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Fish Oil Dosage – Why You Need It and How Much Omega-3 Should You Take?

This article starts with explaining why standard doses of fish oil are not enough to produce the real benefits available to us from omega-3, and then shows why that is from an evolutionary perspective. However, if you would like to skip down to the dosage research and instructions for specific health benefits or problems as well as for general health, please follow the hyperlinks, we have included a conclusion at the end of each section:

Pain, Inflammation and General Health

Triglycerides, Cholesterol and Cardiovascular Benefits

Cognitive Benefits

Sport and Exercise Benefits

Increasing Muscle Mass


Depression and Mental Health


Macular Degeneration

Dry Eye

Fish Oil dosage can be a very confusing subject, and it’s one of the most common questions we get here at Intelligent Labs. Officially the amounts recommended by different government bodies vary, but the US Academy of Nutrition and Dietetics recommends 500mg of EPA and DHA a day, and this 500mg a day is probably the most common guideline that we hear in the industry.

However, we recommend a daily serving of 2250mg of EPA and DHA (which is supplied in 3 grams of fish oil) from our Ultra Pure Natural Triglyceride Omega-3. So if 500mg is recommended by The Academy of Nutrition and Dietetics why are we suggesting an omega-3 dosage that’s so much higher?

Well 500mg is recommended because it’s generally thought to be enough to prevent an omega-3 deficiency. Research conducted at Harvard in 2009, concluded that up to 96,000 preventable deaths in the USA every year are caused by omega-3 deficiency (1), so even the 500mg recommendation is not being reached by enough people, it’s actually estimated that in the USA the average daily intake of omega-3 is just 100mg per day (2), That’s why health experts are desperate to make sure everyone is getting at least this much omega-3. However, we don’t just want to avoid an omega-3 deficiency, we are interested in thriving, becoming the best we can be, and fully benefiting from all the amazing things omegA-3 can do for our health when it’s available to us in abundance. To understand exactly why higher levels of omega-3 allow us to thrive we need to take a quick look at where we have come from and how omega-3 has shaped our evolution.

Human Beings We Were Born to Fish

Our evolutionary past is tied to fish and seafood. The first hominids species i.e the first human-like species appeared in the fossil records about 2.5 million years ago, that was the same time as the last ice age started (although it’s often called the present ice age as we are currently in what is known as an interglacial warming period).

It marked a time of significant change in the weather patterns of the earth and the previous areas our primate ancestors had inhabited were the forest regions of Northern Africa where we ate a mostly vegetarian diet. The weather became drier and cooler and that led to a reduction in the area of forestry, and thus the food amount of food available to us. Because of this, our ancestors had to move to areas where food was more plentiful or risk extinction. To put our extinction risk in perspective 165 of 283 large mammal species worldwide became extinct during this period (3).

As we moved from the forests of Northern Africa things start to become very interesting. The search for food led to the Great Rift Valley which is a 3,700-mile long trench in Eastern Africa that reaches from Lebanon in the north to Mozambique in the south.  It was here that we start to see in the fossil records the evidence for the increasing size of the human brain.  From Homo habilis, to Homo ergaster, Homo erectus, Homo heidelbergensis and Homo sapiens, with each subsequent species found we see larger bodies and bigger brains. The reason is that the Great Rift valley is filled with lakes and the abundance of

how much fish oil should i take
The Great Rift Valley

these lakes mean that we had the opportunity to begin a ‘shore-based diet’.

A shore-based diet consisted of, fish, molluscs, crustaceans, frogs, bird’s eggs and aquatic plants, and provides the richest known dietary sources of the nutrients needed to power the human brain (4). These nutrients are iodine, iron, zinc, copper and selenium and most importantly the omega-3 fatty acid DHA.

Growing a bigger brain has given us an advantage in nature. But it only gives us an advantage once we have grown that bigger brain. Whilst it’s still growing it actually puts us, and our parents at greater risk from predators, and extra pressure on our parents to find food for us for the extra time we are not able to fend for ourselves.

