Ashwagandha

Authors:

Mateusz Sprengel, Radosław Laskowski, Zbigniew Jost

Findings:

This review summarizes evidence suggesting Ashwagandha supplementation aids sleep (especially in insomniacs), reduces stress (lowering cortisol and perceived stress), enhances sports performance (improving strength, power, VO2max, recovery), increases testosterone, improves male fertility, reduces anxiety, and benefits cognitive functions (memory, attention, executive function). Potential mechanisms involve GABAergic activity, HPA axis modulation, antioxidant/anti-inflammatory effects, and hormonal changes. While generally safe with mild, transient side effects reported (similar to placebo), rare cases of reversible liver injury have occurred, necessitating further safety research, especially for high doses and long durations.

Participants:

The review covers studies involving various populations: healthy adults, stressed adults, adults with insomnia, adults with Generalized Anxiety Disorder, adults with fertility issues, young adults (17-45 years, mixed sexes, various fitness levels), elderly individuals, aged overweight males, college students, athletes (hockey players, elite cyclists), children. Specific participant numbers mentioned include N=400 (sleep meta-analysis), N=142 (VO2max meta-analysis), N=615 (sports performance review). Animal (rodent) and cell (glioblastoma, neuroblastoma, muscle) models were also discussed for mechanistic insights.

Dosage:

Dosages varied by study: Sleep (≥600mg/d more effective than <600mg/d, ≥8 weeks better than <8 weeks); Stress (250-500mg daily for 4-13 weeks); VO2max (330-1000mg/d for 2-12 weeks); Sports performance review (120-1250mg daily for 2-12 weeks); Anxiety (125-1000mg/d); Acute cognition (single 400mg dose); Safety studies (300-600mg daily for 8-12 weeks); Liver injury cases (associated with 450-1350mg daily).

Study Quality Assessment:

This document is a narrative review citing systematic reviews, meta-analyses, and randomized controlled trials (RCTs), many of which were double-blind and placebo-controlled. Methodologies mentioned include specific scales (Sleep Quality Scale, Perceived Stress Scale, Hamilton Anxiety Scale, etc.), physiological measures (cortisol, VO2max, strength tests), and biochemical markers. Acknowledged limitations include the paucity of data in certain areas (mechanisms, physical performance, especially in trained athletes), small numbers of studies and heterogeneity in some meta-analyses, potential high risk of bias in early anxiety studies, limited human data on metabolic health and cognition in aging, need for higher quality sleep measurement methods (polysomnography vs. actigraphy), and insufficient data on long-term/high-dose safety. The funding source is mentioned (National Ministry of Science Grant).

All Effects:

Authors:

Alex B Speers

Findings:

Withania somnifera (WS) root and leaf extracts demonstrated noteworthy anti-stress and anti-anxiety activity in both animal and human studies reviewed. WS also showed potential benefits for improving symptoms of depression and insomnia, although fewer studies investigated these applications. Proposed mechanisms involve modulation of the HPA and SAM axes, as well as GABAergic and serotonergic pathways.

Participants:

Human trials involved adults aged 18-85 years (N ranged from 39 to 150), including healthy individuals, those experiencing stress, anxiety (including GAD), insomnia, non-restorative sleep, overweight/obesity with chronic stress, or schizophrenia/schizoaffective disorder. Animal studies involved rats, mice, and horses.

Dosage:

Human trials used daily doses ranging from 120 mg to 1000 mg of various extracts (KSM-66, Sensoril, Shoden, ethanolic extracts) administered once or twice daily, and up to 12 g daily of dried root granules. Animal studies used various doses, often specified in mg/kg body weight (e.g., 10-500 mg/kg p.o. or i.p.) or g/day (horses). Specific standardizations mentioned include >5% withanolides, 5% withanolides, ≥8% withanolide glycosides, 11.90% withanolide glycosides, 35% withanolide glycosides.

Study Quality Assessment:

Review of preclinical (animal) and clinical (human) studies. Human trials described included randomized, double-blind, placebo-controlled designs. Methods mentioned include various behavioral questionnaires (e.g., PSS, HAM-A, DASS, PSQI, GHQ-28, PANSS, RSQ-W, sleep quality ratings), objective sleep actigraphy, and biological markers (e.g., serum cortisol, hsCRP, DHEA-S, testosterone, IL-6, S100B). Sample sizes in human trials ranged from N=39 to N=150. Limitations acknowledged include significant variability in WS extracts tested, lack of consensus on optimum preparation/dosage, need for further elucidation of active compounds, and need for herb-drug interaction studies. Conflicts of interest were declared as none.

All Effects:

Authors:

Abhijit Deshpande, Irin Rosanna Benny, Nushafreen Irani, Ratna Balkrishnan

Participants:

healthy adults

Study Quality Assessment:

randomized, double blind, placebo controlled study

Findings:

Five human trials met inclusion criteria. Three studies compared Ashwagandha (WS) extract dosages to placebo using anxiety scales (two showed significant benefit, one approached significance). Another study found naturopathic care with WS reduced BAI scores more than psychotherapy (56.5% vs 30.5%, p<0.0001). A fifth study found WS reduced PSS scores more than placebo (44.0% vs 5.5%, p<0.0001). All five studies concluded WS resulted in greater improvements on anxiety/stress scales than placebo, but evidence should be viewed cautiously due to methodological issues and potential bias.

Participants:

Human trials participants (details not specified in abstract)

Dosage:

Three studies compared 'several dosage levels of WS extract' with placebos, but specific dosages are not detailed in the abstract.

Study Quality Assessment:

Systematic review of human randomized controlled trials. Searches conducted in PubMed, SCOPUS, CINAHL, Google Scholar, reference lists, and AYUSH Research Portal. Inclusion criteria applied during abstract screening. Outcome measures included Hamilton Anxiety Scale, Beck Anxiety Inventory (BAI), Perceived Stress Scale (PSS). Limitations: All included studies exhibited unclear or high risk of bias; heterogenous design and reporting prevented meta-analysis.

All Effects:

Participants:

N=60 stressed, healthy adults

Dosage:

240 mg of a standardized ashwagandha extract (Shoden) once daily

Study Quality Assessment:

60-day, randomized, double-blind, placebo-controlled study, N=60