American ginseng eased cancer fatigue, but a review found a quarter of products adulterated

Key takeaways

• In a 2013 trial of 364 people with cancer, 2,000 mg a day of American ginseng missed its 4-week goal but eased fatigue more than a placebo by 8 weeks.
• COLD-FX, an American ginseng extract, reduced colds and flu in several trials, and its maker helped fund the studies in older adults.
• In 20 healthy volunteers, 2 grams a day of American ginseng weakened the blood thinner warfarin, so check with your clinician before combining them.
• A 2025 review by American Botanical Council staff, as reported by two trade publications, found that 24.7% of ginseng products tested in published studies were adulterated, and some held hidden erectile dysfunction drugs.
• Wild American ginseng has been under international trade controls since 1975, and exported wild roots must come from plants at least five years old.

Every September, ginseng season opens in 19 states¹. Diggers fan out through the woods, and federal guidance tells them to take only plants whose berries have turned red, then bury those seeds close by¹.

Diggers also learn to read a plant’s age on its root. Every autumn, when the stem dies back, it leaves a scar on the rhizome, the knobby neck at the top of the root. A wild root bound for export needs at least four scars, meaning the plant is five years old or older¹. Before a shipment leaves, federal inspectors count those scars¹.

That much care tells you how prized this root is. American ginseng has been on an international list of species that need trade controls since 1975¹.

Yet the ginseng in a store bottle may not be the plant on the label. A 2025 review of published product tests, written by staff of the American Botanical Council, found that about one in four ginseng products was adulterated².

And real ginseng? It does less than its legend promises, and more than nothing. Its best result came in a large cancer-fatigue trial, and its biggest everyday risk is a clash with a common blood thinner.

“Ginseng” covers three plants, and only two are the real thing

True ginseng belongs to the genus Panax, which holds 16 species². Three are widely grown and used: Asian ginseng, American ginseng and tienchi ginseng (Panax notoginseng)².

Asian ginseng (Panax ginseng) is native to Korea, northeastern China and far-eastern Siberia³. Labels may call it Chinese ginseng or Korean ginseng³. Red ginseng and white ginseng are not separate plants. They are two ways of preparing the same Asian root³.

American ginseng (Panax quinquefolius) grows wild in North American forests, and 19 states, from Alabama to Minnesota and Vermont, allow it to be harvested¹. Some roots are dug wild, and some come from plants grown on purpose, including “wild-simulated” ginseng planted in forests¹. The big U.S. fatigue trial used ginseng from Wisconsin⁴.

“Siberian ginseng” is eleuthero (Eleutherococcus senticosus), a different plant². Since 2002, U.S. law has reserved the word “ginseng” for Panax herbs². Our label decoder article explains that rule.

The root is the part most often used³. Its best-known compounds are ginsenosides, also called panaxosides³. You’ll find ginseng as whole or sliced roots, powdered root, teas, and supplement capsules or extracts¹².

Name you may see	Plant	True ginseng?
Asian, Korean, Chinese, red or white ginseng	Panax ginseng3	Yes
American ginseng	Panax quinquefolius1	Yes
Tienchi or sanchi ginseng	Panax notoginseng2	Yes, a third Panax species
Siberian ginseng, eleuthero	Eleutherococcus senticosus2	No; found as a cheaper substitute12
Indian ginseng	Ashwagandha, an unrelated herb	No; found as a cheaper substitute12
Brazilian ginseng	An unrelated plant	No; found as a cheaper substitute12

In Chinese medicine, ginseng has been a calming herb, not a jolt

In traditional Chinese medicine, Asian ginseng has been used as a calming agent, according to the National Center for Complementary and Integrative Health (NCCIH)³. Practitioners have also treated it as an adaptogen, a substance thought to help the body withstand physical and mental stress³. “Adaptogen” names a traditional idea, not a proven effect; our label decoder article explains the term.

Modern marketing has stretched ginseng much further, promoting it for stress, thinking, flu, fatigue, athletic performance, diabetes, aging, asthma and anxiety³. Notice the irony: a root long used to calm is now sold as a pick-me-up.

American ginseng carries its own North American story. Today the Menominee Indian Tribe of Wisconsin is among the governments with rules for harvesting and trading wild ginseng¹.

Respecting these traditions means taking their claims seriously enough to test them fairly.

The strongest trial tested American ginseng for cancer fatigue

In 2013, a team led by Debra Barton, a nurse and PhD researcher at the Mayo Clinic Cancer Center, published a trial in the Journal of the National Cancer Institute⁴⁵.

The team enrolled 364 fatigued cancer patients and survivors at 40 sites⁴. Each person took either 2,000 mg a day of American ginseng, given as 1,000 mg twice daily, or a look-alike placebo for eight weeks⁴⁵. Neither patients nor researchers knew who got which, a design called double-blind⁴.

