Golden Seal

Goldenseal is one of the herbs we're most careful with, because its effect on your other medicines matters more than anything else. These are the questions our naturopaths ask in store.

A good fit if

• You're an adult and you're not pregnant, breastfeeding or trying to conceive
• You're not taking any prescription medicine right now
• You want a traditional bitter tonic for a short course, not an everyday herb
• You're happy to go on traditional use rather than clinical trials

Check with us first if

• You take a medicine your liver clears with CYP3A4 or CYP2D6. That's a big group, including many statins, some antidepressants, sedatives and calcium channel blockers. In a human trial, goldenseal raised a sedative's blood levels by 40 to 60 per cent.
• You take metformin. In a clinical trial, goldenseal lowered how much of a low metformin dose the body absorbed.
• You take antiretroviral medicine for HIV. Goldenseal is one of the herbs that needs caution alongside it.
• You'll use it on your skin and spend time in the sun. In lab testing, berberine damaged skin cells under UV light.
• You take any prescription medicine at all. Clinical guidance says people on regular medicines should generally avoid goldenseal.

• Root and rhizome powder, in a capsule or tablet. Best known for: The whole traditional herb, used as a bitter for digestion and for mucous membranes. Absorption: Very little of its berberine is absorbed once you swallow it. Typical use: Traditional use only. No trial has tested whether any goldenseal form works.
• Standardised, alkaloid-normalised extract. Best known for: The form used in human trials on drug interactions, not sold for any proven benefit. Absorption: The same limited berberine absorption as root powder. Typical use: 3,210 mg a day was tested for 14 days, to measure drug interactions.
• Liquid extract or tincture. Best known for: The traditional bitter tonic, meant to be tasted before you swallow it. Absorption: No one has compared its absorption with capsules. Typical use: A traditional digestive bitter, taken before meals.
• Combination with echinacea. Best known for: The most common pairing on the shelf. Absorption: Not applicable, as it's a multi-ingredient product. Typical use: Any immune support comes from the echinacea in the mix, not the goldenseal.
• Topical lotion or wash. Best known for: It has a permitted claim for minor cuts and grazes. Absorption: Not applicable. Typical use: Keep treated skin out of the sun. Berberine damaged skin cells under UV light in lab tests.
• Eyewash. Best known for: A historic use, and not one we'd recommend. Absorption: Not applicable. Typical use: There's no modern safety evidence for use in the eyes. Skip it.

Reference values. None. Goldenseal is a herb, not a nutrient, so the NHMRC sets no reference value or RDI for it.

Typical supplemental range. We haven't found an Australian product that sets one. Human trials used a single 3 g dose, 1 g three times a day for 6 days, or a standardised extract at 3,210 mg a day for 14 days. All of them measured drug interactions, not benefits.

Upper level. Australia's permitted ingredients list (Schedule 1) sets no daily cap for Hydrastis canadensis, and we haven't found any other upper limit.

Worth knowing. Short-term use of around 3 g a day hasn't shown serious harm, but long-term safety isn't known, so it's not a herb to take indefinitely. What you need depends on your age, diet and health, so talk to one of our naturopaths.

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• You take medicines cleared by CYP3A4/5, a large group including many statins, calcium channel blockers, some sedatives, immunosuppressants and some cancer treatments such as bosutinib. Goldenseal significantly slowed CYP3A4/5 in human trials, and a modelling study predicts bosutinib levels would rise further, though that hasn't been confirmed in patients.
• You take medicines cleared by CYP2D6, including many antidepressants, some beta blockers and some opioids. Goldenseal slowed this enzyme by about 40 percent in a 28-day human trial.
• You take any prescription medicine. Clinical guidance says most people on any medicine should avoid goldenseal.
• You're on antiretroviral therapy for HIV. Goldenseal is named among the herbs that need caution alongside it.
• You take metformin. A clinical trial found goldenseal reduced absorption of a low metformin dose, though blood glucose control wasn't reported to get worse.
• You take digoxin. A well-controlled trial found no meaningful effect, a genuine reassuring result.
• You're pregnant. Independent sources say to avoid it, so don't take it. There's no required Schedule 1 pregnancy warning, but that's a gap in the rules, not a finding that it's safe.
• You're breastfeeding or caring for a newborn. Berberine can displace bilirubin and may worsen newborn jaundice. Don't take it.
• It's for a child under 2 with breathing or chest symptoms. A required label statement restricts use without medical advice.
• You use it on your skin and will be in the sun or under UV. Berberine damaged human skin cells under UV light in lab tests.
• You plan to use it long term. Safety beyond short courses isn't established.
• Be aware of possible organ effects. A research review flags possible effects on nerves, the liver and sun sensitivity, described as a warning sign rather than an established finding.
• Quality varies. Independent testing has found some commercial goldenseal products don't match their expected make-up. Choose a brand you trust that tests its products.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.