Do black cohosh, rehmannia, dong quai, wild yam, sage, chaste tree (vitex), ginkgo biloba, and licorice have sedative or stimulant effects, or are they essentially neutral on central nervous system activity?

CNS Effects of Herbal Supplements: Sedation vs. Stimulation Profile

Most of these supplements are relatively CNS-neutral in typical doses, with the notable exceptions of sage (which may have mild stimulant properties) and potentially licorice (which can cause CNS effects through mineralocorticoid activity), while black cohosh, dong quai, wild yam, chaste tree, and rehmannia lack significant direct sedative or stimulant effects based on available evidence.

Individual Supplement Analysis

Black Cohosh (Actaea racemosa)

• Black cohosh shows no estrogenic activity in standard in vitro assays and is considered CNS-neutral 1
• Research suggests its mechanism may involve antinociceptive (pain-relieving) rather than hormonal or sedative pathways 2
• Clinical trials and safety reviews do not report sedation or stimulation as adverse effects 3, 4
• ASCO guidelines list black cohosh under vasomotor outcomes with insufficient evidence, not under sedation, anxiety, or fatigue categories, indicating no recognized CNS depressant or stimulant profile 5

Rehmannia (Rehmanniae)

• No evidence in the provided literature addresses CNS effects of rehmannia
• Not mentioned in perioperative sedation guidelines or herb interaction reviews 5, 6
• Should be considered CNS-neutral based on absence from sedation/stimulation literature

Dong Quai (Angelica sinensis)

• Dong quai showed only weak estrogenic receptor binding and no significant CNS activity in cellular assays 1
• Systematic reviews found inconclusive evidence for menopausal symptoms, with no reports of sedation or stimulation 7
• Considered CNS-neutral in clinical practice

Wild Yam

• No evidence in the provided literature addresses CNS effects of wild yam
• Not mentioned in perioperative guidelines or herb interaction databases 5, 6
• Should be considered CNS-neutral based on absence from sedation/stimulation literature

Sage (Salvia officinalis)

• Not specifically addressed in the provided evidence
• Based on general medical knowledge, sage may have mild stimulant properties through cholinergic mechanisms, but this is not clinically significant at typical supplemental doses

Chaste Tree/Vitex (Vitex agnus-castus)

• Chasteberry showed estrogenic activity in breast and endometrial cells but no sedative or stimulant properties were reported 1
• Not listed under anxiety, sedation, or fatigue categories in ASCO integrative therapy guidelines 5
• Considered CNS-neutral

Ginkgo Biloba

• ASCO guidelines list ginkgo under cognition outcomes (with insufficient evidence) and lymphedema, not under sedation, anxiety, or stimulation categories 5
• Perioperative guidelines note ginkgo's antiplatelet effects but do not mention sedative properties 6
• Ginkgo may have mild effects on cerebral blood flow but does not produce clinically significant sedation or stimulation 5
• Considered CNS-neutral regarding sedation/stimulation, though it has antiplatelet effects requiring discontinuation before surgery 6

Licorice (Glycyrrhiza glabra)

• Licorice showed only weak estrogenic receptor binding in cellular assays 1
• The primary concern with licorice is mineralocorticoid activity causing hypertension, hypokalemia, and fluid retention rather than direct CNS effects (general medical knowledge)
• Not listed under sedation or stimulation categories in integrative therapy guidelines 5
• Considered relatively CNS-neutral, though mineralocorticoid effects can indirectly affect mental status through electrolyte disturbances

Clinical Algorithm for Assessment

Step 1: Identify Patient-Specific Concerns

• If the patient is concerned about daytime sedation or needs alertness (driving, operating machinery): None of these supplements pose significant sedation risk at typical doses
• If the patient is concerned about sleep disruption or stimulation: Sage is the only supplement with potential mild stimulant properties, though this is rarely clinically significant

Step 2: Consider Drug Interactions

• Ginkgo has antiplatelet effects and should be discontinued 2 weeks before surgery 6
• None of these supplements have the potent CNS depressant interactions seen with kava, valerian, or ashwagandha 8, 6
• None have the CYP3A4 induction concerns of St. John's wort 9, 6

Step 3: Monitor for Indirect CNS Effects

• Licorice can cause hypertension and hypokalemia, which may indirectly affect mental status (general medical knowledge)
• Black cohosh may provide pain relief through antinociceptive mechanisms, which could be perceived as mild sedation but is actually analgesia 2

Important Caveats

• Herbal supplements lack FDA standardization, meaning CNS effects may vary unpredictably between products and batches 9, 8
• The absence of evidence for sedation/stimulation in clinical trials does not guarantee zero effect in all individuals, particularly at high doses or with specific genetic polymorphisms
• Patients should disclose all supplement use to healthcare providers, especially before starting CNS-active medications or undergoing procedures 9
• The ASCO guidelines' classification of these herbs under "insufficient evidence" categories rather than sedation/anxiety/fatigue categories strongly suggests they lack clinically meaningful CNS depressant or stimulant effects 5