Dr. Kathryn Retzler and HormoneSynergy® teamed up with the top four nutraceutical and supplement manufacturers in the United States to develop a line of private-labeled and custom nutraceuticals to make sure you receive unsurpassed, quality formulas that are affordable and effective.

All supplements that bear a HormoneSynergy® label are manufactured in facilities that have pharmaceutical or NSF certification and are certified for good manufacturing practices (CGMP). One of our manufacturers has recently earned the prestigious Therapeutic Goods Administration (TGA) certification, the Australian equivalent to the U.S. Federal Drug Administration.

It's important to keep in mind that not all supplement brands are alike, no matter what the label or packaging may claim. Recently, the New York State attorney general’s office accused four major retailers on Monday of selling fraudulent and potentially dangerous herbal supplements and demanded that they remove the products from their shelves.

The authorities said they had conducted tests on top-selling store brands of herbal supplements at four national retailers — GNC, Target, Walgreens and Walmart — and found that four out of five of the products did not contain any of the herbs on their labels. The tests showed that pills labeled medicinal herbs often contained little more than cheap fillers like powdered rice, asparagus and houseplants, and in some cases substances that could be dangerous to those with allergies.

All HormoneSynergy® formulas are manufactured by companies that only sell to licensed healthcare providers and all perform product analysis on all ingredients to verify safety, potency, and bio-availability to ensure quality and constituency.

Several HormoneSynergy® supplements have undergone clinical trials to ensure efficacy and all HormoneSynergy® supplements are used by Dr. Retzler in her private practice.

Dr. Retzler and Daniel Soule (HormoneSynergy's Owner) have personally toured all facilities that currently manufacture HormoneSynergy products.
Dr. Retzler and Daniel Soule (HormoneSynergy's® Owner) have personally toured all facilities that currently manufacture HormoneSynergy products.

Quality Standards and Definitions:

NSF/GMP certification

  • Indicates our manufacturers compliance with the U.S. Food and Drug Administration’s regulations (cGMPS) on dietary supplement manufacturing, packaging, labeling, and distribution.
  • Certifies that HormoneSynergy® manufacturers have used the proper methods, equipment, facilities and controls in place to produce dietary supplements. Ensures all HormoneSynergy® products are manufactured safely and that quality is assured.


NSF / GMP for Sport

  • Developed to meet the growing demand of athletes, coaches, and others who have concerns about banned substances in Sports Ensures that the facility has been inspected for a range of harmful, banned, illegal, unauthorized or prohibited substances identified by leading sports organizations, such as the world Anti-Doping Agency (WADA)


TGA (Therapeutic Goods Administration) of Australia

  • Therapeutic Goods Administration (TGA) is Australia's regulatory authority for therapeutic goods. The TGA carry out a range of assessment and monitoring activities to ensure therapeutic goods available in Australia are of an acceptable standard with the aim of ensuring that the Australian community has access, within a reasonable time, to therapeutic advances.
Dr. Retzler celebrates as she personally witnesses the first run of her custom
"LongevityEssentials" pack at one of our four manufacturing facilities.

Customer Reviews

"An excellent seller, immediate service, great product at a great price!"

By frogy on September 8, 2017

"Arrived very promptly and received two emails with helpful information."

By Jill on August 26, 2017

"Outstanding service! Package came early and just what I ordered. Excellent quality product and I'm already sleeping better!!!!!"

By Amazon Customer on December 21, 2017

"Thank for the prompt delivery! At first I was using the CBD Softgels and loved them - I now use CBD With Curcumin and am experiencing even better results. Thank you!"

By Jason on February 24, 2018

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The information provided on this website is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her physician. Please seek advice from a medical professional to help evaluate your symptoms and condition for proper diagnosis.