Flaxseed oil (ALA)

The plant omega-3, pressed from flaxseed, taken by people who avoid fish oil.

People take it for

Cholesterol and blood fats
Inflammation
Blood pressure
Thinking and memory
Blood sugar
Body weight

A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.

Compare flaxseed oil (ALA) prices per dose

What is flaxseed oil (ALA)?

Flaxseed oil is pressed from the seeds of flax, an ancient plant grown around the world for its fibre and its oil. Its omega-3 is alpha-linolenic acid, or ALA: the plant form, and the material the body uses to make DHA, the long-chain omega-3 that oily fish and fish oil supply ready-made. It is sold as a liquid and in softgel capsules, and the figure that matters on the label is the ALA rather than the total oil. It is the omega-3 people reach for when they would rather not take fish.

Why do people take flaxseed oil (ALA)?

Cholesterol and blood fats

The thinking. Cholesterol and triglycerides are the numbers a GP watches, and flax has long been eaten as a heart food. The thinking is that the plant omega-3 changes how the liver packages fat into the blood, so the oil is taken hoping to nudge those numbers down.

What research has found. A meta-analysis of sixty-two trials found lower total cholesterol, triglycerides and LDL, with HDL unchanged, and two more found lower lipoprotein(a), another blood fat linked with heart risk. The picture is not uniform: a review in adults with coronary artery disease found no clear change, and one looking at healthy adults separately found their LDL and triglycerides went up. Most of these trials used ground seed rather than the oil. A fair body of trials has looked at this, and most point the same way.

Inflammation

The thinking. Omega-3 is what people reach for when something aches. The idea is that the plant omega-3 quietens the signals the body sends out when tissue is irritated, which is why the oil is taken for stiffness and general aches.

What research has found. Trials measured blood markers rather than aches: C-reactive protein, interleukin-6, TNF-alpha and the molecules lining blood vessels. Reviews found some markers lower and others unchanged, and which ones moved differed from one review to the next. A meta-analysis of C-reactive protein alone found no overall change, though it did find one among people with a BMI of 30 or more. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.

Blood pressure

The thinking. Blood pressure is the other number people watch, and it is one of the things flaxseed has been measured for most often. The thinking is that the omega-3 and the lignans both affect the tone of blood vessels.

What research has found. Reviews pooling trials of all flaxseed products found small average falls of roughly two to three points in both readings, larger in trials of twelve weeks or more and among people whose pressure was already high. The one review of the oil by itself found a fall in the upper reading and no clear change in the lower; a small trial setting the oil against sunflower oil found both readings lower on the flaxseed oil. A reasonable number of trials have measured this, and most of them agree.

Thinking and memory

The thinking. The brain holds a lot of long-chain omega-3, and the ALA in flaxseed oil is the material the body makes those from, so some people take it in later life hoping to keep their thinking sharp.

What research has found. One randomised trial gave healthy adults aged 65 to 80 either flaxseed oil carrying 2.2 g of ALA a day or a placebo oil, for twelve weeks, and measured six everyday thinking skills. Scores on one of them, a word-finding test, rose more in the flaxseed group; the other five showed no clear difference between the groups. Few studies have measured this yet, so there is little to go on either way.

Blood sugar

The thinking. Steady blood sugar is a reason people give for taking omega-3, and flaxseed has been measured for it a great deal. The thinking is that the fat changes how readily the body’s cells answer to insulin.

What research has found. This is where the form matters most. Reviews pooling all flaxseed products found lower fasting glucose, insulin and insulin resistance, but one that split the trials by what had been given found those falls in the whole ground seed and not in the oil or the lignan extract. Two trials of the oil itself did find lower insulin, and in one of them the oil and fish oil came out much the same. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.

Body weight

The thinking. Flaxseed is often worked into a diet as a filling, fatty food, and has been tested repeatedly as a way of shifting weight. The thinking leans on the whole seed rather than the oil, because fibre is part of the idea.

