American ginseng (Panax quinquefolius) often gets confused with its Asian cousin, but the two plants have different properties. Traditional Chinese medicine considers American ginseng “cooling” rather than “warming,” which is why it’s sometimes recommended for people who find Asian ginseng too stimulating.

I’ve looked through the clinical research on American ginseng to see what it can actually do. The evidence is mixed, as tends to be the case with herbal supplements, but there are a few areas where the data looks genuinely interesting.

What is American ginseng?

American ginseng is a perennial herb native to the deciduous forests of eastern North America, from southern Quebec down to Georgia and as far west as Oklahoma. It belongs to the same genus (Panax) as Asian ginseng, but the two species have distinct chemical profiles.

The active compounds are ginsenosides, a family of saponins found throughout the plant but concentrated in the roots. Researchers have identified over 30 different ginsenosides in American ginseng. These get divided into two main structural groups: the dammarane type (including Rb1, Rc, Rd, Re, and Rg1) and the oleanane type (Ro).

What’s interesting is that the ratio of ginsenosides differs between American and Asian ginseng. American ginseng tends to have higher concentrations of Rb1 and lower concentrations of Rg1, which may explain its traditionally milder, cooling reputation [1].

Beyond ginsenosides, American ginseng contains polysaccharides, polyynes, flavonoids, and volatile oils. The polysaccharides have attracted interest for immune-related effects, though the evidence is still developing.

Why choose American over Asian ginseng?

The traditional explanation is that Asian ginseng is “hot” and can cause overstimulation in some people, particularly those who already run warm or have high blood pressure. American ginseng is considered “cool” and gentler.

From a pharmacological standpoint, this makes some sense. The different ginsenoside ratios likely produce different effects. Some practitioners recommend American ginseng for people who want the adaptogenic benefits of ginseng without the stimulating qualities.

That said, I should note that “hot” and “cold” are traditional medicine concepts that don’t map neatly onto Western physiology. Whether the distinction matters for you depends partly on your philosophical approach to medicine.

What does the research show?

1. Common cold prevention

This is probably the best-studied use of American ginseng. The research centres on a standardised extract called COLD-fX (now known as CVT-E002), which contains specific polysaccharides from the root.

A Cochrane review from 2011 examined five randomised controlled trials involving 747 participants [2]. The extract appeared to reduce both the incidence and duration of colds and other acute respiratory infections. People taking the extract had fewer colds and recovered about 6.2 days faster than those on placebo.

Here’s my concern: all five trials were funded by the manufacturer, and the sample sizes were modest. The Cochrane authors concluded there was insufficient evidence to recommend American ginseng extract for cold prevention. I think that’s fair. The results are suggestive but not conclusive.

If you’re someone who catches every cold going around, it might be worth trying during winter months. But don’t expect miracles.

2. Type 2 diabetes and blood sugar control

There’s reasonable evidence that American ginseng can modestly improve blood sugar control in people with type 2 diabetes.

An 8-week randomised, double-blind, crossover trial gave 24 people with treated type 2 diabetes either American ginseng extract or placebo [3]. The ginseng group showed significant reductions in both fasting blood glucose and HbA1c (glycated haemoglobin, which reflects average blood sugar over roughly three months).

The mechanism likely involves how ginsenosides affect insulin secretion and glucose uptake. Some research suggests they may also reduce intestinal glucose absorption.

According to the NHS, people with diabetes should discuss any supplements with their GP, since they may affect blood sugar levels and interact with medications [4]. This is particularly important if you take insulin or sulphonylureas, where adding a blood sugar-lowering supplement could increase the risk of hypoglycaemia.

My reading: American ginseng isn’t a replacement for proper diabetes management, but it might provide modest additional benefit alongside conventional treatment.

3. Cognitive function and working memory

Working memory is the mental scratch pad you use for temporary information processing. It’s essential for following instructions, reading, mental arithmetic, and reasoning.

