Our History
Master Supplements began with a clear belief: better digestion and microbial balance create the foundation for better health. What started as a focused probiotic company evolved into a comprehensive nutritional science organization serving both consumers and healthcare professionals. Science, practitioner feedback, and a commitment to meaningful innovation have driven each phase of our growth.
Randolph "Randy" Porubcan, the visionary founder of Master Supplements Inc., built a company whose passion for science, innovation, and human health laid the foundation for everything it represents today. Believing true wellness begins in the gut, Randy applied his expertise in biochemistry and microbiology to create advanced nutritional solutions—long before the microbiome became a mainstream healthcare topic.
Leadership Driving Innovation
Master Supplements Inc.'s strength lies in its leadership team, which combines scientific curiosity, business strategy, clinical education, and industry expertise to bring best-in-class nutritional science to market.
Jeff Thurston
Senior Partner & Scientific Strategist
Jeff Thurston brings a uniquely broad scientific perspective to Master Supplements, with decades of experience at the intersection of microbial science, enzyme research, organic agriculture, and nutritional product development. His expertise has been instrumental in shaping the company's systems-based approach to health—emphasizing the interconnection between digestion, immunity, detoxification, and cellular resilience.
Jeff Porubcan
Chief Executive Officer, President
Jeff Porubcan serves as CEO of Master Supplements Inc., overseeing the organization's strategic vision and long-term growth, including U.S. Enzymes and Tomorrow's Nutrition PRO. Under Jeff's leadership, the company has expanded from a respected probiotic innovator into a multi-brand nutritional science organization.
Sonja Yonak
Chief Financial Officer, Vice President
Sonja Yonak plays a critical role in supporting organizational growth, strategic initiatives, and partner relationships across the Master Supplements family of brands. As our in-house microbiologist—and having worked with Randy Porubcan across three labs—Sonja ensures his original dedication and passion for science are honored in every product and formula the company brings to market.
Roland Pankewich
Education & Clinical Communications
Roland Pankewich leads educational strategy and scientific communication for the organization, translating complex nutritional science into actionable knowledge for healthcare practitioners, retail partners, consumers, and clinical teams. He leads our monthly webinars and product trainings and hosts the Following Your Gut Podcast, exploring emerging topics in gut health, functional wellness, and clinical nutrition.
Better Together
Master Supplements, U.S. Enzymes, and Tomorrow’s Nutrition Pro all came together to become collectively stronger. While each company had its specialty, together Healthcare Professionals now have access to a full range of probiotic, enzyme, and fiber supplements.
Master Supplements’ probiotic products rely on high-quality strains, patented deep delivery, and the prebiotic LactoStim®, which dramatically enhances probiotic growth and activity. Our philosophy is that Lactobacillus bacteria and Bifidobacteria affect the immune system differently, colonize specific areas of the G.I. tract, and should therefore be supplemented accordingly.
U.S. Enzymes offers a full line of powerful enzyme supplements, some offering broad support while others are designed for a targeted approach. Certain formulations support digestive health and others work systemically, allowing for customized enzymatic protocols.
Tomorrow’s Nutrition Pro offers a wide range of products with simple active ingredients that are supported by research and proven efficacy. The SunFiber ® ingredient is the most clinically studied fiber source on the planet and is a perfect combination for probiotics and enzymes.
All told, these three Minnesota-based companies are now stronger together. We share the core values of high-quality, honesty, and, most importantly, helping people.