Ashwagandha
Also known as: Withania somnifera, Indian ginseng, Winter cherry, KSM-66
Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
A herbal adaptogen (Withania somnifera root extract) used to lower stress/cortisol and, in some resistance-training RCTs, associated with modest gains in strength, muscle size and testosterone. It is not a hormone, does not aromatize and does not suppress the HPTA, so it needs no PCT. The effects that exist are small relative to any real anabolic, and clinical evidence overall is described as insufficient to confirm safety or efficacy. Rated 1 as an over-the-counter herbal supplement.
Overview
One of the most studied adaptogenic herbs, used for centuries in Ayurvedic medicine and now sold widely (often as the standardised root extract "KSM-66") to reduce stress and anxiety, support sleep, and, in fitness circles, to modestly aid strength and recovery. It has more real human RCT data than most "natural test boosters," but the effects are modest and the overall evidence base is still described as tentative/insufficient.
Important Warnings
- •Avoid during pregnancy and while breastfeeding: NCCIH advises against use in pregnancy and it has not been safety-tested in pregnant women. Historical claims that it has traditional use as an abortifacient are contested (a 2024 critique of Denmark's ban argues this stems from a misreading of sources that actually describe traditional use to help prevent miscarriage), but the precautionary avoidance still stands given the lack of safety data.
- •NCCIH advises against use with autoimmune conditions (e.g. rheumatoid arthritis, lupus, MS), it may stimulate immune activity, and with thyroid disorders, since it can raise thyroid hormone levels.
- •May raise testosterone, avoid in hormone-sensitive conditions such as prostate cancer.
- •Stop at least 1-2 weeks before surgery: its sedative and blood-pressure effects can interact with anesthesia.
- •May interact with sedatives, diabetes medications, blood-pressure medications, immunosuppressants, anticonvulsants and thyroid hormone medications.
- •Rare but serious liver injury (including cases requiring transplant) has been reported, mostly with a 2-12 week latency; avoid with pre-existing liver disease and stop use if jaundice, dark urine or right-upper-quadrant pain occur. This is part of why Denmark withdrew ashwagandha supplements from its market in 2023, though the underlying regulatory risk assessment is itself contested.
Purpose & Use Cases
Stress & Anxiety
At 300-600mg/day of root extract over ~3 months, may help generalised anxiety, though the evidence for efficacy is described as tentative.
Sleep
Limited evidence that the extract may modestly improve sleep quality and quantity, especially in people with insomnia.
Strength / Recovery
In an 8-week resistance-training RCT, a 600mg/day extract was associated with greater strength and muscle-size gains and reduced markers of muscle damage vs placebo.
Modest Testosterone Support
Some trials report small increases in testosterone (e.g. the Wankhede 2015 RCT found roughly a 15-17% rise vs a much smaller placebo change over 8 weeks); a 90-day trial in oligospermic/infertile men (Ambiye et al. 2013) also reported a significant rise in testosterone vs placebo. This is a reason to avoid ashwagandha in hormone-sensitive conditions.
Benefits
- Reasonable RCT evidence for reducing stress/anxiety (still tentative)
- May modestly improve sleep quality
- Associated with modest strength and muscle-size gains alongside training
- Small increases in testosterone reported in some trials
- Non-hormonal: no aromatization, no HPTA shutdown, no PCT
Good to Know
The natural supplement with the most real RCT data here
Unlike most "test boosters," ashwagandha has genuine human RCTs for stress/anxiety and even a resistance-training trial showing modest strength, muscle and testosterone benefits. But the effects are small, and reviews still call the overall evidence tentative/insufficient. It is an adaptogen, not an anabolic.
Withanolides are the active fraction
Bioactivity is attributed to withanolides (triterpene lactones such as withaferin A). Standardised extracts like KSM-66 are marketed by withanolide content.
Can raise testosterone, which is also a caution
Because ashwagandha may increase testosterone, it should be avoided in hormone-sensitive conditions (e.g. prostate cancer) and can theoretically interact with hormone-related medications. Non-hormonal in the steroid sense, so no PCT.
