17's Hair Theory

Understand your hair. Find your routine.

110 pages of hair knowledge and practical care tips from our founder Duygu, known as DUDUSHAIR: master hairstylist, product developer, and tester.

17’s HAIR THEORY guides you from the scalp to the ends. Explained in an easy-to-understand way and immediately applicable to your daily routine.

Here’s what you can expect:

• Understand hair growth and learn the basics of a healthy scalp
• 16 chapters on ingredients, hair care, and maintaining length
• 7 hair care plans and Duygu’s personal Sunday routine
• Help with hair breakage, split ends, and heavily bleached hair
• Dosage guides, before-and-after photos, and templates for your own hair journey