We consider learning about preservatives an integral part of cosmetic formulating and therefore include it in every product making course we have rather than having a separate course on preservation.
The Diploma in Natural Skincare Formulation has a whole module that covers preserving skincare products naturally. You'll learn how to put into place strategies to extend the shelf-life of your products and preserve your products effectively to ensure they stay in optimum condition. We have hand picked our favorite nine COSMOS-approved broad-spectrum preservative blends that are reliable and easy to use. You'll learn our system for combining preservatives and chelators to create a robust broad-spectrum preservative system.
You can find more details about the Diploma in Natural Skincare Formulation here: https://www.schoolofnaturalskincare.com/formulation/
If you would like to experience it first-hand and sample the course materials and lesson presentations, we offer a free trial, with no obligation to buy. You can sign up for it here: https://school-of-natural-skincare.thinkific.com/enroll/1051493
You can download the course prospectus here:
https://schoolofnaturalskincare.lpages.co/prospectus-diploma-in-natural-skincare-formulation/
Our other courses don't go into quite as much detail on preservation but do include comprehensive information on a wide range of natural and organic preservatives, Good Manufacturing Practice plus a checklist of things to do (or not do) to maximize the chances of passing a challenge test.
We also have several classes in our Natural Cosmetic Formulation Club which focus on preservatives, they are:
How Hydrosols can Challenge the Performance of the Preservation System
Do Anhydrous Body Scrubs (made with Sucragel) Need Preservatives?
Do anhydrous products need preservatives?
We also performed two experiments testing the efficacy of different preservatives. They are available in the following classes in the Club:
Experiment and Report: Testing Leucidal Preservatives
Experiment and Report: Testing Four Natural Preservatives
You can find out more about the Club here: https://www.schoolofnaturalskincare.com/club/
Here are some useful blog posts to help you learn more about preservatives:
This blog post explains more about what preservatives are and when to use them: https://www.schoolofnaturalskincare.com/natural-preservatives-in-skincare/
If you would like to know more about which products require preservatives, this article will help: Safe product checklist www.schoolofnaturalskincare.com/checklist-make-safe-natural-skincare-products/
You can learn more about product testing here: https://www.schoolofnaturalskincare.com/selling-homemade-cosmetics-product-testing-safety-assessments/
You can also download our free guide to natural emulsifiers and preservatives, where you can discover the most natural preservatives and emulsifiers for your skincare products. You can download your guide to natural preservatives and emulsifiers here: www.schoolofnaturalskincare.lpages.co/natural-emulsifiers-and-preservatives/