Under active regulatory scrutiny (2023-2025)
Denmark withdrew ashwagandha supplements from sale in 2023 over reproductive/thyroid/liver concerns, and Germany and Sweden have also restricted sales on hepatotoxicity grounds. The underlying Danish risk assessment has been publicly criticised by researchers for relying partly on studies of the leaves/berries rather than the root extract actually sold, so the science here is contested, but it is a real, ongoing regulatory situation worth knowing about, alongside the genuine (rare) hepatotoxicity case reports.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 300 – 500 mg/day |
| Intermediate | 500 – 600 mg/day |
| Advanced | 600 – 600 mg/day |
The anxiety literature uses 300-600mg/day of root extract over ~3 months; the Wankhede 2015 resistance-training RCT used 300mg twice daily (600mg/day) for 8 weeks. "KSM-66" is a widely used standardised full-spectrum root extract, though the trial abstract simply reported "ashwagandha root extract." Generally well tolerated for up to about three months.
~2-11 hours for the major withanolides (withanolide A, withaferin A), per a 2023 human crossover PK study. Varies by extract/dose; comprehensive human PK data is still limited.
Side Effects
Gastrointestinal upset
uncommonDiarrhea, nausea reported by some users.
Take with food; reduce dose.
Sedation / drowsiness
uncommonMild sedation or headache can occur.
Dose in the evening if sedation is unwanted; reduce dose.
Liver injury (rare)
rareAshwagandha can cause hepatotoxicity and has been linked to herb-induced liver injury, particularly in people with pre-existing liver conditions.
Avoid in those with liver disease; use third-party-tested product; stop and seek care if jaundice, dark urine or right-upper-quadrant pain appear.
General Mitigation Strategies
Generally well tolerated for up to about three months with mostly mild side effects. Rare hepatotoxicity/herb-induced liver injury has been reported, avoid with pre-existing liver disease. Avoid during pregnancy and in hormone-sensitive conditions (e.g. prostate cancer) because it may raise testosterone. NCCIH also flags caution/avoidance with autoimmune disease, thyroid disorders and upcoming surgery; general harm-reduction guidance is to stop at least 1-2 weeks beforehand given its sedative and possible blood-pressure-lowering effects. It may interact with sedatives, diabetes medications, blood-pressure medications, immunosuppressants, anticonvulsants and thyroid hormone medications. Current clinical evidence is described as insufficient to fully confirm safety or efficacy.
Post Cycle Therapy (PCT)
Not an androgen and does not suppress the HPTA. No PCT required.
How It Works
The root contains withanolides (a group of triterpene lactones, including withaferin A) plus sitoindosides and alkaloids. As an adaptogen it is best characterised for reducing perceived stress and cortisol. Its testosterone/strength effects (seen in some resistance-training trials) are modest and the mechanism is not fully established; it should be viewed as a stress-and-recovery aid rather than an anabolic agent.
Fundamentals
Reference on the practices relevant to Ashwagandha: how they are done and where they go wrong. Not a recommendation to use it.
Legal Status
Dietary supplement (USA); withdrawn from the market in Denmark (2023) over reproductive/thyroid/liver safety concerns, with Germany and Sweden also restricting sales. The underlying Danish risk assessment is itself disputed by researchers.
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
Ashwagandha (Withania somnifera) is a herbal supplement and is not listed on the WADA Prohibited List. Standard supplement contamination/adulteration caveats apply for tested athletes.
References
- Wikipedia, Withania somnifera (Ashwagandha)
- NCCIH, Ashwagandha: Usefulness and Safety
- Wankhede et al. 2015, muscle strength & recovery RCT (PMID 26609282)
- Ashwagandha-induced liver injury review (PMC11029936)
- Kim et al. 2023: PK/bioequivalence of Withania somnifera extracts, Heliyon (PMC10746415)
- Danish ban on Ashwagandha: Truth, evidence, ethics, and regulations, J Ayurveda Integr Med 2024 (PMC11403136)