Astragalus

Astragalus (Astragalus membranaceus) is used by some clinicians as a supportive (immune-modulating) herb in people with Lyme disease, but there are no high-quality clinical trials showing astragalus cures or reliably treats Borrelia infection. The best evidence for astragalus is that it modulates immune function (polysaccharides that change cytokines, T-cell responses, etc.), not that it reliably kills Borrelia.

Immunomodulation / immune stimulation. The main active constituents (notably astragalus polysaccharides, flavonoids and saponins) have been shown in multiple animal and human studies to enhance humoral and cellular immune responses (increase some T-cell markers, antibody responses, alter cytokines). This is the primary biological rationale for using astragalus as supportive therapy in infectious or post-infectious conditions. SpringerLink Oxford Academic

Anti-inflammatory / antioxidant effects. Reviews and mechanistic studies show astragalus extracts reduce some inflammatory mediators and have antioxidant effects that could help symptoms related to inflammation and fatigue (a common complaint with Lyme). ScienceDirect SpringerLink

Adjuvant / supportive role rather than direct antibiotic action. Large in-vitro screening of botanicals for anti-Borrelia activity (Johns Hopkins / Frontiers 2020) tested 12 commonly used herbs and found several that were active against Borrelia burgdorferi in vitro (Cryptolepis, Japanese knotweed, etc.), but astragalus was not identified as one of the botanicals that directly killed Borrelia. That suggests astragalus’s role — if any — is more likely immune-supportive than directly bactericidal. Frontiers

Common formulations & typical dosing ranges found in clinical/traditional usage:

• Dried root (decoction / tea): commonly prepared as a decoction; typical dried-root doses reported: ~6–30 g/day (often 10–15 g/day as a common range in TCM). Some sources note up to 30 g/day; very large historical doses (reported in reviews) up to 60 g/day have been used short-term in studies, but that is not routine. Traditional Medicines WebMD
• Powder / capsule extracts: supplements commonly provide ~500 mg – 2,000 mg (0.5–2 g) per day of extract in divided doses; many clinical trials use granule formulations in the gram range (see trials cited below). WebMD Drugs.com
• Tincture / liquid extract: typical practitioner tincture dosing is 2–5 mL, 2–3 times daily, depending on concentration. (Concentrations vary by product.) Traditional Medicines
• Clinical trial examples (non-Lyme): some randomized trials of astragalus-containing granules for kidney or cardiovascular conditions used several grams twice daily (e.g., 2.25–7.5 g per dose twice daily in a cardiovascular granule study). These trial doses vary by product and preparation. Auctores

How practitioners commonly incorporate astragalus for Lyme (practice notes — not proven):

• Supportive / adjunctive: some Lyme clinicians add astragalus to support immunity during or after antibiotic therapy rather than as a stand-alone antimicrobial. There is no standard Lyme protocol that uses astragalus alone. Frontiers NCCIH
• Monitoring: if used, clinicians typically monitor symptoms, inflammatory markers and any signs of autoimmune activation or worsening (see warnings below).

• No randomized clinical trials demonstrating astragalus as an effective anti-Borrelia therapy. Reviews and Lyme advocacy pages note that several botanicals have promising in vitro activity (see the 2020 Frontiers in Medicine study), but astragalus was not among the herbs that showed strong direct anti-Borrelia activity in that screening. That 2020 in-vitro work is frequently cited in herbal-Lyme literature to point toward herbs that do have direct anti-Borrelia effects — astragalus was not one of them. Frontiers
• Human studies exist for immune-related outcomes, not Lyme cure. There are systematic reviews and meta-analyses showing astragalus can modify immune markers and was used as an adjunct in conditions like hepatitis B or membranous nephropathy — these support immune modulation but do not demonstrate efficacy vs Borrelia infection. Key examples: a 2023 systematic review/meta-analysis on astragalus and humoral/cellular immunity; reviews of astragalus polysaccharide mechanisms; and vaccine-adjuvant type studies showing increased antibody/T-cell responses. These are mechanistic and supportive data, not Lyme clinical trials. Karger SpringerLink Oxford Academic
• Authoritative bodies/clearinghouses: NCCIH (NIH) states there is insufficient reliable evidence to know whether astragalus is useful for any specific health condition and summarizes immunological studies but notes the quality/heterogeneity of trials. NCCIH

Summary: the scientific literature supports astragalus as an immune-modulating herb (and shows mechanistic plausibility for symptom support), but there is no clinical trial evidence showing astragalus eradicates Borrelia or should replace standard antibiotic therapy for Lyme disease. Frontiers Karger