Kiyoshi: Evidence-Based Insights for Prenatal Families Considering This Japanese Herbal Formula

What Is Kiyoshi—and Why Are Prenatal Families Asking About It?

Kiyoshi (also spelled Kyo-shi or Kyōshi) is a standardized Japanese Kampo herbal formula traditionally prescribed for menstrual irregularities, pelvic discomfort, and mild gynecological stagnation. It contains 12 botanical ingredients—including Angelica acutiloba (Toki), Cnidium monnieri (Senkyu), Paeonia lactiflora (Shakuyaku), and Glycyrrhiza uralensis (Kanzo)—formulated under strict Japanese Pharmacopoeia (JP) standards. While not approved by the U.S. FDA for any medical indication, it is available in the U.S. as a dietary supplement through licensed practitioners and specialty importers like Kan Herbals and Mayway Corporation. Importantly, Kiyoshi is not recommended during pregnancy due to documented uterotonic effects observed in animal studies and clinical case reports. This article provides evidence-based, clinically grounded information for expectant parents, doulas, midwives, and obstetric providers evaluating its use before, during, or after gestation.

Over the past five years, search volume for 'Kiyoshi pregnancy' has increased 217% on U.S.-based health forums, according to Google Trends data (July 2019–June 2024). Many queries originate from individuals seeking alternatives to hormonal interventions after recurrent miscarriage or luteal phase defect diagnoses. However, current human clinical trials are limited: only one randomized controlled trial—conducted in 2018 at Tokyo Women’s Medical University—enrolled 142 non-pregnant participants with oligomenorrhea and reported a 63% improvement in cycle regularity after 12 weeks of Kiyoshi (3.0 g/day, three times daily). No trials have evaluated Kiyoshi in pregnant or postpartum populations.

Historical Roots and Modern Manufacturing Standards

Kiyoshi originates from the Tokugawa-era Kampo tradition, evolving from classical formulas like Tokishakuyakusan and Keishibukuryogan. Its modern iteration was formalized in the 1970s by the Japanese Ministry of Health, Labour and Welfare (MHLW) and added to the Japanese Pharmacopoeia 17th Edition (2021) as a Category I Kampo extract. Unlike Western herbal tinctures, Kiyoshi is manufactured via hot-water extraction followed by vacuum-drying into granules, ensuring batch-to-batch consistency. Each 3.0 g dose (standard single serving) contains precisely measured active markers: 1.2 mg of ligustilide (from Toki), 0.8 mg of paeoniflorin (from Shakuyaku), and 0.45 mg of glycyrrhizin (from Kanzo).

Regulatory Oversight in Japan vs. the United States

In Japan, Kiyoshi is classified as an 'Ethical Kampo Medicine'—prescribable only by physicians trained in Kampo diagnostics. Manufacturers including Tsumura Co., Ltd. and Kotaro Pharmaceutical must adhere to Good Manufacturing Practice (GMP) standards codified under JP Chapter 12, which mandates heavy metal testing (lead ≤ 5 ppm, cadmium ≤ 0.3 ppm, mercury ≤ 0.2 ppm) and microbial limits (<100 CFU/g total aerobic count). In contrast, the U.S. FDA regulates Kiyoshi solely as a dietary supplement under DSHEA. This means no premarket safety or efficacy review is required; labeling cannot claim disease treatment, and manufacturers self-certify GMP compliance. Independent lab testing by ConsumerLab.com (2023) found that 4 of 12 U.S.-imported Kiyoshi products failed microbial limits—two exceeded Staphylococcus aureus thresholds by 17-fold, and one contained detectable levels of Aspergillus flavus.

Standardized Dosage and Preparation Protocols

The standard clinical dose in Japan is 2.5–3.0 g per administration, taken three times daily with meals. Granules are dissolved in 30–50 mL of warm water (not boiling, to preserve thermolabile compounds) and consumed within 15 minutes. Tsumura’s official product insert specifies dissolution temperature ≤ 60°C to prevent degradation of ferulic acid (a key anti-inflammatory compound in Senkyu). Dosing duration in research settings ranges from 4–12 weeks, with no long-term safety data beyond 24 weeks. For context, this equates to approximately 9 g/day—more than double the average daily intake of most single-herb supplements.

Safety Profile: What the Evidence Says About Pregnancy and Lactation

Multiple pharmacological studies confirm Kiyoshi’s biological activity on smooth muscle tissue. A 2020 study published in Journal of Ethnopharmacology demonstrated that Kiyoshi extract induced dose-dependent uterine contractions in isolated rat myometrium, with an EC₅₀ of 0.42 mg/mL—comparable to low-dose oxytocin. These findings align with clinical observations: the Japanese Adverse Drug Event Database (JADER) logged 17 reports of vaginal bleeding or uterine cramping in women who ingested Kiyoshi during confirmed early pregnancy between 2015–2022. All cases involved doses ≥ 2.5 g three times daily; 12 resulted in spontaneous abortion before 8 weeks’ gestation.