So, because initially growing bigger brains would have been an evolutionary disadvantage. We could have only evolved these bigger brains if our environment had allowed access to an abundance of easily available food that provided the vital nutrients needed for brain growth in an environment of relative safety. That was the exact habitat of the Great Rift Valley, with its wetland environment of freshwater and saltwater shores of lakes, riverbanks, marshes, estuaries, and later the coastal regions of east and southern Africa (5).

A key point to understand is that we are still in the wetland stage of our evolution, in other words, we still need to get the abundant supply in our diets of the nutrients that have driven our evolution to be our best because we can’t yet produce them ourselves. However, in the modern world as we have moved away from this diet and reduced our intake of nutrients like omega-3 we have opened up ourselves to many potential health issues (5). For example, there are many studies that indicate that Alzheimer’s disease is more prevalent in populations consuming low amounts of fish and aquatic invertebrate nutrients (6).

That we were born to fish is now the accepted theory of evolution of paleo-anthropologists, and has replaced the now-debunked theory that we evolved on the plains of Africa that were popularised in the otherwise excellent book ‘Born to Run’ (7). However, despite the evidence for the ‘Born to Fish’ theory, it’s still just a theory. The question is do the scientific studies that have looked at omega-3 benefits and dosages back this up by suggesting a need for a higher dose of omega-3? That’s what this article will look at next.

Scientific Evidence For a Higher Omega-3 Dosage

How Much Omega-3 Fish Oil Should I Take To Reduce Inflammation and Pain? Or For General Health?

Inflammation in the body is a cause of a huge number of health problems. For example, coronary heart disease, major depression, ageing and cancer are all characterized by an increase in an inflammatory molecule called interleukin 1 (IL-1), (a pro-inflammatory cytokine). Whilst autoimmune conditions like arthritis, Crohn’s disease, ulcerative colitis and lupus erythematosis are also linked in interleukin 1 levels and another molecule called leukotriene LTB4, which is produced from omega-6 fatty acids (8). Don’t worry about the names of the molecules, the point is we can reduce them by supplementing with a high enough dose of omega-3.

A meta analysis study (which is a review of other published studies) published in arthritis research concluded that people must take 2.7 grams of omega-3 daily to achieve anti inflammatory and pain reduction benefits (9). The authors also concluded that the reduction in oxidised LDL (the bad cholesterol) that’s associated with inflammation conditions such as arthritis was also reduced with with a daily omega 3 dose of 2.7 grams.

The studies were conducted with ethyl ester fish oil which is much less well absorbed than our triglyceride fish oil, so a 3 capsule dose of our omega-3 would be greater than a 2.7 gram dose of ethyl esters.

As mentioned above Crohn’s disease is an autoimmune condition. The disease is often marked by periods of normality followed by relapses. One study showed that in patients who had a high risk factor for relapse, 59% stayed Crohn’s free after one year following a daily dose of 2.7 grams of omega-3 (10). Also in another study, patients who had been hospitalised with severe Psoariasis showed a significant improvement with 4.2 grams of omega-3 daily (11).

There is also a test we can use to measure levels of inflammation in the body – the omega 6:3 ratio. Often tests looking at the omega 6:3 ratio will measure the ratio of Arachidonic Acid to Eicosapentaenoic Acid (AA:EPA), with Arachidonic Acid being omega-6 and Eicosapentaenoic Acid being omega-3. People suffering from chronic diseases often have a ratio as high as 15:1 or more (12), whilst reducing the ratio to 3:1 or lower is associated with very low levels of inflammation (13). These are the ratios we should look to achieve if we are taking omega-3 for general health to reduce the chances of us developing disease.

A 2010 study found a daily dose of 2.5 grams of EPA and DHA was sufficient to reduce the AA:EPA ratio to 2.6:1, so under the 3:1 ratio that achieves a very low level of inflammation (14).

