Omega-3 DHA
Docosahexaenoic acid, a long-chain omega-3 fat from oily fish and microalgae
A long-chain omega-3 fat found in oily fish and algae oil, and the main omega-3 in the brain and the eye. This page covers only studies in people that measured thinking, memory, mood, stress, sleep, energy or quality of life, where DHA is studied mostly for thinking and memory, often in children, pregnancy and later life. Here is every one we could find, sorted from each study's summary.
- Found in: oily fish and algae oil
- Most tested: 800 mg a day
- Usually taken for months
From every paper to the studies that matter
Our search looked only at omega-3 papers on thinking, mood, sleep and energy, not at all omega-3 research. Of those, a smaller share gives omega-3 to people, and a smaller share again gives DHA without EPA, which is what this page is about.
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9,081 papers on omega-3 and thinking, mood, sleep or energy.Every record in PubMed, all years
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643 are about people.The rest: 3,040 lab and animal studies, 2,359 reviews, 3,039 on chemistry, farming and more
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86 give DHA on its own.478 more give DHA with EPA, as in fish or krill oil, or in a blend
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75 are randomised against a placebo.Randomised controlled trials In a randomised controlled trial, people are put into groups by chance, one taking the treatment and one a placebo or other comparison. Chance spreads differences such as age and health evenly, so a difference between the groups is more likely to be down to the treatment., the strongest kind of study
Bar lengths use a square-root scale so the small numbers stay visible.
How much research there is
- 86 studies giving long-chain omega-3 to people, on thinking, mood, sleep and energy
- 75 of them randomised against a placebo A placebo-controlled trial compares a real treatment with a dummy that looks the same, the placebo. People often feel better when they expect to, so comparing against a placebo shows how much of the change comes from the treatment itself.
- 13,144 people taking part, where studies say
- 487 systematic reviews A systematic review searches for every study on a question in a set, written-down way, judges the quality of each and sums up what they show together. Many include a meta-analysis. The Atlas lists these as pooled reviews. pooling the trials
Studies in people, by year published
DHA on its own, without EPA.
What the studies looked at
Each study can measure several things. Choose a topic to see its studies in the list below.
Studies in people with a diagnosed condition are counted here and listed with their population. We describe what they measured, not what they might treat. Most studies also report safety; see below.
What was tested, and how much
Doses here are the total omega-3 a day as each study's summary gives it, so for DHA on its own that is the DHA itself, not the weight of the oil. Fish and algae oils carry different amounts of DHA per capsule, which is why we count what was given. Studies in babies often dosed by body weight or through formula and have no daily dose in milligrams. Most studies ran for months rather than giving one dose.
Daily amount, one dot per study
Studies per extract
Named extracts are the maker's brand. "Not named" means the study didn't say.
All studies in people
Filter the list, then open a study on PubMed. Each row comes from the study's published summary, and many follow children, pregnant women or older adults.
