Adaptogens for "Immune Support": Claims Checked
Claims that adaptogens support or boost immunity checked against reviews of astragalus and ginseng, with cautions for autoimmune conditions and immune-suppressing medicines.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read who should be careful, by situation before you use anything on this page.
> Autoimmune condition, or taking medicine that lowers immune activity? NIH says people with autoimmune diseases should avoid astragalus, and that astragalus may interact with medicines that suppress the immune system. [1] It also says Asian ginseng may worsen autoimmune disorders. [2] Ask the prescriber or pharmacist first.
The claim as it is marketed
Labels say adaptogens "boost" or "support" immunity, often for cold-and-flu season. Harvard Health notes that the idea of boosting immunity is enticing, but the ability to do so has proved elusive, because the immune system is a system and not a single entity. [3] It adds that some herbal preparations alter some components of immune function, but there is no evidence they bolster immunity enough to protect better against infection and disease. [3] Read how the immune system works for background.Plants and parts discussed
- Astragalus root: NIH says the root has been used for centuries in traditional Chinese medicine, often combined with other herbs, and calls it an adaptogen, a natural substance theorized to stimulate resistance to stress. [1] GBIF lists Astragalus mongholicus Bunge as an accepted species; our GBIF check for A. membranaceus matched only the genus, so check which species a product or study names. [4]
- Panax ginseng (Asian ginseng) root and Panax quinquefolius (American ginseng) root: two different species with different studies; see Asian ginseng and American ginseng.
What research found
| Question | What the source found | Strength of evidence |
|---|---|---|
| Does astragalus help any health condition? | NIH: there is not sufficient reliable scientific evidence to know whether astragalus is useful for any health condition. [1] | Insufficient evidence |
| Does astragalus change immune markers? | A 2023 meta-analysis of 19 studies (1,094 participants) reported lower proinflammatory cytokines and higher CD3 and CD4/CD8 values, with substantial heterogeneity between studies. [5] NIH says the studies were small and varied. [1] | Biomarker findings only; clinical benefit not shown |
| Does Asian ginseng prevent flu? | NIH: very preliminary research suggests Asian ginseng extract may help reduce the risk of developing the flu but not the severity or duration of symptoms. [2] | Promising but limited |
| Does ginseng reduce upper respiratory infections? | A 2020 review of nine articles (ten trials) of P. ginseng or P. quinquefolius reported some activity when given alongside influenza vaccination, but risk of bias was high to unclear and the authors said the evidence does not allow conclusions. [6] | Insufficient evidence |
| Does North American ginseng shorten colds? | A 2011 review of five trials, all of North American ginseng, said evidence is insufficient to conclude ginseng reduces incidence or severity of colds, but it appeared to shorten duration when taken preventatively for 8 to 16 weeks. [7] | Mixed |
| Does ashwagandha help against COVID-19? | NIH: there is not sufficient high-quality evidence to support its use. [8] | Insufficient evidence |
A change in a cytokine or a cell count is a biomarker; it is not the same as getting fewer infections. Harvard Health makes the same point: scientists do not know whether an herb that raises antibody levels is actually doing anything beneficial. [3]
Limits
- Different extracts, species, plant parts and amounts were tested; one result cannot be applied to a different product.
- The ginseng review's positive signal came from supplementation alongside influenza vaccination and standard care, so the herb's own contribution is unclear. [6]
- We did not find, in the sources we read, a trial showing an adaptogen prevents a specific infection better than established prevention. This is "Proper evidence not found," searched in PubMed reviews and NIH pages.
Frequently asked questions
Do adaptogens boost the immune system?
No source we read shows that. Harvard Health says there is no evidence that herbal preparations bolster immunity enough to protect better against infection. [3]
Does astragalus help immunity?
Human studies report changes in lab markers, but NIH says there is not sufficient reliable evidence that astragalus is useful for any health condition. [5][1]
Does ginseng prevent colds or flu?
Results are limited and mixed: a review found insufficient evidence on incidence, but North American ginseng appeared to shorten colds in two trials. [7]
Who should avoid these herbs?
NIH says people with autoimmune diseases should avoid astragalus, and Asian ginseng may worsen autoimmune disorders. [1][2]
Can I use these instead of a vaccine?
The ginseng review examined supplementation alongside influenza vaccination, not instead of it. [6]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
- Astragalus: NIH says a thorough safety evaluation has not been done, little is known in pregnancy or breastfeeding, and some animal research suggests toxicity to the fetus. [1]
- Asian ginseng: insomnia is the most common side effect; severe rash, liver damage and severe allergic reactions are uncommon reports; it may interfere with blood clotting. [2]
- Immune-suppressed, transplant, or autoimmune conditions: see adaptogens, autoimmune conditions and immunosuppressants and how interactions work.
- Sleep, activity, nutrition and vaccination are covered in supporting immune health.
References
- Astragalus: Usefulness and Safety (NCCIH, NIH). Read 2026-10-23.
- Asian Ginseng: Usefulness and Safety (NCCIH, NIH). Read 2026-10-23.
- How to boost your immune system (Harvard Health Publishing). Read 2026-10-23.
- GBIF Backbone Taxonomy, species name matching (api.gbif.org species/match), checked for Withania somnifera, Rhodiola rosea, Panax ginseng, Panax quinquefolius, Ocimum sanctum, Astragalus mongholicus, Lepidium meyenii. Read 2026-10-23.
- The Effect of Astragalus on Humoral and Cellular Immune Response: systematic review and meta-analysis of human studies, Complement Med Res 2023 (PubMed 37952511). Read 2026-10-23.
- Ginseng integrative supplementation for seasonal acute upper respiratory infections: systematic review and meta-analysis, Complement Ther Med 2020 (PubMed 32951718). Read 2026-10-23.
- North American and Asian ginseng preparations for prevention of the common cold in healthy adults: a systematic review, Evid Based Complement Alternat Med 2011 (PubMed 19592479). Read 2026-10-23.
- Ashwagandha: Usefulness and Safety (NCCIH, NIH; last updated March 2023). Read 2026-10-23.