Hard water is not a danger to hair health, but rather a cosmetic factor that influences its appearance and texture.

noli's read

There is a broad consensus that hard water does not pose a threat to the biological integrity of the hair. The study published in the 'International Journal of Trichology' (observational study) confirms that while minerals present in hard water can accumulate on the hair fiber, this primarily alters softness, shine, and manageability without weakening the internal structure of the hair. The idea that distilled water is necessary for hair health is therefore an exaggerated interpretation: it is a choice of aesthetic comfort rather than a care recommendation. Using distilled water is not dangerous, but research does not indicate that it is essential for maintaining healthy hair. The scientific community converges on a pragmatic view, downplaying the impact of minerals while acknowledging their effects on hair texture. In short, the scientific priority remains scalp health rather than the absolute purity of wash water.

the sources

1. 1r/HaircareScience