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Last winter, my testosterone, estrogen, and progesterone tanked. Not low. Almost gone.

My doctor put me on all three. The estrogen and progesterone are topicals. I rub them into my skin every morning and every night.

Within a short amount of time, I felt monumentally better.

And that got me thinking about something I couldn’t unthink.

If a hormone cream applied to my skin can change how I feel that fast, what else is happening every time something touches my skin? Because plenty of things touch my skin every single day. My lotion. Soap. Laundry detergent. My makeup. All of it, morning and night, for years.

If topical hormones work by absorbing through the skin, why would I assume everything else touching my skin isn’t also “working,” just in the other direction?

That question sent me down a rabbit hole. Here’s what I found, and here’s what I’ve changed.

Toxic Skincare and Gut Health: Why What Touches Your Skin Doesn’t Stay There

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But first, what actually happens when something touches your skin?

Your skin isn’t a wall. It’s a delivery system.

The outer layer, the stratum corneum, is the main barrier standing between the outside world and your bloodstream. But it isn’t impenetrable. Certain compounds pass through it, reach the dermis, and get pulled into your dermal capillaries, which connect directly to your circulatory system. From there, whatever you applied is no longer just “on” you. It’s in you.¹

This is exactly why transdermal medications work. Nicotine patches, hormone creams, pain patches: they’re all built on the fact that skin absorption reaches the bloodstream. Researchers have documented this same pathway for decades, including cases of serious systemic effects from things like organic solvents and topical anesthetics absorbing through skin in excessive amounts.²

Here’s the detail that changed how I think about my own routine: absorption through skin skips something your gut doesn’t skip. When you eat something, it goes through your liver first. Your liver filters and breaks a lot of it down before it ever reaches the rest of your body. Topical absorption bypasses that step entirely. Whatever gets through your skin goes straight into circulation, unfiltered.

Which means the products on your skin may have more direct access to your body than some of the food on your plate.

The research on what’s actually landing on your skin

I didn’t want a theory. I wanted numbers.

Parabens and phthalates, common preservatives and plasticizers in lotion, makeup, shampoo, and fragrance, are classified as endocrine disruptors. A study measuring urinary biomarkers in a general population found detectable levels of multiple parabens and phthalates in the majority of participants tested.³

A study of pregnant women found that lotion use alone was associated with elevated paraben levels.

Cosmetic and perfume use showed similar jumps in phthalate metabolites in the same study.⁴

A separate study on teen girls found that those who used makeup daily had methyl paraben levels roughly nine times higher than girls who rarely or never used it (120.5 ng/mL vs. 13.4 ng/mL). The same study noted that the average teenage girl uses 17 personal care products a day, compared to 12 for the average adult woman.⁵

Here’s the part that actually gave me hope: when researchers had teen girls switch to phthalate, paraben, and triclosan-free products for just three days, their triclosan levels dropped by 35.7%. Your body responds fast, in both directions.⁶

How this connects to your gut

This is the part nobody was telling me, and it’s the part that matters most if you’re here because of gut health. Which 99.9% of you are.

Endocrine-disrupting chemicals, the same class found in parabens, phthalates, and triclosan, don’t just affect hormones. Multiple studies now show they alter the gut microbiome directly. Animal research has found that exposure to these compounds shifts the ratio of Bacteroidetes to Firmicutes bacteria, the same ratio researchers use as a marker of metabolic and gut health.⁷

A broader review on endocrine disruptors and the gut microbiome found consistent evidence across rodent, fish, and human studies that these chemicals disrupt microbial balance and are linked to metabolic, reproductive, and even neurological effects.⁸

Triclosan specifically (found in some antibacterial soaps and toothpastes) has its own body of research tying it to reduced microbial diversity.⁹

And here’s where my own hormone story loops back in.

Researchers have coined the term “estrobolome” for the specific genes in your gut microbiome responsible for metabolizing estrogen. Some now use the broader term “endobolome” to describe how your gut bacteria process not just hormones, but endocrine-disrupting chemicals too. When gut diversity drops, that processing capacity drops with it.¹⁰

In other words: the same gut that needed extra hormonal support this year is the same gut responsible for metabolizing the hormone disruptors sitting in my skincare cabinet. That’s not a metaphor. That’s the literal biology.

