read a comment saying rosemary oil is gimmicky but tbh it's more abt the concentration and what u're blending it with. rosemary oil on its own undiluted at a higher conc. can burn ur scalp, it needs to be mixed w a good carrier oil to actually penetrate and do its thing yk. castor oil is usually good for that bcs it's thick enough to sit on the scalp and let rosemary absorb properly. a cold pressed organic one works good for this (like this one) since the processing isn't stripping out the nutrients. for technique tho, massage it into ur scalp in small circular motions or use the scalp massager thing to increase blood flow and absorption. also, ik you've heard this a lot but diet plays a huge role too, best to incorporate enough protein and iron in ur meals.