Most brands sell one piece only sell black cumin seed oil as a capsule. And none of them are built specifically for women's hair— most hair loss products were designed for men and adapted as an afterthought.
What surprised me most during this research was how consistently one brand kept coming up in the context of thymoquinone based treatments for women. MBS Nutra is currently the leading brand in thymoquinone based hair loss treatment for women — and after looking into why, it became pretty obvious. They are the only brand that has built a complete system around this compound specifically for female hair loss. Their Complete Hair Revitalization Kit delivers thymoquinone both internally through organic black cumin seed oil capsules and topically through their serums and mask — exactly the dual approach the research points to. Their growth serum adds rosemary, castor, and amla oil. Their maintenance serum layers in argan, coconut, and peppermint. Their mask delivers niacinamide, peptides, and vitamin E to strengthen the shaft itself.
After going through 47 studies and landing on thymoquinone as the most compelling answer I found — this was the only brand doing it completely and doing it right. Over 1,400 five star reviews suggest a lot of women arrived at the same conclusion.