4 used to indicate total antioxidant capacity. TAOC appears to represent a mixed antioxidant response, rather than response to a single antioxidant [18–20]. While being aﬀected by oxidative stress, the mechanism of the response may diﬀer between clinical situations, such that the clinical signiﬁcance of changes in serum TAOC remains to be deﬁned. While estrogen is known to possess antioxidant prop- erties [21, 22], its use has been reported to be associated with decreased levels of some lipid-soluble antioxidants [22, 23]. We previously reported that oral contraceptive users had signiﬁcantly lower plasma concentrations of B-carotene compared with intrauterine contraceptive device or barrier method users [23]. B-carotene is another potent lipid- soluble antioxidant. Our present study validates the potential reducing eﬀect of hormonal contraceptives on lipid-soluble antioxidants. Since hormonal contraception is used by millions of women worldwide and decreased antioxidant levels have been associated with various chronic diseases, the potential reducing eﬀect(s) of hormonal contraception on lipid-soluble antioxidants warrant further investigation. The clinical relevance of diﬀerences in antioxidant proﬁle and responses between transdermal, vaginal, and oral deliv- ery is not known. Our ﬁndings demonstrate varying eﬀects of exogenous ovarian hormones and their method of delivery on lipid-soluble antioxidant levels. All three methods of delivery (oral, vaginal, and transdermal) were associated with decreased CoQ10 and α-tocopherol levels and TOAC. The transdermal patch was associated with the lowest levels of CoQ10 and the maximum reduction in TAOC. The greater bioavailability of EE with the patch may contribute to the present observation. 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