I’m Dr. Theresa Callaghan, PhD, a biochemist with extensive experience in the personal care industry. I hold a PhD in Biochemistry and began my career as a postdoctoral research fellow at the Pasteur Institute in France. During this time, I became involved in LVMH’s Capture project, which led to my transition into corporate global skincare research. 

In 2008, I founded my consultancy to help brands navigate the complex and often challenging landscape of cosmetic claims. I also regularly write for peer-reviewed journals and trade publications, both under my own name and on behalf of clients, with the goal of bringing clarity and insight to an industry that is frequently misunderstood and misinformed. 

For more information about this work, visit my website https://www.ccintl.eu. There, you can also find my written work, including insights on beauty claims and my acclaimed books, Help I’m Covered in Adjectives: Cosmetic Claims & The Consumer; and Cosmetic Claims & The Consumer: The Myth of the Cheap Study.

With nearly years of experience in personal care, I’ve had the privilege of holding key R&D senior roles with leading companies including LVMH (France), Unilever (UK), Marks & Spencer (UK), Johnson & Johnson (France), Evonik (Netherlands, Spain, Germany), Hill-Top Research (UK, USA), and proDERM (Germany). This wealth of experience has provided me with a comprehensive understanding of the industry, allowing me to offer a tailored yet flexible approach to meet the unique needs of my clients. 

In addition to consulting, I am a major contributor to both peer-reviewed and trade journals, often writing on behalf of clients around the world. 

My work has also been featured in various press articles, podcasts, radio shows, and reviews. I  am an active member of several professional societies, including the Society of Cosmetic Scientists (Scandinavia & UK) and the British Herbal Medicine Association. I also serve as an advisor to TKS Science Publisher (Italy), a consulting scientific editor and cosmetic claims columnist for EuroCosmetics Magazine (Germany), and contribute to BEAUTYSTREAMS Building Blocks Pulse. I have also been a guest lecturer for the University of Sunderland’s MSc degree in Cosmetic Science.

Having experience across the diverse sectors of dermatology and personal care allows me to offer a customer-centric approach, one that is both targeted and adaptable to specific industry challenges. 

During 2019 I began writing the Zoe Blaise Mysteries — fictional crime thrillers set against the backdrop of a collapsed beauty industry.

These novels, published seven years later under the pseudonym Tess M. Calloway are fast-paced corporate conspiracy thrillers

My career has given me a unique view behind an industry built upon science, aspiration and image, but also shaped by commercial pressure, corporate ambition and the constant tension between what can be promised and what can be proved.

It is a world that provides fertile ground for fiction.

Writing as Tess M. Calloway, I draw upon that experience to create the Zoe Blaise Mysteries, a series of conspiracy thrillers in which science, money and power collide. At their centre is Zoe Blaise, a forensic accountant and reluctant investigator whose determination to follow the evidence repeatedly draws her into a world where corporate reputations can be worth billions—and where some people will go to extraordinary lengths to protect them.

Beginning with Pink Bobbit and continuing through Cold Indifference and Digital Facade, the series moves between Cardiff, London, Milan and beyond, combining financial investigation with cosmetic science, emerging technology and the darker consequences of unchecked ambition.

With Shadow Ledger, I turn back the clock to explore the origins of Orpheus Consulting and the story of Giovanni Jones—the enigmatic man readers came to know as the Count. His journey reveals how one failure, one decision and the consequences that followed helped create the world Zoe would eventually enter.

Although the novels are works of fiction, their foundations are deliberately authentic. I bring decades of scientific and industry experience to the stories while allowing me the freedom every thriller writer treasures: to take something plausible and ask just how far it might go.

Because behind the glossy campaigns, scientific promises and immaculate corporate façades, there are always people. And people have secrets.

The Zoe Blaise Mysteries, are where science meets deception, power has a price, and the truth is rarely what it first appears to be.

I have been interviewed by BBC Radio as well as Writing IE and others. A full interview by TRE radio, discussing the Zoe Blaise series, crimes, characters and insights is available on Youtube.