How to Repair Your Skin Barrier: A Dermatologist's Guide with Dr. Marie Jhin

Dr. Marie Jhin is a board-certified dermatologist, author, and skincare expert with decades of experience in medical and cosmetic dermatology. She is the Chief Medical Officer of Musely and founder of Premier Aesthetic Dermatology in the San Francisco Bay Area. Dr. Jhin previously served as an adjunct clinical instructor in dermatology at Stanford University for 10 years and is the author of two books focused on Asian and K-beauty Secrets. As a Korean American dermatologist, she brings a unique perspective to the intersection of dermatologic science, aesthetics, cultural beauty traditions, and healthy aging. Her philosophy is simple: effective skincare should be science-backed, personalized, and sustainable.

What inspired you to become a dermatologist?

I knew I wanted to be a physician from the time I was a little girl, but it was during a semester abroad in Kenya that I truly understood the impact a doctor could have on someone’s life. I had the opportunity to help deliver babies in a public hospital, and that experience really solidified my decision to pursue medicine.

I initially began a residency in internal medicine, and during a rotation in dermatology, something clicked. I noticed that the dermatologists genuinely loved what they did—and they were happy! I loved the variety of the field: I could care for patients of all ages and backgrounds, diagnose medical conditions, perform procedures, and use my hands every day.

Skin is also our most visible organ, so patients are incredibly motivated. When you successfully treat a skin condition or help someone feel better about their appearance, you can see the impact it has on their confidence and quality of life. Some of my patients tell me I’m an artist, and I love that dermatology allows me to combine that artistic side with medicine, science, and visual diagnosis.

As a Korean American, I’ve also always been fascinated by the way different cultures approach skin, beauty, and aging. That interest eventually led me to write two books on Asian beauty and skincare. Dermatology has really allowed me to bring together so many things I love—science, medicine, artistry, culture, and most importantly, helping people look and feel their best.

In your experience, what is one product or step you think is missing from most people’s skincare routines?

Consistency! People often think they need another product, when what they really need is a routine they can stick with. If I had to choose one actual product, though, it would be sunscreen. Daily broad-spectrum sunscreen is still one of the most effective things we can do to prevent premature skin aging, uneven pigmentation, and skin cancer. And it only works if you actually use it consistently.

What does your own skincare routine look like?

My routine is actually pretty simple. In the morning, I focus on antioxidant protection, hydration, and sunscreen. At night, I use tretinoin and targeted treatments depending on what my skin needs. I’m a big believer in active ingredients, but I also pay attention to my skin barrier and back off when my skin is irritated or dry. Skincare doesn’t have to be complicated to be effective.

What exactly is the skin barrier, and why is it so important for healthy skin?

Think of the skin barrier as your body’s protective outer wall. The outermost layer of the skin helps keep water in while keeping irritants, allergens, and environmental stressors out. When that barrier is healthy, skin tends to feel smooth, comfortable, and hydrated. When it becomes disrupted, you may experience dryness, burning, itching, redness, flaking, or increased sensitivity. A healthy barrier is really the foundation of healthy skin.

What ingredients should people look for when they want to support and strengthen their skin barrier?

I look for ingredients that hydrate, calm, and help replenish the skin barrier. Ceramides are especially important because they help replace the lipids naturally found in our skin, while humectants such as hyaluronic acid and glycerin attract and hold onto water. I also love soothing ingredients like panthenol and Centella asiatica, particularly for sensitive or easily irritated skin.

Editor's Note: Our Trust Your Worth Hydration Relief Essence Spray is formulated with 5% Centella asiatica and 1% panthenol to hydrate and soothe sensitive, easily irritated skin. Fragrance-free and dermatologist-tested on sensitive skin. 

Is there a practice or trend in the skincare industry that you believe may actually be doing more harm than good when it comes to the skin barrier?

Over-exfoliation and the idea that stronger or higher percentages automatically mean better results. There’s a tendency to think, “If 0.05% is good, then 0.1% must be better,” but that’s not always true in skincare. The most effective concentration is the one your skin can tolerate consistently.

Social media has also encouraged people to layer multiple powerful actives—acids, retinoids, scrubs, peels—sometimes all in the same routine. This can lead to chronic irritation and a compromised skin barrier, which may ultimately work against what you’re trying to achieve.

I always tell my patients that your skin doesn’t need to sting, peel, or feel tight for a product to be working. More is not always better, and stronger is not always better. Sometimes doing less—and doing it consistently—actually gives you better skin.

What role does hydration play in calming eczema-prone skin and supporting long-term skin health?

Hydration is especially important for eczema-prone skin because the skin barrier is already more vulnerable to water loss and environmental irritants. Regular moisturizing helps restore that barrier, reduce dryness and itching, and make the skin less reactive.

I generally recommend applying a fragrance-free cream or ointment shortly after bathing, while the skin is still slightly damp. For eczema-prone skin, moisturizing shouldn't just be something you do during a flare—it should be part of the everyday routine.

Editor's Note: Looking for a fragrance-free hydration step for eczema-prone skin? Trust Your Worth Hydration Relief Essence Spray has earned the National Eczema Association Seal of Acceptance™. Mist it onto slightly damp skin before your moisturizer. 

Can using “too many good ingredients” actually make your skin worse?

Absolutely. Ingredients can be wonderful individually and still become irritating when they're layered together or used too frequently. Retinoids, exfoliating acids, vitamin C, benzoyl peroxide, and other actives all have a place in skincare, but using too many at once can overwhelm the skin.

I like to introduce active ingredients one at a time. That gives your skin time to adjust and also makes it much easier to identify the culprit if irritation develops.

When working with individuals who have sensitive or highly reactive skin, what is your best advice for building a simple and effective skincare routine?

Start with the basics: a gentle cleanser, a fragrance-free moisturizer, and a broad-spectrum sunscreen. Give the skin time to settle before adding anything else.

Once the skin is comfortable, introduce only one new product at a time and start slowly—sometimes just a few times a week. Sensitive skin doesn't mean you can never use effective active ingredients; it means you need to be more thoughtful about how you introduce them.

The goal shouldn't be to have the longest skincare routine. The goal is healthy skin.

Interview conducted by MaLonn McNeill and Angel Wang.