A randomised, double-blind, placebo-controlled crossover trial tested a standardised American ginseng extract (branded Cereboost, containing 10.65% ginsenosides) in 32 healthy adults [5]. Participants showed significant improvements in working memory performance within hours of taking the supplement.

This was a short-term study looking at acute effects, not long-term cognitive benefits. But the results were statistically significant and the study design was reasonably rigorous.

The proposed mechanism involves ginsenosides’ effects on acetylcholine and other neurotransmitters involved in memory. Some ginsenosides may also improve cerebral blood flow.

I find this genuinely interesting, though I’d want to see longer-term studies before drawing strong conclusions about cognitive enhancement.

Fatigue plagues cancer patients. It’s not ordinary tiredness. Cancer-related fatigue is a profound, persistent exhaustion that doesn’t improve with rest or sleep.

A large randomised, double-blind trial enrolled 364 cancer patients experiencing fatigue [6]. Participants received either 2000 mg of American ginseng daily or placebo for eight weeks. The ginseng group showed significant improvements on the Multidimensional Fatigue Symptom Inventory.

The improvement wasn’t dramatic, but it was statistically significant and clinically meaningful for many participants. The researchers suggested the mechanism might involve regulation of inflammatory pathways and the hypothalamic-pituitary-adrenal axis, which governs the body’s stress response.

This strikes me as one of the more promising uses for American ginseng. Cancer patients dealing with persistent fatigue have few good options, and the side effect profile of ginseng is relatively mild.

5. Oxidative stress protection

Oxidative stress occurs when reactive oxygen species overwhelm the body’s antioxidant defences. Some oxidative activity is normal, but too much contributes to ageing and disease.

A controlled study of 14 healthy adults found that drinking American ginseng tea (200 mL) protected cellular DNA from oxidative damage in the short term, as measured by the Comet assay [7].

The sample size here is tiny, so I wouldn’t draw strong conclusions. But it’s consistent with the known antioxidant properties of ginsenosides and polyphenols in ginseng.

6. Radiation protection

This is a more niche application, but it’s scientifically interesting. People undergoing radiation therapy for cancer sustain damage to healthy cells alongside tumour cells. Finding ways to protect normal tissue could improve treatment tolerability.

An in vitro study found that American ginseng extract reduced radiation-induced cellular damage to a degree comparable to amifostine (WR-1065), the only FDA-approved radioprotector [8]. The effect was measured using a micronucleus assay, which detects chromosomal damage.

This is cell culture research, not a human trial, so the clinical relevance is uncertain. But it’s an area worth watching, particularly for people undergoing radiation treatment.

7. Blood pressure regulation

Hypertension affects roughly a third of adults. Untreated, it raises the risk of heart attack, stroke, and kidney damage. Most cases are “essential” hypertension with no identifiable cause.

A 12-week randomised, double-blind trial studied 64 patients with well-controlled essential hypertension who also had type 2 diabetes [9]. Those taking 3 grams of American ginseng daily showed reduced arterial stiffness (measured by augmentation index) and an 11.7% reduction in systolic blood pressure compared to placebo. Diastolic blood pressure wasn’t significantly affected.

This is a modest effect, but in someone already managing hypertension with medication, it could provide additional benefit. The combination with diabetes is relevant because these conditions often occur together and share underlying vascular dysfunction.

Side effects of American ginseng

At typical doses and durations, American ginseng has a good safety profile. Most people tolerate it well.

Reported side effects include:

Digestive upset (diarrhoea, nausea, stomach discomfort)
Insomnia or difficulty sleeping
Headache
Restlessness or nervousness
Changes in blood pressure (increases or decreases)
Breast tenderness in women
Itching or skin reactions

Rare but serious reactions have been reported, including cholestatic hepatitis, severe allergic skin reactions (Stevens-Johnson syndrome), and cerebral arteritis. These are very uncommon but worth knowing about.

Safety precautions and contraindications

1. Pregnancy and breastfeeding — There’s insufficient safety data, so most guidelines recommend avoiding American ginseng during pregnancy and lactation.

