Rosmarinic Acid

Pharmacology & Research

Rosmarinic acid is the signature polyphenol of the mint family — the compound that gives rosemary, lemon balm, perilla, sage, oregano and spearmint much of their antioxidant and anti-inflammatory character, and a reliable chemotaxonomic marker of the Lamiaceae (and Boraginaceae). It has a genuine and unusually human evidence base for a plant phenolic: real randomised trials in seasonal allergy, attention and memory, anxiety and knee osteoarthritis. But there is one caveat that governs the entire page, and it is not a minor one: essentially none of that evidence used isolated rosmarinic acid. Every positive trial used a standardised herb extract — perilla, spearmint or lemon balm — in which rosmarinic acid is the marker and a plausible active within a polyphenol mixture ^{1,2Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →}. On top of that, rosmarinic acid is poorly absorbed and heavily metabolised to smaller phenolics (caffeic, ferulic acids) ^{11Reference 11Baba S et al. · 2005Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humansView study →}. So the honest reading is: promising herbal evidence, credited to a marker molecule, not proof of the isolate.

1. Cognition, attention & memory

The most-replicated modern signal, all from one branded extract. A high-rosmarinic-acid spearmint extract (Kemin “Neumentix”, standardised to ≥14.5% rosmarinic acid, ~900 mg/day ≈ 130 mg RA) improved quality of working memory (+15%) and spatial working-memory accuracy in older adults with age-associated memory impairment ^{2Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →}, improved sustained attention (~11%) in healthy active adults ^{3Reference 3Falcone PH et al. · 2019RCTThe attention-enhancing effects of spearmint extract supplementation in healthy men and women — a randomized, double-blind, placebo-controlled, parallel trialView study →}, and improved reactive agility and post-exertion executive function in further trials ^{4Reference 4Falcone PH et al. · 2018RCTEfficacy of a nootropic spearmint extract on reactive agility — a randomized, double-blind, placebo-controlled, parallel trialView study →}. Lemon balm extracts add a modest cognitive signal — slowing neuropsychiatric decline in mild Alzheimer’s/MCI ^{9Reference 9Noguchi-Shinohara M et al. · 2020Safety and efficacy of Melissa officinalis extract containing rosmarinic acid in the prevention of Alzheimer’s disease progressionView study →} and improving cognition in older adults without dementia ^{10Reference 10Noguchi-Shinohara M et al. · 2023RCTEffects of Melissa officinalis extract containing rosmarinic acid on cognition in older adults without dementia — a randomized controlled trialView study →}.

Gap: these are extract trials (a polyphenol mixture, RA the marker), the flagship cognition work is industry-sponsored (Kemin), and effect sizes are modest — none isolates rosmarinic acid’s own contribution ^{2,3Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →Reference 3Falcone PH et al. · 2019RCTThe attention-enhancing effects of spearmint extract supplementation in healthy men and women — a randomized, double-blind, placebo-controlled, parallel trialView study →}.

2. Allergic rhinitis & seasonal allergy

Rosmarinic acid’s classic clinical result. A 21-day randomised, placebo-controlled trial of a Perilla frutescens extract enriched for rosmarinic acid (50 or 200 mg/day) improved responder rates for itchy nose and watery/itchy eyes and reduced neutrophil and eosinophil infiltration in nasal lavage in people with seasonal allergic rhinoconjunctivitis ^{1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →}.

Gap: it is a perilla extract, not isolated rosmarinic acid, and rests on a single small trial ^{1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →} (a companion paper re-reports the same study, so it isn’t independent confirmation). Promising and mechanistically coherent — RA is anti-inflammatory ^{15Reference 15Luo C et al. · 2020ReviewA review of the anti-inflammatory effects of rosmarinic acid on inflammatory diseasesView study →} — but thin.

3. Anxiety, mood & sleep

Carried by lemon balm (Melissa officinalis), where rosmarinic acid is the major polyphenol. A meta-analysis of lemon-balm RCTs found reductions in anxiety and depressive symptoms ^{8Reference 8Ghazizadeh J et al. · 2021Meta-analysisThe effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials — a systematic review and meta-analysisView study →}, and a placebo-controlled trial of a phospholipid-formulated lemon-balm extract improved emotional distress and sleep in stressed adults ^{7Reference 7Bano A et al. · 2023The possible “calming effect” of subchronic supplementation of a standardised phospholipid carrier-based Melissa officinalis L. extract in healthy adults with emotional distress and poor sleepView study →}; an early open-label pilot reported large anxiety/insomnia improvements but had no placebo control ^{6Reference 6Cases J et al. · 2011Pilot trial of Melissa officinalis L. leaf extract in the treatment of volunteers suffering from mild-to-moderate anxiety disorders and sleep disturbancesView study →}.