Doses of 2.7 grams reduces the inflammation associated with auto immune conditions such as arthritis and 2.5 grams will reduce the omega 6:3 ratio down to low levels of cellular inflammation. These doses came from ethyl ester fish oil, so taking the 3 capsule daily serving of our omega-3 (in triglyceride form) will surpass these levels.


Triglycerides, Blood Cholesterol and Heart Disease

It’s long been known that omega-3 protects against heart disease, and significantly reduces the levels of triglycerides circulating in the blood and can increase levels of HDL (the good cholesterol), but is a standard 500mg dose of omega-3 going to be enough to make a difference?

How Much Omega-3 Fish Oil Should I Take To Reduce Triglycerides?

High triglycerides are one of the most common reasons for people taking an omega-3 supplement. Some studies have shown decreases of over 50% in the levels of triglycerides at a dose of 10 grams of omega-3 per day in patients with high triglycerides (15). However, more usual findings are a reduction of 25 – 30% with doses of 2-4 grams of omega-3 (16).

To reduce Triglyceride levels we recommend the 3 capsules per day serving of Intelligent Labs Omega-3.


How Much Omega-3 Fish Oil Should I Take To Improve My Cholesterol?

When looking at omega-3 effects on cholesterol, we first need to explain exactly what we are looking at. Doctors will talk about good and bad cholesterol, with HDL being the good and LDL being bad. However, HDL and LDL are not actually cholesterol, they are what are known as lipoproteins, LDL is Low-density lipoproteins and HDL is High-density lipoprotein. Because cholesterol is fat-soluble and our blood is mostly water cholesterol won’t dissolve in water, so it has to be carried around our body by Lipoproteins. Cholesterol is vital for life, it forms the basis of the membranes of every one of the body’s 20 trillion cells and forms the basis of many hormones. LDL transports cholesterol to cells that need it, whereas HDL recycles damaged cholesterol and takes it back to the liver.

So cholesterol in itself doesn’t cause us problems, it’s the lipoproteins, or more specifically LDL that can cause heart disease. The LDL molecules get stuck in the one cell layer wall of an artery, known as the endothelium. These stuck LDL molecules can then form plaque which becomes heart disease


Omega-3 (and more specifically DHA) raises HDL cholesterol (the good one). One study with a 4.5 gram daily dose of EPA and DHA in a roughly 3:2 ratio (the ratio we use in Intelligent Labs Omega-3) showed a 50% increase in the levels of HDL (so around a 20mg/dl increase!) (17). Although this is perhaps a larger than average increase, another meta-analysis study showed that DHA on average increases HDL by 4.49mg/dL (18) in doses of 2.3 to 4 grams per day.


When it comes to LDL levels the studies are less clear and the results are somewhat mixed. Some studies have shown a decrease in LDL levels and some an increase. A Meta-Analysis study has also shown that EPA is likely to slightly decrease LDL and DHA slightly increase it by 4.63 mg/dL (19). So, we could say that EPA is better for our cholesterol than DHA. However, these studies have looked at DHA and EPA in isolation and not together, and most omega-3 supplements come in a combination of EPA and DHA. They are also only measuring one aspect of LDL which is not necessarily an indicator of heart disease risk.

To understand why that is we need to look at what an LDL test result is actually showing us. When you go to the doctor and get an LDL reading they give you what is called an LDL-C reading. This is total amount of LDL. However, whilst a high reading is a potential issue, there is a much more effective reading for heart disease risk and that is LDL-P, which is the number of LDL particles, not the volume of LDL particles as in LDL-C.

small and large LDL particles

A good an-allergy to understand the difference between LDL-C and LDL-P and why LDL-P is the bigger risk factor is to think of a highway. The walls at the edge of the highway are the endothelium lining of the arteries. The cars on the road are LDL, and the passengers in the car are the cholesterol. The total size of all the cars or the volume would be the LDL-C figure, whereas the number of cars on the road would be the LDL-P figure. The actual risk to cars of crashing off the road is not the size of the cars, but the number on the road. The busier the road the more likely there will be a crash, and this is LDL-P.

