This Mistake Completely KILLS Keratin Results
Why You Should Never Do Henna or Protein Treatments
Before or Right After a Keratin Treatment
If you’re considering a keratin treatment to smooth frizz and add shine to your curls, this guide is a must read. In this post, I’ll walk you through a real keratin treatment process I did on a client, explain why you should avoid henna hair dye and protein treatments before or shortly after your keratin service, and share the products that deliver the best results.
What is a Keratin Treatment and Why Is It So Popular?
Keratin treatments are professional smoothing services that reduce frizz, enhance shine, and make styling easier, especially for curly and textured hair. Your hair naturally contains keratin, a protein that provides structure and strength, but heat styling, coloring, and environmental damage weaken it over time.
A keratin treatment works by coating your hair strands with a layer of keratin, which is then sealed in with heat from a flat iron. This fills in gaps along the hair shaft, leaving your curls smoother, softer, and less prone to frizz (even in humid weather).
My Favorite Keratin Treatment: Cezanne Smoothing Keratin Treatment
For my client, I used the Cezanne Smoothing Keratin Treatment, a salon-quality formula that’s 100% formaldehyde-free and uses natural ingredients. This makes it a gentle yet effective option, which is especially important for curly hair that needs smoothing without damage.
Why Henna Hair Dye Clashes with Keratin Treatments
One big mistake I see keratin clients make is applying henna hair dye too close to their keratin appointment. Henna is a natural plant-based dye made from Lawsonia inermis leaves. It coats the hair shaft and can last 4 to 6 weeks, adding rich color and shine.
However, henna molecules bind tightly to keratin in the hair. This prevents the liquid keratin from fully penetrating the hair cortex, causing the keratin treatment to sit on the surface without fusing properly. The result? Uneven, minimal smoothing and a shorter lifespan for your treatment.
Important: Some commercial black hennas contain metallic salts, which can react unpredictably under the high heat of the keratin flat iron, causing patchy results or even damage.
My recommendation: Wait at least 4 to 6 weeks (preferably longer) after henna before getting a keratin treatment. My client waited 4 months, ensuring safe and beautiful results.
Why You Should Avoid Protein Treatments Right After Keratin
Many clients ask if they can use strengthening or protein treatments like Olaplex or K18 soon after keratin. These products work by restructuring and repairing the hair from within, but keratin needs time to settle and stabilize on the hair shaft.
Using protein treatments too soon can:
Break down or weaken the keratin layer
Cause hair to become stiff, dry, and brittle due to protein overload
Act like clarifying shampoos and lift the keratin treatment prematurely
Since keratin itself is a protein treatment, your hair likely won’t need extra protein for at least 4 to 6 weeks. Focus on moisture and gentle cleansing instead.
Once your keratin treatment start to wash out over time, then you can use a strengthening treatment to reinforce the keratin before your next salon appointment. Only use these type of treatments about once a month for long lasting results.
Final Results: Smooth, Shiny, and Healthy Hair
After processing and blow-drying, my client’s hair showed dramatic improvement: defined coils, reduced frizz, richer color, and a healthy sheen. The keratin treatment worked as a “reset” for her hair, smoothing and strengthening fine strands while allowing her curls to bounce back naturally.
Keratin Treatment Aftercare Tips
Use sulfate-free shampoos and conditioners to preserve the keratin layer.
Avoid washing your hair for 48 to 72 hours after the treatment to let it fully set. (This depends on the formula used!)
Minimize heat styling to extend the life of your keratin treatment.
Schedule trims every 3 months to maintain healthy ends.
Ready for Your Keratin Treatment?
If you’ve used henna or protein treatments recently, give your hair time to rest and recover before getting keratin. When done right, keratin treatments can transform your hair care routine and keep your curls looking their best.