Gap: all lemon-balm extract (mixture) data — the meta-analysis pools heterogeneous Melissa preparations, and the strongest-sounding pilot ^{6Reference 6Cases J et al. · 2011Pilot trial of Melissa officinalis L. leaf extract in the treatment of volunteers suffering from mild-to-moderate anxiety disorders and sleep disturbancesView study →} is uncontrolled. Rosmarinic acid is the plausible active, not a proven one ^{7,8Reference 7Bano A et al. · 2023The possible “calming effect” of subchronic supplementation of a standardised phospholipid carrier-based Melissa officinalis L. extract in healthy adults with emotional distress and poor sleepView study →Reference 8Ghazizadeh J et al. · 2021Meta-analysisThe effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials — a systematic review and meta-analysisView study →}.

4. Osteoarthritis

A high-rosmarinic-acid spearmint tea taken twice daily for 16 weeks reduced WOMAC pain in knee osteoarthritis, where an ordinary (low-RA) spearmint tea did not — with stiffness and physical-function improving in both arms ^{5Reference 5Connelly AE et al. · 2014High-rosmarinic acid spearmint tea in the management of knee osteoarthritis symptomsView study →}.

Gap: a whole-plant tea, not isolated RA; the comparator was ordinary spearmint tea rather than a true placebo; and it is a single trial. Suggestive, appropriately capped ^{5Reference 5Connelly AE et al. · 2014High-rosmarinic acid spearmint tea in the management of knee osteoarthritis symptomsView study →}.

Mechanisms

Target / pathway	Effect	Relevant to	Evidence
NF-κB / TNF-α, IL-1β, IL-6, COX-2 suppression	anti-inflammatory	allergy, OA	review of preclinical 15Reference 15Luo C et al. · 2020ReviewA review of the anti-inflammatory effects of rosmarinic acid on inflammatory diseasesView study →
Mast-cell / eosinophil & neutrophil inhibition	anti-allergic	allergic rhinitis	human (extract) + preclinical 1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →
Antioxidant / radical scavenging (catechol groups)	antioxidant	general	in vitro
GABA-transaminase inhibition (lemon balm)	anxiolytic	anxiety	in vitro 8Reference 8Ghazizadeh J et al. · 2021Meta-analysisThe effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials — a systematic review and meta-analysisView study →
HSV attachment/penetration inhibition	antiviral	(herbal)	in vitro (Melissa) 16Reference 16Astani A et al. · 2014Attachment and penetration of acyclovir-resistant herpes simplex virus are inhibited by Melissa officinalis extractView study →

Pharmacokinetics

Rosmarinic acid is poorly bioavailable, and what is absorbed is largely not rosmarinic acid by the time it circulates. The core human study — oral perilla-extract rosmarinic acid — showed that it is absorbed but excreted in urine mainly as metabolites and conjugates: methylated, sulfated and glucuronidated forms, plus the degradation products caffeic acid, ferulic acid and m-coumaric acid ^{11Reference 11Baba S et al. · 2005Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humansView study →}. As an ester of two catechol-bearing halves it is a natural substrate for both gut-wall/hepatic conjugation and gut-microbial cleavage, so the microbiome contributes substantially to its breakdown into smaller absorbable phenolics, with the expected person-to-person variation ^{14Reference 14Thumann TA et al. · 2019The role of gut microbiota for the activity of medicinal plants traditionally used in the European Union for gastrointestinal disordersView study →}. Reviews of hydroxycinnamic-acid pharmacokinetics place rosmarinic acid firmly in the low-oral-bioavailability, extensively-first-pass-metabolised category ^{12Reference 12Amoah SK et al. · 2016Rosmarinic acid — pharmaceutical and clinical aspectsView study →}. The practical consequence is the same one that recurs across the polyphenols: a good deal of rosmarinic acid’s activity in a person may actually be the activity of its metabolites (caffeic and ferulic acids among them), and intact-rosmarinic-acid tissue exposure from an oral dose is modest ^{11,12Reference 11Baba S et al. · 2005Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humansView study →Reference 12Amoah SK et al. · 2016Rosmarinic acid — pharmaceutical and clinical aspectsView study →}.

