As with most fish oils, it contains high levels of omega 3 fatty acids and vitamins such as vitamin A and vitamin D. There are no set limit to taking cod liver oil however 1-2 capsules per day will me more than enough for the average person. The only precautuion to take is when you are pregnant as Vitamin A may cause harm to the baby. 

Below is some benefits that can come from taking cod liver oil supplementation. 

• May reduce inflammation- chronic inflammation which can increase the risk of high blood pressure and several other diseases can be suppressed by the omega-3 fatty acids due to the fatty acids suppressing the proteins that promote it. 
• May improve bone health- as you age, you start to lose bone mass; this could lead to fractures and other injuries. Cod liver oil is high in vitamin D that allows your body to absorb calcium allowing to keep your bones strong and healthy. 
• May support eye health- the omega 3 fatty acids and Vitamin A in cod liver oil have been shown to protect against vision loss through inflammation eye diseases like glaucoma and age-related macular degeneration (AMD). 
• May reduce heart disease risk- This is highle due to the omega-3 fatty acids too; it is shown to reduce triglycerides by 15-30%,  lower blood pressure, increase HDL cholesterol (good cholesterol) and prevent plaque forming in arteries which lowers chances of stoke and heart attacks. 
• May prevent joint pain- the fats present in the fish oil are healthy fats that include natural chemicals; they play a role by keeping your joints healthy by restoring and supplementing joint tissues. The natural chemicals provide the joints with lubrication that reduces the rubbing together of joints meaning there will be less pain and strains.