Hair growth is a biological process with specific patterns and angles, not just “up” or “out.” Its direction is determined by biology. Understanding these offers insights into daily hair care and styling.
The Biology of Hair Growth Direction
The primary determinant of hair growth direction is the angle of each hair follicle within the skin. Follicles are often tilted, dictating the hair shaft’s path as it emerges. This angle is largely predetermined by genetics.
As new hair cells are produced at the follicle’s base, the hair shaft is pushed upwards and outwards, following its established angle. These genetically influenced angles vary across body regions, explaining why hair grows differently on your scalp, eyebrows, or arms.
Natural Patterns and Variations
Hair exhibits distinct growth directions across the body. For instance, scalp hair typically grows downward or outward, while eyebrow hair grows more horizontally.
Common variations in scalp hair growth include hair whorls and cowlicks. A hair whorl is a circular or spiral pattern, often at the crown, where hair grows around a central point. These whorls can be clockwise or counter-clockwise and are largely genetic, developing during fetal development.
Cowlicks, often confused with whorls, are specific tufts of hair that stand out or grow in a different direction than the surrounding hair, making them difficult to style. While whorls describe the overall circular pattern, a cowlick is the resistant tuft within or near such a pattern, or in other areas where follicle angles sharply change.
These patterns are unique to individuals, and their direction and location are influenced by multiple genes. Hair texture, such as straight, wavy, or curly, also plays a role in how hair appears to lie and behave, even though the underlying follicle angle determines the true growth direction. For example, curly hair might appear to grow in multiple directions due to its coil, even if the follicle angle is consistent.
Managing Hair Growth Direction
Understanding your natural hair growth direction can significantly influence daily hair care and styling choices. When cutting hair, especially for short styles or shaving, knowing whether to cut “with” or “against” the grain can prevent irritation and achieve desired looks. Cutting against the natural growth direction often results in a closer shave or a shorter, more textured haircut.
For areas with cowlicks or whorls, this knowledge becomes particularly useful. Instead of fighting these natural patterns, stylists can incorporate them into a haircut, or use techniques to either tame them or enhance them as part of a style. For instance, leaving these areas slightly longer can help them lie flatter, or a skilled cut can blend them seamlessly into the overall style.
While the underlying growth direction determined by your hair follicles cannot be permanently changed, styling techniques and products can temporarily alter the perceived direction of hair. Blow-drying against the natural grain, using specific brushes, or applying styling products can train hair to lie in a different way. However, once the hair is wet or the styling products wear off, the hair will typically revert to its natural growth pattern.