Clinical trials

Rosmarinic acid’s human record is real but entirely extract-based — and worth reading with the vehicle in mind:

Perilla	Spearmint	Lemon balm
Allergic rhinitis 1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →	Attention, working memory, OA 2,3,5Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →Reference 3Falcone PH et al. · 2019RCTThe attention-enhancing effects of spearmint extract supplementation in healthy men and women — a randomized, double-blind, placebo-controlled, parallel trialView study →Reference 5Connelly AE et al. · 2014High-rosmarinic acid spearmint tea in the management of knee osteoarthritis symptomsView study →	Anxiety, mood, sleep, cognition 7,8,10Reference 7Bano A et al. · 2023The possible “calming effect” of subchronic supplementation of a standardised phospholipid carrier-based Melissa officinalis L. extract in healthy adults with emotional distress and poor sleepView study →Reference 8Ghazizadeh J et al. · 2021Meta-analysisThe effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials — a systematic review and meta-analysisView study →Reference 10Noguchi-Shinohara M et al. · 2023RCTEffects of Melissa officinalis extract containing rosmarinic acid on cognition in older adults without dementia — a randomized controlled trialView study →

Last checked: July 2026.

Isolate vs. Plant Studies

Rosmarinic acid is the clearest case in this database of a molecule whose reputation is really its source herbs’ reputation. No verified human trial has tested purified rosmarinic acid — the allergy data are a perilla extract ^{1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →}, the cognition data a spearmint extract standardised to RA ^{2Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →}, the anxiety data lemon balm extracts ^{8Reference 8Ghazizadeh J et al. · 2021Meta-analysisThe effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials — a systematic review and meta-analysisView study →}, and the osteoarthritis data a spearmint tea ^{5Reference 5Connelly AE et al. · 2014High-rosmarinic acid spearmint tea in the management of knee osteoarthritis symptomsView study →}. In each, rosmarinic acid is the standardisation marker and a plausible active, but it travels with caffeic-acid derivatives, flavonoids, volatile terpenes (in the mints) and, in rosemary and sage, the diterpenes carnosic acid and carnosol — so attributing the whole effect to “rosmarinic acid” overstates what is known. Its poor bioavailability compounds the point: much of the in-body activity may belong to its metabolites ^{11Reference 11Baba S et al. · 2005Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humansView study →}. Within this database rosmarinic acid is a genuine, often dominant, constituent of many Lamiaceae — the antioxidant backbone of rosemary and sage, the principal marker of lemon balm (where it also underlies the herb’s antiherpetic activity in vitro ^{16Reference 16Astani A et al. · 2014Attachment and penetration of acyclovir-resistant herpes simplex virus are inhibited by Melissa officinalis extractView study →}), the dominant phenolic of yerba santa, and the biosynthetic precursor of the salvianolic acids in dan shen — all legitimate occurrence-level facts rather than endorsements of isolated-RA supplements.

Prevalence in Nature

Rosmarinic acid is a chemotaxonomic marker: it is the family signature of the Lamiaceae (mint family) and Boraginaceae, and is essentially absent from non-mint-family foods — you will not find meaningful rosmarinic acid in cereals, most fruit and vegetables, alliums or legumes. Within the mint family it is often the single most abundant phenolic. On a dry-weight basis the richest sources are lemon balm (commercial lots ranging widely, ~0.16 up to ~49 mg/g, good material ~20–40) and yerba santa (~22–53 mg/g), followed by peppermint (up to ~17 mg/g), sage (~3–21, mean ~15), spearmint (~6–14), rosemary (~9–11), oregano (~6), perilla (~0.8–15, mean ~6) and sweet basil (~3 mg/g) ^{21,22,23,24,25Reference 21Arceusz A · 2013Quality consistency evaluation of Melissa officinalis L. commercial herbs by HPLC fingerprint and quantitation of selected phenolic acidsView study →Reference 222025Rosmarinic acid and phenolic content of dried sage (Salvia officinalis)View study →Reference 23Yang H et al. · 2013Contents of rosmarinic acid in Perilla frutescens by plant part determined by HPLCView study →Reference 24Satyal P et al. · 2026Chemical composition of Eriodictyon californicum (California yerba santa) cultivated in Ontario, Oregon, USAView study →Reference 25Neveu V et al. · 2010Phenol-Explorer — an online comprehensive database on polyphenol contents in foods (rosmarinic acid, Lamiaceae seasonings report)View study →}. The single most important caveat for reading these numbers is basis: fresh culinary herbs are 80–90% water, so on a per-gram basis a fresh herb reads roughly 8–10× lower than the same herb dried — always state whether a figure is fresh or dry. Standardised extracts (a lemon-balm “5% RA” extract, a spearmint extract at ~23% RA) are a third, non-comparable basis and shouldn’t be mixed with whole-herb figures. Beyond the Lamiaceae, Boraginaceae such as comfrey and borage carry rosmarinic acid too, generally at lower and more variable levels. There are no non-plant sources.

