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Ashwagandha

Supplement herb / adaptogen sleepbrain & moodfitness
Aka: Withania somnifera, KSM-66, Sensoril
Brands seen in Singapore: California Gold Nutrition, Swanson Vitamins, NOW Foods, Life Extension, Nutricost
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Sleep and stress · anxiety unclear · sport unproven (NCCIH)
When to take
Daily
Take with
Milk or water · what all five sleep trials instructed
Studied for
Sleep trials ran 6–12 weeks, more effect past 8
Pros & cons
Pros
  • NCCIH: some preparations may help insomnia and stress
  • 5 sleep RCTS (n=400): small but significant benefit
  • NCCIH: may be safe short term (up to 3 months) only
Cons
  • Rare liver injury cases linked to supplements (NCCIH)
  • Drowsiness, stomach upset, diarrhea, vomiting reported
  • No long-term safety data · trials small, all in india
Sources
  1. NCCIH — Ashwagandha: Usefulness and Safety (What Have We Learned; last updated March 2023) · read 2026-08-27
    what it says
    “some ashwagandha preparations may be effective for insomnia and stress. However, evidence is unclear about its effects on anxiety … There isn't enough evidence to determine if ashwagandha is helpful for … athletic performance, cognitive function”
  2. NCCIH — Ashwagandha (How Much Do We Know) · read 2026-08-27
    what it says
    “Many clinical trials (studies in people) have looked at the use of ashwagandha for a variety of health conditions. However, many of the studies have had small sample sizes and have used a variety of ashwagandha preparations”
  3. NCCIH — Ashwagandha (What Do We Know About Safety: duration, side effects) · read 2026-08-27
    what it says
    “Ashwagandha may be safe when taken in the short term (up to 3 months). There is not enough information to allow conclusions about its long-term safety to be reached … may cause drowsiness, stomach upset, diarrhea, and vomiting”
  4. NCCIH — Ashwagandha (Safety: liver injury) · read 2026-08-27
    what it says
    “Although it is rare, there have been a number of cases that link liver injury to ashwagandha supplements”
  5. NCCIH — Ashwagandha (Safety: who should not use it) · read 2026-08-27
    what it says
    “Ashwagandha should be avoided during pregnancy and should not be used while breastfeeding. Ashwagandha is not recommended for people who are about to have surgery, or for those who have autoimmune or thyroid disorders”
  6. NCCIH — Ashwagandha (Safety: testosterone / prostate) · read 2026-08-27
    what it says
    “Because ashwagandha may increase testosterone levels, people with hormone-sensitive prostate cancer should avoid its use”
  7. NCCIH — Ashwagandha (Safety: drug interactions) · read 2026-08-27
    what it says
    “There is evidence that ashwagandha might interact with some medications, including those for diabetes and high blood pressure, medicines that decrease the immune system response (immunosuppressants), sedatives, anti-seizure medications (anticonvulsants), and thyroid hormone medications”
  8. Effect of Ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis (Cheah et al., PLoS One 2021) · read 2026-08-27
    what it says
    “five randomized controlled trials containing 400 participants were analyzed. Ashwagandha extract exhibited a small but significant effect on overall sleep … No serious side effects were reported … data on the serious adverse effects of Ashwagandha extract are limited”
  9. Cheah et al., PLoS One 2021 — subgroup findings and administration · read 2026-08-27
    what it says
    “The effects on sleep were more prominent in the subgroup of adults diagnosed with insomnia, treatment dosage ≥600 mg/day, and treatment duration ≥8 weeks … All trials instructed their participants to consume Ashwagandha extract capsule, either with milk or water”
  10. Cheah et al., PLoS One 2021 — included trials (setting, extracts, durations) · read 2026-08-27
    what it says
    “All trials were conducted in India … Four trials … used KSM-66 … one trial … used Shoden® … one trial was conducted for six weeks, two for eight weeks, one for 10 weeks, and one for 12 weeks”
  11. Cheah et al., PLoS One 2021 — daily doses used · read 2026-08-27
    what it says
    “One trial used Ashwagandha extract in the dose of 120 mg per day, one trial compared … 250 mg per day and 600 mg per day … and three trials used … 600 mg per day”
  12. Cheah et al., PLoS One 2021 — inclusion criteria · read 2026-08-27
    what it says
    “Randomized controlled trials that examined the effect of Ashwagandha extract versus placebo on sleep in human participants 18 years old and above were considered”
  13. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (Oct 2025) · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list [ashwagandha / Withania somnifera not listed in Annex A or B]”
  14. iHerb Singapore — Ashwagandha category (SG$ pricing, default order) · read 2026-08-27
    what it says
    “California Gold Nutrition, Ashwagandha, 500 mg, 120 Veggie Capsules … Swanson Vitamins, Full Spectrum® Ashwagandha, 450 mg … NOW Foods, KSM-66 Ashwagandha®, 600 mg … Life Extension, Optimized Ashwagandha … Nutricost, KSM-66®, Ashwagandha Root Extract”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.