The result was mixed in an instructive way. At four weeks, the trial’s main checkpoint, the ginseng group’s fatigue scores had improved more than the placebo group’s, but not by enough to rule out chance⁴. By eight weeks, the gap was larger and statistically significant: about 20 points of improvement on ginseng versus about 10 on placebo⁴. People still in active cancer treatment seemed to benefit most⁴.

Side effects reported by patients and graded by clinicians did not differ between the groups⁴. The researchers suggested a meaningful benefit might take about two months to appear⁵.

One trial isn’t the final word, but a large, multicenter, placebo-controlled study is unusually strong evidence for an herb. A broader 2023 review of 19 studies with 2,413 people found a possible small benefit of Asian ginseng for general fatigue, though NCCIH notes that not all research agrees³.

COLD-FX: a cold remedy tested mostly with its maker’s support

COLD-FX is a standardized extract of American ginseng, called CVT-E002 in studies⁷. It came from CV Technologies, a spin-off company of the University of Alberta in Canada⁶.

In a trial reported in the Canadian Medical Association Journal in 2005, 323 adults took COLD-FX or a placebo for four winter months⁶. All had caught at least two colds or similar infections the year before⁶. The COLD-FX group had 25% fewer upper respiratory infections, and repeat infections fell from 22.8% of the placebo group to 10%⁶.

Earlier trials in older adults pointed the same way. In two studies of 198 nursing home and assisted living residents in total, people took 200 mg twice daily⁷. Lab-confirmed flu struck 1 of 97 on the extract and 7 of 101 on placebo⁷. Most participants had already received a flu shot⁷.

Two cautions apply. First, the trials in older adults were partly funded by CV Technologies, the extract’s maker, according to a 2010 report in Internal Medicine News⁷. The university’s report on the 2005 trial didn’t say who paid for it⁶. Maker funding doesn’t make results false, but it calls for independent confirmation.

Second, the same extract didn’t reduce respiratory infections in people with chronic lymphocytic leukemia, a blood cancer, in a study presented at a Society for Integrative Oncology conference⁷.

Thinking, blood sugar and sexual function: smaller promises

Thinking and memory. A handful of studies hint that Asian ginseng may sharpen attention, mental math and reaction speed in people in midlife, with no such effect in younger adults³. Memory gains showed up only when ginkgo was added to the mix³.

Blood sugar. A 2022 review of 20 studies with 1,295 people found improvements in fasting blood sugar, total cholesterol and some markers of inflammation in people with prediabetes and diabetes³. But NCCIH calls the research on day-to-day blood sugar control in diabetes inconclusive and conflicting³.

Erectile dysfunction. A 2021 Cochrane review pooled nine placebo-controlled trials with 587 men who had mild to moderate erectile dysfunction⁸. Ginseng had only trivial effects on standard erectile function scores⁸. Men taking it more often reported being able to have intercourse, but the certainty of that evidence was low⁸. No trial compared ginseng with proven drugs such as sildenafil (Viagra)⁸.

Athletic performance. Most research shows Asian ginseng doesn’t improve it³.

Here is how the main uses rate.

Use	Form and dose studied	What was found	Evidence level
Cancer-related fatigue	American ginseng, 1,000 mg twice daily for 8 weeks45	Missed 4-week goal; better than placebo at 8 weeks4	Promising but early
General fatigue	Asian ginseng, various products3	Possible small benefit; inconsistent3	Promising but early
Preventing colds and flu	COLD-FX extract, daily for 2 to 4 months; 200 mg twice daily in older adults67	Fewer infections; maker helped fund some studies7	Promising but early
Thinking in middle age	Asian ginseng, small studies3	Some measures improved; not in young adults3	Promising but early
Blood sugar in diabetes	Various Panax products3	Fasting sugar improved; overall control unclear3	Promising but early
Erectile dysfunction	Various ginseng products, up to 12 weeks8	Trivial effects on function scores; mostly low certainty8	Not enough evidence
Athletic performance	Asian ginseng3	Mostly no improvement3	Evidence says no, or unsafe
Taking it with warfarin	American ginseng, 2 grams a day910	Blood thinner weakened910	Evidence says no, or unsafe

The warfarin surprise and other safety notes

In 2004, Chun-Su Yuan and colleagues at the University of Chicago tested American ginseng with warfarin, a blood thinner that prevents clots⁹¹⁰. They gave 20 healthy volunteers warfarin, and then either 1 gram of ginseng twice daily or a placebo⁹¹⁰.

