It can either be a source of pleasure or a total nightmare to look in the mirror one day and see that your straight hair has turned curly. You may ask yourself, “Why is my hair curling up all of a sudden?“.

A sudden difference in texture indicates a change, but the cause of that change can vary from climate and weather to stress, changing hormones, or even illness. 

Understanding how your hair can suddenly turn curly means focusing on hair at the biological level. If you do in fact have the genes for both curly and straight hair, then an environmental or physiological factor can trigger a change.

It’s hard to say for certain what the exact cause of your curling hair may be, but all of the different reasons can help you move through a process of elimination to find out. 

Reasons Why Your Hair Is Curling Up

Below are six common reasons why your hair may be curling up unexpectedly. 

1. Different Climate/Weather

The same type of humid weather that can make straight hair fall flat can enhance your curls, or even turn casually wavy hair into ringlets. This can happen on an especially humid and rainy day in your regular environment, or it can happen if you move or take a trip to a stickier climate. 

In terms of gene expression, pollution can actually be a major factor as to why your hair is curling up. Directly, pollution won’t cause a change in your hair, but poor air quality in industrialized areas can affect our hormones and that, in turn, might affect a change in the texture of your hair. 

2. Changing Hormones 

Hair changing from straight to curly often indicates a hormonal shift within the body. Factors like menopause, pregnancy, puberty, and even taking birth control, can have a drastic, switching effect on your hair’s texture.