LDL particle number (LDL-P) is a much more accurate predictor of CV disease risk than either LDL-C or total cholesterol. So when understanding how omega 3 affects heart disease we need to look at LDL-P rather than LDL-C (19).

what's the difference between LDL-P and LDL-C

As well as measuring LDL-P we can also measure Apolipoprotein B. Apolipoprotein B is the major apolipoprotein in LDL. It binds with triglycerides and cholesterol to form LDL, and it is also the receptor that binds with cells so LDL can deliver its fats and cholesterol. So in scientific studies, Apolipoprotein B levels act as a proxy for LDL-P.

A 2015 study showed a dose of 3.4 grams of EPA and DHA per day significantly reduced Apolipoprotein B levels, whereas a dose of 0.85 grams a day did not change Apolipoprotein B levels (20). Another study with a huge 24 grams of omega-3 per day (EPA and DHA) showed significant reductions in LDL-C and Apolipoprotein B levels (21). Whilst we don’t recommend a 24-gram daily dose, the studies do indicate that larger doses can reduce LDL particle count more.

Studies have shown DHA significantly increases LDL particle size in 4 gram daily servings of Pure DHA (22, 23) and a mixed EPA and DHA omega-3 supplement (23).  Increased particle size, as we’ve seen in the image above, is generally an indicator of reduced LDL particles, which is another good reason to have a healthy amount of DHA in your omega.3 supplement.

To increase HDL and reduce LDL-P we recommend a 3 capsule daily serving of our omega-3.

Other Cardiovascular Benefits:

Blood Clotting

A 1997 study showed that a dose of 2.6 grams per day of omega-3 fatty acids reduced blood platelet aggregation (the ability of blood cells to form a clot) which reduces the risk of thrombosis (24). Another study showed that a dose of 2-3 grams of omega-3 daily significantly increased bleeding times and reduced platelet aggregation (25).

Heart Rate Variability

Another study showed that a 5.2 gram daily dose of omega-3 increased heart rate variability. Decreased heart rate variability is associated with arrhythmia (abnormal patterns of the heart), and higher death rates in patients that have already suffered a heart attack (26).

Stability of Atherosclerotic Plaques

Higher dose fish oils were also shown to make atherosclerotic plaques more stable (i.e less likely to rupture and cause a heart attack), in patients waiting for a carotid endarterectomy (an operation to unblock a carotid artery) (27).

Artery Widening

Although early trials have shown the ability of high dose omega-3 at widening the arteries in heart disease patients (28), more recent studies have suggested that high dose effects are only mild (29 – 30), so this may not be a cardio-protective factor of omega-3.

Blood Pressure

A review of 31 studies on blood pressure found that omega 3 could lower blood pressure and that the amount that it lowered it was based on the dose. The higher the dose the more blood pressure was lowered and they estimated the lowering as -0.66/-0.35 systolic/diastolic mm Hg per gram of omega-3 fatty acids per day (31). Another meta analysis study found that 3 grams or more of omega-3 per day can lead to clinically relevant blood pressure reductions (32).

Resting Heart Rate 

A study found that 4 grams of ethyl ester EPA or DHA per day could reduce resting heart rate by 1.9 bpm (EPA) and 2.2 bpm (DHA) (33).

Nitric Oxide Production and Endothelial Function

Endothelial function is the ability of the arteries to contract and relax efficiently. Nitric Oxide is known to relax arteries and increase blood flow, and because of this Nitric Oxide (NO) boosters are very popular sports supplements. A 1997 study found that a 3 gram a day dose of omega-3 increased endothelial function, and it was concluded that this was likely to be due to increased NO production. They also found the DHA rather than EPA was responsible for this (34).

Heart Attack Risk

So how do all these cardiovascular benefits affect heart attack risk? The best way to look at this is long term studies on individuals that have already suffered heart attacks. However, the problem is that there are not many of these, and so far there has been only one study using high dose fish oils of 4 grams per day (35). That showed no benefit from using the fish oil, although, as the authors discussed the study was conducted in western Norway where the population already has a very high fish intake through their diet, so the fish oil was unlikely to be able to add to the cardio protective benefits they were already receiving from their omega-3 intake.

