There isn’t enough existing scientific study into the medicinal use of rehmannia to be able to say for certain how or why it has certain effects on specific illnesses and symptoms though many sing it’s praises.
Notably, it may stimulate the part of your brain responsible for regulating mood, making it a potentially useful supplement for people with anxiety. Additionally, some studies have suggested that it stimulates red blood cell production, which in turn has the effect of improving bone marrow production, staving off osteoporosis, curing anemia and fatigue, and helping with heavy or painful periods. Still other preliminary research suggests that one of the chemical compounds in rehmannia may prevent cell death, meaning it has potential applications as both a treatment for neurodegenerative and neurological disorders (like Alzheimer’s and ADHD) as well as a day-to-day anti-aging supplement.
As a result of all this, rehmannia is a popular ingredient in TCM’s general tonics (sometimes called “Yin” tonics). These potent, mineral-rich mixed decoctions include a variety of herbs and are meant for daily (or regular) ingestion or, at the very least, use at the first signs of illness.
PREPARATION & ADMINISTRATION
Rehmannia is one of the few TCM herbs that’s available in almost every form. Folks interested in gaining its benefits gradually can eat the roots steamed, baked, or raw. Additionally, rehmannia roots are often available as pills and extracts, and both the whole roots and powdered roots can be used for teas.
There’s also little information out there about the potential side effects and drug interactions of rehmannia supplements, a fact that is further complicated by the lack of regulation on herbal supplement manufacturing and sales. This lack of regulation hits rehmannia exceptionally hard, as two batches of powdered rehmannia rarely have the same concentration or strength, even coming from the same company.
You should consult with a certified herbalist, physician or other qualified healthcare professional before taking rehmannia.
Bai, Lin, et al. “Rehmannia Glutinosa – Exhibits Anti-Aging Effect through Maintaining the Quiescence and Decreasing the Senescence of Hematopoietic Stem Cells.” Animal Models and Experimental Medicine, John Wiley and Sons Inc., 24 Oct. 2018
Goldman, Rena. “Rehmannia: A Chinese Mystery.” Healthline, Healthline Media, 1 Sept. 2017
Leong, Pou K., et al. “Development of Chinese Herbal Health Products for the Prevention of Aging-Associated Diseases.” Natural Products and Drug Discovery, Elsevier, 23 Feb. 2018
“Rehmannia: Uses, Side Effects, Interactions, Dosage, and Warning.” WebMD, WebMD
Wexler, Marisa. “10 Rehmannia Root Benefits Side Effects.” SelfHacked, SelfHacked, 5 Dec. 2019
Xie, Peishan, et al. “Searching Clue of the Relationship between the Alteration of Bioactive Ingredients and the Herbal ‘Property’ Transformation from Raw Rehmanniae Radix (Sheng-Di-Huang) to Steam-Heating-Processed Rehmanniae Radix (Shu-Di-Huang) by Chromatographic Fingerprint Analysis.” Chinese Medicine, Scientific Research Publishing, 20 May 2014
Yuan, et al. “The Therapeutic Effect of the Chinese Herbal Medicine, Rehmanniae Radix Preparata, in Attention Deficit Hyperactivity Disorder via Reversal of Structural Abnormalities in the Cortex.” Evidence-Based Complementary and Alternative Medicine, Hindawi, 14 Oct. 2018
Zhang, Yanjie, et al. “Chinese Herbal Medicines on Cognitive Function and Activity of Daily Living in Senior Adults with Alzheimer’s Disease: a Systematic Review and Meta-Analysis.” Integrative Medicine Research, Elsevier, 22 Apr. 2019