Ginseng

People usually come to ginseng when tiredness hangs around even after a good night's sleep. These are the questions our naturopaths ask in store, which are mostly about which species and what else you already take.

A good fit if

• You're after support for everyday tiredness and stamina, which is the use with the most trial evidence
• You'll give it eight to 12 weeks, because that's how long the trials that found an effect ran
• You can find a label that names the species, the plant part and the ginsenoside standardisation
• You're an adult and you're not pregnant or breastfeeding, which is where the European regulator draws the line

Check with us first if

• You take warfarin. There are case reports, and controlled studies haven't confirmed a meaningful interaction with Asian ginseng, but one systematic review found American ginseng changed how warfarin works in the body. This isn't one to manage yourself.
• You take insulin, a sulfonylurea or metformin. Ginseng lowers fasting blood sugar by a small but real amount, and American ginseng reduces the rise after a meal, so your prescriber may want to monitor you.
• You take phenelzine or another MAOI antidepressant. A possible interaction appears in the safety research.
• You take a medicine where small changes in blood level matter and that your body clears through CYP3A or P-glycoprotein. Studies found ginseng weakly speeds up and weakly slows these pathways, and close monitoring is still advised.
• You take blood pressure medicine. Pooling 17 trials found no effect either way, which is reassuring, but your prescriber should still know what you're taking.
• You sleep poorly. Disturbed sleep is one of the more commonly reported side effects, and taking it in the morning is the usual answer.
• You're looking at a multi-herb formula rather than ginseng on its own. Serious side effects have been reported with combination products containing ginseng, though the other ingredients couldn't be ruled out as the cause.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.

• Korean white ginseng (Panax ginseng, air-dried). Best known for: The classic unprocessed root, and the traditional ginseng for energy and stamina. Absorption: How it's extracted changes what you get: whole root and 30, 50 and 70 per cent ethanol extracts gave the same blood sugar response after a meal, while the extracts shifted insulin sensitivity. Typical use: Most of the general Panax ginseng research used unspecified or white preparations. Given once at 1, 3 and 6 g, it improved a measure of artery stiffness (augmentation index) at 3 g and didn't move any glucose or blood pressure measure.
• Korean red ginseng (Panax ginseng, steamed then dried). Best known for: The most tested form in the family, and traditionally the warmer one. Absorption: Steaming rearranges the ginsenosides and forms Rg3, which is found only in red ginseng. Typical use: Trials cover fatigue, immune markers, blood pressure, blood sugar and sexual function. Several missed their main goal, including chronic fatigue at 3 g a day, and much of the positive work appears in journals that specialise in ginseng.
• American ginseng (Panax quinquefolius). Best known for: A different species with a different ginsenoside profile, not just a different growing region. Absorption: The short-term effect on glucose depended on timing rather than dose: only the dose taken 40 minutes before a carbohydrate meal worked, and 1 g did as well as 3 g. Typical use: Two well-defined uses: working memory and attention within hours at 100 to 400 mg of a standardised extract, and blood sugar after a meal at 1 to 3 g. Two trials found it didn't lower blood pressure where Korean red ginseng did.
• Fermented red ginseng. Best known for: Red ginseng broken down by microbes (fermented) before it reaches you. Absorption: Fermentation is known to increase absorption from the gut and activity in the body. Typical use: One trial in 42 people over four weeks: blood sugar after a meal fell and insulin rose, while fasting glucose, insulin and blood fats didn't change.
• Ginseng berry extract. Best known for: The fruit rather than the root, with a different ginsenoside profile again. Absorption: Not established for the berry compared with the root. Typical use: Two trials, one of them a blend with whey protein. Berry results can't be applied to a root product, and root is mostly what's sold here.
• Isolated ginsenoside complexes. Best known for: Not a whole-root preparation at all. Absorption: Not established compared with root preparations. Typical use: One trial in 117 people: 500 mg a day improved VO2max over 12 weeks of supervised training, 100 mg a day didn't, and neither improved strength. No Schedule 1 name contains the word ginsenoside, so how such a product stands in Australia is unclear.
• Siberian ginseng (Eleutherococcus senticosus). Best known for: Not a Panax species, and grouped with ginseng only through the 20th-century idea of adaptogens. Absorption: Not comparable; it's a different genus with its own chemistry. Typical use: An allowed ingredient in its own right, with its own separate evidence, none of it borrowed from Panax. Its own best fatigue trial showed no overall benefit.

Reference values. There isn't one. Ginseng is a herb, not a nutrient, so there's no recommended intake and no deficiency to correct.

Typical supplemental range. Australian capsules and tablets usually contain 200 mg to 1 g of root powder or extract, sometimes given as a dry-root equivalent. Trial doses are higher and vary more. Korean red ginseng trials generally used 1.8 to 3.6 g a day and American ginseng root 1 to 3 g a day, while the working-memory research used only 100 to 400 mg of one extract standardised to 10.65 per cent ginsenosides. The largest fatigue trial used 2,000 mg a day for eight weeks, in a group of people a listed medicine can't make claims about. Trial doses vary 15-fold, so results from one product don't carry over to another. Check the species, plant part, dose and standardisation on the label against the trial you're relying on.

Upper level. There's no upper limit. Australia's permitted ingredients list (Schedule 1) sets no daily maximum and no restriction on how it's taken for any Panax ginseng, and no upper level of intake has been set. That doesn't mean more is fine. The company selling it still has to hold evidence for its dose, and a 30-day study in rats found side effects from ginseng rose with the dose.

Worth knowing. Timing matters. In short-term trials, American ginseng's effect on blood sugar depended on taking it 40 minutes before a carbohydrate meal rather than on the dose, and the researchers advised people without diabetes to take it with the meal instead, to avoid blood sugar dropping too low. Poor sleep is one of the more commonly reported side effects, so taking it in the morning is sensible. On how long to take it, the European traditional-use guidance says to see a doctor or pharmacist if symptoms last more than two weeks, while the trials that did find effects usually ran for eight to 12 weeks. 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. The European traditional-use monograph says not to use it, and advises particular caution in the first trimester.
• Breastfeeding. The same monograph says not to use it, and there are no human studies in breastfeeding.
• Children and teenagers under 18. The same monograph says not to use it.
• Allergy to the plant. Don't take it; itching and hives were the most common side effects in one red ginseng trial.
• Warfarin. There are case reports, and one systematic review found American ginseng changed how warfarin works. Check with your prescriber.
• Medicines that lower blood sugar, including insulin, sulfonylureas and metformin. Ginseng has a small but real effect on glucose. Check with your prescriber.
• Phenelzine and other MAOI antidepressants, and alcohol. Possible interactions have been reported in the safety research.
• Medicines broken down by CYP3A or moved by P-glycoprotein, where the safe dose range is narrow. Effects were weak in testing, but close monitoring is advised.
• Combination products. Serious side effects and deaths have been reported with multi-ingredient products containing ginseng, though the cause wasn't pinned down.
• Headache, disturbed sleep and upset stomach are the most commonly reported side effects of ginseng on its own.
• Higher doses. A 30-day rat study found side effects rose with the dose. Stay within the label.
• Adulteration. A widely repeated case of masculinising effects was traced to an added substance, not to ginseng. Buy products with an AUST L number.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.