Biosynthetically rosmarinic acid is unusual and elegant: it is an ester built from two amino-acid-derived halves — the caffeic-acid portion from phenylalanine (via the phenylpropanoid pathway) and the 3,4-dihydroxyphenyllactic acid portion from tyrosine — joined and then hydroxylated to the final catechol-rich diester ^{19,20Reference 19Petersen M · 2003Rosmarinic acidView study →Reference 20Petersen M et al. · 2009Evolution of rosmarinic acid biosynthesisView study →}. That two-amino-acid origin distinguishes it from most simple phenolic acids and is conserved across the Lamiaceae. In dan shen (Salvia miltiorrhiza) rosmarinic acid is further elaborated into the salvianolic acids, the water-soluble actives of that herb.

Discovery & Synthesis

Rosmarinic acid was first isolated from rosemary (Rosmarinus officinalis, now Salvia rosmarinus) and is named for it; the isolation is attributed to the Italian chemists Scarpati and Oriente in 1958, a report that predates PubMed indexing and so is treated here as reported rather than primary-sourced ^{19Reference 19Petersen M · 2003Rosmarinic acidView study →}. Chemically it is a caffeic-acid ester — more precisely the ester of caffeic acid and 3-(3,4-dihydroxyphenyl)lactic acid — a depside carrying two catechol groups, which is the structural basis for its strong antioxidant and metal-chelating behaviour. It occurs predominantly as the (R) enantiomer. Its close biosynthetic relatives, the salvianolic acids of dan shen, are effectively rosmarinic-acid oligomers.

Commercial rosmarinic acid is obtained almost entirely by extraction from Lamiaceae biomass — lemon balm, rosemary, sage, perilla and spearmint are the usual feedstocks — and by purification from the same rosemary/sage extracts that supply the food industry’s antioxidant preparations. Plant cell-culture and hairy-root systems (which can accumulate rosmarinic acid to high levels) are an established alternative production route, and enzymatic/biotechnological syntheses exist, but agricultural extraction dominates supply.

Patents: not yet researched (future patent-loop pass).

Toxicity & Safety

As a constituent of everyday culinary herbs — rosemary, sage, basil, oregano, mint, lemon balm — rosmarinic acid has a long history of safe dietary exposure and a low-toxicity profile, and the standardised-extract trials above reported good tolerability at their studied doses ^{12,13Reference 12Amoah SK et al. · 2016Rosmarinic acid — pharmaceutical and clinical aspectsView study →Reference 13Noguchi-Shinohara M et al. · 2015RCTPharmacokinetics, safety and tolerability of Melissa officinalis extract which contained rosmarinic acid in healthy individuals — a randomized controlled trialView study →}. Rosemary extract standardised to rosmarinic/carnosic acids is even an established food antioxidant (E392 in the EU) ^{18Reference 18Wong YT et al. · 2025Development of a modified QuEChERS extraction for the detection of rosemary extracts (E392) in food by LC-MS/MSView study →}.

The practical cautions are modest and mostly herb-level. Allergic contact dermatitis to rosemary and other Lamiaceae is documented, with cross-reactivity across the family — relevant for topical exposure in sensitised individuals ^{17Reference 17González-Mahave I et al. · 2006Rosemary contact dermatitis and cross-reactivity with other Labiate plantsView study →}. As a polyphenol with antioxidant/mild antiplatelet character, a theoretical additive effect with antiplatelet or anticoagulant drugs is reasonable to note though not clinically established. Concentrated high-dose isolated-rosmarinic-acid supplementation is simply not well characterised in humans, since the trials used extracts.

Dosage

There is no established dose of isolated rosmarinic acid, because no human trial has tested the pure compound. The extract trials deliver, in rosmarinic-acid terms, roughly: perilla ~50–200 mg/day (allergy) ^{1Reference 1Takano H et al. · 2004Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenol, inhibits seasonal allergic rhinoconjunctivitis in humansView study →}; spearmint (Neumentix) ~130 mg/day (cognition) ^{2Reference 2Herrlinger KA et al. · 2018Spearmint extract improves working memory in men and women with age-associated memory impairmentView study →}; lemon balm dosed to ~500 mg/day (cognition/anxiety) ^{10Reference 10Noguchi-Shinohara M et al. · 2023RCTEffects of Melissa officinalis extract containing rosmarinic acid on cognition in older adults without dementia — a randomized controlled trialView study →}. Because rosmarinic acid is poorly absorbed and largely metabolised to caffeic/ferulic acids, extract intake and any “pure rosmarinic acid” figure are not interchangeable.

These are research figures from extract trials, not a recommendation — the honest position is that isolated-rosmarinic-acid dosing in humans is unstudied.

References