Do This BEFORE Your Next Extensions Install
Traditional Sew-In Extensions + Keratin Treatment: The Ultimate Combo for Healthy Curly Hair
Welcome (or welcome back)! In today’s post, I’m walking you through how I install a traditional sew-in on one of my returning clients and the number one secret that’s helping my curly-haired clients avoid damage and actually grow longer, stronger hair with extensions.
If you’re curious about the best way to prep your natural hair for extensions or you’ve been wondering whether a keratin treatment before a sew-in is worth it, keep reading!
Sew In Extensions Prep
Before installing any type of hair extensions, I always start detox with a clarifying shampoo. This removes buildup, oil, and impurities so I’m working on a clean canvas.
In this case, my client’s curls looked healthy and hydrated. That’s because she came in three weeks prior for her first keratin treatment.
What Is a Keratin Treatment and
Why Do I Recommend It Before Extensions?
So what’s my secret? Keratin treatments. Most of my curly clients get a keratin treatment before any extension install. Here's why:
Reduces frizz
Smooths the cuticle
Makes hair more manageable
Strengthens hair by infusing protein
Gives your curls a gentle stretch without altering your curl type
It creates the perfect base for styles like sew-ins and helps hair remain manageable and less prone to breakage throughout the wear.
Repair and Strengthen Before Protective Styling
After detoxing her scalp, I apply an Olaplex treatment. Unlike keratin (which smooths and strengthens with protein), Olaplex works by repairing broken bonds inside the hair shaft. This ensures that even if the hair was previously damaged, it’s strong and healthy underneath the extensions.
I always recommend pairing Olaplex with a keratin treatment because it prolongs the keratin results without stripping them. It strengthens from within, while keratin works on the outer layer.
I always follow up with a steam treatment. Steaming deeply hydrates the hair and scalp, which is key before installing a protective style like a sew-in. Since your natural hair won’t be exposed to moisture as often, I pack in as much hydration as possible now to protect the hair long-term.
Products to Protect Keratin Treated Hair
After steaming, I rinse out the Olaplex with a moisture-rich shampoo that is both color-safe and keratin-safe. This step is crucial: shampoos that strip keratin can undo all your treatment benefits. My go-to shampoo leaves the hair clean, soft, and moisturized without leaving any heavy residue.
Next up is the Deep Repair Treatment, which is my salon's bestseller. It delivers slip for easy detangling, serious moisture, and strength without weighing the hair down. This product also contains keratin, helping to prolong the smoothing effects of her earlier treatment.
It’s perfect for clients with fine to medium hair because it moisturizes without greasy buildup.
Prepping for the Blowout
I prep her for the blowout with my go-to Emergency Miracle Treatment leave-in conditioner. I never skip this step as it adds moisture and helps your style last longer.
For heat protection, I use Le Deux blow dry cream, which offers both moisture and heat defense. This combo prevents the dry, crunchy feeling blowouts can sometimes cause and keeps the hair soft and manageable.
To seal in moisture and cut down blow-dry time, I apply Amethyst Oil. It adds shine, protects from heat, and leaves the hair silky-smooth.
The Benefits of a Keratin Treatment for Curly Hair
(Especially Before Extensions)
Let’s talk about why keratin treatments are a game-changer for curly hair:
Reduces frizz and makes curls less reactive to humidity
Simplifies detangling, reducing breakage and shedding
Strengthens hair with added protein
Softly stretches curls for easier blending with extensions (without changing your curl type)
Want to learn more? I have a full keratin treatment playlist on YouTube showing different curl types and real results.
After the blowout, I braid her down using Flex Paste braiding gel. This gel has tiny molecules that hold the braids in place but absorb into the hair without buildup. That means the scalp stays moisturized and breathable, which is perfect for clients who want to wash their hair during wear.
I skip the hair net and instead use braiding hair to reinforce the base. This keeps the scalp accessible and the style long-lasting.
To soothe her scalp post-braid, I apply Amethyst Oil one last time. This will help ease any tension and prevents post-braid itchiness.
What Is a Traditional Sew-In & Why Is It Great for Natural Hair?
For this look, I’m using 20" kinky straight Cambodian hair extensions. I only need two bundles because look how full they are! This texture blends beautifully with natural hair and straightens like a dream.
Let’s cover some of the top benefits of traditional sew-in extensions:
Protective styling: Most of your hair is braided and tucked away
Low manipulation: Even with leave-out, you’re not constantly styling your natural hair
Versatility: Try different looks while your real hair grows
Washable: You can still wash your hair and scalp, unlike with some twist or braid styles
Pairing Keratin Treatments and Sew-Ins:
The Ultimate Duo for Curly Hair
Here’s why these two treatments work so well together:
Keratin preps the hair to handle tension from braids/extensions
Smoother texture = better blend with extensions
Humidity resistance keeps your styles lasting longer
Less flat ironing needed on your leave-out, preserving hair health
Maintenance Tips:
How to Care for Sew-Ins with a Keratin Treatment
To keep your install looking and feeling fresh:
Wash your hair every 1–2 weeks using an applicator bottle for easy scalp access
Use lightweight conditioner to avoid buildup around the tracks
Minimize heat on your leave-out—use heatless styling when possible
Always use a heat protectant if flat ironing is needed
Final Look:
Can we take a moment for this final look? Her keratin treatment and kinky straight bundles give her the perfect blend of volume, length, and manageability. Only two bundles, and the hair is still full and flowy.
Want to know why sew-ins are the best protective style for natural hair? Be sure to read this blog post.
Until next time! Keep those curls moisturized and protected!