After two weeks, ginseng had lowered warfarin levels in the blood and weakened its effect⁹. The INR, a blood test that measures how long blood takes to clot, dropped by a small but significant amount¹⁰. The likely reason is that ginseng speeds up liver enzymes that clear warfarin from the body⁹¹⁰.

The finding surprised the researchers, because ginseng on its own may promote bleeding⁹. NCCIH also says ginseng may interfere with blood clotting³. Warfarin works in a narrow range, so even a small change matters⁹. If you take warfarin or another blood thinner, don’t start or stop ginseng without talking with your clinician.

Other cautions from NCCIH³:

• Sleep. Trouble sleeping tops the list of complaints.
• Diabetes. Ginseng might push blood sugar down, so talk with your clinician first if you take diabetes medicine.
• Pregnancy and breastfeeding. Swallowed during pregnancy, ginseng may not be safe; in animal tests, a compound from the plant led to birth defects. Safety while nursing is largely unknown, and some experts say to skip ginseng in both situations.
• Children. Some experts say infants and children shouldn’t take it.
• Autoimmune disease. Ginseng could make conditions such as lupus or rheumatoid arthritis flare.
• Rare reactions. A few people have had a severe rash, liver damage or a serious allergic reaction.
• How long. Up to six months at usual amounts looks safe for most adults; longer use hasn’t been settled.

Surgery is another reason to tell your clinicians. Some supplements raise bleeding risk or change how you respond to anesthesia, so mention all of them well before an operation¹⁴.

What about “ginseng abuse syndrome”? Ronald K. Siegel, a researcher in a University of California psychiatry department, used that phrase in a 1979 paper in JAMA¹¹¹⁵. In a 1980 report, he described 18 long-term ginseng users¹¹. Just one developed the syndrome: high blood pressure, nervousness, sleeplessness, skin eruptions, swelling and morning diarrhea¹¹.

Siegel tied it to excessive doses, caffeine and possible allergy¹¹. One case among 18 users is a thin basis for a named syndrome. Still, the warning holds: a 2002 review co-written by Chun-Su Yuan notes that high doses may cause insomnia, headaches and diarrhea¹⁵.

Wild roots are protected, and many bottles aren’t what they claim

American ginseng was listed under the Convention on International Trade in Endangered Species (CITES) in 1975, out of concern that trade was driving overharvest¹. Exporters need a permit, and roots must be certified by the state or tribe where they were dug¹. The five-year minimum age for exported wild roots dates to 1999¹³. Today some states require plants to be 10 years old¹.

Digging is illegal on all National Park Service land and on most state lands and national forests¹. If you see illegal digging, you can report it to state agencies or the U.S. Fish and Wildlife Service¹.

The store shelf has its own problem. In 2025, researchers from the Botanical Adulterants Prevention Program (BAPP) reviewed 48 published studies of commercial ginseng products². The American Botanical Council (ABC) manages BAPP with the American Herbal Pharmacopoeia and the National Center for Natural Products Research¹². All three authors work for ABC, and we could not open the journal paper itself, so the figures below come from two trade-press reports that agree²¹².

Across 40 of those studies, 211 of 853 products, or 24.7%, were adulterated²¹². Most often, cheaper plants sold as Siberian, Indian or Brazilian “ginseng” had been swapped in¹². In eight studies that looked for drugs, 28 of 57 products held undeclared pharmaceutical ingredients². The main ones were the erectile dysfunction drugs sildenafil and tadalafil¹².

Supplements were at higher risk than powdered root or ginseng tea². The review also flagged subtler tricks: younger roots sold as older ones, spent root left over from making extracts, and other plant parts blended in with root². Five- and six-year-old roots can cost 30% to 60% more than four-year-old roots, which gives sellers a reason to cut corners².

Your ginseng profile card and label check

Match a product to the evidence, then run the label check before you buy.

Question	Asian ginseng	American ginseng	COLD-FX extract
Latin name on label	Panax ginseng3	Panax quinquefolius1	Standardized American ginseng extract7
Part	Root3	Root1	Extract7
Best-studied use	Fatigue, thinking, blood sugar (small effects)3	Cancer-related fatigue4	Preventing colds and flu67
Dose studied	Varies by study3	1,000 mg twice daily, 8 weeks45	200 mg twice daily7
Check first if you	Take a blood thinner or diabetes medicine, or have an autoimmune disease3	Take warfarin910	Take warfarin; it’s an American ginseng product79
Pregnant, nursing or a child	Some experts advise against it3	No safety data in our sources; NCCIH’s caution covers Asian ginseng3	Same gap; ask a clinician first3

Label check

• The Latin name, Panax ginseng or Panax quinquefolius, is printed, not just “ginseng blend.”
• The label says root, not leaf or “aerial parts,” unless that’s what you want.
• The amount per serving is stated, so you can compare it with the dose studied.
• The product carries a third-party testing seal that checks identity, not only purity.
• Be wary of ginseng sold for sexual performance; the hidden drugs found most often were erectile dysfunction medicines¹².
• If the product is labeled wild American ginseng, the seller should be able to tell you which state or tribe certified it¹.