| Study | Who took part | People | Extract and daily dose | Length |
|---|---|---|---|---|
| Yassine 2026RCT, placebo | Older adults at risk of dementia, APOE e4 | 365 | Not named, 2,000 mg | 104 weeks |
| Yuan 2026RCT, placebo | Older adults with mild cognitive impairment | 360 | Not named, 1,000 mg | 52 weeks |
| Perales-Puchalt 2025RCT, placebo | People with dementia | 402 | Not named | 78 weeks |
| Duan 2025RCT, placebo | Older adults with mild cognitive impairment (DHA arm) | 280 | Not named, 800 mg | 52 weeks |
| Colombo 2025RCT, active or other control | Pregnant women (infants assessed), DHA 200 vs 800 mg | 215 | Not named, 800 mg | – |
| Li 2024RCT, placebo | Older adults with mild cognitive impairment (DHA arm) | 280 | Not named, 800 mg | 52 weeks |
| Bai 2024RCT, placebo | Older adults with mild cognitive impairment (DHA arm), follow-up | 160 | Not named | 26 weeks |
| Paquet 2024RCT, placebo | Very preterm infants (via maternal breastmilk), 5-year follow-up | 132 | Not named | – |
| Barion 2024Non-randomised controlled | Very and extremely preterm infants | 59 | Not named | – |
| Yassine 2023RCT, placebo | APOE4 carriers without dementia | 365 | Not named | 104 weeks |
| Gould 2023RCT, active or other control | Preterm infants born under 29 weeks | 204 | Not named | – |
| Piperoglou 2023Crossover, placebo | Patients with residual depression/anxiety symptoms | 47 | Not named | – |
| Bantugan 2023RCT, placebo | APOE4 carriers and noncarriers, DHA pilot | – | Not named | – |
| Sullivan 2023RCT, placebo | Children born before 29 weeks gestation | – | Not named | – |
| Guillot 2022RCT, placebo | Breastfeeding mothers of very preterm infants | 528 | Not named | – |
| Gustafson 2022RCT, placebo | Children of mothers given prenatal DHA | 167 | Not named, 600 mg | – |
| Gould 2022RCT, placebo | Children born before 29 weeks gestation | – | Not named | – |
| Gonzalez Casanova 2021RCT, placebo | Pregnant women, offspring at 5 years | 1,094 | Not named, 400 mg | 20 weeks |
| Gould 2021RCT, placebo | School-aged children of supplemented mothers | 543 | Not named, 800 mg | 20 weeks |
| Li 2021RCT, placebo | Older adults with mild cognitive impairment | 240 | Not named, 800 mg | 26 weeks |
| Hewawasam 2021RCT, placebo | Infants born preterm | 120 | Not named | – |
| Yang 2021RCT, placebo | Healthy school-aged children in rural China | 106 | Not named, 300 mg | 26 weeks |
| Dong 2021RCT, placebo | HIV patients with neurocognitive impairment | 68 | Not named, 3,150 mg | 26 weeks |
| Ciappolino 2020RCT, placebo | Euthymic bipolar patients and healthy controls | 46 | Not named, 1,250 mg | 12 weeks |
| Arellanes 2020RCT, placebo | Older adults, APOE4 carriers and non-carriers | 33 | Not named, 2,152 mg | 26 weeks |
| Ghasemi Fard 2020RCT, active or other control | Healthy toddlers | – | Microencapsulated tuna oil | 4 weeks |
| Tomaszewski 2020RCT, placebo | Adults with mild to moderate Alzheimer's disease | – | Not named | – |
| Eslamian 2020RCT, placebo | Men with asthenozoospermia | – | Not named | – |
| Gawlik 2020RCT, placebo | Children of mothers given DHA in pregnancy | – | Not named, 800 mg | – |
| Colombo 2019RCT, placebo | Pregnant women and their children | 301 | Not named, 600 mg | – |
| Mazahery 2019RCT, placebo | Children with autism spectrum disorder | 73 | Not named, 722 mg | – |
| Crippa 2019RCT, placebo | Drug-naive children with ADHD | 50 | Not named | 26 weeks |
| Rodríguez 2019RCT, placebo | Children and adolescents with ADHD | – | High-DHA triglyceride, 1,000 mg | – |
| Montgomery 2018RCT, placebo | Healthy schoolchildren, 7-9 years | 376 | Not named, 600 mg | 16 weeks |
| Demmelmair 2018RCT, placebo | Children with phenylketonuria | 109 | Not named | 26 weeks |
| Mulder 2018RCT, placebo | Children whose mothers took DHA in pregnancy | 98 | Not named, 400 mg | – |
| Smith 2018Single-arm or open-label | Adults with major depression | 28 | Not named, 520 mg | 8 weeks |
| Zhang 2018RCT, placebo | Older adults with mild cognitive impairment | – | Not named, 2,000 mg | 104 weeks |
