged Rats Supplemented with 8– and 10-Carbon Medium Chain Triglycerides and, with Carmen Sandi of EPFL, Medium chain triglyceride diet reduces anxiety-like behaviors and enhances social competitiveness in rats.
Siobhan shares inventorship of the Nestlé (Nestec S.A.) patent filings Medium chain fatty acids and their triglycerides for treating anxiety, Method for improving cognition, and Nutritional composition comprising a probiotic for the prevention and/or treatment of anxiety disorders and related conditions in a mammal.
Between 2007 and 2011, she was a project manager and scientist at Unilever research and development in Vlaardingen, the Netherlands, designing clinical studies on the cognitive and affective effects of food-derived bioactives.
She was first author of Differential contributions of theobromine and caffeine on mood, psychomotor performance and blood pressure in Physiology & Behavior and Effect of hydrolysed egg protein on brain tryptophan availability in the British Journal of Nutrition, and is a named inventor on Unilever's Frozen Confectionery and Beverage Products and Tea-based product patent filings.
Siobhan earned her BSc in Biological Chemistry from the University of Chicago and her PhD in Biomedical Sciences (Neuroscience) from the University at Albany in 2003. From 2003 to 2007, she was a postdoctoral fellow in the laboratory of John Neumaier in the Department of Psychiatry and Behavioral Sciences at the University of Washington, researching the cognition-enhancing potential of serotonin 5-HT6 receptor manipulation.
Her postdoctoral publications include 5-HT6 receptors: a novel target for cognitive enhancement, Increased expression of 5-HT6 receptors in the rat dorsomedial striatum impairs instrumental learning, and Adaptations in 5-HT receptor expression and function: implications for treatment of cognitive impairment in aging.
Since 2011, she has held a chair role with ILSI Europe (the Brussels-based European branch of the International Life Sciences Institute), and she contributed to its expert-group consensus papers Examining techniques for measuring the effects of nutrients on mental performance and mood state in the European Journal of Nutrition and, from its Nutrition and Mental Performance Task Force, Nutrition for the ageing brain: Towards evidence for an optimal diet in Ageing Research Reviews.
A frequent speaker and podcast guest, Siobhan joined the panel The Gender Gap in Longevity: Female Health, Male Health and Closing the Divide at The Longevity Show 2026 at Tobacco Dock, London, in June 2026, alongside Helen O'Neill of Hertility, Mike Kirby of the British Society for Sexual Medicine, and Poonam Desai, and was profiled as a speaker for the Growth Asia Summit 2026 in Singapore.
Watch Mitochondria Expert: This Supplement Reversed Vascular Aging by 20 Years, How Mitochondria Drive Cellular Aging with Cynthia Thurlow, Aging Starts In Your Mitochondria. Slow it Down With This with our Nathalie Niddam, and Resiliency Radio with Dr. Jill: Targeting Mitochondria for Healthy Aging and Resilience with Jill Carnahan.
Listen to Is Mitochondria-Targeting the Best New Strategy for Longevity?, Menopause Upgrade: A Novel Molecule That Protects Brain and Heart: Leading Mitochondria Researcher Explains on Hack My Age, and The Hidden Reason You're Aging Faster Than Your Age (It Starts in Your 20s) with Ben Azadi.
Read Siobhan Mitchell Of MitoQ: 5 Things You Should Do To Become a Thought Leader In Your Industry and Q&A with MitoQ Chief Scientific Officer Siobhan Mitchell, drawn from her conversation with our Joseph Cohen on The Joe Cohen Show.
Visit her LinkedIn profile, Google Scholar page, and ResearchGate profile. Follow her on X.