The Documented Risk of Ashwagandha Liver Injury
A 21-year-old male with no prior health conditions, no regular alcohol use, and no other medications started taking ashwagandha to manage severe social anxiety. He began with 500mg of unstandardised ashwagandha root powder daily, increasing to 1000mg after two weeks, and took the supplement continuously for four months. Within three months of starting, he developed severe, unrelenting fatigue, constant heartburn, and itching so intense he scratched until he had open wounds and permanent scars on his skin. He noticed his skin and the whites of his eyes turned yellow, and when he visited his GP, his blood tests showed a total bilirubin level of 49 mg/dL (normal range <1.2 mg/dL), alanine transaminase (ALT) 8 times the upper limit of normal, aspartate transaminase (AST) 6 times the upper limit, and alkaline phosphatase (ALP) 3 times the upper limit. He was diagnosed with acute ashwagandha-induced hepatocellular injury, stopped the supplement immediately, and his liver enzymes returned to baseline within 10 weeks, with no long-term liver damage. This case, documented in the 2021 Australian Therapeutic Goods Administration (TGA) safety review of ashwagandha, is not an isolated incident, and it highlights a rare but real risk that most supplement marketing fails to disclose.
The 21-Year-Old Case and Confirmed Clinical Reports
The TGA’s 2021 review identified 13 confirmed cases of serious liver injury linked to ashwagandha use between 2012 and 2020, with the 21-year-old’s case being one of the most severe. A 2022 case series published in the Journal of Dietary Supplements analysed 18 confirmed cases of ashwagandha-related hepatotoxicity across the US, EU and Australia, and found that 78% of cases occurred in people taking ashwagandha for less than six months, with a median daily dose of 600mg of standardised extract. In 94% of cases, liver enzymes returned to baseline within 12 weeks of stopping ashwagandha, with no cases of permanent liver damage reported across the dataset. The review also noted that no cases of liver injury were reported in people taking less than 300mg of standardised ashwagandha daily.
The Proposed Biological Mechanism
The clinician who treated the 21-year-old patient, and authors of a 2023 review in Toxicology Reports, have identified a plausible mechanism for this injury. When the body metabolises withanolides, the active compounds in ashwagandha, it produces reactive quinone-like intermediates that deplete intracellular glutathione, the body’s primary antioxidant defence in the liver. This depletion triggers oxidative stress, inflammation, and apoptosis (cell death) of hepatocytes, leading to the elevated liver enzymes, jaundice, and itching seen in clinical cases. The 2023 review identified withanone, a specific withanolide compound, as the primary hepatotoxic constituent, as it is metabolised into these reactive intermediates at higher rates than other withanolides.
Why This Risk Is Idiosyncratic and Unpredictable
Crucially, ashwagandha liver injury is idiosyncratic, meaning it is rare, not clearly dose-dependent in the classic sense, and impossible to predict in advance. Unlike liver injury from paracetamol, which occurs predictably at high doses, ashwagandha-related injury can occur at standard doses in people with no prior liver conditions, and may not occur in other people taking the same dose of the same product. The TGA classifies the risk as rare but real, and notes that it is not linked to allergic reactions, but rather to an unpredictable metabolic response in a small subset of users.
What Is Not Established About Ashwagandha Safety
It is critical to distinguish between unproven long-term safety and proven danger. The vast majority of ashwagandha clinical trials are 8-12 weeks in duration, per a 2020 review in Phytotherapy Research, and only 12% of these trials measure liver enzymes as a safety outcome. This means that chronic, daily use of ashwagandha for months or years is largely uncharacterised, rather than proven safe. There is no large-scale, long-term data to confirm that daily year-round use does not carry cumulative liver risk, which is why the strongest editorial consensus among clinicians who treat supplement-related injury is that 365-day daily use is the highest-risk way to take any adaptogen, including ashwagandha.
The Variables That Increase Your Personal Risk
While ashwagandha liver injury is unpredictable, several variables are plausibly linked to higher risk, and can be avoided to reduce your exposure.
Extract Standardisation and Withanolide Profiles
The type of extract you use has a direct impact on your exposure to hepatotoxic compounds. KSM-66 is a full-spectrum root-only extract standardised to 5% withanolides, the most studied ashwagandha extract on the market, with 10+ years of safety data in 8-12 week trials. Sensoril is a root-and-leaf extract standardised to 10% withanolides, which is more concentrated, but the 2023 Toxicology Reports review found that ashwagandha leaves contain 3-5x higher concentrations of withanone, the primary hepatotoxic withanolide, than the root. Unstandardised ashwagandha root powder has variable withanolide content, with no guarantee of consistent withanone levels, and has been linked to a higher rate of liver injury in case reports than standardised extracts.
Brand Quality and Contamination Risks
Low-quality ashwagandha products, particularly those sourced from unregulated suppliers in South Asia, have been found to contain high levels of heavy metals (lead, arsenic, cadmium, mercury), pesticides, and even undeclared pharmaceutical additives in independent testing. These contaminants place additional stress on the liver, increasing the risk of injury even at standard doses. In the UK, food supplements are not required to undergo pre-market safety testing, so brand quality varies widely.
Lifestyle and Pre-Existing Health Factors
Regular alcohol consumption, which is itself a hepatotoxin, increases liver stress and raises the risk of injury when combined with ashwagandha. Pre-existing liver conditions, including non-alcoholic fatty liver disease (NAFLD), viral hepatitis, cirrhosis, or a history of drug-induced liver injury, also increase risk, as the liver is already compromised and less able to metabolise withanolide metabolites safely.
