Here's why:
* Developer is a chemical: 20 volume developer is a powerful chemical designed to lift hair color. It's not meant to be used directly on hair without a professional hair color product.
* Unpredictable results: Mixing developer and shampoo will likely lead to unpredictable results, potentially damaging your hair. You could end up with uneven, patchy, or even orange or brassy tones.
* Safety risks: Mixing these ingredients could cause skin irritation, chemical burns, or allergic reactions.
If you want to lighten your hair, I recommend these safer options:
* Professional salon color: This is the safest and most reliable way to achieve desired results. A professional stylist can assess your hair type and color and recommend the appropriate products and techniques.
* Over-the-counter hair lighteners: These products are specifically designed for at-home use, but always follow the instructions carefully.
* Natural lightening methods: Using lemon juice or chamomile tea can lighten hair gradually, but they may not be as effective as other methods.
Remember, your hair's health is important. It's always best to consult with a professional stylist before attempting any major hair color changes.