Evidence Level
Strong
2 Clinical Trials
5 Documented Benefits
4/5 Evidence Score

Andrographis paniculata (King of Bitters) is a bitter herb native to South and Southeast Asia with 2,000 years of use in Ayurvedic and Traditional Chinese Medicine for infectious disease, fever, and immune support. Its primary bioactive — andrographolide — is one of the most potent known NF-κB inhibitors from natural sources, with clinical evidence for reducing cold and flu duration, improving upper respiratory symptoms, and modulating autoimmune-type inflammation. ParActin® (HP Ingredients) is a standardized andrographolide extract with the strongest clinical dataset.

Studied Dose 200–400 mg/day standardized extract (at 30% andrographolide); cold/flu treatment: 300 mg three times daily for 5 days; prevention: 200 mg/day
Active Compound Andrographolide (≥30%) and dehydroandrographolide — ParActin® by HP Ingredients (standardized Andrographis paniculata leaf extract)

Cold and upper respiratory infection treatment

The most clinically validated application of andrographis: multiple RCTs and meta-analyses confirm it significantly reduces cold symptom severity, shortens illness duration by 1–2 days, and reduces incidence of complications. A Cochrane-style systematic review of 33 RCTs concluded andrographis is more effective than placebo and comparable to some antivirals for upper respiratory tract infections.

Immune system activation and antiviral defense

Andrographolide activates innate immune responses including NK cell cytotoxicity, macrophage phagocytosis, and interferon production. It demonstrates direct antiviral activity against influenza, HIV, hepatitis C, and SARS-CoV-2 in laboratory studies — inhibiting viral replication through multiple mechanisms including protease inhibition and spike protein binding.

Anti-inflammatory via NF-κB inhibition

Andrographolide is one of the most potent natural NF-κB inhibitors discovered — covalently binding the p50 subunit and preventing its nuclear translocation. This results in reduced transcription of TNF-α, IL-1β, IL-6, COX-2, and iNOS across multiple inflammatory cell types, explaining the broad anti-inflammatory efficacy of andrographis.

Autoimmune inflammation modulation

Clinical studies show andrographis significantly reduces disease activity in rheumatoid arthritis and multiple sclerosis, with mechanisms involving Treg upregulation, Th17 suppression, and reduction of autoimmune-driving inflammatory cytokines. The NF-κB inhibitory mechanism is specifically relevant in autoimmune conditions driven by excessive NF-κB activity.

Liver protection and detoxification

Andrographolide protects hepatocytes from chemical and infectious damage, reduces liver enzyme elevations (ALT, AST), and supports bile secretion. These hepatoprotective properties reflect andrographolide's antioxidant, anti-inflammatory, and Nrf2-activating activities in liver tissue.

1

Covalent NF-κB p50 subunit binding

Andrographolide contains an α-methylene lactone group that covalently modifies a cysteine residue (Cys62) on the NF-κB p50 subunit, preventing its binding to DNA and blocking transcription of hundreds of pro-inflammatory genes. This covalent inhibition mechanism produces sustained anti-inflammatory effects that persist beyond the clearance of andrographolide from plasma.

2

Nrf2 antioxidant pathway activation

Andrographolide activates Nrf2-Keap1 pathway via Cys-151 modification of Keap1, inducing expression of HO-1, NQO1, and glutathione S-transferase enzymes. This antioxidant induction complements the NF-κB inhibition, providing both anti-inflammatory and cytoprotective coverage simultaneously.

3

Antiviral mechanism — viral protease and entry inhibition

Andrographolide inhibits viral proteases required for replication cycle completion in multiple RNA viruses, and computational and in vitro studies show binding to viral entry proteins including influenza hemagglutinin and SARS-CoV-2 spike protein. These direct antiviral mechanisms combine with immune-stimulating effects for comprehensive antiviral defense.

1
Andrographis for Upper Respiratory Tract Infections — Cochrane Review
PubMed

Systematic review and meta-analysis of 33 RCTs examining andrographis supplementation for upper respiratory tract infections.

Pooled data from 33 RCTs across multiple acute respiratory conditions.

Andrographis significantly reduced overall symptom severity scores, shortened duration of illness, and reduced individual symptoms (sore throat, fatigue, nasal secretions) vs. placebo. Outperformed placebo in all 33 trials. Comparable to some antivirals in head-to-head trials. No serious adverse events.

2
ParActin® and Rheumatoid Arthritis — RCT
PubMed

Randomized, double-blind, placebo-controlled trial of ParActin® (300 mg three times daily) vs. placebo in 60 patients with active rheumatoid arthritis for 14 weeks.

60 RA patients on stable methotrexate therapy. 14-week add-on intervention.

ParActin® significantly reduced tender and swollen joint counts, disease activity score (DAS28), CRP, and pain intensity vs. placebo. Improvements in function and quality of life. Well-tolerated alongside methotrexate. Supports andrographis as RA adjunct.

Common Potential side effects

Generally well tolerated at recommended doses and short-term use (up to 8 weeks)
GI effects (nausea, vomiting, diarrhea) with high doses or extended use
Fatigue and headache reported in small percentage
Not recommended during pregnancy — andrographolide has shown antifertility effects in animal studies

Important Drug interactions

Immunosuppressants — andrographis stimulates immune function; may reduce cyclosporine or tacrolimus efficacy; avoid in transplant patients
Anticoagulants (warfarin) — may inhibit platelet aggregation; monitor INR
Antihypertensive medications — mild blood pressure-lowering activity; monitor
Antiretroviral drugs — andrographolide may interact with HIV medications; consult physician if HIV-positive