Hannah Zulueta TCM Herbs · Kidney
Rehmannia Six and Rehmannia Eight
Two formulas. One for the warm dog, one for the cold.
Their names sound alike, but each carries its own healing signature. Rehmannia Six suits a dog that runs warm. Rehmannia Eight suits a dog that runs cold. Here is how to tell which one your dog needs, and why these formulas have endured since the Han Dynasty.
At a glance
Eight is Six, plus two
Rehmannia Six (Liu Wei Di Huang Wan) is the foundational formula, six herbs that nourish Kidney Yin. Rehmannia Eight (Ba Wei Di Huang Wan) takes those same six and adds two warming herbs, to bring heat to a cold body.
Old medicine
From the Han to the Song
These are ancient formulas. Rehmannia Eight is recorded in the Jin Gui Yao Lue, Zhang Zhongjing’s classic written around 200 CE in the late Han Dynasty, which makes it roughly eighteen hundred years old. Rehmannia Six came centuries later, around 1119 CE in the Song Dynasty, when the pediatrician Qian Yi took the eight-herb formula and removed the two warming herbs to make a gentler version for children.
So although we build Eight from Six here for clarity, history ran the other way. The eight-herb formula came first, and the six-herb one was drawn out of it.
Start with your dog
Which formula fits?
Tap what describes your dog. The fit and the reasoning come up below.
Rehmannia Six. The foundational Yin formula.
Tongue red, dry, and small.
It nourishes Kidney Yin and supports kidney and liver. Reach for it when your dog shows deficient Yin signs: a dry coat, seeking cool spots, restlessness at night, with good metabolic function and a clear dislike of warm weather.
Rehmannia Eight. The same six, warmed.
Tongue pale, wet, and swollen, and the dog seeks heat.
The two added herbs warm the Yang and improve circulation. Reach for it with weak back legs, senior changes, poor circulation, a need for metabolic support, and a clear discomfort in cold weather.
For a kidney dog, Rehmannia Eight is usually the choice.
The one exception is Yin Fire, an internal heat that runs underneath. It shows as panting, agitation, recurring UTIs, and restlessness at night, with thirst that comes and goes depending on whether the dog is truly hot.
Inside the formula
What each herb does
Every herb has a specific role, and they work in harmony. Rehmannia root leads.
East meets West
Two languages for one garden
For thousands of years, Chinese medicine has spoken of Qi and Blood, Yin and Yang, organ systems that mean far more than the anatomy they share a name with. To a Western ear, that language can feel foreign. It is like two gardeners describing the same plot, one in soil pH and nitrogen, the other in the earth’s nurturing energy and seasonal rhythm. Both are true.
When I first studied this medicine, I wanted to teach everyone the classical framework, the poetry of it. Over the years my love for it only deepened, but my way of sharing it changed. Instead of explaining Kidney Yin deficiency, I could talk about cellular repair and stress adaptation. Rather than Liver Qi stagnation, I could talk about stress response and hormone balance.
Not because the science is better. Because it is familiar.
So when I translate these formulas into the language of biochemistry below, I am not choosing one tradition over the other. I am building a bridge between them, drawn from classical texts, centuries of clinical use, and published research.
What the research shows
The biomedical translation
Tap each to open. Drawn from published studies on Liu Wei Di Huang Wan and Ba Wei Di Huang Wan.
It protects the kidney’s filters
The formulas help maintain the kidney’s filtering structures, supporting the specialized podocyte cells that line them, preserving tubule integrity, and easing oxidative stress through the body’s own antioxidant defenses. In research terms, that runs through MAPK, NF-kB, and Nrf2 signaling, with support for mitochondrial function in kidney cells.
It helps manage proteinuria
These formulas help the filtration barrier stay selective, so the kidney keeps the proteins it should and sheds only waste. They support the slit-diaphragm proteins nephrin and podocin, reduce inflammatory leakage, and help normalize the albumin-to-creatinine ratio. This matters across diabetic, autoimmune, and age-related causes of protein loss.