2. Diabetes medications — Because American ginseng can lower blood sugar, combining it with diabetes medications may increase hypoglycaemia risk. Relevant medications include insulin, metformin, glimepiride, glyburide, pioglitazone, rosiglitazone, glipizide, and tolbutamide. Monitor blood glucose carefully and discuss with your doctor.

3. Oestrogen-sensitive conditions — Some ginsenosides may have weak oestrogenic effects. People with breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids should use caution.

4. Insomnia — Although American ginseng is considered less stimulating than Asian ginseng, it can still cause sleep problems in sensitive individuals. Avoid taking it in the evening.

5. Schizophrenia and related conditions — High doses have been associated with sleep disturbance, restlessness, and agitation. Use cautiously if you have schizophrenia or other psychiatric conditions.

6. Surgery — American ginseng may affect blood sugar control and potentially bleeding. Stop taking it at least two weeks before any scheduled surgery.

7. Warfarin (blood thinners) — American ginseng may reduce the effectiveness of warfarin, potentially increasing clotting risk. If you take anticoagulants, discuss with your doctor before using ginseng.

8. Monoamine oxidase inhibitors (MAOIs) — Combining American ginseng with MAOIs like phenelzine or tranylcypromine may cause anxiety, headache, irritability, and insomnia.

Recommended dosage

Clinical trials have used doses ranging from 200 mg to 3 grams daily. For blood sugar effects, 3 grams appears to be the common dose in research. For cognitive effects, 200-400 mg of standardised extract has been studied.

The ginsenoside content varies considerably between products, which makes it difficult to give precise recommendations. Look for products standardised to a specific ginsenoside percentage (often around 4-5%) from reputable manufacturers.

The bottom line

American ginseng is a reasonable choice for people interested in adaptogens who find Asian ginseng too stimulating. The evidence is strongest for modest effects on blood sugar control and cancer-related fatigue. The cold prevention data is intriguing but needs independent replication.

Like most herbal supplements, it’s not a miracle cure for anything. But it appears reasonably safe for most people and may provide genuine, if modest, benefits in specific contexts.

References

Qi LW, Wang CZ, Yuan CS. Ginsenosides from American ginseng: chemical and pharmacological diversity. Phytochemistry. 2011;72(8):689-699. PubMed
Seida JK, Durec T, Kuhle S. North American (Panax quinquefolius) and Asian Ginseng (Panax ginseng) Preparations for Prevention of the Common Cold in Healthy Adults: A Systematic Review. Evidence-Based Complementary and Alternative Medicine. 2011;2011:282151. PMC
Vuksan V, et al. Efficacy and safety of American ginseng (Panax quinquefolius L.) extract on glycemic control and cardiovascular risk factors in individuals with type 2 diabetes: a double-blind, randomized, cross-over clinical trial. Eur J Nutr. 2019;58(3):1237-1245. PubMed
NHS. Herbal medicines. NHS Website
Scholey A, et al. Effects of American ginseng (Panax quinquefolius) on neurocognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study. Psychopharmacology. 2010;212(3):345-356. PMC
Barton DL, et al. Wisconsin Ginseng (Panax quinquefolius) to improve cancer-related fatigue: a randomized, double-blind trial, N07C2. J Natl Cancer Inst. 2013;105(16):1230-1238. PMC
Lee J, et al. Protective effect of American ginseng on oxidative stress-induced cellular damage in human lymphocytes. Int J Food Sci Nutr. 2016;67(3):293-299. PubMed
Poon PY, Kwok HH, Yue PY, et al. Cytoprotective effect of a proprietary panax notoginseng formulation on human bronchial epithelial cells. Mutat Res. 2010;690(1-2):46-52. PubMed
Mucalo I, et al. Effect of American ginseng (Panax quinquefolius L.) on arterial stiffness in subjects with type-2 diabetes and concomitant hypertension. J Ethnopharmacol. 2013;150(1):148-153. PubMed