Arachidonic Acid
Also called ARA, AA, 20:4n-6, arachidonate.
Best grade C across 8 graded outcomes Fatty acid Last checked
The short answer
From 9 sourcesArachidonic acid is an omega-6 fat that the body turns into prostaglandins. In resistance-trained men, three small trials disagree: two found no strength, muscle or protein-synthesis advantage at 1–1.5 g a day, while a partly industry-funded trial reported more lean mass. Infant-formula and older-adult trials paired it with DHA or measured only markers.
Every graded outcome on this page
8 rows · line = participants- CGrade CCognitive development in infants given DHA plus ARAInfant developmentn 1,039
- DGrade DBlood ARA, ARA metabolites and clinical blood tests (safety markers)Safety markersn 118
- DGrade DStrength, body composition and anaerobic power during resistance trainingStrength & musclen 31
- DGrade DLean mass, strength and power during 8 weeks of strength trainingStrength & musclen 30
- DGrade DCoronary flow velocity reserve (small-vessel blood flow in the heart)Heartn 28
- DGrade DP300 event-related potential (a brain-response marker linked to attention)Brain markersn 25
- DGrade DMuscle protein synthesis and anabolic signalling after resistance exerciseStrength & musclen 19
- ∅No effectComplications of prematurity (lung disease, retinopathy, gut and brain injury)Preterm infantsn 2,567
- 5 more graded outcomes, in the evidence chapter
Key facts
- Strength trials
- Two trials of about 30 trained men each: one found no strength or muscle advantage over placebo at 1 g/day for 50 days, the other reported gains in lean mass, strength and power over 8 weeks12
- Muscle protein synthesis
- 1.5 g/day for 4 weeks did not change muscle protein synthesis or anabolic signalling after a workout in 19 trained men6
- Funding
- The positive muscle trial was partly funded by the maker of a commercial ARA product (X-Factor Advanced)2
- Older adults
- 240 mg/day for 1 month shortened P300 latency, a brain-response marker, in 25 healthy older men3
- Safety-marker trial
- 240 or 720 mg/day for 4 weeks raised blood ARA in a dose-dependent way without raising ARA-derived metabolites or changing clinical blood tests5
- Washout
- Blood ARA returned to near baseline within 4 weeks of stopping5
- Adult safety review
- A 2019 systematic review of 14 RCTs found no adverse effects in adults of up to 1,000–1,500 mg/day on blood lipids, platelet aggregation, blood clotting, immune function or inflammation7
What it is
Arachidonic acid (ARA) is a long-chain omega-6 fatty acid found in meat, eggs and fish and sold as a training supplement.
How it works
ProposedARA is a 20-carbon omega-6 fatty acid stored in cell-membrane phospholipids. When released, it is converted into eicosanoids such as prostaglandin E2, which are involved in inflammation and in muscle repair signalling. Training supplements are based on the idea that more ARA in muscle amplifies this signal; in one trial PGE2 only tended to rise, and in older adults extra ARA did not raise measured ARA metabolites.15
Forms, side by side
2 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.
Arachidonic Acid forms compared
2 forms| 2 forms | ARA-enriched oil (fungal triglyceride) capsules | ARA training supplement (1 g/day class) |
|---|---|---|
| Absorption in people | Raised plasma phospholipid ARA in a dose-dependent way within 2 weeks; levels returned to near baseline 4 weeks after stopping.5 | Not reported in the abstracts of the training trials.1 |
| GI tolerance | No changes in clinical blood parameters at 240 or 720 mg/day for 4 weeks.5 | The 50-day trial reported lower IL-6 at day 25 and no between-group differences in anabolic or catabolic hormones.1 |
| Studied for | Brain-response and heart markers in older adults; safety markers | Strength, power and body composition during resistance training |
- ARA-enriched oil (fungal triglyceride) capsules
- Absorption in people
- Raised plasma phospholipid ARA in a dose-dependent way within 2 weeks; levels returned to near baseline 4 weeks after stopping.5
- GI tolerance
- No changes in clinical blood parameters at 240 or 720 mg/day for 4 weeks.5
- Studied for
- Brain-response and heart markers in older adults; safety markers
- ARA training supplement (1 g/day class)
What the human research says
Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.
Trial map
8 graded outcomes, largest study first8 graded outcomes: 3 improved, 1 mixed, 4 no effect. The largest, a 2025 meta-analysis of 2,567 people on complications of prematurity (lung disease, retinopathy, gut and brain injury), found no effect.