It supports metabolism
The formulas improve glucose utilization and insulin sensitivity, help regulate lipid metabolism, and support steady cellular energy. In a diabetic kidney, they also reduce the advanced glycation end-products that drive damage, with protective compounds from Cornus fruit.
It calms inflammation and balances immunity
They help balance the immune response, easing pro-inflammatory signaling and steadying T-helper cell ratios. In immune-driven kidney conditions, research shows reduced proteinuria, less immune-complex deposition, and lower auto-antibody levels.
It supports the aging body
The formulas support calcium balance and bone density, aid cellular repair, ease age-related oxidative damage, help regulate parathyroid hormone, and support cognitive function through neurotrophic factors.
References
These are the papers behind the science on this page, including the formula synergy research further down, in case you or your dog’s veterinarian want to look closer.
- Chen, H. T., Tung, C. H., Yu, B. H., Chang, C. M., & Chen, Y. C. (2024). Renal and survival benefits of seventeen prescribed Chinese herbal medicines against oxidative-inflammatory stress in systemic lupus erythematosus patients with chronic kidney disease: A real-world longitudinal study. Frontiers in Pharmacology, 14, 1309582. doi.org/10.3389/fphar.2023.1309582
- Chen, L. (2013). Liuwei Dihuang Wan on the new progress of the study of chronic kidney disease. Journal of Hunan University of Chinese Medicine.
- Cheng, X. R., Qi, C. H., Wang, T. X., Zhou, W. X., & Zhang, Y. X. (2019). Characteristics of the traditional Liu-Wei-Di-Huang prescription reassessed in modern pharmacology. Chinese Journal of Natural Medicines, 17(2), 103-121. doi.org/10.1016/S1875-5364(19)30013-5
- Hsu, P., Tsai, Y., Lai, J., Wu, C., Lin, S., & Huang, C. (2014). Integrating traditional Chinese medicine healthcare into diabetes care by reducing the risk of developing kidney failure among type 2 diabetic patients: A population-based case-control study. Journal of Ethnopharmacology, 156, 358-364. doi.org/10.1016/j.jep.2014.08.029
- Ikeda, R., & Mizoguchi, K. (2009). Hachimijiogan (Ba-Wei-Di-Huang-Wan), a herbal medicine, improves unbalance of calcium metabolism in aged rats. Journal of Ethnopharmacology, 124(2), 176-181. doi.org/10.1016/j.jep.2009.04.044
- Liang, X., Li, H., & Li, S. (2014). A novel network pharmacology approach to analyse traditional herbal formulae: the Liu-Wei-Di-Huang pill as a case study. Molecular BioSystems, 10(5), 1014-1022. doi.org/10.1039/C3MB70507B
- Park, C., Tanaka, T., & Yokozawa, T. (2022). Identification of active component of Hachimi-jio-gan ameliorating diabetic nephropathy. Journal of Integrative Medicine. doi.org/10.30564/jim.v11i1.4112
- Tian, J., Huang, Y., Wu, T., Huang, H., Ko, K., Zhu, B., & Chen, J. (2021). The use of Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations in ameliorating chronic kidney disease by enhancing mitochondrial function. Frontiers in Pharmacology, 12. doi.org/10.3389/fphar.2021.622498
- Zhou, X., Seto, S. W., Chang, D., Kiat, H., Razmovski-Naumovski, V., Chan, K., & Bensoussan, A. (2016). Synergistic effects of Chinese herbal medicine: A comprehensive review of methodology and current research. Frontiers in Pharmacology, 7, 201. doi.org/10.3389/fphar.2016.00201
Why a formula, not a single herb
The parts do not work the same way alone
Herbal formulas are built on a principle called Jun-Chen-Zuo-Shi: one herb leads, called the chief. Others extend or support its effect. One offsets side effects. One directs the formula to its target and holds the group together. Rehmannia root is the chief here. Every other herb, including the two warming ones added for Eight, is built around it.
