A possible catalyst for irritation is using the oil alone. Despite what the TikTok videos might suggest, pure rosemary essential oil (this goes for essential oils in general) is very potent and could cause scalp irritation. Worse yet, it might have the opposite of the intended effect. “Maintaining a healthy scalp plays a fundamental role in supporting healthy hair growth by providing conditions to optimize the function of the hair follicle,” adds Dr. Wong. “There are many examples in which an unhealthy scalp can lead to increased hair loss, such as eczema, psoriasis, fungal infections, or yeast overgrowth.”
