Helen Avery vividly recalls the day she felt a cold breeze on the back of her head. She touched her scalp and discovered a shocking development: a bald spot the size of a tennis ball. Avery, then 40 years old, had survived breast cancer just a year before. She had lost her hair during chemotherapy but it had all grown back. There were no patches, no noticeable thinning.
For one thing, studies usually recommend using at least 5% minoxidil for improving hair growth, so rosemary oil wasn’t tested against a rigorous treatment regimen. “If the ingredient really did work , why haven’t there been a bunch of other studies published in the last 10 years ?” says Romanowski. A promising ingredient would have likely been more thoroughly studied to replicate results and confirm efficacy.