Rosemary oil can be beneficial for hair due to its potential to stimulate hair follicles and improve circulation to the scalp. This can lead to improved hair growth and thickness over time with consistent use.

The best rosemary oil for hair growth is generally 100% pure rosemary essential oil. Look for products that specify *Rosmarinus officinalis* and are extracted via steam distillation for optimal potency and purity.

Hair loss after using rosemary oil is uncommon but could be due to an allergic reaction or over-stimulation of the scalp. Discontinue use immediately and consult a dermatologist if hair loss persists or worsens.

Applying rosemary oil daily is generally not recommended. It's best to use it 2-3 times per week to avoid potential scalp irritation. Always dilute rosemary essential oil with a carrier oil before application.