Black Cohosh

Black cohosh helps a lot of women through hot flushes and night sweats, but it isn't right for everyone. These are the quick questions our naturopaths ask in store.

A good fit if

• You're an adult woman in perimenopause or menopause dealing with hot flushes or night sweats
• You'd like to try a well-studied herb before thinking about hormone therapy
• You're happy to give it a proper trial of several weeks before deciding whether it's working
• You don't have liver problems and aren't taking a combination product with St John's wort
• You want a standardised extract with a clear dose, close to what the positive trials used

Check with us first if

• You take a prescription medicine your body processes with the CYP2D6 enzyme, such as some antidepressants, or tamoxifen. Human studies found only a small effect, but check first.
• You're looking at a combination product that also contains St John's wort. In that case, the interactions to worry about are St John's wort's, not black cohosh's.
• You've had breast cancer or are being treated for it now. Current evidence doesn't show an increased risk, but talk to your oncologist first.
• You're trying to get pregnant or managing PCOS. The evidence here is thin, and there's no permitted claim for this use in Australia.

• Isopropanolic extract (iCR). Best known for: The single most studied form; behind most positive trial results. Absorption: Standardised, typically dosed at 40 mg drug equivalent a day. Typical use: The form to look for if you want the strongest evidence behind it.
• Ethanolic extract (CR BNO 1055). Best known for: The second extract with published clinical data. Absorption: Studied at 40 mg a day. Typical use: Found no added bone density benefit over exercise alone.
• Dry extract (generic). Best known for: Whatever the specific product's own ratio and solvent support. Absorption: No pooled data; depends entirely on the extract behind the label. Typical use: Check the label rather than assume it matches a trial dose.
• Root and rhizome powder. Best known for: Traditional use framing, closest to historical preparation. Absorption: Not concentrated; no clinical trials tested powder specifically. Typical use: The weakest clinical evidence base of the four forms.

Reference values. None. Black cohosh is a herb, not an essential nutrient, so the NHMRC sets no recommended intake for it.

Typical supplemental range. Australian listed medicines are usually labelled by the amount of dried root they're equivalent to, rather than the weight of the extract. Clinical trials mostly used about 40 mg a day of standardised extract, and the guidance we reviewed puts the usual range at 40 to 80 mg a day.

Upper level. There's no NHMRC upper limit, and Australia's permitted ingredients list (Schedule 1) sets no maximum daily dose. The safety research goes up to about 128 mg a day taken for three to six months.

Worth knowing. Trials rarely ran longer than 12 months, and European guidance advises against taking it for more than six months without checking with a doctor. What you need depends on your age, diet and health, so talk to one of our naturopaths.

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Pregnancy. Not for use; refer to a doctor.
• Breastfeeding. Not for use; safety hasn't been established.
• Existing or past liver disease. Avoid as a precaution.
• Jaundice, dark urine, nausea, vomiting, unusual tiredness, abdominal pain or loss of appetite. Stop and see a doctor straight away.
• Sudden nausea, vomiting or stomach upset after the first one or two doses. Stop and seek advice.
• Allergic skin reactions or facial or limb swelling. Stop and seek advice.
• Combination products containing St John's wort. Assess the interaction profile as St John's wort's, an extensive one, not black cohosh's low one.
• Medicines broken down by CYP2D6, such as some antidepressants and tamoxifen. Human data show a small effect described as not clinically relevant, but check first.
• Current or past breast cancer. Evidence doesn't show increased risk, but check with your oncologist before use.
• Duration of use. Not for more than six months without checking with a doctor.
• Adult women only. Not studied in men, teenagers or children.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.