Rehmannia glutinosa — The Yin-Nourishing Adaptogen
Rehmannia glutinosa is a foundational herb in Traditional Chinese Medicine, traditionally used to nourish Yin and support kidney function. In the context of longevity, its active compounds, such as catalpol, demonstrate antioxidant properties and the ability to reduce cellular senescence in preclinical models.
Mechanism of Action
Rehmannia glutinosa contains bioactive iridoid glycosides, notably catalpol, which exert neuroprotective and anti-inflammatory effects. In preclinical models, it has been shown to maintain the quiescence and decrease the senescence of hematopoietic stem cells (HSCs). Catalpol modulates endogenous metabolic pathways, reduces reactive oxygen species (ROS) levels, and enhances antioxidant enzyme activity. It also appears to influence gut microbiota and strengthen the intestinal barrier, though its specific longevity pathways in humans remain poorly characterised.
Human Trial Evidence
No published human longevity trials. Animal/in-vitro evidence only. Clinical trials in humans have primarily focused on acne and skin hydration using leaf extracts, rather than systemic aging or longevity endpoints.
Dosing Protocol
Standardised extracts are typically dosed at 500–1,000 mg daily, while traditional preparations use 3–6 g of root powder or 10–50 g in decoctions. It is often cycled or combined with other adaptogens. No specific dose-finding studies for longevity have been established in humans.
Safety & Contraindications
Generally considered safe and well-tolerated in traditional doses for up to 8 weeks. It may cause mild gastrointestinal upset in some individuals. Due to potential hypoglycaemic effects, it should be used with caution in patients taking blood sugar-lowering medications. Avoid during pregnancy and lactation due to insufficient safety data.