What characteristic is typical of thio relaxers?

Thio relaxers are indeed characterized by a high pH level. This alkaline nature is essential as it helps to break down the disulfide bonds in the hair structure, allowing for the smoothing and straightening effects that thio relaxers are known for. The high pH facilitates the chemical reaction necessary for altering the hair's curl pattern, making it suitable for achieving a more straightened look.

Understanding the role of pH in hair treatments is crucial because it not only affects the effectiveness of the relaxers but also highlights the importance of following up with appropriate products to maintain hair health after processing. In contrast, other options like low smell, less hair damage, and quick processing time may apply to different types of hair treatments or to advancements in product formulations, but they do not accurately represent a defining characteristic of thio relaxers.