The “best” hair grade is generally considered to be 10A or higher (such as 11A or 13A), which is typically unprocessed virgin hair from a single donor with all cuticles intact and aligned. However, the grading system is not standardized or regulated, so the most important factor is the reputation of the supplier. 
Understanding Hair Grades
The “A” grading system (e.g., 5A, 7A, 10A) was created by manufacturers as a marketing shorthand to indicate quality, but different suppliers may use different criteria for the same grade. Generally, higher “A” grades denote thicker hair with fewer short strands mixed in, sometimes referred to as “double drawn” or “super double drawn”. 
Key Quality Indicators
Instead of relying solely on the “A” grade number, consider these factors when choosing hair extensions:
  • Remy or Virgin Hair: Look for 100% human hair where the cuticles are intact and aligned in the same direction. This is known as Remy hair and drastically reduces tangling and shedding. Virgin hair is a premium form of Remy hair that has never been chemically treated (dyed, bleached, or permed).
  • Sourcing: Ideally, the hair should come from a single donor for consistent quality and texture.
  • Thickness: Higher quality hair (like 10A) is typically thick and full from the weft to the ends, ensuring a natural, voluminous look.
  • Processing: Minimally processed hair is less prone to damage and can be styled, dyed, or bleached more effectively.
  • Supplier Reputation: Purchase from reputable suppliers who are transparent about their sourcing and processing methods, and check for real user reviews (e.g., on Google)
Ultimately, the “best” hair for you depends on your budget and desired longevity. Higher quality, such as 10A virgin Remy hair, will be a greater upfront investment but can last for two years or more with proper care, while lower grades offer more budget-friendly options for shorter-term use.