Supplements for immune support

16 compounds relevant to immune support, ranked by overall evidence grade.

Overall grade: Grade A
Last revised: Jul 10, 2026; 16
graded outcomes: 0
references listed

Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.

2 at grade A · 5 at grade B · 8 at grade C · 1 at grade D — 16 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
Vitamin DA steroid hormone precursor that most temperate-latitude adults run low on — worth correcting, oversold as a cure-all.	Evidence grade A	Unclear	mixed
Vitamin CAn essential antioxidant and enzyme cofactor — cures scurvy, modestly shortens colds, and triples plant-iron absorption.	Evidence grade A	Unclear	mixed
Vitamin AEssential for vision and immunity; a public-health hero in deficiency, and a supplement to handle carefully — beta-carotene raised lung-cancer risk in smokers.	Evidence grade B	Unclear	mixed
ZincAn immune and hormone cofactor that shortens colds when dosed right — and drains copper when overdone.	Evidence grade B	Unclear	mixed
CranberryGenuinely reduces recurrent UTIs via proanthocyanidins — prevention, not treatment.	Evidence grade B	Unclear	mixed
AndrographisOne of the better-evidenced herbs for shortening upper-respiratory infections.	Evidence grade B	Unclear	mixed
Beta-GlucansTwo different molecules under one name: oat beta-glucan reliably lowers LDL; yeast/mushroom beta-glucan modulates immunity.	Evidence grade B	Unclear	mixed
ElderberryA popular cold-and-flu berry with small, industry-tinged trials suggesting shorter symptoms — real but overstated.	Evidence grade C	Unclear	mixed
EchinaceaThe classic cold herb — meta-analyses hover near null, with maybe a small prevention/duration effect for some preparations.	Evidence grade C	Unclear	mixed
ReishiA calming medicinal mushroom with immune and sleep signals — better data as a cancer-care adjunct than as a daily tonic.	Evidence grade C	Unclear	mixed
Turkey TailThe best-evidenced medicinal mushroom — its PSK/PSP fractions are real cancer-immunotherapy adjuncts in Asia.	Evidence grade C	Unclear	mixed
AstragalusA traditional immune tonic with adjunct-in-chemo and kidney-protection signals — thin standalone evidence.	Evidence grade C	Unclear	mixed
Olive Leaf ExtractAn oleuropein-rich extract with modest blood-pressure data and antioxidant claims.	Evidence grade C	Unclear	mixed
American GinsengDistinct from Asian ginseng — its best data are for glucose control and reducing cold frequency.	Evidence grade C	Unclear	mixed
L-LysineAn essential amino acid with modest evidence for reducing cold-sore (herpes) recurrences.	Evidence grade C	Unclear	mixed
ChagaAn antioxidant-rich fungus with essentially no human trials — and a real oxalate/kidney caution.	Evidence grade D	Unclear	mixed

Vitamin DEvidence grade A
A steroid hormone precursor that most temperate-latitude adults run low on — worth correcting, oversold as a cure-all.
Unclearmixed
Vitamin CEvidence grade A
An essential antioxidant and enzyme cofactor — cures scurvy, modestly shortens colds, and triples plant-iron absorption.
Unclearmixed
Vitamin AEvidence grade B
Essential for vision and immunity; a public-health hero in deficiency, and a supplement to handle carefully — beta-carotene raised lung-cancer risk in smokers.
Unclearmixed
ZincEvidence grade B
An immune and hormone cofactor that shortens colds when dosed right — and drains copper when overdone.
Unclearmixed
CranberryEvidence grade B
Genuinely reduces recurrent UTIs via proanthocyanidins — prevention, not treatment.
Unclearmixed
AndrographisEvidence grade B
One of the better-evidenced herbs for shortening upper-respiratory infections.
Unclearmixed
Beta-GlucansEvidence grade B
Two different molecules under one name: oat beta-glucan reliably lowers LDL; yeast/mushroom beta-glucan modulates immunity.
Unclearmixed
ElderberryEvidence grade C
A popular cold-and-flu berry with small, industry-tinged trials suggesting shorter symptoms — real but overstated.
Unclearmixed
EchinaceaEvidence grade C
The classic cold herb — meta-analyses hover near null, with maybe a small prevention/duration effect for some preparations.
Unclearmixed
ReishiEvidence grade C
A calming medicinal mushroom with immune and sleep signals — better data as a cancer-care adjunct than as a daily tonic.
Unclearmixed
Turkey TailEvidence grade C
The best-evidenced medicinal mushroom — its PSK/PSP fractions are real cancer-immunotherapy adjuncts in Asia.
Unclearmixed
AstragalusEvidence grade C
A traditional immune tonic with adjunct-in-chemo and kidney-protection signals — thin standalone evidence.
Unclearmixed
Olive Leaf ExtractEvidence grade C
An oleuropein-rich extract with modest blood-pressure data and antioxidant claims.
Unclearmixed
American GinsengEvidence grade C
Distinct from Asian ginseng — its best data are for glucose control and reducing cold frequency.
Unclearmixed
L-LysineEvidence grade C
An essential amino acid with modest evidence for reducing cold-sore (herpes) recurrences.
Unclearmixed
ChagaEvidence grade D
An antioxidant-rich fungus with essentially no human trials — and a real oxalate/kidney caution.
Unclearmixed

