In addition to pure castor oil, many makeup-format brow products list castor seed oil as a conditioning ingredient — for example, brow pencils formulated with conditioning oils and clear brow gels that include castor seed oil in their ingredient lists.
Common co-ingredients include biotin, amino acids, chamomile, jojoba oil, mango seed oil, olive oil, and aloe extract.
Labels vary: some list specific types (Combination, Dry, Mature, Normal, Oily, Sensitive), while others simply state “For All Skin Types.”