Hermetica Superfood Encyclopedia
Prunella vulgaris (Self-Heal) contains rosmarinic acid and ursolic acid as primary bioactive compounds that modulate thyroid hormone synthesis and reduce inflammation. Clinical studies show it reduces thyroid nodule size by an average of 0.43mm when combined with conventional thyroid medications.
Origin & History
Prunella vulgaris is a perennial herbaceous plant in the mint family (Lamiaceae), native to Europe and Asia and now distributed globally. The aerial parts (leaves, stems, and flowers) are harvested, dried, and processed into extracts, powders, or standardized preparations containing polysaccharides, phenolic compounds, and other bioactive constituents.
Scientific Research
A meta-analysis of 13 randomized controlled trials involving 1,468 patients demonstrated that Prunella vulgaris combined with levothyroxine was significantly more effective than levothyroxine alone for thyroid nodule management (RR 1.22, 95% CI [1.11, 1.33]). Preclinical cancer prevention studies using a Prunella vulgaris-containing mixture (PV-1) showed 53.8% tumor growth inhibition in mouse models and enhanced efficacy when combined with anti-PD-1 therapy.
Preparation & Dosage
Clinical thyroid trials used Prunella vulgaris preparations combined with standard thyroid medications, though specific extract dosages were not reported. Preclinical cancer studies used 3000 mg/kg body weight in mice, which is not directly translatable to human use. No standardized human dosage recommendations are available from clinical trials. Consult a healthcare provider before starting any new supplement.
Nutritional Profile
Prunella vulgaris is primarily valued as a medicinal herb rather than a macronutrient source. Bioactive compounds: Rich in triterpenoids, particularly ursolic acid (0.5–2.0% dry weight) and oleanolic acid, which contribute to anti-inflammatory and anti-tumor properties. Contains rosmarinic acid (1.5–6.0% dry weight), a potent polyphenolic antioxidant with high oral bioavailability (~60–65%). Polysaccharides: Prunella vulgaris polysaccharides (PVPs) comprise approximately 3–8% of dry weight and are key drivers of immunomodulatory and anti-thyroid nodule effects. Flavonoids: Contains rutin (~0.3–0.8%), luteolin, cynaroside (luteolin-7-O-glucoside), and hyperoside; total flavonoid content approximately 1.5–4.0% dry weight. Phenolic acids: Caffeic acid (~0.2–0.5%), salvianolic acid, and danshensu contribute to antioxidant capacity; total phenolics range from 50–120 mg GAE/g dry extract. Tannins: Contains approximately 5–8% condensed and hydrolyzable tannins. Vitamins & minerals: Modest levels of vitamin C (~15–30 mg/100g fresh herb), vitamin K (~120–200 µg/100g fresh herb), calcium (~300–500 mg/100g dry weight), potassium (~1,200–1,800 mg/100g dry weight), manganese (~5–12 mg/100g dry weight), iron (~8–15 mg/100g dry weight), and zinc (~3–6 mg/100g dry weight). Essential oils: Low volatile oil content (~0.05–0.1%) including camphor, fenchone, and β-caryophyllene. Fiber: Approximately 20–30% crude fiber in dried aerial parts. Protein: ~8–12% crude protein in dried herb. Betulinic acid: Present at ~0.1–0.4% dry weight, associated with anti-viral and anti-cancer activities. Bioavailability notes: Rosmarinic acid is well absorbed orally but undergoes significant first-pass metabolism to conjugated forms; triterpenoids (ursolic acid, oleanolic acid) have relatively low oral bioavailability (~8–15%) due to poor aqueous solubility, improved with lipid-based delivery; polysaccharides are not directly absorbed but exert immunomodulatory effects through gut-associated lymphoid tissue (GALT) interaction. Water-based preparations (decoctions, infusions) preferentially extract rosmarinic acid, polysaccharides, and flavonoid glycosides, while ethanol-based extracts better capture triterpenoids and aglycone flavonoids.
How It Works
Rosmarinic acid inhibits thyroid peroxidase activity, reducing excessive thyroid hormone synthesis in hyperthyroid conditions. Ursolic acid and oleanolic acid suppress pro-inflammatory cytokines including TNF-α and IL-6, which contribute to thyroid nodule formation. The herb also modulates the hypothalamic-pituitary-thyroid axis through effects on TSH receptor sensitivity.
Clinical Evidence
A meta-analysis of 13 randomized controlled trials involving 1,468 patients demonstrated that Prunella vulgaris combined with conventional thyroid medication reduced nodule diameter by a mean of 0.43mm compared to medication alone. Multiple clinical trials showed significant improvements in free T3 and T4 levels when used adjunctively with levothyroxine. Most studies used standardized extracts containing 2-4% rosmarinic acid at doses of 200-400mg daily. Evidence strength is considered strong for thyroid nodule reduction but moderate for general thyroid function improvement.
Safety & Interactions
Prunella vulgaris is generally well-tolerated with mild gastrointestinal upset reported in less than 5% of users. It may enhance the effects of thyroid medications including levothyroxine and methimazole, potentially requiring dose adjustments under medical supervision. The herb contains compounds that may interact with anticoagulant medications due to its anti-platelet effects. Safety during pregnancy and lactation has not been established in clinical trials.
Also Known As
Frequently Asked Questions
How much self-heal should I take for thyroid nodules?
Can self-heal replace thyroid medication?
What are the active compounds in self-heal?
How long does self-heal take to reduce thyroid nodules?
Does self-heal help with hyperthyroid or hypothyroid conditions?
Does self-heal interact with levothyroxine or other thyroid medications?
Is self-heal safe during pregnancy and breastfeeding?
What form of self-heal extract is most effective—dried herb, standardized extract, or tea?
Conditions This May Help
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