Herb module

Tu Si Zi

Chinese Dodder SeedsCuscuta chinensis

Tiny seeds from a twining vine, used to strengthen Kidney Yang, nourish Yin and hold on to precious Jing.

Tu Si Zi is the small seed of Chinese dodder, a gentle and balanced tonic in Traditional Chinese Medicine. In Zoi's Kidney Meridian™ formula it supports both the warming Yang and the nourishing Yin of the Kidneys and Liver. It also helps the body hold on to its Jing, the deep essence we draw on throughout life.

Best functions

Strengthens Yang and nourishes Yin
Tonifies the Kidneys and Liver
Astringes Jing and urine and benefits the Marrow
Benefits the Spleen and steadies loose digestion

Fascinating facts

Dodder is a parasitic vine. It has almost no leaves or green color and twines thin yellow-orange threads around other plants, drawing its nourishment straight from its host.
Tu Si Zi is neutral in temperature. That balance lets it support both Yang and Yin, which is unusual for a tonic herb.
A traditional study note gives Tu Si Zi the nickname "the Yin-Yang Kidney balancer" because it can nourish both sides at once.
Animal studies have looked at Semen Cuscutae and found increases in bone density, bone mass and bone structure.

In Traditional Chinese Medicine

Tu Si Zi is a sweet, pungent herb that is neutral in nature. It belongs to the tonic herbs and enters the Kidney and Liver meridians.

Go deeperDownload the fact sheet on the Kidney Meridian page

Biomedical deep dive

Tu Si Zi Chinese Dodder Seeds

From the Zoi Medicinals fact sheets’ Biomedical Details, with lines from Noa’s herb notes marked “Noa’s notes”.

On the fact sheet

Tu Si Zi (Chinese Dodder Seeds, Semen Cuscutae) is neutral and enters the KI and LIV meridians; strengthens Yang, nourishes Yin, astringes Jing and urine and benefits the Marrow, tonifies the Kidney and Liver, benefits the Spleen, stops diarrhea, calms the fetus. Kidney Meridian sheet

Key active constituents

Cuscuta seed polysaccharides (complex plant sugars), named in a cited bone study (Kidney Meridian sheet references).

Pharmacology and mechanisms

The Kidney Meridian sheet says Semen Cuscutae increased bone density, improved bone microstructure and increased bone mass in an osteoporosis model.
Animal studies suggest positive effects on estrogen levels, ovulation and progesterone signaling.
In male animal studies it improved sperm concentration and motility, and oxidative balance in the testicles.
Flavonoids promote osteoblast differentiation (formation of bone-building cells); bone-protective. Noa’s notes
Improved sperm motility and testosterone levels in animal models. Noa’s notes
Anti-aging: activates autophagy (cell cleanup) pathways and extended lifespan in C. elegans worm models. · Noa’s notes

What the research says

In ovariectomized mice (a menopause bone-loss model), Cuscuta seed limited bone breakdown by osteoclasts, the cells that resorb bone (Yang et al., J Ethnopharmacol 2022).
Cuscuta seed polysaccharide was associated with less bone loss in ovariectomized rats (Liu et al., Biomed Pharmacother 2020).

Safety, interactions and cautions

Every Zoi fact sheet: do not use if pregnant or breastfeeding unless directed by your health care practitioner.

In these Zoi formulas

Kidney Meridian (#8 on the fact sheet)

These statements have not been evaluated by the FDA. This product is not meant to diagnose, treat, cure or prevent any disease.