| Zhang 2017RCT, placebo | Older adults with mild cognitive impairment | 240 | Not named, 2,000 mg | 52 weeks |
| Hashimoto 2017RCT, placebo | Oldest elderly with dementia in care homes | 75 | Not named, 1,720 mg | 52 weeks |
| Gould 2017RCT, placebo | Children of mothers given DHA in pregnancy | – | Not named | – |
| Ramakrishnan 2016RCT, placebo | Children of Mexican mothers given DHA in pregnancy | 1,094 | Not named, 400 mg | – |
| Jackson 2016RCT, placebo | Healthy older adults with memory complaints | 86 | Not named | 26 weeks |
| Yassine 2016RCT, placebo | Alzheimer disease patients (APOE genotype substudy) | 70 | Not named | 78 weeks |
| Gould 2016RCT, placebo | Pregnant women, subgroup analysis | – | Not named, 800 mg | – |
| Colombo 2016RCT, placebo | Infants of mothers given DHA in pregnancy | – | Not named, 600 mg | – |
| Collins 2015RCT, active or other control | Preterm infants followed to age 7 | 657 | Not named | – |
| Montgomery 2014RCT, placebo | Children aged 7-9 underperforming in reading | 362 | Not named, 600 mg | 16 weeks |
| Gould 2014RCT, placebo | Preschoolers whose mothers took DHA in pregnancy | 185 | Not named, 800 mg | 20 weeks |
| Keenan 2014RCT, placebo | Pregnant African American women, low income | 64 | Not named, 450 mg | – |
| Harden 2014RCT, active or other control | Overweight and obese women | – | Not named | 12 weeks |
| Makrides 2014RCT, placebo | Children of mothers given prenatal DHA | – | Not named | – |
| Benton 2013RCT, placebo | Young adult women | 285 | Not named, 400 mg | 7 weeks |
| Stonehouse 2013RCT, placebo | Healthy young adults with low DHA intake | 176 | Not named, 1,160 mg | 26 weeks |
| Long 2013RCT, placebo | Young men without aggression history | 173 | Not named | 13 weeks |
| Drover 2013RCT, placebo | Infants fed DHA-supplemented formula | – | Not named | – |
| Richardson 2012RCT, placebo | Children aged 7-9 underperforming in reading | 362 | Not named, 600 mg | 16 weeks |
| Judge 2012RCT, placebo | Pregnant women, infant sleep after birth | 48 | Not named, 300 mg | 15 weeks |
| Yi 2011RCT, placebo | Females with phenylketonuria aged 12-47 | 33 | Not named | 20 weeks |
| Yurko-Mauro 2010RCT, placebo | Healthy older adults with age-related cognitive decline | 485 | Not named, 900 mg | 24 weeks |
| Quinn 2010RCT, placebo | Mild to moderate Alzheimer disease | 402 | Algal DHA, 2,000 mg | 78 weeks |
| McNamara 2010RCT, placebo | Healthy boys aged 8-10 | 33 | Not named, 1,200 mg | 8 weeks |
| Jensen 2010RCT, placebo | Breastfeeding mothers and children followed to age 5 | – | High-DHA algal oil, 200 mg | 17 weeks |
| Doornbos 2009RCT, placebo | Pregnant and postpartum women | 119 | Not named, 220 mg | – |
| Kennedy 2009RCT, placebo | Healthy children aged 10-12 | 90 | Not named, 1,000 mg | 8 weeks |
| Ryan 2008RCT, placebo | Healthy preschool children | 175 | Not named, 400 mg | 17 weeks |
| Johnson 2008RCT, placebo | Healthy older women | 49 | Not named, 800 mg | 17 weeks |
| Mischoulon 2008RCT, active or other control | Adults with major depression | 35 | Not named | 12 weeks |
| Birch 2007RCT, placebo | Healthy term infants followed to age 4 | 79 | Not named | – |
| Judge 2007RCT, placebo | Pregnant women and infants | 29 | Not named, 214 mg | 16 weeks |
| Hirayama 2004RCT, placebo | Children with ADHD | 40 | Not named, 514 mg | 9 weeks |
| Auestad 2003RCT, active or other control | Healthy term infants | 196 | Not named | 52 weeks |
| Marangell 2003RCT, placebo | Major depression patients | 36 | Not named, 2,000 mg | 6 weeks |
| Llorente 2003RCT, placebo | Breast-feeding postpartum women | – | Not named, 200 mg | 17 weeks |
| Hamazaki 2002RCT, placebo | Healthy older Thai adults | 40 | Not named, 1,500 mg | 9 weeks |
| Voigt 2001RCT, placebo | Children with ADHD on stimulants | 63 | Not named, 345 mg | 17 weeks |
| Birch 2000RCT, active or other control | Healthy term infants | 56 | Not named | 17 weeks |
