5 Flaxseed Oil Side Effects and Best Dosage

While there are many flaxseed oil nutritional benefits, there are also some potential negative effects and it’s important to take the correct amount.

This page lists the main 5 reported side effects of flax oil and suggests a dosage method based on slow increase to reduce the chances of a negative reaction.

Also ahead, the how and when to take it for the best results and work out your own ideal daily intake

5 Side Effects of Flaxseed Oil

1. Blood Thinning Precautions

The omega-3 fatty acids in flax oil can help make blood platelets less sticky, potentially reducing the chances of a dangerous blood clot forming in our arteries.

This same effect though may amplify the action of blood thinning medications which can be an unwanted site effect of flaxseed oil.

It is very important to check with your doctor before taking it if you are using prescription drugs for blood thinning.

Supplementing at high doses with the oil may increase the risk of bleeding during or after surgery. It is recommended to stop taking flax, or any other omega-3 supplements, two weeks before undergoing major surgery.

2. May Affect Blood Sugar

Taking large doses of flax oil may slightly lower blood sugar levels. This would generally be a good thing, especially if you are using flaxseed oil for weight loss.

There is some concern though that people taking blood sugar lowering medications at the same time as flax could reduce their blood sugar too low.

Once again, consult your doctor and avoid taking the oil at the same time as any important medications, regardless of the health condition.

3. Pregnancy Concerns

Flaxseed oil is generally considered highly beneficial for women, especially for better skin and healthier hair.

It is not recommended for pregnant women though, especially those in their second or third trimester.

This is due to some research suggesting a possible increase in the chance of a premature birth with large doses of the oil.

While far from proven, it would be best to discuss this with your obstetrician or other healthcare professional before taking it during pregnancy.

Some medical resources also suggest not using flaxseed products when breast-feeding, though no research is cited for this warning. Additionally, good levels of omega-3 fats in a breastfeeding women’s diet would be healthier than excessive amounts of omega-6.

4. Allergic Reactions 

Very occasionally, allergic reactions to flax oil have been reported that may include rashes, itching and swelling.

These instances are considered very rare and I have seen no research confirming flax compounds that would cause allergy symptoms.

5. Gastrointestinal Problems

Digestive problems like bloating and gas are sometimes associated with flax, though this is usually the high-fiber ground meal, rather than the extracted oil.

Occasionally an upset stomach and diarrhea has been reported with taking 30 grams or more in one dose of flaxseed oil. This is a large amount and probably too much to start with initially.

Below is a method for slowly increasing your dosage to get the maximum benefit while reducing the risk of flaxseed side effects.

How and When to Take Flax Oil for Maximum Benefit

Flax is a powerful supplement and increasing your intake of omega-3 fatty acids and the other nutrients in it can have many benefits. That said, some people do seem to react badly to large doses , especially if they have never had it before.

To minimize the chances of side effects, it is best to start off with a high quality and organic oil like this, take just a small amount the first week and increase your daily dose on a weekly basis.

Particularly if your diet has been lacking in omega-3 fats in the past, it will be more beneficial to increase your dosage steadily over several weeks, rather than immediately taking your maximum dose.

Taking flaxseed oil in this way gives your body time to adapt to a new omega-3 to omega-6 fat ratio, minimizing the risk of side effects.

You can also monitor any positive results from taking the oil and get an idea of your ideal daily intake.

Having flax oil with a meal is usually recommended over having it on an empty stomach. Splitting the dosage between morning and evening is also generally preferred, rather than having it all in one go.

It is also important to use a high-quality oil that is cold pressed and unrefined. There are several of the best of these listed in the page on where to buy flaxseed oil online.

Best Flaxseed Oil Daily Dosage

Week 1

With all this in mind, it is a good idea to start your first week of taking the oil with just 1 gram in the morning with breakfast and 1 gram with your evening meal.

This is only around a quarter of a teaspoon of the liquid oil or usually one flax oil capsule, but check the dosage information on the container.

Week 2

For the following week this amount could be doubled to 4 grams a day. Split into 2 grams with breakfast or lunch and 2 grams with dinner. This is around half a teaspoon or two of these organic flax oil capsules.

Week 3 and Beyond

By the third week you could double this again to a teaspoon or 4 capsules at around 4 grams per morning and 4 grams in the evening.

8 to 10 grams daily should be a good flaxseed oil dosage in the higher range for most people.

If you wish to increase the amount taken beyond here it would be preferable to add to the total amount by just an extra gram per morning and evening for the subsequent weeks.

Finding the Right Amount for You

If you do experience any side effects from taking flaxseed oil you could either stop immediately and try again from the initial dose, or even just 1 grams a day.

Alternatively, you could cut the amount you take back by half or even a quarter and slowly built up by a gram a week to a level where you are seeing benefits without any negative effects.

Some people report very positive results with 2 tablespoons a day of fresh organic flax oil like this one I use. That’s around 30 grams. Others have side effects at these larger amounts.

By starting a lower flax oil dosage and building up the amount of oil you take each week, your body is less likely to have a bad reaction to it.

You may also find you are getting good results at 8 to 10 grams per day or even lower and don’t need to go up to the higher dose.

I hope these dosage recommendations and list of flaxseed side effects to be aware of has been helpful. I’d be interested to hear what you think and your own experiences with taking it regularly.