Black Walnut Extract is prepared from the hulls of the nuts of the Black Walnut Tree (Juglans nigra). Black Walnut is a deciduous flowering tree that is native to Eastern North America, but is now naturalized in many regions. Black walnut was used for centuries by Native Americans for both medicinal purposes and as a dye.
The use of Black Walnut is fairly common in modern Homeopathic and Naturopathic medicine. Black Walnut Extract is a common Naturopathic acne treatment and it is purported to have astringent and antibacterial properties that can help control acne symptoms. For the treatment of acne, Black Walnut Extract is most commonly blended with other active ingredients and administered topically, but it can also be consumed orally as an herbal supplement.
The husk of Black Walnuts contain some compounds that may have biological activity, such as juglone and plumbagin. Juglone has been reported to have antibacterial, antiparasitic and antifungal properties. Black Walnut trees actively secrete chemicals into the surrounding environment that suppress the growth of other plants, in order to give the Black Walnut a competitive advantage. Juglone is one of those chemicals. These chemicals may also help the plant protect against bacterial, fungal, parasitic and viral pathogens. Some Naturopathic practitioners believe that these molecules can also help suppress the growth of acne-causing bacteria, such as Propionibacterium acnes.
Unfortunately, there has been minimal scientific research into whether Black Walnut hull extracts are toxic to acne-causing bacteria, or whether treatments that contain Black Walnut extract help reduce the frequency or severity of acne symptoms. There are some people who claim that their acne symptoms improved after incorporating Black Walnut into their treatment regimens, but these claims can not be independently evaluated. Overall, the effectiveness of Black Walnut extracts for the treatment of acne remains unclear.
Topical herbal therapies an alternative and complementary choice to combat acne. Kapoor, et al. 2011.
Herbal remedies for acne. Kumar, et al. 2005.
Antibacterial activity of juglone against Staphylococcus aureus: from apparent to proteomic. Wang, et al. 2016.
Plumbagin inhibits LPS-induced inflammation through the inactivation of the nuclear factor-kappa B and mitogen activated protein kinase signaling pathways in RAW 264.7 cells. Wang, et al. 2014.
Dermatitis due to black walnut juice. Siegel. 1954.
Potential phytotherapy of atopic dermatitis, acne, psoriasis, vitiligo. Khan, et al. 2016.