Compound Monograph
Syringic acid
Syringic acid is a dimethoxy hydroxybenzoic (phenolic) acid — the 3,5-dimethoxy relative of gallic and vanillic acid — found across fruits, whole grains, honey and wine. A well-characterized dietary antioxidant with broad but entirely preclinical antidiabetic and organ-protective activity, moderate native oral bioavailability, and no human trials of the isolate.
Sources · 8
Where Does It Come From?
Syringic acid is a naturally occurring hydroxybenzoic acid (phenolic acid), found in Chickweed, Marshmallow, Yerba maté and 5 other sources. It is well tolerated orally (low toxicity).
Principal source Chickweed Stellaria media Herb monograph → 
Source Cramp Bark Viburnum opulus Herb monograph → 
Source Isatis Isatis indigotica Herb monograph → 
Source Marshmallow Althaea officinalis Herb monograph → 
Source Yerba Maté Ilex paraguariensis Herb monograph → Concentration
Content by Source
Concentrations not reported. No percent-dry-weight or mg/g figures have been published for this compound in its source plants.
Syringic acid at a Glance
Syringic acid is a dimethoxy hydroxybenzoic acid — the 3,5-dimethoxy relative of gallic and vanillic acid — found across fruits, whole grains, honey and wine.
It is a well-characterised dietary antioxidant with a broad but entirely preclinical activity profile.
What It's Used For
Syringic acid is a dimethoxy phenolic acid — the 3,5-dimethoxy sibling of gallic acid and vanillic acid — and a ubiquitous dietary compound found in fruits, whole grains, honey and wine. Its best-substantiated property is antioxidant activity: the dimethoxy-phenol ring is a direct radical scavenger, and in cell and animal models it raises endogenous defenses (SOD, catalase, glutathione) via Nrf2 1,
Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Zero human isolate trials, so scores stay low by design.
The dimethoxy-phenol ring neutralizes ROS directly, and in cell/animal models syringic acid raises SOD, catalase and glutathione via Nrf2 — the property under all the disease claims below 1,
Gap: mechanism, not outcome — no human antioxidant-biomarker trial of the isolate; all data in-vitro or rodent 1Reference 1ReviewSyringic acid — a review of its occurrence, biosynthesis, and pharmacological importanceView study →.
In diabetic rodents, syringic acid lowers hyperglycemia and protects heart, kidney, liver and nerve tissue from chronic-hyperglycemia damage 3Reference 3AnimalSyringic acid ameliorates cardiac, hepatic, renal and neuronal damage induced by chronic hyperglycaemia in Wistar ratsView study →, and accelerates diabetic wound healing 4Reference 4AnimalAcceleration of wound-healing activity with syringic acid in streptozotocin-induced diabetic ratsView study →.
Gap: entirely rodent; no human glycemic trial, and effect sizes and dose translation are unestablished 3,
Syringic acid suppresses pro-inflammatory signaling (NF-κB, NLRP3/caspase-1/IL-1β) while activating PPARγ/Nrf2 — shown in keratinocytes 5Reference 5Syringic acid suppresses Cutibacterium acnes-induced inflammation in keratinocytes via NLRP3/caspase-1/IL-1β by activating PPARγ/Nrf2View study → and as a recurring secondary readout across the organ-protection studies 2Reference 2Antioxidant and anti-inflammatory potential of syringic acid: mechanistic insights and pathway interactionsView study →.
Gap: no isolated-compound human anti-inflammatory data; supports mechanism, not a treatment claim 2,
Syringic acid reduces CCl₄-induced liver injury 6Reference 6Hepatoprotective effect of syringic acid and vanillic acid on CCl₄-induced liver injuryView study →, mitigates myocardial ischemia-reperfusion injury via PI3K/Akt/GSK-3β 7Reference 7Syringic acid mitigates myocardial ischaemia-reperfusion injury by activating the PI3K/Akt/GSK-3β pathwayView study →, and is protective in neuronal oxygen-glucose-deprivation models 8Reference 8Neuroprotective effects of syringic acid against OGD/R-induced injury in cultured hippocampal neuronsView study →.
Gap: all rodent/in-vitro; these benefits are downstream antioxidant/anti-inflammatory effects, not demonstrated clinical uses 6,
Syringic acid induces apoptosis and inhibits proliferation (AKT/mTOR) in colorectal and gastric cancer models, in vitro and in vivo 9Reference 9In-vitro and in-vivo anticancer effects of syringic acid on colorectal cancerView study →.
Gap: cell-line and rodent only, often at supraphysiologic concentrations — not evidence for human cancer therapy 9Reference 9In-vitro and in-vivo anticancer effects of syringic acid on colorectal cancerView study →.
Mechanisms
| Target / pathway | Effect | Relevant to |
|---|---|---|
| Direct radical scavenging (dimethoxy-phenol) | neutralizes ROS | antioxidant (all uses) |
| Nrf2 / antioxidant enzymes | ↑ SOD, catalase, glutathione | antioxidantorgan protection |
| NF-κB / NLRP3–caspase-1–IL-1β | suppressed | anti-inflammatoryorgan protection |
| PPARγ | activated (↑ insulin sensitivity, anti-inflammatory) | metabolic |
| PI3K/Akt/GSK-3β | ↓ myocardial ischemia-reperfusion injury | cardioprotective |
| AKT/mTOR → apoptosis | pro-apoptotic in tumor cells | anticancer (preclinical) |
Pharmacokinetics
Syringic acid is orally absorbed as a small phenolic acid and undergoes phase-II conjugation (methylation, glucuronidation, sulfation) typical of hydroxybenzoic acids, giving moderate but limited native oral bioavailability. That ceiling is why much of the recent literature is formulation work — self-microemulsifying systems, liposomes and micelles — aimed at raising exposure and antioxidant/hepatoprotective efficiency over the free acid 10Reference 10Improved oral bioavailability and hypolipidemic effect of syringic acid via a self-microemulsifying drug-delivery systemView study →. No dedicated human single-dose pharmacokinetic study of the isolate exists; human exposure is inferred from general dietary-phenolic handling.
