The community debates the trade-off between thermal damage caused by blow-drying and the risk of hair fragility or scalp health issues associated with air-drying too slowly.

noli's read

The community is converging on the idea that blow-drying, when performed correctly (sufficient distance, moderate temperature), is not necessarily more damaging than air-drying. Research, notably reported by cosmetic chemistry experts such as LabMuffin, supports the finding that prolonged air-drying can indeed cause the hair shaft to swell due to water absorption, making the fiber more vulnerable to mechanical damage. Conversely, excessive and localized heat weakens the cuticle, but air-drying is not without risks if moisture remains for too long, creating an environment favorable to microbial imbalances on the scalp. There is no strong clinical evidence mandating a single method; the scientific consensus emphasizes the importance of technique (temperature, movement, distance) over the tool itself. Claims regarding heat protectant products are mixed: they do protect well against heat, but can effectively leave residues if the hair is fine. In short, moderation and adaptation to one's hair type take precedence over a binary choice between air and heat.

the sources

1. 1r/HaircareScience