What “Non-Toxic” Actually Means: A Course

Dr. Meg Christensen is the founder of Interior Medicine, a physician-created resource on non-toxic home products and household exposures. Her layer-by-layer analysis of materials and products draws on her background in medicine, biochemistry, epidemiology, and clinical research.

Published March 2026 | Updated April 2026

What "Non-Toxic" Actually Means is a free, visual course designed to permanently change how you think about toxicity, products, brands, and every health claim you will ever encounter.

Here’s what it covers:

Course CurriculumWhat “Non-Toxic” Actually Means: A Course by Interior Medicine
Course Curriculum

        
        10 parts
      

        
        Self-paced
      

        
        Free
      

        
          
          
        
      
Part 1
Why Nobody Agrees on What “Non-Toxic” Means
Why hazard and exposure aren't the same as toxicity, why studies that look legit often aren't, why two smart people read the same facts opposite ways, and what all the confusion is costing us.
01
A Framework for Assessing Any Health Risk
Why EWG ratings, Prop 65 warnings, and “sunscreen in blood” headlines all measure something other than toxicity. The six-step toxicology framework that names what they are instead.
02
Separating Good Science From Recycled Fear
Seven questions that turn “a study said it's toxic” into something you can actually evaluate, and how to tell whether someone has read the research or just copied a viral study title.
03
Why “Is It Non-Toxic?” Has No Clean Answer
Just how complex a single product really is, why a tidy yes-or-no on “non-toxic” doesn't exist, and why that's freeing rather than discouraging.
04
Why Smart People Disagree About the Same Facts
A personality quiz that reveals the lens you've been using to interpret EMF risk, and why the person who disagrees with you isn't being unreasonable.
05
What The Confusion Costs Us
Brands cashing in on the confusion, social media fights, family tension, misinformation, and the real risks we miss while panicking about the wrong ones.

        
          
          
          
          
        
      
Part 2
The Interior Medicine Method
The process I use to cut through all the confusion above, written out so you can see the reasoning and adapt it. How to assess a product when there's no ingredients list, which certifications mean something, real product walkthroughs, and finally an answer to the question this course started with.
06
When There's No Ingredients List: What Chemistry Tells You
When the label tells you nothing, the chemistry still does. How to predict what a material releases into your home and whether it can reach your body, just from knowing what it's made of.
07
When There's No Ingredients List: What Certifications Tell You
When the label tells you nothing, some certifications fill in the blanks. Which ones do real work, which ones are pay-to-play, and which mean nothing at all.
08
The Method: How I Actually Assess a Product
The exact layer-by-layer method behind every Interior Medicine review. Take it, adapt it, run anything in your home through it.
09
The Method: Real Product Examples
The method walked through on real products: couches, cookware, air and water filters, cleaning sprays, and ceramic dishware.
10
So, What Does “Non-Toxic” Mean?
An actual answer to the question this course started with, calibrated to your life, your tolerance for uncertainty, and what you can actually control.

        
          
          
        
      
The finish line
Graduation
Curious, not anxious. Skeptical, not dismissive. Ready for the next viral study, the next family debate, the next non-toxic claim.

A Quick Note on Language

You might notice I use the words non-toxic, chemical, toxin, and toxic on Interior Medicine even though this course rests on the fact that there is no agreed-upon definition of the term non-toxic yet. Everything, even water, is made of chemicals, so nothing is truly chemical-free. Likewise, toxin refers to a natural substance like a plant poison or venom, whereas toxicant is a more accurate term for the chemicals in products that have a negative health impact. I recognize that something that is toxic does not automatically make it a risk to your health personally.

I choose to use these scientifically inaccurate words anyway purely for practical purposes, for now. These words are currently the most culturally agreed-upon, descriptive, and accessible terms that allow people to find the information they’re looking for. Accurate terminology is important, which is why this note, and this course exist.

The whole course will be available soon. Join the Interior Medicine Newsletter to be the first to know. Thank you!

Part 1: A Framework For Assessing Any Health Risk (Coming Soon) ➜