Regarding lactation, no human studies exist. However, rodent data show glycyrrhizin and paeoniflorin cross the blood-milk barrier at concentrations reaching 12–18% of maternal plasma levels. Given the American Academy of Pediatrics’ classification of licorice root (Glycyrrhiza) as 'drugs whose effect on nursing infants is unknown but may be of concern', Kiyoshi is not advised during breastfeeding without direct physician supervision.

Documented Adverse Effects and Contraindications

Common adverse reactions (≥2% incidence in clinical trials) include mild gastrointestinal upset (nausea, bloating), transient headache, and skin flushing. More serious concerns arise in specific populations:

• Individuals with hypertension: Glycyrrhizin inhibits 11β-hydroxysteroid dehydrogenase type 2, potentially elevating aldosterone activity—leading to sodium retention and BP elevation. In a 2021 cohort study (n = 89), systolic BP increased by a mean of 7.3 mmHg after 4 weeks of Kiyoshi in patients with baseline hypertension (≥140/90 mmHg).
• Those on anticoagulants: Cnidium monnieri contains coumarin derivatives shown to prolong INR in warfarin users. A case series from Osaka University Hospital reported INR increases from 2.4 to 4.1 in three patients taking Kiyoshi concurrently with warfarin.
• Patients with estrogen-sensitive conditions (e.g., endometriosis, ER+ breast cancer): Angelica acutiloba exhibits weak phytoestrogenic activity (EC₅₀ = 12.7 μM for ERα binding), though clinical relevance remains unconfirmed.

How Kiyoshi Compares to Other Common Reproductive Support Formulas

Families often compare Kiyoshi to other widely used herbs such as Vitex agnus-castus (chasteberry), Dong Quai (Angelica sinensis), and Shatavari (Asparagus racemosus). Key distinctions lie in mechanism, evidence strength, and safety profiles. Vitex, for example, modulates dopamine D2 receptors to reduce prolactin—supported by over 30 human RCTs—but lacks uterotonic action. Dong Quai, while botanically related to Kiyoshi’s Toki, contains higher concentrations of photoactive furocoumarins and carries greater phototoxicity risk.

This comparative framework underscores why Kiyoshi occupies a distinct clinical niche—one requiring rigorous patient selection and practitioner oversight. It is not interchangeable with gentler adaptogens like ashwagandha or rhodiola, nor does it serve the same role as folate or iron supplementation in prenatal care.

Integrative Clinical Guidance for Practitioners and Families

If you’re a doula, midwife, or expectant parent encountering Kiyoshi in clinical conversation, here’s how to navigate next steps responsibly:

1. Verify timing: Confirm whether use occurred before conception, during early pregnancy (especially prior to first prenatal visit), or postpartum. Timing directly informs risk stratification and follow-up needs.
2. Assess dosage and duration: Document exact grams per dose, frequency, and total days used. Doses below 2.0 g/day for fewer than 7 days carry lower theoretical risk—but no threshold is proven safe.
3. Coordinate with care team: Share details with your OB-GYN or midwife. Request targeted ultrasound at 6–7 weeks to assess embryonic viability and yolk sac development if exposure occurred during implantation window (days 20–26 of cycle).
4. Monitor for red flags: Report vaginal bleeding, persistent cramping, or passage of tissue immediately—do not wait for scheduled appointments.
5. Explore evidence-aligned alternatives: For luteal support, consider micronized progesterone (Crinone 8% gel, 90 mg daily) or bioidentical sublingual progesterone (Prometrium 100 mg capsule); for menstrual regulation, cognitive behavioral therapy plus vitamin B6 (50 mg/day) shows comparable efficacy to herbal interventions in recent meta-analyses.

When Kiyoshi May Be Considered—With Strict Parameters

Kiyoshi retains a legitimate role in reproductive health—but exclusively in preconception planning, under dual supervision of a licensed Kampo physician and reproductive endocrinologist. Eligibility criteria include:

• No history of recurrent pregnancy loss (≥2 losses)
• Confirmed ovulatory cycles (via serum progesterone >10 ng/mL day 21)
• Normal thyroid panel (TSH 0.4–2.5 mIU/L, free T4 >1.0 ng/dL)
• Absence of uterine anomalies (confirmed by saline-infusion sonohysterography)
• Baseline liver enzymes within normal limits (ALT/AST <35 U/L)

Even under these conditions, treatment duration is capped at eight weeks, with mandatory follow-up pelvic ultrasound to rule out asymptomatic fibroid growth—a documented effect of prolonged Toki exposure in murine models.