Stop and call your clinician if you notice signs of the rare reactions NCCIH lists, such as a severe rash or signs of liver trouble³. Do the same if you bleed or bruise more easily, since NCCIH says ginseng may interfere with clotting³. A severe allergic reaction, another rare problem on NCCIH’s list, is an emergency: call 911³. Bring the bottle with you.

Respect for this plant also means leaving some in the woods: buy only legally certified wild root, or choose cultivated ginseng.

Questions readers ask

The bottom line

Ginseng earns more respect than many trendy herbs. A large, placebo-controlled trial found American ginseng eased cancer-related fatigue after about two months, and an extract tested largely with its maker’s support reduced colds. Claims for memory, blood sugar and sexual performance rest on small or trivial effects.

The bigger risks are practical. Ginseng can weaken warfarin, may lower blood sugar and is best avoided in pregnancy and for children. And one review found that about a quarter of tested products weren’t what they claimed. Buy root labeled with its Latin name, check with your clinician if you take medicines, and leave wild plants to diggers who follow the rules.

Keep exploring: botanical names on supplement labels.

Related reading

• Only Panax can be called ginseng on U.S. labels, and this is how to decode the rest
• What centuries of traditional use can and can’t tell you
• Ashwagandha lowers a stress hormone, and regulators are now splitting root from leaf
• What gets into supplements that isn’t on the label
• Some healthy habits clash with your medicines, so check these goals first

Sources

1. U.S. Fish and Wildlife Service, International Affairs. “Information for Ginseng Diggers, Dealers, and Exporters.” USFWS, accessed October 2026. fws.gov
2. Daniells S. “Ginseng adulteration remains a significant concern, says BAPP review” (on Orhan N, Gafner S, Blumenthal M, Natural Product Communications, 2025;20(12)). NutraIngredients, January 19, 2026. nutraingredients.com
3. National Center for Complementary and Integrative Health. “Asian Ginseng.” NIH, last updated February 2025. nccih.nih.gov
4. Institut National du Cancer (France). Abstract summary of Barton DL, et al. “Wisconsin Ginseng (Panax quinquefolius) to Improve Cancer-Related Fatigue: A Randomized, Double-Blind Trial, N07C2.” Journal of the National Cancer Institute, 2013. Nota Bene Cancer bulletin no. 192. cancer.fr
5. Green LM. “Ginseng Improves Cancer-Related Fatigue in Phase III Trial.” OncLive, September 3, 2013. onclive.com
6. University of Alberta. “Folio,” November 4, 2005 (news report on the COLD-FX trial in the Canadian Medical Association Journal).
7. Internal Medicine News. “Ginseng Cuts Respiratory Infections in Elderly, but Not in Leukemia Patients.” MDedge, December 30, 2010. mdedge.com
8. Lee HW, Lee MS, Kim T-H, et al. “Ginseng for erectile dysfunction.” Cochrane Database of Systematic Reviews, 2021, Issue 4, CD012654 (abstract). cochranelibrary.com
9. UChicago Medicine. “Ginseng reduces effects of anti-clotting drug.” News release on Yuan CS, et al., Annals of Internal Medicine, July 6, 2004. uchicagomedicine.org
10. American Family Physician. “Tips from Other Journals: American Ginseng Reduces Warfarin’s Effect” (on Yuan CS, et al., Ann Intern Med 2004;141:23-27). AFP 2005;71(9):1802-1804. aafp.org
11. Siegel RK. “Ginseng use among two groups in the United States.” Proceedings of the Ginseng Society Conference, Korean Society of Ginseng, 1980:229-236 (abstract). koreascience.kr
12. SupplySide Supplement Journal. “Ginseng adulteration remains prevalent, review finds.” January 13, 2026. supplysidesj.com
13. Ford P, U.S. CITES Scientific Authority, U.S. Fish and Wildlife Service. “Case Study: Panax quinquefolius (American ginseng).” International Expert Workshop on CITES Non-Detriment Findings, Cancun, November 2008. cites.org
14. National Center for Complementary and Integrative Health. “Using Dietary Supplements Wisely.” NIH, last updated January 2019, accessed October 2026. nccih.nih.gov
15. Xie JT, Mehendale SR, Maleckar SA, Yuan CS. “Is ginseng free from adverse effects?” Advances in Traditional Medicine, 2002;2(2):80-86 (abstract and reference list). koreascience.kr