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Do creams really penetrate the skin? And if they do, how deep and how safely?

On the Meder Beauty Podcast, I explain how skincare actually moves through the skin barrier and why penetration is not simply a marketing promise, but a scientific and safety question. I break down the 500 Dalton rule, which ingredients can truly pass through the stratum corneum, and why size, location, and even time of day influence absorption.

I talk about peptides, retinol, niacinamide, acids, and the surprising role of water as one of the strongest penetration enhancers. I also explain why over-exfoliation, microneedling, and barrier damage can increase permeability, sometimes in ways that are not beneficial. Penetration should be selective, smart, and controlled. In this conversation, I’ll help you understand what really reaches your skin and what should not.

Episode resources:

The 500 Dalton rule for the skin penetration of chemical compounds and drugs

Learn more from the previous episodes:

Your Skin’s Hidden Ecosystem: Why the Microbiome Matters More Than You Think

The Magic of Peptides: Why They’re Transforming Skincare Forever

Beyond Retinol: The New Science of Safer, Smarter Skincare

Understanding Acne: Myths vs. Science

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Meder by Dr. Tiina Meder

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Meder Beauty YouTube

Listen to the Meder Beauty Podcast on Apple Podcasts

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In this episode, I’m joined by Sarah Drew, a long-time member of the Meder Beauty team and a frequent guest on the podcast, to talk about how skin reacts to changes in climate, location, and lifestyle.

Drawing from our shared experience working with clients across different environments, and from my own travel between Northern Europe and South Florida, we explore why healthy skin is naturally adaptive and what signs show that skin is struggling to adjust. We discuss how temperature, humidity, UV exposure, air conditioning, water quality, stress, sleep, and food choices affect the skin barrier and microbiome. We also share practical guidance on how to prepare your skin before travel, what to adjust during climate transitions, and why slowing down instead of over treating is often the most effective approach. This episode is about listening to your skin and supporting it through change, not forcing it to behave.

Learn more from the previous episodes:

Beat Jet Lag: Skincare, Sleep & Travel Secrets

Understanding Acne: Myths vs. Science

Sun Protection Strategy: More Than Sunscreen!

How Australian Skin Practitioners Handle Sun Damage

Connect with us:

Sarah Drew Instagram

Meder by Dr. Tiina Meder

Meder Beauty Instagram

Meder Beauty Facebook

Meder Beauty TikTok

Meder Beauty LinkedIn

Meder Beauty YouTube

Listen to the Meder Beauty Podcast on Apple Podcasts

Send a text

In this episode, I explore the connection between neuroscience, neurotherapy, and skincare, a topic that is finally gaining the attention it deserves.

Skin and the nervous system are embryological siblings. They develop together, communicate constantly, and use the same biochemical language throughout our lives. This is why stress, lack of sleep, anxiety, and emotional discomfort can instantly change the way our skin looks and feels. I explain how inflammation, microbiome imbalance, and nervous system overactivation contribute to conditions like acne, rosacea, eczema, and chronic itch, and why irritating or sensitizing skincare can affect not only the skin, but also the brain.

This episode is about understanding skin as a communication organ, not just a surface to be treated. When we calm the skin, we calm the nervous system. And that changes everything.

Learn more from the previous episodes:

Food, Microbiome & Skin: The Forgotten Connection

Your Skin’s Hidden Ecosystem: Why the Microbiome Matters More Than You Think

The Sensitive Skin Epidemic: What Your Skin Is Trying to Tell You

Understanding Acne: Myths vs. Science

Episode resources:

Laurent Misery - Dermatologist known for research on neurocutaneous interactions and skin neuroscience

Connect with us:

Meder by Dr. Tiina Meder

Meder Beauty Instagram

Meder Beauty Facebook

Meder Beauty TikTok

Meder Beauty LinkedIn

Meder Beauty YouTube

Listen to the Meder Beauty Podcast on Apple Podcasts