Clinical trials
There are no human trials of isolated syringic acid for any indication. All efficacy evidence is in-vitro, rodent, or whole-extract (where syringic acid is one marker phenolic).
| Completed | Planned | Terminated | Preclinical |
|---|---|---|---|
| —(none, isolate) | — | — | Extensive |
Last checked: July 2026.
Toxicity & Safety
Syringic acid is something most people already eat every day, and at those amounts it looks benign — the open question is the isolated supplement, for which there is simply no human safety dataset at all.
- A ubiquitous dietary phenolic. Present in fruits, berries, whole grains, honey and wine, and regarded as low-toxicity at dietary and studied preclinical doses.
- Protective in liver-injury models. It has been co-administered as a protective agent against drug-induced liver injury.
- No human safety data for the isolate. No verified interaction, contraindication or overdose dataset exists.
- Theoretical polyphenol cautions. High-concentration pro-oxidant behavior and competition at conjugation enzymes are possible but not clinically documented.
Full Safety & Interactions Detail
Syringic acid is a ubiquitous dietary phenolic — present in many fruits and berries, whole grains, honey and wine, and in herbs such as chickweed, marshmallow and yerba maté — and is regarded as low-toxicity at dietary and studied preclinical doses; it has even been co-administered as a protective agent against drug-induced liver injury. As with other polyphenols, high-concentration pro-oxidant behavior and competition at conjugation enzymes are theoretically possible but not clinically documented for the isolate. No verified human interaction, contraindication or overdose dataset exists. No reproductive-safety or human data exist for isolated or supplemental syringic acid. It is a normal food constituent at dietary levels; supraphysiologic intake has not been studied.
Dosage
There is no established therapeutic dose. Rodent studies typically used ~25–100 mg/kg/day orally, which does not translate to a human dose, and there is no human isolate dose. Because native oral bioavailability is only moderate, any biological effect likely depends on repeated intake or enhanced-delivery formulations rather than a single dose 10Reference 10Improved oral bioavailability and hypolipidemic effect of syringic acid via a self-microemulsifying drug-delivery systemView study →.
References
- Srinivasulu C, et al. (2018). Syringic acid — a review of its occurrence, biosynthesis, and pharmacological importance. Biomedicine & Pharmacotherapy. https://pubmed.ncbi.nlm.nih.gov/30243088/
- Zhao Z, Yang Q, Sun Y, et al. (2025). Antioxidant and anti-inflammatory potential of syringic acid: mechanistic insights and pathway interactions. Frontiers in Pharmacology. https://pubmed.ncbi.nlm.nih.gov/40703347/
- Mirza AC, Panchal SS, Allam AA, et al. (2022). Syringic acid ameliorates cardiac, hepatic, renal and neuronal damage induced by chronic hyperglycaemia in Wistar rats. Molecules. https://pubmed.ncbi.nlm.nih.gov/36235257/
- Ren J, Yang M, Xu F, et al. (2019). Acceleration of wound-healing activity with syringic acid in streptozotocin-induced diabetic rats. Life Sciences. https://pubmed.ncbi.nlm.nih.gov/31386877/
- Xiong H, Li X, Mou X, et al. (2024). Syringic acid suppresses Cutibacterium acnes-induced inflammation in keratinocytes via NLRP3/caspase-1/IL-1β by activating PPARγ/Nrf2. International Immunopharmacology. https://pubmed.ncbi.nlm.nih.gov/39033661/
- Itoh A, Isoda K, Kondoh M, et al. (2010). Hepatoprotective effect of syringic acid and vanillic acid on CCl₄-induced liver injury. Biological & Pharmaceutical Bulletin. https://pubmed.ncbi.nlm.nih.gov/20522963/
- Liu G, Zhang BF, Hu Q, et al. (2020). Syringic acid mitigates myocardial ischaemia-reperfusion injury by activating the PI3K/Akt/GSK-3β pathway. Biochemical and Biophysical Research Communications. https://pubmed.ncbi.nlm.nih.gov/32798018/
- Cao Y, Zhang L, Sun S, et al. (2016). Neuroprotective effects of syringic acid against OGD/R-induced injury in cultured hippocampal neurons. International Journal of Molecular Medicine. https://pubmed.ncbi.nlm.nih.gov/27278454/
- Mihanfar A, Darband SG, Sadighparvar S, et al. (2021). In-vitro and in-vivo anticancer effects of syringic acid on colorectal cancer. Chemico-Biological Interactions. https://pubmed.ncbi.nlm.nih.gov/33548266/
- Sun C, Li W, Zhang H, et al. (2021). Improved oral bioavailability and hypolipidemic effect of syringic acid via a self-microemulsifying drug-delivery system. AAPS PharmSciTech. https://pubmed.ncbi.nlm.nih.gov/33439366/
