Flatstem Milkvetch Seed

Chinese
沙苑子
Pinyin
Sha Yuan Zi
Latin
Semen Astragali Complanati

TCM Properties

Taste
sweet
Temperature
warm
Channels
Kidney, Liver

Traditional Use

Primary Actions

  • Tonifies Kidney yang and secures essence - Sha Yuan Zi is a classic deficiency herb for spermatorrhea, urinary frequency, weakness of the lower back, and reproductive leakage patterns.
  • Nourishes the Liver and improves vision - traditional use extends to dim vision or blurred sight when Liver-Kidney deficiency rather than acute excess is the root.
  • Stabilizes the lower burner gently - compared with harsher astringents, it secures without being excessively drying or mineral-heavy.

Secondary Actions

  • Sha Yuan Zi is especially useful when leakage and weakness coexist, because it both supplements and secures rather than simply astringing.
  • Its warm, sweet, seed-based nature makes it relatively gentle, so it often appears in long-term deficiency formulas.

Classic Formulas

  • Traditional Kidney-deficiency formulas pair Sha Yuan Zi with Tu Si Zi, Fu Pen Zi, or Qian Shi for essence leakage and urinary frequency.
  • Vision-support combinations use Sha Yuan Zi with Gou Qi Zi and Ju Hua when deficiency affects the eyes.
  • Reproductive-tonic strategies often combine it with Du Zhong, Ba Ji Tian, or Gou Ji when low-back weakness and sexual debility are prominent.

Classical References

  • Traditional herbology classifies Sha Yuan Zi as sweet and warm, entering the Kidney and Liver to supplement deficiency, secure essence, and brighten the eyes.
  • It is one of the gentler seed tonics used for leakage patterns, especially when stronger hot yang tonics would be too forceful.
  • Because it both tonifies and secures, it fits chronic deficiency formulas better than short-term symptomatic strategies.

Modern Research

Active Compounds

  • Flavonoid glycosides such as complanatosides - the best-known marker compounds in commercial Sha Yuan Zi quality work
  • Saponins and triterpenoid-related constituents - supportive components in broader pharmacologic study
  • Phenolic compounds - relevant to antioxidant and metabolic interest
  • Seed lipids and minor nitrogenous constituents - part of the seed's tonic profile

Studied Effects

  • A 2020 paper profiled bioactive flavonoid glycosides in commercial Astragali Complanati Semen, improving the chemical basis for modern Sha Yuan Zi standardization (PMID 33081333).
  • Metabolomics-based research reported a hypocholesterolemic effect from Astragali Complanati Semen, suggesting broader cardiometabolic relevance beyond its classical reproductive use (PMID 28753987).
  • Semen Astragali Complanati enhanced bone formation in osteoporotic rats, which provides a modern experimental bridge to the herb's traditional role in weakness and deficiency of the low back and bones (PMID 23782721).
  • A total flavonoid fraction from Astragalus complanatus showed antihypertensive activity in rats, though this remains preclinical evidence rather than direct clinical confirmation (PMID 16201455).

PubMed References

Safety & Interactions

Contraindications

  • Damp-heat or excess conditions causing urinary symptoms rather than deficiency leakage
  • Fire from yin deficiency without true Kidney-yang weakness

Cautions

  • Sha Yuan Zi is generally mild, but it is not the right choice for acute infection or inflammatory urinary complaints driven by damp-heat.
  • Concentrated extracts studied in modern research are not necessarily equivalent to classical seed decoctions.
  • MSK page not found - drug interaction data not available from Memorial Sloan Kettering integrative medicine database

Drug Interactions

  • Antihypertensive medications - theoretical additive effect based on preclinical flavonoid research

Conditions