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: Elderberry (grade C); Echinacea (grade C); Reishi (grade C); Turkey Tail (grade C); Astragalus (grade C); Olive Leaf Extract (grade C); American Ginseng (grade C); L-Lysine (grade C); Chaga (grade D).
Studies disagree: Vitamin D (mixed agreement); Vitamin C (mixed agreement); Vitamin A (mixed agreement); Zinc (mixed agreement); Cranberry (mixed agreement); Andrographis (mixed agreement); Beta-Glucans (mixed agreement).

The evidence in words

The shortlist

Every compound in the knowledge base tagged to immune support, ordered by how strong its overall evidence is. Start at the top; the grade is the honest filter.

Worth considering first

Vitamin D (A) — A steroid hormone precursor that most temperate-latitude adults run low on — worth correcting, oversold as a cure-all. · Vitamin C (A) — An essential antioxidant and enzyme cofactor — cures scurvy, modestly shortens colds, and triples plant-iron absorption. · Vitamin A (B) — Essential for vision and immunity; a public-health hero in deficiency, and a supplement to handle carefully — beta-carotene raised lung-cancer risk in smokers. · Zinc (B) — An immune and hormone cofactor that shortens colds when dosed right — and drains copper when overdone. · Cranberry (B) — Genuinely reduces recurrent UTIs via proanthocyanidins — prevention, not treatment. · Andrographis (B) — One of the better-evidenced herbs for shortening upper-respiratory infections. · Beta-Glucans (B) — Two different molecules under one name: oat beta-glucan reliably lowers LDL; yeast/mushroom beta-glucan modulates immunity.

Lower-evidence options

Elderberry (C) — A popular cold-and-flu berry with small, industry-tinged trials suggesting shorter symptoms — real but overstated. · Echinacea (C) — The classic cold herb — meta-analyses hover near null, with maybe a small prevention/duration effect for some preparations. · Reishi (C) — A calming medicinal mushroom with immune and sleep signals — better data as a cancer-care adjunct than as a daily tonic. · Turkey Tail (C) — The best-evidenced medicinal mushroom — its PSK/PSP fractions are real cancer-immunotherapy adjuncts in Asia. · Astragalus (C) — A traditional immune tonic with adjunct-in-chemo and kidney-protection signals — thin standalone evidence. · Olive Leaf Extract (C) — An oleuropein-rich extract with modest blood-pressure data and antioxidant claims. · American Ginseng (C) — Distinct from Asian ginseng — its best data are for glucose control and reducing cold frequency. · L-Lysine (C) — An essential amino acid with modest evidence for reducing cold-sore (herpes) recurrences. · Chaga (D) — An antioxidant-rich fungus with essentially no human trials — and a real oxalate/kidney caution.

Goes with

Vitamin DGrade AEvidence grade A
Vitamin CGrade AEvidence grade A
Vitamin AGrade BEvidence grade B
ZincGrade BEvidence grade B
CranberryGrade BEvidence grade B
AndrographisGrade BEvidence grade B
Beta-GlucansGrade BEvidence grade B
ElderberryGrade CEvidence grade C

Entries that share this one's tags or conditions.

American GinsengDistinct from Asian ginseng — its best data are for glucose control and reducing cold frequency.Evidence grade C
American Ginseng for Cold incidence/durationEvidence grade C — Specific extractEvidence grade C
American Ginseng for Post-meal glucoseEvidence grade C — ModestEvidence grade C
American Ginseng: dosage and how to take itStandardized extract per goal.Evidence grade C

Sources

This entry lists no references of its own — it is assembled from the entries it links to, whose sources are on their pages.

Last revised Jul 10, 2026. A grade is this entry's reading of the evidence, not medical advice.