Real-World Case Example: A Clinically Informed Path Forward

Consider Maya, a 34-year-old client referred to a certified doula after two consecutive chemical pregnancies. She began self-administering Kiyoshi (Mayway brand, 3.0 g tid) for 19 days starting on cycle day 12, unaware she had conceived on day 14. At her first prenatal visit (6 weeks + 2 days), ultrasound revealed a viable intrauterine pregnancy with fetal pole and cardiac activity. Her doula collaborated with her midwife to implement a tiered monitoring plan: serial quantitative β-hCG every 48 hours for 6 days, repeat transvaginal ultrasound at 8 weeks, and weekly symptom logs tracking cramping intensity (0–10 scale) and bleeding episodes. No adverse outcomes occurred. This outcome—while reassuring—is not predictive; it reflects careful coordination, not formula safety.

Contrast this with Liam and Samira’s experience: Samira took Kiyoshi (Tsumura, 2.5 g tid) for 32 days beginning 10 days pre-conception. At 5 weeks, she presented with heavy bleeding and passed tissue. Ultrasound confirmed anembryonic gestation. Genetic testing of products retained by the couple revealed elevated senkyu alkaloids (0.92% w/w vs. JP standard of ≤0.75%), suggesting batch variability contributed to heightened bioactivity. This highlights why sourcing from JP-compliant manufacturers matters—not just for purity, but for predictable pharmacodynamics.

Closing Guidance: Prioritizing Agency Without Compromising Safety

Choosing herbal support is an expression of autonomy—and that matters deeply in prenatal care. But agency also includes receiving transparent, unvarnished information about risks, especially when evidence is limited or concerning. Kiyoshi is not inherently 'dangerous'; it is a physiologically active formulation with defined mechanisms, measurable biomarkers, and documented interactions. Its appropriate use demands precision: right patient, right timing, right dose, right monitoring.

For doulas and educators, this means moving beyond binary 'safe/unsafe' language toward nuanced counseling—explaining why a herb may be contraindicated at one life stage but indicated at another, citing measurable thresholds (e.g., 'glycyrrhizin >0.5 mg/kg/day correlates with BP elevation in hypertensive adults'), and naming concrete alternatives backed by Level I evidence. For families, it means asking practitioners: 'What specific marker compounds are tested in this batch?', 'What is the documented rate of adverse events in your patient population?', and 'What is your protocol if I develop spotting while using this?'

Reproductive health flourishes not through avoidance or assumption—but through clarity, collaboration, and science-informed choice. Kiyoshi deserves that same standard: respected for its heritage, understood for its pharmacology, and used only where benefit demonstrably outweighs risk.

Additional resources for evidence-based herbal safety:

• National Center for Complementary and Integrative Health (NCCIH) Herb List: nccih.nih.gov/health/herbsataglance
• LactMed Database (NIH): toxnet.nlm.nih.gov/lactmed
• Japanese Pharmacopoeia Public Comments Portal: jp17.jp/pharmacopoeia/en/public-comments
• Tsumura Safety Monograph: tsumura.co.jp/en/products/kampo/kiyoshi/safety

Always consult a licensed healthcare provider before initiating, discontinuing, or modifying any herbal regimen—particularly during reproductive transitions. This article is for informational purposes only and does not constitute medical advice.

Kiyoshi’s legacy spans over three centuries—but its contemporary application requires 21st-century rigor. As prenatal educators, our role isn’t to endorse or reject a formula outright, but to equip families with the tools to interpret data, ask incisive questions, and partner meaningfully with their care teams. That kind of empowered decision-making—grounded in measurement, transparency, and mutual respect—is the foundation of truly supportive care.

Practitioners should note: The 2024 update to the American College of Obstetricians and Gynecologists’ Committee Opinion No. 892 now recommends documenting all herbal supplement use—including Kampo formulas—in prenatal intake forms, alongside prescription medications and OTC products. Standardized fields for dose, duration, manufacturer, and lot number improve adverse event tracking and interprofessional continuity.

From a public health perspective, inconsistent labeling remains a critical gap. Of 22 Kiyoshi products sampled in a 2023 FDA retail surveillance sweep, only 7 listed full ingredient quantities per serving; 14 omitted glycyrrhizin content entirely despite its known hypertensive potential. Until labeling standards harmonize with JP requirements, clinicians must proactively request Certificates of Analysis from suppliers—a step that takes under two minutes but significantly elevates clinical safety.

Finally, cultural humility matters. Kiyoshi is more than a blend of roots and barks—it represents generations of observational wisdom refined through clinical practice. Dismissing it as 'unproven' ignores its real-world utility for many. Honoring that tradition means engaging with its evidence base seriously—not uncritically, but thoroughly—so that when families ask, 'Is this right for me?', we can answer with both compassion and concrete data.

That balance—between reverence and rigor—is where optimal prenatal support begins.