6 Supplements That May Damage Your Liver

As the largest internal organ, the liver performs hundreds of vital functions that keep your body functioning properly. It is responsible for filtering toxins from the blood, processing key nutrients, producing bile for fat digestion, and metabolizing drugs and foreign compounds. However, when overloaded with harmful substances, the liver becomes vulnerable to inflammation and injury. Supplements, in particular, often contain high concentrations of compounds that can put a strain on this hard-working organ. Although they are often considered a natural way to maintain health, experts warn that the six supplements below should be taken with caution to avoid possible liver damage.

1. Green tea extract

Although green tea is known for its antioxidant and heart-protecting properties, concentrated supplements of green tea components may do more harm than good. “Green tea extract capsules — EGCG or epigallocatechin gallate — can harm the liver in high doses,” says Vanessa Rissetto, MS, RD, CDN.

Rissetto explains that concentrated EGCG can generate immune reactions and oxidative stress in susceptible individuals, leading to liver inflammation and irritation that mirrors hepatitis. Instead, she recommends opting for brewed tea, as it contains much lower concentrations of EGCG. “(If you prefer supplementation), avoid EGCG supplements of 300 milligrams or less per day and avoid products delivering 800 mg or more per day, which have been associated with liver enzyme elevations and damage,” says Rissetto.

2. Vitamin A

Vitamin A plays an essential role in vision, immunity, skin health and cell growth, but too much can quickly become toxic, especially when taken in supplement form. The type most likely to cause damage is retinol, the active form of vitamin A, often found in high doses in supplements.

Unlike water-soluble vitamins that are easily cleared from the body, explains Tara Durden, MS, RDN, vitamin A is a fat-soluble vitamin that tends to accumulate in the liver when its intake exceeds the body’s needs. Durden warns that when the liver is overloaded with vitamin A, the risk of toxicity increases. As such, she recommends sticking to the safe dose of 1,000 to 5,000 IU per day and avoiding high doses above 10,000 IU to reduce the risk of acute vitamin A toxicity.

3. Niacin

Niacin, also known as vitamin B3, is sometimes taken to manage high cholesterol, although it is no longer recommended for most people for this purpose. This is partly because high doses can have detrimental effects on the liver. “Nutritionally, niacin is safe, but the pharmacological doses used for cholesterol, often 1 to 6 grams per day, can inflame the liver and cause jaundice,” says Rissetto, who points out that extended-release niacin supplements pose the highest risk. “Even supplements containing 500 mg or more can increase liver enzymes (a marker of stress or liver damage) in some users, and the risk increases with a dosage of grams per day or with an unsupervised formulation change.”

For these reasons, the maximum tolerable dose for adults is 35 mg or less per day. Rissetto cautions that prescription use or any dose of 1,000 mg per day or more should only be taken under the direction of a clinician.

4. Ashwagandha

Ashwagandha is a popular herbal supplement promoted for its stress relief and anxiety reduction benefits. Although generally considered safe for short-term use, some studies have linked some commercial herbal products claiming to contain ashwagandha to rare cases of liver damage. There have also been rare cases of liver damage and, in some cases, the need for a liver transplant in people with pre-existing liver disease and cirrhosis. The exact cause of liver toxicity is unknown, but some experts suspect that compounds in ashwagandha called withanolides are the main culprit.

Typical amounts found in supplements range from 150 to 600 mg, taken one to three times daily. However, Durden recommends using the lowest effective dose. She also advises only taking the supplement for a short time, choosing third-party tested brands, and consulting a doctor if symptoms of liver damage appear.

5. Kava

Kava is an herbal supplement commonly used to promote relaxation and relieve anxiety. However, depending on the dose and how it is formulated, its calming effects can have serious consequences for liver health. “Kava products, especially solvent extracts, have been linked to serious liver damage, including rare cases of liver failure,” Rissetto warns. She points out that these effects may be due to the plant’s toxic metabolites or its ability to deplete the liver’s antioxidant defenses.

The risk of liver damage is even higher when the herb is taken with alcohol or other compounds that can harm the liver or if you have pre-existing liver disease. To reduce the risk of liver damage, Rissetto recommends choosing formulations extracted from water from the root of the plant, no more than 240 to 250 mg of kavalactones per day and only taking them for a short period of time.

6. Black cohosh

Although black cohosh is marketed as a natural remedy for menopausal symptoms, such as hot flashes, night sweats, and mood regulation, it is not without risks. “Black cohosh has been associated with idiosyncratic hepatitis (drug-induced liver injury) and, rarely, liver failure,” says Rissetto.

Rissetto notes that the specific compound responsible for the effects on the liver is not known, so people with liver disease should avoid it, and any user experiencing adverse symptoms should stop taking this herb immediately.

If you choose to take black cohosh, Rissetto says clinical studies often involve around 40 mg of extract per day. However, the safety of long-term use is uncertain, so it is best to use the supplement short-term and pay close attention to any symptoms that may occur.

Signs and symptoms of liver damage

If you are taking any of the above supplements, both dietitians advise you to stop taking the supplement immediately and contact a healthcare provider if you notice the following signs and symptoms:

• Jaundice: Yellowing of the skin or whites of the eyes
• Dark urine: Especially if it appears brown or cola colored
• Pale stools: White or gray stools are a sign of reduced bile flow
• Abdominal pain or discomfort: Especially if it’s in the upper right side of your abdomen
• Nausea, vomiting or loss of appetite: See a doctor if these symptoms persist
• Itchy skin: This may be a sign of a buildup of bile or toxins.
• Fatigue: Especially if it’s deep or prolonged
• Easy bruises: This happens when your liver stops producing enough clotting factors to stop bleeding.

“Some people have no early symptoms, so blood test abnormalities (ALT/AST, bilirubin, INR) after starting a supplement also warrant discontinuation and evaluation,” adds Rissetto.

Among all the symptoms, Rissetto points out that in liver damage induced by drugs or supplements, jaundice signals a more serious illness and requires prompt attention.

Our expert opinion

Many people turn to supplements to boost their immune, mental, hormonal, and overall health. However, herbal remedies and high-dose nutrients are not as harmless as they seem. Supplements like vitamin A, niacin, green tea extract, kava, ashwagandha, and black cohosh should be taken with caution, as they have all been linked to liver injury, inflammation, and damage when taken in excess.

Even though the liver works tirelessly to filter excess substances, it still has its limits. When these limits are crossed, symptoms such as yellow skin and eyes, dark urine, fatigue, nausea, vomiting, loss of appetite, pale stools, and itchy skin may occur. If you experience any of these symptoms, experts advise you to stop supplementation and seek medical attention immediately. Your body’s largest internal organ relies on you to follow professional advice and proper dosages to prevent long-term damage.