1Complications of prematurity (lung disease, retinopathy, gut and brain injury)
No effect · No-effect grade · Meta-analysis, 2,567 people, 2025
Preterm infants born at 34 weeks or earlier or weighing 2,000 g or less, 11 trials
Dose, result and source| Outcome | Found | People | Study | Who was studied |
|---|---|---|---|---|
| Complications of prematurity (lung disease, retinopathy, gut and brain injury) | No effect | 2,567 | No-effect grade · Meta-analysis, 2025 | Preterm infants born at 34 weeks or earlier or weighing 2,000 g or less, 11 trials |
| Cognitive development in infants given DHA plus ARA | Mixed | 1,039 | Grade C · Meta-analysis, 2025 | Infants in 9 randomized trials of DHA and ARA supplementation |
| Blood ARA, ARA metabolites and clinical blood tests (safety markers) | No effect | 118 | Grade D · RCT, 2011 | Healthy Japanese men and women aged 55–70 (118 randomised to placebo, low or high dose) |
| Strength, body composition and anaerobic power during resistance training | No effect | 31 | Grade D · RCT, 2007 | Resistance-trained men (15 ARA, 16 placebo) |
| Lean mass, strength and power during 8 weeks of strength training | Improved | 30 | Grade D · RCT, 2016 | Strength-trained young men (mean age 20) |
| Coronary flow velocity reserve (small-vessel blood flow in the heart) | Improved | 28 | Grade D · RCT, 2008 | Japanese older adults (19 men, mean age 65) |
| P300 event-related potential (a brain-response marker linked to attention) | Improved | 25 | Grade D · Crossover RCT, 2009 | Healthy older Japanese men |
| Muscle protein synthesis and anabolic signalling after resistance exercise | No effect | 19 | Grade D · RCT, 2018 | Resistance-trained men (at least 1 year of training) |
Every graded row
8 rowsShowing 8 of 8 outcomes. Human trials only.
CGrade CCognitive development in infants given DHA plus ARAInfant developmentCognition SMD +0.21Meta-analysis · 9 studies
n 1,039 · 2025
Mixed Pooled cognitive scores were slightly higher (SMD 0.21, 95% CI 0.03 to 0.38), but Bayley mental (MDI) and psychomotor (PDI) scores did not differ overall; both were higher in the subgroup with a DHA:ARA ratio of 0.5 to 1.
- Design
- Meta-analysis, 9 studies, n = 1,039, 2025
- Population
- Infants in 9 randomized trials of DHA and ARA supplementation
- Form
- DHA plus ARA (combined, in formula or supplements)
- Dose
- Varied by trial; DHA:ARA ratios analysed as subgroups
- Duration
- Varied by trial (not given in the abstract)
- Source
- Reference 8 · PubMed 40292560 (opens PubMed)
DGrade DBlood ARA, ARA metabolites and clinical blood tests (safety markers)Safety markersNo effectRCT
n 118 · 2011
No effect Plasma phospholipid ARA rose dose-dependently and fell back to near baseline after washout. Urinary and plasma ARA metabolites (thromboxane, prostacyclin and PGE2 markers, lipoxin A4) and clinical blood parameters for cardiovascular, inflammatory and allergic disease did not change.
- Design
- RCT, n = 118, 2011
- Population
- Healthy Japanese men and women aged 55–70 (118 randomised to placebo, low or high dose)
- Form
- ARA-enriched oil vs placebo
- Dose
- 240 or 720 mg ARA/day
- Duration
- 4 weeks, then 4-week washout
- Source
- Reference 5 · PubMed 22188761 (opens PubMed)
DGrade DStrength, body composition and anaerobic power during resistance trainingStrength & muscleNo strength or muscle differenceRCT
n 31 · 2007
No effect Wingate relative peak power was higher after 50 days and IL-6 was lower at day 25 in the ARA group, but there were no significant differences versus placebo in body composition, strength, anabolic or catabolic hormones, or markers of muscle hypertrophy.
- Design
- RCT, n = 31, 2007
- Population
- Resistance-trained men (15 ARA, 16 placebo)
- Form
- Arachidonic acid vs corn-oil placebo
- Dose
- 1 g/day
- Duration
- 50 days
- Source
- Reference 1 · PubMed 18045476 (opens PubMed)
DGrade DLean mass, strength and power during 8 weeks of strength trainingStrength & muscle+2.9% lean mass (ARA group only)RCT
n 30 · 2016
Improved Lean body mass (+2.9%), upper-body strength (+8.7%) and peak power (+12.7%) increased only in the ARA group.
- Design
- RCT, n = 30, 2016
- Population
- Strength-trained young men (mean age 20)
- Form
- ARA supplement vs placebo
- Dose
- Not stated in the abstract
- Duration
- 8 weeks
- Source
- Reference 2 · PubMed 27182886 (opens PubMed)
DGrade DCoronary flow velocity reserve (small-vessel blood flow in the heart)HeartImprovedRCT
n 28 · 2008
Improved Coronary flow velocity reserve rose from 3.85 to 4.46 (p = 0.0023) with the fatty acids, and hyperaemic flow velocity was higher than with placebo (73 vs 64 cm/s, p < 0.01).