What research has found. Three reviews, two of them pooling 45 and 64 trials, found small average reductions in weight, BMI and waist measurement, of the order of half a kilo to a kilo. The subgroups where it showed most clearly were trials using 30 g a day or more of the whole seed, running twelve weeks or longer, in people who were overweight, rather than trials of the oil. This is one of the best-studied uses, and several reviews of trials broadly agree.

What does flaxseed oil (ALA) do in the body?

Alpha-linolenic acid is an essential fat, which means the body cannot build it and has to take it in. Some is burned for energy, some is laid into the membranes of cells, and some is used as the starting material for DHA, the long-chain omega-3 that the brain and the eyes hold most of and that fish oil supplies already made.

Reviews put flaxseed’s effects down to three things working together rather than one: the ALA, a lignan called secoisolariciresinol diglucoside, and the fibre. Between them they are described as quietening inflammation, mopping up oxidation and changing how the body handles blood fats. The oil carries the ALA alone, while ground seed carries all three, which is why a trial of the seed and a trial of the oil are not testing quite the same thing.

What do people say about taking flaxseed oil (ALA)?

These are anecdotes people have shared, not evidence.

What people like

Five of these six threads come from one parenting community, so the picture leans towards women, parents and children rather than everyone.
The commonest thing posters say they notice is easier digestion and more regular habits, almost always from the ground seed rather than the oil.
In the older threads parents chose the oil over fish oil for a child’s skin, and one described a large change over two years.
Several in the menopause thread said their hair felt better on it, and one said her hair loss slowed when she kept it up.

Common complaints

Quite a few say plainly that they cannot tell it is doing anything, and carry on taking it in hope.
Wind, stomach cramps and a dramatically quicker transit come up repeatedly, mostly from posters who started on a full tablespoon rather than a teaspoon.
Going rancid is the running worry: posters describe an odd smell, disagree about whether it needs the fridge, and admit they are unsure.
In one thread posters doubted the plant omega-3 stands in for fish oil, since it carries no EPA, and the questioner changed her mind.
Posters disagree about the taste of the oil: one found it tasteless and easy, another found it fishy and high in calories.

How people take it

Most posters in the two busiest threads eat the ground seed rather than the oil: a tablespoon stirred into porridge, yogurt, smoothies or overnight oats.
The oil is kept cold and used cold: stirred into dressings, shakes or juice, and added after cooking rather than heated.
Starting on a teaspoon and building up is the repeated suggestion, because a full tablespoon from the first day upsets some people’s guts.
Nobody describes a quick change: three or four weeks is the figure given, and several say a fair amount is needed.

Read from these public discussions:

Anyone take flaxseed (Mumsnet, 2021)
Flaxseed (Mumsnet, 2025)
flax seed oil-anyone else tried it? (Mumsnet, 2012)
Flaxseed oil / Fish oil for eczema (Mumsnet, 2006)
Flax oil (Mumsnet, 2005)
Flax seeds and or Flax seed oil. How do you take it (Cathe Friedrich Fitness Forums, 2004)

What forms of flaxseed oil (ALA) are there?

Form	What’s different	Per serving, on products we list
Flaxseed oil (ALA)	The oil pressed from flaxseed, sold as a liquid or in softgels; its omega-3 is alpha-linolenic acid.	2.04 g

What else is worth knowing about flaxseed oil (ALA)?

Labels give the ALA per serving as well as the total oil, and the two are far apart: the capsules used in trials held 1,000 mg of flaxseed oil carrying 400 mg of ALA. ALA per serving is what our price tables compare.
Much of the flaxseed research used 30 g a day of the ground seed, a food carrying fibre and lignans as well as the oil. Where reviews separated the two, they did not always find the same thing.
Most trials were in adults who already had raised blood fats, metabolic syndrome, type 2 diabetes or heart disease, rather than in healthy people.
Trials of the oil itself used from about 2 g a day up to 20 g, and one used 25 ml, usually over six to twelve weeks.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

The research behind this page (31 studies)

How much does flaxseed oil (ALA) cost?

That depends on the form and the pack, so we work out the price of the same dose of every flaxseed oil (ALA) product we can find and rank them.

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