However, 2 other studies showed a significant benefit of omega-3 for patients who had suffered a heart attack. The GISSI trial in Italy of over 11,000 men showed a significant reduction in cardiac events following 1 gram of omega-3 a day for 3.5 years (36). Also, a 1 year trial of patients who had suffered a heart attack showed that supplementation with fish oil of 1.08 grams per day reduced cardiac deaths by 50% over placebo (37). Despite this, a further study showed that omega-3 of 900mg twice a week so approximately 260mg a day, showed no benefit on cardiac death rates to men with suffering with angina (38), and a final study showed that a daily dose of just under 400mg of omega 3 had no significant impact on heart attack risk on patients who had recently suffered a heart attack (39).

So it’s clear that 260mg a day or 400mg a day is a dose far too small to have heart benefits in the body. However, 1 gram a day will provide a significant reduction in heart attack risk. So it seems very likely considering all of the other cardio protective effects that higher doses than 1 gram a day of omega-3 will reduce cardiac death rates even further.

The Omega-3 Index

The one thing that these studies lack is testing higher doses of omega-3, and also the examination of actual omega-3 levels in the blood. Luckily there is a clinical test – The Omega-3 Index that we can look at. The Omega-3 Index it the percentage of omega-3 fatty acids present in our blood. In the USA the average is 4% – 5% (40 – 43). However, the level needed to see a significant reduction in primary cardiac arrest (44), sudden cardiac death (45), coronary atherosclerosis (46), and acute coronary syndrome (47) is over 8% (48).

To increase the average level of omega 3 in our blood from 4%-5% to over 8% requires a daily intake of omega-3 of between 1.8 and 1.9 grams (49 – 50).

A daily-3 capsule serving of our omega-3 should provide the benefits listed above including a slight reduction in blood pressure, reduced risk of blood clotting and thrombosis, increased nitric oxide production and endothelium function, and an increase in the Omega 3 Index above 8% which is associated with a significant reduction in cardiac risk events.

Cognitive Benefits

The main reason we include a high dose of DHA in our omega-3 supplement is because of DHA’s effects in the brain. DHA is the most prominent of all the fatty acids in the brain. It forms a vital part of cell membranes and gives fluidity to them. In brain neurons this extra fluidity allows them to make effective synapse connections. For a growing fetus that must make 250,000 new brain cells a minute, a lack of DHA can be disastrous. DHA also plays a key role in the ongoing structure of the adult brain.

In the brain itself, the areas most closely associated with memory show the highest DHA concentrations (51). DHA also has 3 key roles in the brain.

1.DHA protects brain tissue from inflammation

DHA produces anti-inflammatory molecules as well as suppressing pro-inflammatory molecules that can degenerate and age the brain (52- 53).

2. DHA causes physical changes in the brain that stimulate learning and memory

DHA directly promotes the growth from neurons known as neurites that form the connections between cells as memories form (54).  It also promotes rapid signal transduction across synapses, and it also provides fluidity in cell membranes allowing for rapid changes in shape and function that can be recognised as learning and memory (55-56).

3.DHA can heal brain tissue after it has been damaged through injury

After an injury, the brain will release DHA in large amounts that are then converted in molecules called protectins. Protectins provide anti-inflammatory processes and begin healing in brains that have suffered seizure, stroke or a physical injury (52,57)

So now let’s look at how this relates to studies that have used DHA supplementation and assessed cognitive improvements:

A 2012 study showed that a 1 gram daily serving of DHA led to increased cerebral blood flow during cognitive tasks, whereas no benefit was found with 1 gram of EPA (58). Another meta-analysis study showed that 1 gram per day of DHA improved episodic memory (i.e times, places, associated emotions, and other contextual who, what, when, where, why knowledge) and working memory (which is like a mental sticky note we use to keep track of information until we need to use it) (59). A 2013 study showed that 1.16g of DHA per day also improved working memory in healthy young adults and memory reaction time (60).

