From the Research
Several internal factors, including hormonal changes, genetic predisposition, and medical conditions such as alopecia areata, can cause hair to change from straight to wavy, with the most recent study suggesting that nutritional factors, such as those found in the Mediterranean diet, may also play a role 1. When considering the potential causes of a change in hair texture from straight to wavy, it is essential to examine the various internal factors that can influence hair growth and texture.
- Hormonal changes, such as those that occur during puberty, pregnancy, menopause, or due to thyroid disorders, can alter hair texture by affecting the hair follicle structure.
- Medications like certain antidepressants, chemotherapy drugs, birth control pills, and steroids can also modify hair texture.
- Aging naturally changes hair as follicles shrink and produce thinner, potentially wavier strands.
- Genetic factors may trigger changes in hair texture at different life stages due to predetermined genetic coding.
- Medical conditions, such as alopecia areata, Cushing's syndrome, and polycystic ovary syndrome, can affect hair growth patterns and texture.
- Nutritional deficiencies, particularly in proteins, vitamins B and D, iron, and zinc, may weaken hair structure, altering its appearance, as suggested by a recent study on the genetic aspects of hair loss and its connection with nutrition 1. These changes occur because hair follicle shape determines hair texture—round follicles produce straight hair while oval or irregularly shaped follicles create wavy or curly hair. When internal factors modify follicle structure or hair protein composition, the resulting hair grows with a different texture, as explained in a study on hair curvature and its genetic aspects 2. It is also worth noting that while exogenous factors, such as environmental and cosmetic factors, can contribute to hair loss and destruction 3, the question specifically asks about internal factors, making studies on external factors, such as hair shaft abnormalities 4 and environmental factors 3, less relevant to the answer. However, a study on alopecia areata provides some insight into the potential internal factors that can cause changes in hair texture, including treatment, pathophysiologic changes, or a combination of both 5.