Benefits
Upper respiratory tract infections
This is the one claim the cited research genuinely supports. A 2017 systematic review and meta-analysis pooling 33 randomized trials in 7,175 adults and children found andrographis eased cough and sore throat and shortened the time to symptom resolution compared with placebo, and an independent 2004 systematic review of 7 double-blind trials reached a similar conclusion. Both sets of authors flagged that the overall quality of the trials was poor and that results varied widely between them. Several trials tested combination products such as Kan Jang, which is andrographis plus eleuthero, rather than andrographis on its own. What is supported is easing symptoms once a cold has started, not preventing infection and not curing it.
Joint and arthritis claims: not supported by the research cited here
None of the studies cited on this page looked at joints, arthritis or inflammatory markers. Every reference here is about acute respiratory infection, so we cannot tell you that andrographis does anything for joint pain or swelling. Rheumatoid arthritis is a diagnosed medical condition that needs a doctor's care, and no supplement should be used in place of prescribed treatment.
Bowel disease claims: not supported by the research cited here
No study cited on this page involved ulcerative colitis or any bowel condition, and no comparison with prescription mesalamine appears anywhere in the cited research. Ulcerative colitis is a serious diagnosed illness that requires medical care, and andrographis should not be presented as an alternative to prescribed treatment for it.
How andrographolides behave in the laboratory
In cell and laboratory studies, andrographolides dampen signaling through the NF-kB pathway and lower pro-inflammatory messenger molecules. That is offered as one possible explanation for the respiratory symptom findings. None of the human studies cited on this page measured inflammation, so this is not proof of an anti-inflammatory effect in people and it does not extend the ingredient to other inflammatory conditions.
Antiviral activity (preclinical)
In test tube and animal work, andrographolide slows the replication of several respiratory viruses. This has not been shown in people: none of the human studies cited on this page measured virus levels or infection rates, so treat it as laboratory background rather than evidence that andrographis fights a virus in your body.
Liver claims: no supporting study on this page
Andrographis has a long traditional reputation for liver support, but not one of the studies cited on this page measured liver enzymes or any other marker of liver function. There is no evidence here to support a liver claim in either direction.
Bitter taste tolerability issues
Andrographis is extremely bitter ('King of Bitters' is literal). Quality capsules and tablets manage this issue; liquid extracts and traditional preparations require taste tolerance. Worth noting for those considering different formulations.
Mechanism of action
Covalent NF-κB p50 subunit binding
In cell studies, andrographolide's alpha-methylene lactone group attaches to a cysteine residue (Cys62) on the NF-kB p50 protein, which stops it binding DNA and switching on pro-inflammatory genes. This has been worked out in laboratory experiments rather than in people, and it has not been shown to produce a measurable anti-inflammatory effect in any human study cited on this page.
Nrf2 antioxidant pathway activation
In laboratory models, andrographolide activates the Nrf2-Keap1 pathway by modifying Keap1 at Cys-151, which turns on antioxidant enzymes such as HO-1, NQO1 and glutathione S-transferase. This is cell culture work. It suggests a plausible way the compound could be protective, but no human study cited on this page measured antioxidant or protective effects.
Antiviral activity seen in test tube and computer models
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. All of this comes from test tube and computer modeling work. Andrographis has not been tested as an antiviral treatment in any human trial cited here, and none of this means it will stop you catching or clearing a virus.
Clinical trials
Evidence review and pooled analysis of 33 randomized controlled trials (n=7,175) examining A. paniculata (alone or in herbal mixtures) for acute respiratory tract infections in adults and children. (Hu et al. 2017, PLOS One)
7,175 patients across 33 clinical trials of varying populations and settings.
Andrographis significantly improved cough (SMD: -0.39) and sore throat (SMD: -1.13) vs placebo. Statistically significant effect on overall ARTI symptoms vs placebo, usual care, and other herbal therapies. Shortened duration of cough, sore throat, and time to symptom resolution. Important limits: the authors rated the overall quality of the included trials as poor and found high variation between them, and many of the trials used andrographis inside herbal mixtures rather than on its own. The authors said the results should be interpreted cautiously. The finding is short-term relief of symptoms, not prevention of infection and not a cure.
Randomized, double-blind, placebo-controlled trial of a standardized A. paniculata extract (KalmCold, 200 mg/day) versus placebo in people with an uncomplicated upper respiratory tract infection. (Saxena et al. 2010, Phytomedicine)
223 people with an uncomplicated upper respiratory tract infection.
KalmCold reduced overall upper respiratory symptom severity compared with placebo, with the difference reaching statistical significance from about day 3. Two limits worth knowing: this result belongs to that specific branded extract at that dose rather than to andrographis products in general, and it describes easing the symptoms of an infection people already had.