| Hamazaki 2000RCT, placebo | Students under exam stress | 41 | Not named, 1,500 mg | 13 weeks |
| Hamazaki 1999RCT, placebo | Students under exam stress | 42 | Not named, 1,500 mg | 13 weeks |
| Sawazaki 1999RCT, placebo | Medical students under exam stress | 14 | Not named, 1,500 mg | 9 weeks |
| Terano 1999RCT, placebo | Patients with dementia from cerebrovascular disease | – | Not named | – |
| Scott 1998RCT, active or other control | Healthy term infants | 274 | Not named | 52 weeks |
| Hamazaki 1998RCT, placebo | University students, nonstressful conditions | 46 | Not named, 1,500 mg | 13 weeks |
| Hamazaki 1996RCT, placebo | Students under exam stress | 41 | Not named, 1,500 mg | 13 weeks |
| Carlson 1996RCT, placebo | Preterm infants | – | Not named | 9 weeks |
| Werkman 1996RCT, placebo | Preterm infants | – | Not named | 40 weeks |
What's known about safety
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In trials
Reviews of omega-3 trials found no rise in side effects or in bleeding compared with placebo. DHA alone at 2 to 4 g a day raised LDL cholesterol by about 3%. Studies on this page gave up to about 3 g a day, some for two years.
Bafkar 2024, review of 23 trials; Javaid 2024, review of 11 trials on bleeding; EFSA 2012 opinion on EPA, DHA and DPA; this page's study list
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In the UK
DHA-rich oil from microalgae (Schizochytrium) is an authorised novel food in Great Britain, with set limits for each source, such as 1 g of oil a day in supplements and a warning not to give it to children under 3. EFSA found supplemental DHA up to about 1 g a day raised no safety concerns, and set no upper limit.
FSA novel food register and safety assessments of Schizochytrium oil; Novel Foods (Wales) Regulations 2022; EFSA 2012 opinion, Oct 2026
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Check first
Omega-3 oils can slightly slow blood clotting, which a review says may matter for people taking blood thinners such as antiplatelets or warfarin. Speak to a pharmacist or doctor first if you take a blood thinner, or to your midwife or doctor if you're pregnant or breastfeeding.
Carr 2018, review of fish oil and bleeding; Begtrup 2017, review of 52 studies
Where these studies come from
We list every published study in people that gave long-chain omega-3 and measured thinking, memory, mood, stress, sleep, energy or quality of life, from one search shared with the omega-3 EPA page. DHA given without EPA, including algal DHA oil, counts as DHA on its own. Fish, krill and cod liver oil, which carry EPA and DHA together, and omega-3 not broken down count as a blend. Plant omega-3 from flaxseed, eating fish, and people who chose to take supplements themselves are left out. This first version is built from each study's summary; full-paper checks come next.
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We search
PubMed, the world's main library of medical research, for every paper on L-theanine.
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We keep studies in people
Lab and animal work is counted but left out of the list, because it doesn't tell you what happens in people.
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We note the basics
Who took part, how many, how much and for how long, from each study's published summary. A second check corrects what the first read gets wrong.
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We read them in full
Results appear once we've read the whole paper and checked every number. The date at the top shows when this entry was last updated.
Download the study list
Every study in people as a spreadsheet, 86 rows, free to reuse with a link back.
Versions
Each update to the data gets a new version number, so you can tell what changed and when.
See every version
1.0 · 24 Oct 2026. First release. Every published study giving DHA to people that measured thinking, memory, mood, stress, sleep, energy or quality of life is listed from its summary. None is read in full yet.
