Suo Yang (Fleshy Stem of Cynomorium)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Suo Yang?

  Roughly 6–15 g in decoction is the standard materia medica range, with some references citing a slightly wider 4.5–15 g. As a root/stem tonic herb it is prepared as part of a standard water decoction alongside other herbs in the formula.

  Source: Bensky, Materia Medica (3rd ed.); cross-checked against other reputable TCM references. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Suo Yang?

  Suo Yang is contraindicated in Kidney-yin deficiency with heat (deficient-heat/effulgent-fire) signs, in diarrhea caused by Spleen deficiency, and in constipation caused by excess heat. Because it is warming, using it for heat-type dryness rather than yang/blood/essence-deficiency dryness risks aggravating the underlying heat.

  Source: Bensky, Materia Medica (3rd ed.) consensus, cross-checked against other reputable TCM references. Traditional-use framing; not medical advice.

Chinese Herb Toxicity & Overdose

• Low, based on formal animal toxicity testing. A dedicated toxicity assessment of Suo Yang found no abnormal behavior or mortality in an acute-toxicity mouse study up to 18 g/kg (roughly 432× the human clinical-equivalent dose), negative results across three genetic-toxicity assays (bacterial reverse mutation, micronucleus, and chromosomal aberration), and no significant differences in body weight, hematology, blood chemistry, or organ weights in a 90-day repeated-oral-dose rat study at up to 4.16 g/kg (about 25–100× clinical dose). The authors concluded Suo Yang can reasonably be considered a safe herbal medicine at the doses tested. This is animal/preclinical evidence, not a human safety guarantee.

  Source: PMID 30949225, PMC 6425418, DOI 10.1155/2019/9819643 (acute, genetic, and 90-day repeated-oral toxicity study). Reference note, not a safety guarantee.

Herb-Drug Interactions

• No well-established clinical herb–drug interactions are documented for Suo Yang. Preclinical research below shows it can modulate testosterone-synthesis pathways and inhibit phosphodiesterase-5 (PDE5) — the same enzyme family targeted by prescription erectile-dysfunction medications — so practitioner awareness is reasonable for patients on hormone therapy or PDE5-inhibitor medication. This is a precautionary, mechanism-based note from animal research, not a demonstrated clinical interaction. (Flagged for practitioner confirmation.)

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Suo Yang (Cynomorium songaricum)?

  Yes — preclinical (animal and in vitro) research on toxicity, reproductive/hormonal effects, and erectile function, but no human clinical trials identified. The findings are consistent with, and offer mechanistic context for, Suo Yang’s traditional Kidney-yang and essence-tonifying use.

  • Safety/toxicology (animal) — a combined acute-, genetic-, and 90-day repeated-oral-toxicity study in mice and rats found no significant adverse effects at doses well above clinical-equivalent levels, concluding Suo Yang can reasonably be considered a safe herbal medicine at the doses tested.
  • Reproductive function / testosterone pathway (animal + cell culture) — a flavonoid-enriched extract of Cynomorium songaricum reduced cyclophosphamide-induced reproductive damage in mice, improved sperm count and testicular/epididymal pathology, and raised serum testosterone by upregulating steroidogenic enzyme genes (StAR, CYP11A1, CYP17A1, 3β-HSD) along the hypothalamic-pituitary-gonadal axis, in both mouse and cell-culture models.
  • Erectile function / PDE5 inhibition (animal + in vitro) — polysaccharides isolated from Cynomorium songaricum inhibited phosphodiesterase-5 (PDE5) in vitro, elevated cGMP, and increased intracavernosal pressure in an orchiectomized-rat model of erectile dysfunction, proposed as a mechanistic basis for the herb’s traditional use in impotence.

  All three lines of evidence are preclinical (animal/in vitro); no human clinical trials of Suo Yang were identified in this review.

  Sources: PMID 30949225, PMC 6425418, DOI 10.1155/2019/9819643 (toxicity study); PMID 39239657, PMC 11374658, DOI 10.3389/fphar.2024.1457780 (reproductive/testosterone-pathway study); PMID 41554452, DOI 10.1016/j.jep.2026.121228 (PDE5-inhibition/erectile-function study). Research context, not a therapeutic claim.

Chinese Herb Notes

• How is Suo Yang different from Rou Cong Rong?

  Both tonify the Kidneys, fortify yang, augment the essence, and moisten the intestines — and both treat impotence, infertility, a weak lower back, and constipation. The distinction is one of emphasis: Rou Cong Rong is the more moistening of the two and is the stronger choice when constipation is prominent, while Suo Yang is more potent at fortifying the yang and, entering the Liver channel as well, carries an added role in strengthening the sinews and bones (atrophy/wéi disorders) that Rou Cong Rong does not emphasize.

  Common combination (confirmed against Sacred Lotus formula membership): Suo Yang appears in Hu Qian Wan (Hidden Tiger Pill), a formula that nourishes yin and clears deficiency heat while using Suo Yang’s sinew-and-bone–strengthening action to address the atrophy/weakness component of the pattern — a yang-within-yin role.

  Source: Bensky comparison of Suo Yang & Rou Cong Rong (materia medica consensus, mirrored in the Rou Cong Rong entry on this site); combination confirmed against Sacred Lotus formula membership.