What Happens When You Take Vitamin D and Omega-3 Together?

Vitamin D helps maintain healthy bones and muscles. Omega-3 fatty acids support a healthy heart and improve immune system function. Combining supplements can help reduce inflammation and manage certain health conditions.

Some studies suggest that vitamin D supplements may help reduce cancer and muscle pain, especially in people with low vitamin D levels. Omega-3s have been shown to prevent pain from getting worse.

Taking vitamin D and omega-3s together may help prevent and manage chronic pain due to their anti-inflammatory effects. A 2022 study found that taking both supplements together reduced pain more effectively than taking either supplement alone.​

However, not all studies support the use of omega-3 fatty acids and vitamin D to reduce pain. A 2020 study observed that American adults with chronic knee pain who took both omega-3 and vitamin D for more than five years saw no significant decrease in pain.

Studies show that taking about 1 gram of omega-3 per day can slow biological aging by up to four months. However, researchers have found that taking omega-3 and vitamin D together has even greater benefits for biological aging. Biological aging reflects the condition of your organs and tissues and can predict your risk of diseases like Alzheimer’s and stroke.

A 2025 study found that daily vitamin D supplementation of approximately 2,000 international units (IU) per day can reduce biological aging, with or without omega-3 fatty acids.

If you are considering taking supplements for this purpose, consider talking to your healthcare professional. Taking omega-3 or vitamin D might be more beneficial than taking both, especially if you have an underlying condition.

Vitamin D helps reduce inflammation in the brain and may help improve cognition and mood. Omega-3s are also brain food and can help boost cognition. Additionally, the anti-inflammatory properties of omega-3s can stabilize the nervous system and improve mood.

Taking vitamin D and omega-3 supplements simultaneously may improve depression and anxiety. The two supplements work together to relieve depression by reducing inflammation and balancing brain chemicals.

However, if you have depression or anxiety, talk to your doctor, as supplements do not help treat the underlying cause of depression.

Studies suggest that vitamin D can significantly improve sleep quality, especially in older adults and pregnant women. Omega-3s have also been shown to improve sleep quality.

A 2021 study found that taking magnesium and omega-3 together helped improve sleep quality in women. However, there is not enough evidence to recommend taking omega-3 and vitamin D together to improve sleep quality. If you’re concerned about your sleep quality, talk to your doctor about supplement recommendations and other possible solutions.

Vitamin D may reduce the risk of heart attacks in patients with heart disease. Omega-3s help reduce triglyceride levels and prevent platelets from sticking together, which can help you stay healthy and protect your heart from stroke.

Results are mixed on the heart health benefits of taking both supplements together. Some studies suggest that taking vitamin D and omega-3 together may help reduce the risk of disease-related deaths in patients suffering from a heart attack, stroke, or heart failure. Other studies have not found a significant benefit to taking the two supplements together to prevent heart disease.

Omega-3 fatty acids can help improve bone formation and prevent bone breakdown. Vitamin D helps your body absorb calcium, which can help you maintain strong bones. Omega-3 and vitamin D may help reduce the risk of osteoporosis (weak, brittle bones).

Taking vitamin D and omega-3 fatty acids together may help improve bone health and reduce fractures.

Some research has shown that taking omega-3 fatty acids and vitamin D together can help lower blood sugar levels. A 2021 study found that taking vitamin D and omega-3 fatty acids for about six weeks effectively reduced blood sugar levels in women with gestational diabetes (a type of diabetes during pregnancy). However, omega-3s are not recommended during pregnancy without first talking to your healthcare professional.

The combination of omega-3 fatty acids and vitamin D is probably safe when used at recommended doses. However, this combination of supplements may not be suitable for everyone, especially people living with certain conditions or taking certain medications.​

Do not take omega-3 and vitamin D without talking to your healthcare professional if you:

• have severe allergies to fish or shellfish, as many omega-3 supplements are made from fish oil
• have kidney or liver disease
• Take medications that increase your risk of bleeding (for example, warfarin), because omega-3s may increase your risk of bleeding
• Take medications like statins (atorvastatin or simvastatin) and thiazide diuretics (Hygroton and Microzide)
• are pregnant or breastfeeding