Add to that the established gut-skin axis, the bidirectional relationship where gut dysbiosis shows up on your skin (think eczema, rosacea, acne) and skin health reflects back on gut inflammation.¹¹

Your skin and your gut were never separate systems. They were always talking to each other.

It’s not just what you rub on. It’s what you wash your clothes in.

I didn’t expect laundry detergent to be part of this story, but it is.

Fragranced laundry products release volatile organic compounds, VOCs, that don’t stay in the wash. University of Washington researchers sampled the air coming out of home dryer vents after a normal load with scented detergent and dryer sheets. They found more than 25 VOCs in the emissions, including acetaldehyde and benzene, both classified as hazardous air pollutants.¹²

That’s the air. Now think about the fabric itself, sitting against your skin (all of it, for hours, every single day) after being washed in the same fragranced formula.¹³

Your sheets. Underwear. Your kid’s pajamas. All of it, touching skin for 8 to 10 hours a night.

What I use now

Three categories sit at the center of my switch: skincare, makeup, and laundry and home. These are easy swaps you can make today.

1] Skincare

Herbal Face Food is my go-to. Raw, plant-based active formulas, no fillers, no synthetic chemicals. I use The Serum and The Cure every day, morning and night, the same routine I used to hand over to whatever drugstore lotion was in the cabinet.

2] Makeup

withSimplicity is a smaller clean beauty line out of Virginia, and it’s definitely my favorite makeup line I’ve ever come across. Plant-based, organic, vegan, no sulfates, no parabens, no synthetic fragrance, no fillers. It’s proof clean makeup doesn’t mean giving up pigment or performance.

3] Laundry and home

Truly Free Home replaced every fragranced detergent and cleaner in my house. Dye-free, plant-derived surfactants, biodegradable ingredients, made in the USA. Your first order comes as a bundle, so you’re not committing to a subscription just to try it.

A generic list, for ideas

Herbal Face Food, WITHSIMPLICITY and Truly Free are what I personally use. But those are only three categories. Here are others worth a second look, whether or not you switch:

• Perfume and cologne. One of the biggest sources of fragrance-related phthalate exposure in the research above.
• Deodorant. Applied daily, often on broken or freshly shaved skin, which increases absorption.
• Sunscreen. Worn for hours, often reapplied, often on your largest exposed skin area.
• Body lotion. The paraben jump above came from lotion alone. [Which is why I only use The Lotion from Herbal Face Food now.]
• Shampoo and conditioner. Rinsed, but still in contact with scalp skin for minutes at a time.
• Dish soap. Your hands are in it multiple times a day.

You don’t have to overhaul everything on day one. Pick the product you use most, and start there.

The bottom line

I’m not telling you this to scare you. I’m telling you because it worked for me, in a way I felt within days, and because the research backs up why.

Start with what touches your skin the most. For me, that was makeup, skincare, and laundry.

Xox,

SKH

Affiliate disclosure: The products and links in this post are affiliates. When you purchase anything from them, you will save a hefty amount and I make a small commission. This is part of my business that helps keep this website afloat for me to bring you the information for free. And I’m so grateful for you.

1. https://www.sciencedirect.com/science/article/abs/pii/S0273230019301928 ↩︎
2. https://www.ncbi.nlm.nih.gov/books/NBK225150/ ↩︎
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC3955696/ ↩︎
4. https://pubmed.ncbi.nlm.nih.gov/24149971/ ↩︎
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC6037613/ ↩︎
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC6037613/ ↩︎
7. https://pmc.ncbi.nlm.nih.gov/articles/PMC7231259/ ↩︎
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC12758922/ ↩︎
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC10922364/ ↩︎
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC7733930/ ↩︎
11. https://www.tandfonline.com/doi/full/10.1080/19490976.2025.2473524 ↩︎
12. https://www.sciencedaily.com/releases/2011/08/110824091537.htm ↩︎
13. https://pmc.ncbi.nlm.nih.gov/articles/PMC3226517/ ↩︎