Ginkgo biloba is an herbal supplement often promoted for its perceived ability to enhance cognitive function and memory. Its ability to improve blood circulation may make ginkgo beneficial to the eyes and blood vessels. Fish oil supplements are valued for their high concentrations of omega-3 fatty acids, which play important roles in the body and can have preventative health benefits. Of the two supplements, fish oil has been proved effective for lowering triglycerides, while ginkgo biloba is not backed by enough evidence to affirm it is effective for any particular use.

Ginkgo Basics

Ginkgo biloba leaves contain antioxidants known as flavonoids and terpenoids, which can help neutralize free radicals that contribute to cancer, heart disease and Alzheimer's disease, notes University of Maryland Medical Center. The flavonoids and terpenoids in ginkgo biloba function in different ways. While flavonoids help protect nerves, blood vessels and muscles of the heart, terpenoids can improve blood flow by helping dilate blood vessels and causing blood platelets to be less sticky. Ginkgo biloba is most well-known as a "brain supplement" and is commonly taken to improve memory and cognitive function, as well as protect against dementia.

Effectiveness of Ginkgo Biloba

Ginkgo biloba is often used to treat conditions that stem from a lack of blood flow such as claudication as well as eye-related problems, including glaucoma, age-related macular degeneration and diabetic eye disease. MedlinePlus rates ginkgo biloba as "possibly effective" for treating Alzheimer's disease, improved thinking in both young and older individuals, Raynaud’s syndrome, claudication, peripheral vascular disease, vertigo and dizziness, glaucoma, premenstrual syndrome and improving color vision in those with diabetes.

Fish Oil Basics

The omega-3 fatty acids in fish oil, which include docosahexaenoic acid and eicosapentaenoic acid, have made it a favorite supplement for protecting the heart, decreasing inflammation and improving overall health, notes Harvard Medical School. Deficiencies in these important fats have been linked to cardiovascular disease, certain cancers, arthritis, mood disorders and other conditions. Fish oil is one of the most studied dietary supplements, with potential uses including weight loss, arthritis, premenstrual disorder, bipolar disorder, osteoporosis and attention-deficit disorder, according to New York University Langone Medical Center.

Effectiveness of Fish Oil

Fish oil is often used to lower blood pressure and cholesterol levels -- two factors directly linked to heart disease and stroke. Similar to ginkgo biloba, fish oil has earned a reputation as a "brain supplement" that can help with a variety of mental disorders, including Alzheimer's disease. MedlinePlus has rated fish oil "effective" for lowering high triglycerides and "likely effective" for keeping the heart free of disease. It is also rated as "possibly effective" for wide variety of conditions, including menstrual pain, arthritis, weight loss, kidney problems, bipolar disorder, psoriasis and asthma.