Serum TEWL uses cholesterol, fatty acids, and plant oils to prevent transepidermal water loss (TEWL) and repair skin’s lipid barrier. Ideal for dry, irritated, or post-procedure skin, this guide breaks down each ingredient, its purpose, and what to avoid when using it.
If your skin feels tight, flaky, or stings with water, you're likely experiencing barrier damage, and TEWL is to blame. Transepidermal water loss (TEWL) is the silent culprit behind chronic dryness and post-treatment irritation.
Serum TEWL by Biologique Recherche is formulated to solve exactly that. It seals in hydration, strengthens the barrier, and supports real skin recovery.
In this guide, we break down the ingredients that make it work, what to avoid pairing with it, and how to use it correctly. Let’s dive in.
Is Your Skin Barrier Crying Out For Help?
When clients tell me their skin feels tight, flaky, or even stings with water, I know it’s transepidermal water loss (TEWL): the invisible leak in your barrier where hydration escapes faster than products can replace it.
Signs include constant thirst, redness, rough patches, and irritation.
Left unchecked, TEWL accelerates aging, weakens resilience, and makes every active feel harsher than it should.
Triggers are everywhere: over-exfoliation, starting retinol without support, harsh seasonal changes, and yes, even long, hot showers.
Won’t A Lipid Serum Break Me Out?
Oily doesn’t mean lipid-rich. In fact, oily skin with a weak barrier breaks out more. The right lipids restore balance, calm inflammation, and stop the cycle of reactivity.
Serum TEWL: The Secret Weapon For Stronger Skin
Think of Serum TEWL as a lipid shield, not a moisturizer.
A moisturizer hydrates by pulling water into the skin, but Serum TEWL’s job is to make sure that hydration doesn’t escape. It’s the final lock on the door.
Who needs it most? My dry, winter-sensitive clients love it. Those recovering from peels, lasers, or even a harsh retinol phase find it essential. It’s also a savior for eczema-prone skin and anyone who’s felt their barrier give up after too much exfoliation.
Serum TEWL seals in hydration, restores the skin barrier, and prevents dehydration. But it is not a hydrating serum.
You’ll still want humectants like hyaluronic acid or glycerin underneath.
Do I Still Need A Moisturizer If I’m Using Serum TEWL?
Yes, Serum TEWL locks in the benefits of your moisturizer. Without that base layer, you’re just sealing in dryness.
The Building Blocks Of Serum TEWL Explained
This formula is powerful because it goes beyond basic occlusion. Every ingredient plays a specific role in barrier recovery:
Lipid-Replenishing
- Phytosterols – mimic natural skin lipids, helping rebuild the matrix that keeps the barrier intact.
- Cholesterol – a skin-identical molecule that strengthens structure and resilience.
- Fatty Acids – reduce inflammation while providing sealing power to lock in moisture.
Healing & Protective Oils
- Sea Buckthorn Oil – rich in omega-7, it calms irritation and supports healing.
- Raspberry Seed Oil – packed with antioxidants, it soothes inflammation while defending against free radicals.
- Jojoba, Sesame & Macadamia Oils – nutrient-dense oils that reinforce barrier function without feeling greasy.
Anti-Oxidants
- Cranberry Extract – loaded with vitamin E, known for wound-healing and protective qualities.
- Rosemary & Bitter Orange Flower Oils – natural extracts that assist with cell repair and overall skin resilience.
Won’t All These Oils Clog My Pores Or Worsen Fungal Acne?
No. These are breathable, plant-based lipids that absorb quickly and support the skin’s natural ecosystem. They’re nothing like petroleum-based slugging methods that can trap heat, dirt, and bacteria.
Ingredients You Should NOT Mix With Serum TEWL
Now, here’s where I need to play skincare referee. Serum TEWL is powerful, but it’s not meant to play nice with everything. Pairing it with the wrong ingredients can undo the barrier repair you’re working so hard to achieve.
- AHAs/BHAs – These acids are exfoliators, and while they’re great in the right context, they also strip away lipids. Using them too close to Serum TEWL defeats the purpose by increasing water loss.
- Retinol (unless layered properly) – Retinol itself is not the enemy, but when paired incorrectly it leads to over-exfoliation. Think of Serum TEWL as your “retinol buffer.” Never put it underneath, always on top.
- Fragrance-heavy oils – They might smell luxurious, but fragrance molecules are common irritants and can inflame an already compromised barrier.
- Alcohol-based toners – Fast-drying alcohols undo the protective lipid seal TEWL provides. Save them for a stronger skin moment, not barrier repair.
Best Product Pairings: What Works With Serum TEWL
Barrier repair is never about one product, it’s about synergy. These are my favorite Biologique Recherche partners for Serum TEWL:
1. Lait Dermo-S
This is my go-to cleanser when the skin is fragile. It respects the barrier, doesn’t strip, and leaves skin prepped for hydration.
For clients who overdo acids or are post-procedure, this is the safest starting point before layering on hydration.
2. Serum Amniotique VG Or Serum Colostrum VG
If your skin is dehydrated but still oily or combination, Serum Amniotique VG is beautifully light and water-rich. If your skin is dry, fragile, or recovering, Serum Colostrum VG gives deeper lipid support.
Both work perfectly under Serum TEWL to provide the water before you lock it in.
3. Creme Masque Vernix
When I want to see overnight transformation, I reach for Creme Masque Vernix. Its biomimetic lipids mimic the skin’s natural composition, making it the ultimate partner for TEWL serum.
Especially after retinol, peels, or a long winter day, this duo restores comfort and elasticity like nothing else.
Serum TEWL FAQs You’ve Been Wondering About
I hear these questions from clients all the time, so let’s get them answered clearly:
When Do I Apply Serum TEWL In My Routine?
Always as the final step. In the morning, layer it after your moisturizer but before sunscreen. At night, apply it after your moisturizer, and before any finishing serums if you’re using them. Think of it as the seal, not the filler.
Can I Use This Around Eyes Or Lips?
Absolutely around the lips, it’s one of my favorite tricks for chapped skin. Around the eyes, only if you’re not sensitive. If your eyes react easily, I’d recommend keeping TEWL for the face and lips, and using a dedicated eye product instead.
Is It Safe For Acne-Prone Skin?
Yes, and here’s where clients are often surprised. When skin is stripped and inflamed, breakouts worsen. Serum TEWL calms the barrier, lowers irritation, and makes skin less reactive. Balanced skin actually breaks out less.
Your Skin’s Barrier Isn’t Optional
Your barrier is your frontline defense. Without it, hydration leaks out, inflammation ramps up, and every active product in your cabinet struggles to do its job.
Serum TEWL isn’t just another serum, it’s a recovery protocol. When your skin is supported at the barrier level, everything else works better.
Clients often come to me frustrated: they’ve tried everything, their skin looks worse, and they’re exhausted by the cycle of irritation. This serum changes that.
✨ If your skin is flaky, tight, or even stings when water touches it, this is your sign. Don’t keep fighting your skin, nourish it, seal it, and watch it transform.
At KarinaNYC, we don’t believe in band-aid skincare. We believe in results. And results always start with a healthy, resilient barrier.
Your Barrier Recovery Starts Here: With KarinaNYC
You don’t need more products, you need the right ones. If your skin is dry, flaky, or inflamed, barrier repair is where to begin. That’s what I do every single day in my clinic, and it’s why clients see results they can feel.
🛍️ Want a personalized routine that actually works?
Book a virtual consultation or explore our curated barrier repair collection at KarinaNYC.com.
