The ZRT Laboratory Blog

The ZRT Blog is an extensive resource for patients and health care providers searching for health and hormone testing information. Here, you can read about ZRT’s cutting edge research, advances in testing, wellness advice, and health industry highlights.



Dr. Thomas Guilliams

Thomas G. Guilliams, PhD, earned his doctorate from the Medical College of Wisconsin where he studied molecular immunology in the Microbiology Department. Since 1996, he has spent his time studying the mechanisms and actions of natural-based therapies, and is an expert in the therapeutic uses of nutritional supplements. As the VP of Science and Regulatory Affairs for Ortho Molecular Products, he has developed a wide array of products and programs which allow clinicians to use nutritional supplements and lifestyle interventions as safe, evidence-based and effective tools for a variety of patients. Dr. Guilliams teaches at the University of Wisconsin School of Pharmacy, where he holds an appointment as a Clinical Instructor, and at the University of Minnesota School of Pharmacy, and he is a faculty member of the Fellowship in Anti-aging Regenerative and Functional Medicine (A4M).
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Recent Posts

Re-assessing the Notion of "Pregnenolone Steal"

Posted by Dr. Thomas Guilliams on Wednesday, 21 June

ThinkstockPhotos-687447022-pregnenolone-.jpgWhen clinicians measure salivary cortisol and DHEA (DHEA-S) to assess stress and HPA axis function, it is common to find DHEA levels below the reference range in a number of individuals. A common explanation for the depletion of DHEA and other hormones (e.g., progesterone, testosterone) due to chronic stress is the phenomenon known as "pregnenolone steal."

The pregnenolone steal notion states that since all steroid hormones use pregnenolone (derived from cholesterol) as a precursor, the elevated secretion of cortisol caused by acute or chronic stress will inevitably result in less available pregnenolone to serve as a precursor for the production of DHEA and other down-stream hormones.

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Is it Adrenal Fatigue? Reassessing the Nomenclature of HPA Axis Dysfunction.

Posted by Dr. Thomas Guilliams on Tuesday, 25 April

hPA.Axis_lores_crop.jpgSometimes, when we endeavor to understand and describe complicated medical topics, there is a temptation to find a simple explanation to cut through the complexity. These explanations can help bridge the knowledge gap for a while, but as our knowledge grows, they lose some of their original usefulness (e.g., the notion of “good” and “bad” cholesterol).

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