Review: Green Pastures Fermented Cod Liver Oil

By Adrian Oaks / January 16, 2016

Green Pastures is a family owned business that was created in 2000 by Dave Wetzel and his wife. Originally, Dave imported cod liver oil from Iceland to mix with the butter oil produced on his farm. However after a visit to commercial fish oil production facilities Dave noticed a disturbing trend – the fish oil process used to produce the cod liver oil he was importing was highly denatured. This was due to a 4 step process that involved bleaching and deodorization. There was only 1 factory that even bothered to add the lost (natural) vitamins back in. Most factories were already using synthetic varieties of vitamins.

Dave could see the writing on the wall, so he started to do his own research and happened upon the ancient method of fermentation. It took him 6 years to perfect and adapt the method to modern day use. Due to the time investment, Green Pasture products emphasize quality over quantity with a focus on old school production practices. Specifically, Green Pastures models their products off the studies and teachings of Weston Price, who created a nutrient dense mixture by combining high vitamin butter oil and fermented cod liver oil.

Since Green Pastures is actually a farm that produces its own grass fed butter oil in addition to their cod/skate/ coconut oils, it should be noted that the products they produce are marketed as food – not supplements. I believe this is Green Pastures creative way of circumventing the increasing regulation of the supplement market.

Fermentation & Absorption

Green Pastures maintains that due to the industrial revolution much of the manufacturing processes for making fish oils changed to a more inferior, automated variety. They maintain that the fish oils on the market today aren’t nearly as potent as they were 100 years ago. As such, Green Pastures produces fish oil the slow way – by fermentation. Fermentation of fish oils was quite common before the industrial era, but since the advent of mechanized food production this method has fallen out of style. To oversimplify things, fermentation is a process that converts sugars to acids. The process of creating fermented cod liver oil is simple – you place cod livers in a airtight container and let them site for a given period of time (typically 6 months to a year). Since there is no heat or filtration involved fermented cod liver oil does not suffer from any nutrient degradation or loss.

In terms of absorption, Fermented fish oil is a far superior type of oil processing when compared to the typical types one sees on the market, such triglyceride, esther ethyl, or even phospholipid.

Taste & Consistency

Green Pastures butter oil/cod liver oil blend comes in 3 flavors: cinnamon, chocolate, and unflavored. The standard cod liver oil comes in mint and orange. In general I have found that the cinnamon/mint flavor masks the taste the best. Chocolate/orange is so-so and I would avoid the unflavored variety. The unconventional production method used to create fermented cod liver oil has its drawbacks – mainly in the actual taste. This product is very pungent, especially the gel varieties. If you are someone like me who dislikes the smell of fish you may want to purchase the capsule variety of this product. Even then, expect a great deal of fishy aftertaste. This can be inconsistent and it seems to depend of the color of the oils of your particular batch. The general rule is: the darker the oil the more pungent the taste, although this isn't the case 100% of the time.


This product is probably one of the more effective fish oils on the market. Due to the unique method of its manufacture, Green Pastures fish oils contain many other vitamins and minerals that competing products lack. Chief among these would be the naturally occurring vitamins A & D. These create a synergistic effect with the vitamin K in the butter oil that provides an extra benefit to bone health & skeletal structure. This effect was studied extensively by Dr. Weston Price. Price used fermented cod liver oil to treat dental caries and was very successful. Additionally, this product contains no synthetic vitamin additives which can cause reactions in certain people. In this regard it is more like a whole food product. If your taking this to treat a condition, you should notice a positive effect after 1 – 2 weeks.


Green Pastures prices its products at around 60$ shipped for either the high vitamin butter oil or just the plain cod liver oil, this fish oil comes in at the high end compared to its competitors. This can be a major drawback to those living on a budget. If you are just looking for general health maintenance I would advise halving your daily dosage. Due to its relatively high potency you may be able to get away with a smaller dose. This will save you a great deal of money in the long run. Also of note are the serving sizes of the capsules and gel varieties. The gel contains a full 36 more servings than the capsule variety, quite a big difference. Those trying to get as much bang for their buck as possible may want to opt for the gel version.


Containment's are a big concern among supplement manufactures, and Green Pastures performs rigorous testing on all of their batches. The heavy metal content is below detectable levels and the PCB’s number in the .99 ppm, well below WHO standards. Green Pastures claims that due to the smaller batches they produce, the number of tests performed per gallon of fish oil is substantially greater than competing products.

Further Reading

This fish oil is a premium product at a premium price. If you are someone who is in relatively good health you may not need such an optimized product and should perhaps opt for one of the cheaper brands of fish oil. However for those suffering from nagging or severe health issues – especially dental cavities – this product is probably worth a look. Also, I recommend you opt for the butter oil and cod liver oil combo, as it is only a few dollars more than the plain cod liver oil and offers additional benefits to your overall health. If you wish to learn more about cod liver oil in general, we have a excellent write up here. If you want would to take a look at other types of fish oils, check out our homepage.