- Design
- RCT, n = 28, 2008
- Population
- Japanese older adults (19 men, mean age 65)
- Form
- ARA plus DHA capsules vs placebo
- Dose
- 240 mg ARA + 240 mg DHA per day
- Duration
- 3 months
- Source
- Reference 4 · PubMed 17591648 (opens PubMed)
DGrade DP300 event-related potential (a brain-response marker linked to attention)Brain markersImprovedCrossover RCT
n 25 · 2009
Improved P300 latency was significantly shorter and P300 amplitude higher than with olive oil, and serum phospholipid ARA rose.
- Design
- Crossover RCT, n = 25, 2009
- Population
- Healthy older Japanese men
- Form
- ARA-enriched triglyceride oil (SUNTGA40S) vs olive-oil capsules
- Dose
- 600 mg oil/day supplying 240 mg ARA
- Duration
- 1 month
- Source
- Reference 3 · PubMed 19752581 (opens PubMed)
DGrade DMuscle protein synthesis and anabolic signalling after resistance exerciseStrength & muscleNo difference in muscle protein synthesisRCT
n 19 · 2018
No effect Muscle protein synthesis over 4 hours of recovery did not differ from placebo (P = 0.212), and neither did mTOR signalling or the rise in satellite cells; a ribosome-biogenesis marker (45S pre-rRNA) rose at 48 hours only with ARA.
- Design
- RCT, n = 19, 2018
- Population
- Resistance-trained men (at least 1 year of training)
- Form
- Arachidonic acid vs corn-soy-oil placebo
- Dose
- 1.5 g/day
- Duration
- 4 weeks, then one resistance-exercise session
- Source
- Reference 6 · PubMed 29389245 (opens PubMed)
∅No effectComplications of prematurity (lung disease, retinopathy, gut and brain injury)Preterm infantsNo protection from complicationsMeta-analysis · 11 studies
n 2,567 · 2025
No effect DHA with or without ARA did not lower retinopathy of prematurity, necrotising enterocolitis, sepsis, brain haemorrhage or in-hospital death, and raised the risk of bronchopulmonary dysplasia (RR 1.11, 95% CI 1.00 to 1.22). In the DHA-plus-ARA subgroup that lung-disease risk did not rise.
- Design
- Meta-analysis, 11 studies, n = 2,567, 2025
- Population
- Preterm infants born at 34 weeks or earlier or weighing 2,000 g or less, 11 trials
- Form
- Enteral DHA with or without ARA (separate from formula and intravenous nutrition)
- Dose
- Varied by trial (not given in the abstract)
- Duration
- Neonatal intensive-care stay
- Source
- Reference 9 · PubMed 40233974 (opens PubMed)
What the numbers add up to
Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.
The muscle evidence splits
Older-adult data are markers only
Studied doses
Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.
Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.
Doses studied in human trials
Interactions and safety
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
What Arachidonic Acid meets
0 cited rows 1 tested togetherMedicines 0
No medicine rows in our sources.
Supplements and foods 1
- Tested together in a graded trial
Choose a medicine or supplement above to read its cited rows here.
Also cited: 1 tested together
Omega-3Omega-3 page
Tested together
Coronary flow velocity reserve (small-vessel blood flow in the heart). Graded on the Arachidonic Acid page; tested together is not a claim that they work better together.
Interactions
0 agentsNone found in our sources.
Check with what you take
Kept on this device onlyAdd what you take. We list every interaction our evidence profiles cite between Arachidonic Acid and your picks, and between your picks.
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Add a supplement or medicine you take to check it against Arachidonic Acid.
Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.
Who should be careful
4 groups- Pregnancy, breastfeeding and children
- No trial in our sources gave ARA supplements to pregnant or breastfeeding women, and LactMed has no ARA entry. Infants have received ARA only together with DHA, in formula or hospital feeding (see the evidence table); adult trials enrolled young trained men and healthy 55–70-year-olds for 4 weeks to 3 months.89135
- People with inflammatory or allergic conditions
- ARA is the starting material for inflammatory eicosanoids. The trial that found no rise in ARA metabolites enrolled only healthy people aged 55–70, so it does not show safety in people with these conditions.5
- People with heart disease
- The heart-flow trial combined ARA with DHA and measured a marker over 3 months; it gives no outcome data for people with diagnosed heart disease.4
- Bleeding and clotting
- A 2019 systematic review of 14 RCTs found no effect on platelet aggregation or blood clotting in adults taking up to 1,000–1,500 mg/day; its authors say higher intakes need further study.7
ARA and inflammation markers
3 notesShort trials did not show a rise in inflammatory metabolites.
