Menopause

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 most studied form, and behind most of the positive trial results. Absorption: Standardised, and usually dosed at 40 mg (dried herb 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: It gave no extra bone density benefit over exercise alone.
• Dry extract (generic). Best known for: Whatever the product's own ratio and solvent support. Absorption: No pooled data; it depends entirely on the extract behind the label. Typical use: Check the label rather than assuming it matches a trial dose.
• Root and rhizome powder. Best known for: Fits traditional use, and is closest to how it was historically prepared. Absorption: Not concentrated, and no clinical trials tested powder specifically. Typical use: The weakest clinical evidence 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.

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

• Pregnancy. Don't take it; talk to your doctor.
• Breastfeeding. Don't take it; safety hasn't been established.
• Current or past liver disease. Don't take it, as a precaution.
• Jaundice, dark urine, nausea, vomiting, unusual tiredness, tummy 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 get advice.
• Allergic skin reactions, or swelling of the face or limbs. Stop and get advice.
• Combination products containing St John's wort. Judge the interaction risk by St John's wort, which has many interactions, not by black cohosh, which has few.
• 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. The evidence doesn't show increased risk, but check with your oncologist first.
• Length of use. Don't take it for more than six months without checking with a doctor.
• Adult women only. It hasn't been studied in men, teenagers or children.
• If you take prescription medicines, check with your doctor, pharmacist or one of our naturopaths before you start.