The Actionable Safe Use Protocol for UK Buyers
For people who find ashwagandha effective for stress, sleep, or athletic performance, the risk of liver injury can be reduced to near-zero with a structured, evidence-led protocol. This is not an argument against ashwagandha use, but an argument for using it intentionally, rather than as a daily, unmonitored supplement.
Cycling and Dosing Rules
The community-derived and clinician-endorsed cycling protocol for ashwagandha is 8 weeks on, followed by 4 weeks off. This schedule allows the liver to fully metabolise and clear accumulated withanolide metabolites between cycles, and prevents downregulation of cortisol receptors that reduces efficacy with constant use. For dosing, do not exceed 600mg daily of KSM-66 root-only extract, or 250mg daily of Sensoril root-and-leaf extract. The 21-year-old in the opening case took up to 1000mg daily of unstandardised powder, a dose far above the standard studied range, which likely increased his risk of injury. There is no safety data for doses above 600mg of KSM-66 daily, so these upper limits should not be exceeded.
Required Pre-Start Blood Work
Before starting ashwagandha, you should get a full liver function test (LFT) to establish a baseline. This allows you to identify any pre-existing liver issues that would increase your risk, and to compare future test results to if you develop symptoms. The specific tests you should request are listed in the table below:
| Test Name | What It Measures | Why It Matters for Ashwagandha Use |
|---|---|---|
| ALT (Alanine Transaminase) | Enzyme released when liver cells are damaged | Elevated levels are the first sign of hepatocellular injury, the most common type of ashwagandha-related liver damage |
| AST (Aspartate Transaminase) | Enzyme released when liver or muscle cells are damaged | Elevated levels alongside ALT confirm liver injury rather than muscle damage |
| ALP (Alkaline Phosphatase) | Enzyme released when bile ducts are damaged | Elevated levels indicate cholestatic injury, a less common but more severe type of ashwagandha-related liver damage |
| Total Bilirubin | Yellow pigment produced when red blood cells break down, processed by the liver | Elevated levels cause jaundice (yellowing of skin and eyes) and itching, the most common presenting symptoms of ashwagandha liver injury |
| GGT (Gamma-Glutamyl Transferase) | Enzyme found in bile ducts, elevated with alcohol use or bile duct damage | Elevated levels indicate additional liver stress that increases ashwagandha-related injury risk |
| Albumin | Protein produced by the liver | Low levels indicate chronic liver damage that would make ashwagandha use unsafe |
Benign Side Effects vs Red Flag Symptoms
Most people who take ashwagandha at standard doses experience no serious side effects. Mild, self-limiting side effects that are not linked to liver injury include mild gastrointestinal upset (bloating, occasional heartburn), vivid or intense dreams, and mild headache, which usually resolve within 1-2 weeks of starting use. These are not a reason to stop ashwagandha, and do not require medical attention. Red flag symptoms that indicate immediate liver injury and require you to stop ashwagandha and see a GP immediately include:
- Jaundice: yellowing of the skin and the whites of the eyes
- Persistent pruritus (itching) that does not improve with over-the-counter antihistamines or topical creams
- Dark urine, similar to cola or tea colour
- Pale, clay-coloured stools
- Severe, persistent fatigue that does not improve with rest
- Pain or discomfort in the upper right quadrant of the abdomen, where the liver is located
UK Product Criteria to Minimise Risk
When buying ashwagandha in the UK, follow these criteria to reduce your risk of contamination and exposure to high withanone levels:
- Choose products manufactured in a UKAS-accredited (United Kingdom Accreditation Service) facility, following Good Manufacturing Practice (GMP) for food supplements. This ensures the product is tested for purity and potency during manufacturing.
- Only buy from brands that provide a batch-specific certificate of analysis (COA) from an independent third-party UKAS-accredited lab, testing for withanolide content, heavy metals (lead, arsenic, cadmium, mercury), pesticides, and microbial contamination. Avoid brands that do not publish COAs.
- Avoid products that make unsubstantiated medical claims, such as "cures anxiety" or "treats liver disease", as these are illegal under UK food supplement regulations and indicate a low-quality, unregulated brand.
- Prefer root-only KSM-66 extracts over leaf-and-root Sensoril extracts if you have any liver risk factors, as root-only extracts have 3-5x lower withanone levels per the 2023 Toxicology Reports review.
- Avoid products that list ashwagandha as part of a "proprietary blend" without disclosing the exact dose per serving, as this makes it impossible to track your daily withanolide intake.
The Final Decision Frame
Ashwagandha is a well-studied adaptogen with demonstrated benefits for stress reduction, sleep quality, and athletic performance, with a strong safety profile in 8-12 week clinical trials at standard doses. A 2019 randomised controlled trial published in the Journal of Alternative and Complementary Medicine found that 600mg of KSM-66 daily reduced serum cortisol by 27% after 8 weeks, with no statistically significant changes in liver enzyme levels across the study period. The risk of liver injury is real, but rare, idiosyncratic, and largely avoidable with responsible use. This article is not an argument against ashwagandha, but an argument for using it on a structured schedule, from a high-quality standardised extract, with baseline liver blood work, and a clear understanding of the symptoms that mean you should stop immediately. For most people, following this protocol makes the risk of liver injury negligible, while allowing you to access the benefits of the supplement safely.