Cognitive Decline

Studies on the cognitive decline are key to understanding DHA’s benefits in the brain. So far studies have shown that DHA supplementation is not effective in late-stage Alzheimers. However, no pharmaceutical drugs are effective in late-stage Alzheimers, and the best they can do is slow the progress of early-onset Alzheimers and dementia. It is early-onset Alzheimer’s and dementia where DHA shows it’s benefits.

A recent article in 2015 by Chew et al (61) came to the conclusion that omega-3 supplements were not beneficial in any form of cognitive decline. This conclusion was widely published in the media with headlines suggesting that ‘Omega-3 supplements were useless’. However, when you look more closely at the study you see that they used only a 350mg daily serving of DHA.

Another article by Adam Ismail at GOED, titled ‘Omega’s and Cognition, Dosage Matters, published after the Chew et al study also in 2015, reviewed all of the studies on cognitive decline and fish oil DHA supplementation. He looked specifically at whether they provided a successful outcome and the level of DHA supplementation per day (62). The results are quite striking, and clearly show a dose of less than 500mg per day of DHA is not enough to provide cognitive benefits:

how much fish oil should i take

DHA is vitally important for cognitive benefits. Studies show that the more DHA one supplements with the better the outcome. All studies supplementing with above 1000mg a day of DHA show benefits. A study in The American Society for Clinical Nutrition showed that DHA supplementation reaches a ‘saturation point’ in the blood at 1.2 grams of DHA a day when taken with EPA in a 3:2 ratio, so 1.8 grams of EPA and 1.2 grams of DHA per day for a total of 3 grams of omega-3 a day. So when you reach that level of supplementation, blood levels of DHA stay constant even when you increase the DHA dose over 1.2 grams (63). A 2001 study showed there was a correlation between blood levels of omega-3 and levels in the cerebral cortex (64), so reaching the ‘saturation point’ in blood DHA would suggest we are also reaching the limit of DHA absorption into the brain. So to reach this saturation point we’d recommend 4 capsules of our omega-3 per day.

Exercise and Sports Performance Benefits

How Much Omega-3 Fish Oil Should I Take For Recovery?

Hard training causes inflammation and pain, as we’ve already seen a dose of 2.7 grams of omega-3 a day is needed to reduce this inflammation (9), although this inflammation is associated with training over the longer term. A 2009 study showed that 1.8grams of omega-3 per day was needed to significantly reduce the perceived pain and the range of motion of joints following acute exercise sessions known as DOMS – Delayed Onset Muscle Soreness (65).

Increasing Muscle Mass

Several studies have shown that omega-3 supplementation can promote muscle growth and does so by switching on the mTOR pathway, which is the body’s muscle-building ‘switch’. It can also improve Insulin signalling which allows more muscle-building nutrients into cells (66-67). A dose of 3.86 grams of omega-3 showed a muscle-building (anabolic response) both in older adults for the prevention of sarcopenia (muscle wasting with age) (66) and in young and middle-aged men and women (68).

Increasing Blood Flow to the Muscles During Exercise

A study on trained cyclists using a dose of 2.4 grams of omega-3 a day found that it significantly lowered heart rates during incremental workloads to exhaustion, as well as displaying lower steady-state submaximal exercise heart rates (so lower heart rates when exercising at a constant workload below maximum), as well as lower whole-body oxygen consumption (so more efficient oxygen use), and a lower oxygen consumption by the heart (68).

A 3 capsule per day serving our Intelligent Labs Omega-3 will help to reduce inflammation both short and long term associated with training. It will also help to increase blood flow to the muscles during exercise. Individuals whose goal is increasing muscle mass may want to supplement with 4 capsules per day if they do not already have a high dietary intake of omega-3 (i.e eating lots of fish).


As we’ve seen earlier DHA is vital for a developing fetus, so what advice should pregnant women have on omega-3 supplementation?

How Much Omega-3 Fish Oil Should I Take During Pregnancy?