This is not just tradition talking. A 2014 study mapped how the hundreds of chemical constituents in Liu Wei Di Huang Wan, the formula behind Rehmannia Six, interact with their biological targets. The formula’s effect could not be explained by looking at any single herb’s ingredients on their own. The synergy showed up specifically in how the herbs worked together to support the endocrine, immune, and metabolic systems.
This kind of research is still young. A 2016 review of the evidence for herbal synergy found real support for it in some formulas, but also found that proving synergy in something this complex is genuinely hard to do well, and called for more rigorous studies before drawing firm conclusions. The theory is old. The proof is still catching up. Both studies are linked in the references above.
Sourcing
This is where it lives or dies
Sourcing matters more here than almost anywhere. Rehmannia Eight works because of its structure, the six herbs held in their tonifying and draining balance, with the two warming herbs layered on top. A formula that does not follow that structure misses the mark completely, whatever the label claims it does.
Using these for dogs
Dose, source, and safety
Veterinary practitioners adapt these formulas for dogs by adjusting the human dose to body weight and the individual animal. Always work with a veterinarian skilled in TCM herbs before starting a protocol. They can diagnose the pattern correctly, choose the right formula, and monitor and adjust as you go.
The version counts for as much as the formula name. Ba Wei Di Huang Wan comes in about seven variations, and the Kan Herb Company version is noted for strong Yang-warming.
These formulas are normally something a practitioner hands you, not something you pick off a shelf yourself. If you go looking anyway, be as careful about the supplier as your practitioner would be. Kan Herb Company is the one supplier I know of that has made this directly accessible to dog parents, and they carry both Rehmannia Six and Rehmannia Eight formulated for dogs.
Note: Some links in this article are affiliate links (Amazon Associates or other programs I participate in). At no charge to you, as an affiliate, I earn from qualifying purchases.
Kan Herb Company’s Amazon storefront carries the full pet line, including this Rehmannia Eight combination for dogs and cats.
How humans use these too
People reach for these formulas in perimenopause and menopause, in the elderly years, for Kidney Yin or Yang deficiency, and for metabolic support. The same logic that guides the warm or cold dog guides the person.
Getting help
You do not have to work this out alone
A page can explain the formula. It cannot examine your dog. Here is where to find the people who can.
The other half of the plan
Herbs support the kidney. Food does the daily work.
Your vet should give you real food choices as part of the treatment: a therapeutic kidney diet, a fresh option, or a combination of both. Herbs do not replace that conversation.
If your vet clears fresh food and you want to feed it yourself, a base mix is the easiest place to start. Dr. Harvey’s is a good one to look at first.
A kidney dog rarely has just one problem, though. Hyperkalemia, hypokalemia, diabetes, and pancreatitis often stack on top of the kidney picture, and that is where a base mix runs out of room. A recipe built for your dog specifically, with all of it in view at once, takes over from there.
A final note
Age with grace.
Aging is inevitable, and the body will show some wear. Through all of it, the goal is to age with grace. My preference will always be whole foods to fuel the body, and herbs to support how well it functions. No two sunsets paint the sky the same way, and no two dogs heal the same way. Some flourish with simple changes, others need gentler nurturing, always honoring their own age and rhythm.
If you feel called to explore these herbs for your dog, the safest first step is a trained TCM herbalist. When you are ready, we can build a dietary plan together.
Hannah Zulueta obtained her Certificate in Canine Nutrition from CASI Institute. She is also studying for her Doctorate in Acupuncture, Traditional Chinese Medicine, and Herbalism from the esteemed Pacific College of Health and Medicine. If you’re as keenly interested in health for yourself, visit her website for human health: Satori Acupuncture and Herbs.
She resides in San Diego with her three dogs, Maggie, Orbit, and Mr. Higgins.
She is available for one on one consultations. She develops evidence-based recipes that meet both NRC and AAFCO nutritional standards while integrating the therapeutic food principles of Traditional Chinese Veterinary Medicine into her formulations.
Additionally, you can find her sharing free content on Instagram.
