Nutrition Education
about me
Gerda Endemann

Threshold Enterprises

Since October 2011, I’ve been a Senior Researcher in the Department of Research & Development at Threshold Enterprises in Scotts Valley, CA. Threshold manufactures the Source Naturals and Planetary Herbals brands of food supplements.

Source Naturals was one of the first brands to combine herbal ingredients with vitamins and minerals in a multipronged approach to health. When I started working here I did not know much about herbal medicine, and focused on the nutrients I was familiar with. It was easy for me to provide scientific substantiation for claims of the value of vitamins, minerals and other food components.

However in the past 2 years I’ve learned a lot about the incredible value that herbs add to our food supplements. Some of my favorites are Holy Basil ( for stress and Wellness Herbal Resistance Liquid ( at the first sign of a cold coming on.

The FDA requires that any claims we make as to the value of food supplements must be backed up by a written substantiation that summarizes the scientific research and/or traditional use our claims are based on. In R&D at Threshold, we are making sure that any claims for new products are well substantiated and are continually working on updating claims on older products as needed. Let us know if you have questions about the validity of any claims on our products.

Threshold is somewhat unusual in that all stages of manufacturing supplements are carried out in our facility in Scotts Valley, CA. In addition to R&D, we have facilities for manufacturing and packaging, marketing and sales, distribution, and last but not least, quality control. Our manufacturing facility has been certified by the NSF, a well known nonprofit certifying agency, as using Good Manufacturing Practices, or GMP. We test all of our ingredients to be sure that they contain the desired amounts of active ingredients and that they do not contain heavy metals or other contaminants.