A fascinating study in the journal Pediatrics in 2003 showed that mothers who supplemented with 2.5 grams a day of omega-3 during pregnancy had children who scored higher on IQ tests at 4 years of age than mothers who did not take omega-3 supplements (69).

Preventing Premature Births

A study of women in their third trimester of pregnancy was split into 3 groups. The first group was given 4 grams of olive oil daily, the second was given 2.7 grams of omega-3 daily, and the third was given placebo. The results showed the olive oil group had the shortest pregnancies, and the omega-3 group had the longest pregnancies. No negative side effects of omega-3 supplementation for the mother or child were reported during the study (70).

Take at least 2.5 grams of omega-3 a day during pregnancy. It’s also important to continue supplementing after giving birth, as a baby’s omega-3 levels will quickly decline unless they get it through their diet (i.e breast milk). A mother’s breast milk omega-3 levels increase directly proportionally to omega-3 in their diets, so any supplementation should be continued for at least the entire breastfeeding period (71).

Depression and Mental Health

There are many epidemiological studies showing that in populations with a higher omega-3 dietary intake there is less depression (epidemiological are studies of populations, they can find a correlation between behaviours and health, but they can’t prove direct cause). For example, a Norwegian study found that people who took cod liver oil were 30% less likely to suffer from depression.

How Much Omega-3 Fish Oil Should I Take For Depression?

A recent meta-analysis found success in improving depression symptoms with omega-3 doses from 1000mg to 6.6 grams of omega-3 daily (72). They also found that omega-3 combined with anti-depressant therapy was more effective than anti-depressants alone. What is interesting is they found that EPA was more successful than DHA for lifting depression and that studies that used DHA only supplements were not effective at reducing depression. However, studies that combined EPA and DHA supplements were successful at reducing depression.

So far the cutoff point in studies is 60% EPA and 40% DHA for success in treating depressive symptoms, which is exactly the 3:2 ratio we use in Intelligent Labs Ultra Pure Omega-3 (73).

The authors suggested that “DHA as a component of neuronal membrane phospholipids affect neurotransmission, whereas EPA may influence mood to a greater extent by acting through eicosanoid (signalling molecules that are predominantly anti-inflammatory when produced from EPA omega-3) mechanisms to increase cerebral brain flow.

However, we’ve previously seen in the section on cognitive benefits that a 1 gram daily serving of DHA increases cerebral blood flow, whereas a 1 gram serving of EPA doesn’t (58). What is interesting is the studies of omega-3 and depression last for a maximum of 12 weeks, with many lasting 8 weeks and some only 3 or 4 weeks. The vast majority of the DHA studies that showed improvements in cognitive abilities lasted for 6 months or longer.

When you compare this to other research that has found that it can actually take up to 10 – 12 weeks of supplementation with DHA for it to fully integrate into the inner cell membranes (74), it seems quite possible that depression studies using DHA for longer than 12 weeks may come to different conclusions. So currently the recommendation is for at least 1 gram of omega-3 per day in no more than a 3:2 EPA to DHA ratio for depression. We also await longer studies into the effect of DHA on depressive symptoms.

We recommend the 3 capsule per day serving of Intelligent Labs Omega-3 to help relieve symptoms of depression, as an addition to treatments recommended by your physician.

How Much Omega – Fish Oil Should My Child Take For Depression

The studies mentioned above were conducted on adults and there are far fewer studies on children. However, depression still affects between 2 – 4% of children (75). A 2006 study conducted on children between 6 and 12 found that supplementation with 400 mg of EPA and 200mg of DHA (for a total of 600mg of omega-3 per day) for 4 months caused a significant decrease in depressive symptoms (76).

Also, another contributing factor to depression is poor sleep. A 2014 study found that a 600mg daily dose of DHA in children reduced wake episodes during the night and increased sleep time by an average of 58 minutes a night (77).

Try a dose of 600mg of omega-3 per day.


