Supplement with a purpose.

Vitamin D supports normal nerve and muscle function, calcium absorption and bone health. For whole-person mental-health care, meeting this need supports the physical foundation that sits alongside mood, energy and daily functioning. Your skin can make vitamin D with sunlight exposure, but sun exposure also carries risks.

Food sources: Fatty fish, egg yolks, and milk or plant drinks fortified with vitamin D. Check labels because amounts vary.

How it may help: Correcting a deficiency is a clear reason to consider supplementation. Some studies also suggest a benefit for depressive symptoms, although results vary and a mood benefit is not assured. We consider vitamin D as part of a broader plan, not a stand-alone depression treatment. Testing may be useful in some circumstances, and excess intake can be harmful.

Source: NIH vitamin D fact sheet and 2026 review of vitamin D and depressive symptoms.

B12 helps keep your nerves and red blood cells healthy and supports DNA production. A deficiency can affect how you feel and think, contributing to fatigue, low mood, confusion or memory problems. Identifying a true deficiency gives us a specific, treatable issue to address.

Food sources: Fish, meat, eggs and dairy, plus fortified cereals and some nutritional yeasts. People who avoid animal foods need reliable fortified foods or another source of B12.

How it may help: Replacing low B12 can help relieve deficiency-related fatigue and protect nerve health. This can be a meaningful part of care when a nutritional problem overlaps with mental-health symptoms. The right approach depends on intake and absorption; extra B12 does not boost energy or endurance when you already get enough.

Source: NIH vitamin B12 fact sheet.

Magnesium helps regulate nerve and muscle function and supports the processes your body uses to make protein, bone and DNA. Meeting your magnesium needs is one way to support a healthy nervous system, particularly when your usual food intake falls short.

Food sources: Beans, nuts, seeds, whole grains and leafy green vegetables.

How it may help: A supplement may help close an intake gap or address low levels related to a clinical condition. Some small studies suggest possible sleep benefits, but the evidence is limited and does not establish magnesium as a treatment for insomnia or anxiety. Supplemental magnesium can cause diarrhea and interact with medicines. Kidney disease increases the risk of buildup, so review use with your clinician.

Sources: NIH magnesium fact sheet and kidney function considerations and NCCIH review of sleep research.

Omega-3 fats help form the membranes of brain cells, making them part of the brain's normal structure and function. Your body cannot make the essential fat ALA and converts only a small amount into EPA and DHA, so food choices matter.

Food sources: Salmon, sardines and other seafood supply EPA and DHA; walnuts, flaxseed and chia seeds provide ALA.

How it may help: Fish-oil or algae-based supplements can supply EPA and DHA when intake is limited. Some studies suggest a modest added benefit alongside antidepressants for selected people with depression. Findings are mixed, so we discuss potential usefulness in the context of your overall treatment. Omega-3s do not replace psychiatric care, and high doses may interact with blood thinners.

Sources: NIH omega-3 fact sheet and NCCIH review of depression evidence.

Iron helps your body make hemoglobin, which carries oxygen to the brain and the rest of the body. Iron-deficiency anemia can leave you feeling drained and can affect concentration and memory. Recognizing this overlap matters when low energy or trouble focusing is part of the picture.

Food sources: Meat, seafood, beans, lentils and fortified cereals. Pairing plant sources with vitamin C foods, such as citrus or peppers, helps absorption.

How it may help: Treating an identified iron deficiency can help restore energy and address symptoms related to anemia. The cause also needs evaluation; tiredness alone is not a reason to start iron. Excess iron can be harmful, can interfere with medicines such as levothyroxine, and must be kept away from children.

Source: NIH iron fact sheet.

Folate supports DNA production and cell division and participates in processes involved in brain function. Deficiency can contribute to fatigue, irritability and difficulty concentrating. Folic acid and L-methylfolate are different forms, and their uses in mental-health care are not interchangeable.

Food sources: Leafy greens, beans, peas, oranges and enriched grain products.

How it may help: Correcting inadequate intake can address a nutritional contributor to symptoms. For some people whose depression has only partly improved with an antidepressant, clinician-supervised L-methylfolate may offer an additional benefit; evidence is limited and response varies. Folic acid is also important before and during early pregnancy. Discuss prenatal needs with your clinician. High supplemental folate can hide the anemia of B12 deficiency while nerve damage continues, so high-dose use needs medical supervision.

Source: NIH folate fact sheet and NIH review of folate and depression.