The side effects of squalene, or shark liver oil, have not been well studied, according to WebMD and Drugs.com. Humans and pigs have contracted pneumonia from breathing it in, and some people complain about its bad odor and taste. Experts advise that pregnant women and women who are breastfeeding avoid it.
The interaction of shark liver oil with other medications has also not been well studied, says WebMD and Drugs.com.
Three types of shark are used to make squalene, says WebMD. They are the deep sea shark, the dog fish and the basking shark. The oil from their livers is used by patients undergoing radiation therapy and chemotherapy to treat cancer. It is also used to combat the common cold and influenza and as a support for the immune system. Some people rub shark liver oil into their skin to treat skin disorders, including skin cancer. However, there is insufficient evidence that shark liver oil is effective against these conditions. Studies on animals indicate that shark liver oil may enhance fertility.
However, some studies suggest that squalene might have a role in reducing levels of cholesterol and triglycerides, says the National Institutes of Health. It might be used to boost the effect of cholesterol-lowering drugs.