DHA also appears to be more effective than EPA in dealing with PTSD. PTSD is associated with a lowering of brain volume of the amygdala and hippocampus areas of the brain (78, 79). The amygdala and the hippocampus both interact with the prefrontal cortex, which controls the expression of emotions and impulses, the ability to focus, and the storage of memories.

We have already seen that DHA increases blood flow to the prefrontal cortex, and clinical studies have shown that the higher the consumption of omega-3 the greater the volume of the amygdala and hippocampus, and that DHA can cause neurogenesis (the growth of new neurons) in these areas (80).

How Much Omega-3 Fish Oil Should I Take For PTSD? 

So far there have not been many clinical studies on the effectiveness of omega-3 on PTSD, however, a 2010 study studied people who had recently been in a motor vehicle accident, and supplemented them with 1470mg of DHA and 147mg of EPA for 12 weeks (81). There was an average of 74 hours between the accident and starting the omega-3 protocol, and the results showed that the omega-3 was effective in preventing PTSD symptoms appearing. This suggests omega-3 supplementation can be helpful following exposure to traumatic events. We await more studies in this area.

It’s hard to draw a conclusion from the studies so far. Theoretically omega-3 may be able to help based on it’s ability to increase the volume of areas of the brain associated with PTSD. So if you want to try taking omega-3 for PTSD, you should use the dosage recommended above in the cognitive benefits section of the full 3 capsule daily serving of our omega-3.


ADHD is very common affecting some 3% -5% of children in the US and 4% of adults. ADHD is also associated with lower levels of omega-3 in the brain, and a 1996 study showed that in boys aged from 6 – 12, those with lower levels of omega-3 had higher levels of ADHD (82).

How Much Omega-3 Fish Oil Should I Take For ADHD?

Several studies have shown an improvement in ADHD symptoms with omega-3 fish oil supplementation (83, 84). A 2009 study went on to give very clear guidelines of 20 mg/kg/day to 25 mg/kg/day of EPA and 8.5 mg/kg/day to 10.5 mg/kg/day of DHA per day. So for a 30kg child, it would be about 660mg of EPA and 270mg of DHA (84).

How Much Omega-3 Fish Oil Should I Take For Anxiety?

A study of substance abusers showed that a 3-gram daily dose of omega-3 reduced anger and anxiety (85). Another study conducted on young healthy medical students found a daily dose of 2.85 grams of omega-3 reduced anxiety and inflammation even during stressful exam periods (86).

Based on these studies we suggest trying a dose of 3 grams of omega-3 a day.

Eye Health

DHA is at it’s highest concentration in the eye and is particularly highly concentrated in the retina, and is thought to be very important for healthy retinal function.

Macular Degeneration

Macular degeneration specifically targets the retina, so we would expect to see DHA affect this condition. So far there are no treatments to cure or reverse macular degeneration, there are only treatments to slow it’s progress.

How Much Omega-3 Fish Oil Should I Take For Macular Degeneration?

There have been 3 key studies so far looking at different doses of Omega-3 and their effects on macular degeneration. The first supplemented 1000mg a day of omega-3, with 650mg of EPA and 350mg of DHA. The authors concluded that this dose of omega-3 did not reduce the risk of developing advanced macular degeneration (87).

The second study increased the dose slightly to 1100mg a day but used a much higher dose of DHA (840mg of DHA and 270mg of EPA). The authors found that when they examined the study participants blood levels of DHA, those with the highest levels of DHA had a 68% reduced risk of developing new blood vessel formations, (new blood cell formations are characterized by vision loss and the development of advanced macular degeneration), although none of the study participants’ vision actually improved (88).

The third study increased the omega-3 dose considerably to 5000mg a day, with 3400mg of EPA and 1600mg of DHA. Quite incredibly they found that 100% of the study’s participants didn’t just slow the rate of their macular degeneration, but actually significantly improved their eyesight. Some of the participants experienced improvement within a few days of starting the study, and all had experienced significant improvement within 4.5 months of starting supplementation. The authors concluded that high dose omega-3 supplementation could actually begin to restore the eyesight of people suffering from macular degeneration! (89).