- Metabolites
- At 240 or 720 mg/day for 4 weeks, ARA metabolites in blood and urine did not change, and blood ARA was not correlated with metabolite levels.5
- During training
- In trained men, IL-6 was lower at day 25 with 1 g/day ARA, and PGE2 only tended to be higher.1
- Across trials
- A 2019 systematic review found no adverse effects in adults up to at least 1,000–1,500 mg/day on blood lipids, platelet aggregation, blood clotting, immune function, inflammation or urinary ARA metabolites.7
How to read the label
What to check on the Supplement Facts panel.
How to read the label
2 checksFrequently asked questions
Short answers to common questions; the numbers link to the sources below.
Common questions
6 answersDoes arachidonic acid build muscle?
Does it raise inflammation?
Does it help memory in older adults?
One small trial found faster brain responses (P300) after 1 month at 240 mg/day, but it did not measure memory or daily function.3
Are arachidonic acid supplements safe?
How long does it stay in the blood?
Blood ARA rose within 2 weeks of supplementing and returned to near baseline within 4 weeks of stopping.5
Why is arachidonic acid added to infant formula?
Sources
9 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.
Sources cited on this page
9 sources- 1Effects of arachidonic acid supplementation on training adaptations in resistance-trained males.RCT J Int Soc Sports Nutr, 2007 · PMID 18045476
- 2Effects of Arachidonic Acid Supplementation on Acute Anabolic Signaling and Chronic Functional Performance and Body Composition Adaptations.RCT PLoS One, 2016 · PMID 27182886
- 3Arachidonic acid supplementation decreases P300 latency and increases P300 amplitude of event-related potentials in healthy elderly men.Crossover RCT Neuropsychobiology, 2009 · PMID 19752581
- 4Arachidonic acid and docosahexaenoic acid supplementation increases coronary flow velocity reserve in Japanese elderly individuals.RCT Heart, 2008 · PMID 17591648
- 5Supplementation of arachidonic acid-enriched oil increases arachidonic acid contents in plasma phospholipids, but does not increase their metabolites and clinical parameters in Japanese healthy elderly individuals: a randomized controlled study.RCT Lipids Health Dis, 2011 · PMID 22188761
- 6Effect of dietary arachidonic acid supplementation on acute muscle adaptive responses to resistance exercise in trained men: a randomized controlled trial.RCT J Appl Physiol (1985), 2018 · PMID 29389245
- 7A systematic review of the effects of increasing arachidonic acid intake on PUFA status, metabolism and health-related outcomes in humans.Systematic review Br J Nutr, 2019 · PMID 31130146
- 8Effects of Different Proportions of DHA and ARA on Cognitive Development in Infants: A Meta-Analysis.Meta-analysis Nutrients, 2025 · PMID 40292560
- 9Effect of enteral supplementation of DHA with or without ARA in preterm infants: a meta-analysis.Meta-analysis Arch Dis Child Fetal Neonatal Ed, 2025 · PMID 40233974
What changed
Every dated change to this page: what changed, who made it and why.
Change log
3 entries| Date | Change | Who and why |
|---|---|---|
| summary, key facts, evidence, studied doses, who should avoid, safety, FAQ, questions, related | Re-searched PubMed for ARA supplementation RCTs and meta-analyses to 2026. Added a 2018 muscle-biopsy RCT (PMID 29389245; 1.5 g/day for 4 weeks, no change in muscle protein synthesis), a 2025 infant cognition meta-analysis of DHA plus ARA (PMID 40292560) and, as a supervised clinical-use row, a 2025 preterm-infant meta-analysis (PMID 40233974; totals from PMC12772574). Added the 2019 systematic review of ARA intake in adults (PMID 31130146) for safety, clotting and inflammation notes. Studied-dose maximum raised to 1.5 g/day; summary rewritten to match. No LactMed or LiverTox entry for ARA (checked), noted in the pregnancy line. Interactions: none documented in LiverTox, LactMed, NCCIH or MedlinePlus (no entries) or in the 2019 review, so the list stays empty. Replaced the 'What is arachidonic acid?' FAQ with infant-formula and safety questions, added questions this page answers and the performance goal-hub link. | Writer: Kymata Health EditorialTrigger: A–Z audit against docs/supplements/AUDIT-STANDARD.md |
| all | Independent adversarial review: disclosed Suntory co-authors and the unstated randomisation in the coronary-flow trial; removed food sources from an FAQ answer whose cited trials do not state them. | Writer: Kymata Health EditorialTrigger: review |
| all | Initial editorial evidence review (first draft). Every PMID checked against NCBI E-utilities esummary (titles and years taken from the record, none retracted) and the abstract read for each cited row. Studied doses are reported as research doses, not dosing advice. | Writer: Kymata Health EditorialTrigger: new page |
Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.