* Limited Lifting Power: High-lift browns typically lift 3-4 levels of natural hair color. When hair is already dyed dark, the dye molecules are already present, and the high-lift color needs to lift both the artificial color and the natural pigment which often requires a higher volume developer than included in the kit.
* Uneven Results: Applying it to previously dyed hair can result in uneven lift and color, with the roots lifting more than the dyed portion.
* Damage: Trying to lift through existing dye can be very damaging to your hair, leading to dryness, breakage, and a brassy, muddy tone.
If you have dyed dark hair and want to lighten it, here's what you should consider instead:
1. Color Remover: A color remover is a product designed to remove artificial hair dye, not natural pigment. This will give you a clean slate to work with. *Follow the product instructions carefully.*
2. Bleach Bath (for small changes) or Bleach: You may need to bleach your hair to lift the artificial color. Doing this at home is tricky and carries risks of damage and unevenness.
3. Professional Color Correction: The safest and most predictable option is to consult a professional hairstylist. They can assess your hair's condition and use appropriate products and techniques to achieve your desired result while minimizing damage.
In short: L'Oreal Feria High Lift Brown is generally not a good choice for previously dyed dark hair. You'll likely need a different approach to lighten it safely and effectively.