Supplements and Mental Health: What the Evidence Says
Short answer
For most supplements people take for mood or anxiety, NIH's NCCIH describes the evidence as uncertain, mixed or not supportive. St. John's wort may help some people with mild to moderate depression but can interact dangerously with many medicines. Omega-3s are uncertain, SAMe is not supported, and vitamin D did not prevent depression in a large trial. FDA does not approve supplements before sale, and none should replace treatment.
In crisis or thinking about suicide? Call or text 988 now (in New York City it reaches NYC 988). If you are in immediate danger, call 911.
This guide is not enough if
- You are thinking about suicide or harming yourself. Call or text 988, or call 911 if you are in danger now.
- You want to replace a prescribed medicine with a supplement. Talk with your prescriber before you change anything.
- You are pregnant, breastfeeding, or choosing for a child. Many supplements have not been tested in these groups, so ask a clinician first.
- You need a dose or a product recommendation. This guide explains the evidence; it does not recommend products.
Why people look at supplements, and what this guide covers
You may want something you can start on your own, something that feels more natural, or something to add to treatment that is only partly working. Those are common reasons, and they deserve a straight answer about what the research shows.
The National Center for Complementary and Integrative Health (NCCIH), part of NIH, describes integrative health as bringing conventional and complementary approaches together in a coordinated way. On depression it is direct: depression can be a serious illness, and a complementary approach should not replace conventional care or be a reason to delay seeing a provider.
This guide is a short decision layer. For the wider evidence picture, read how strong the evidence for integrative psychiatry is and the integrative psychiatry guide.
How FDA regulates supplements differently from medicines
A prescription drug has to show safety and effectiveness to the FDA before it is sold. Supplements do not. The FDA says it regulates dietary supplements under a different set of rules, that the companies are responsible for evaluating the safety and labeling of their products before marketing, and that the agency can act against an adulterated or misbranded product once it is on the market. NCCIH puts it plainly: the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed.
That gap has practical effects. NCCIH lists several:
- What is on the label may not be what is in the product.
- Some products have been found to contain prescription drugs or other ingredients not listed on the label.
- A label that says "standardized" does not necessarily mean consistent quality.
- "Natural" does not always mean safe. NCCIH gives kava, which can cause liver disease, as an example.
- Many supplements have not been tested in pregnant women, nursing mothers or children.
What NCCIH says about common mood and anxiety supplements
St. John's wort has the most research. NCCIH says studies indicate it may be helpful for mild or moderate depression, while its provider summary calls the evidence far from definitive. The bigger issue is safety: NCCIH warns that it can weaken the effects of many medicines, lists some antidepressants, birth control pills and warfarin among the drugs it interacts with, and says combining it with certain antidepressants may lead to serotonin-related side effects that can be serious.
For the others, NCCIH is more cautious. It says it is uncertain whether omega-3 supplements help depression, and that current research does not support SAMe or inositol for depression. Vitamin D was tested in a large trial of 18,353 adults aged 50 or older who did not have clinically relevant depressive symptoms at the start; over a median of 5.3 years, vitamin D3 did not prevent depression (opens in a new tab) compared with placebo. That trial looked at prevention, not at people with a deficiency or with active depression.
For anxiety, NCCIH notes that anxiety disorders are generally treated with psychotherapy, medication or both. It says kava supplements may have a small effect on anxiety but have been linked to a risk of severe liver injury, that a chamomile supplement might help generalized anxiety disorder in preliminary studies, and that oral lavender may help in an analysis limited by low-quality studies. "May help" in these summaries means the research is not settled, not that a product works for most people.
| Supplement | What NCCIH or NIH says about mood | Safety and interaction notes |
|---|---|---|
| St. John's wort | May help some people with mild or moderate depression; evidence far from definitive | Can interact in dangerous, sometimes life-threatening ways with many medicines |
| Omega-3 fatty acids | Uncertain whether they help depression | Generally well tolerated; NCCIH flags a bleeding-time concern with drugs that affect platelets |
| SAMe | Current research does not support it for depression | Might interact with serotonin-raising drugs; may worsen mania in bipolar disorder |
| Vitamin D | Did not prevent depression in a large trial of adults 50 and older | A trial of prevention, not of treating a deficiency |
| Kava | May have a small effect on anxiety | Linked to a risk of severe liver injury |
| Chamomile and lavender | Chamomile might help generalized anxiety (preliminary); oral lavender may help anxiety (low-quality studies) | Tell your prescriber before adding either |
Interactions: the reason to tell your prescriber
The FDA says certain supplements can change the absorption, metabolism or excretion of a medication, which can leave you with too much or too little of it. NCCIH adds specific cautions: SAMe might interact with antidepressants and other products that raise serotonin, and people with bipolar disorder should not take SAMe for depression except under a provider's supervision because it may worsen mania.
So treat a supplement like a medicine when you talk with your care team. Bring a written list of everything you take, including teas, powders and gummies. Mind Body Seven asks new patients to bring a list of prescription and over-the-counter medications to the first visit, and it helps to add supplements to that list. Supplements that interact with psychiatric medication covers specific combinations.
Timing matters too. The FDA suggests telling your health care providers what other supplements and medications you take before you add a new supplement. NCCIH adds that you should tell your providers about all supplements before surgery, because some may raise bleeding risk or affect anesthesia. If you are pregnant or could become pregnant, NCCIH notes that St. John's wort use during pregnancy may be unsafe.
How to weigh a supplement with your clinician
A short, honest conversation is more useful than a long shopping list. These questions help keep it focused:
- What symptom or problem would this supplement be for, and what does NCCIH or NIH say about it?
- Could it interact with any medicine I take, or with a medical condition I have?
- Is there a reason to check a level first, such as vitamin D or B12, and what would we do with the result?
- How long would we try it, and how will we judge whether it helps?
- What should make me stop it and call you?
When a supplement is not the right next step
If you are thinking about suicide or harming yourself, a supplement is not the answer right now. Call or text 988, or call 911 if you are in immediate danger, and see crisis and hotline resources.
A supplement is also the wrong first move if your symptoms are severe or getting worse, if a clinician has diagnosed bipolar disorder, or if you are thinking of stopping a prescribed medicine to try one. In those cases, start with a clinician. Questions to ask before starting psychiatric medication helps with that conversation, and mind-body practices and mental health covers non-supplement options. If you want help sorting out nutrition and supplements alongside conventional care, Mind Body Seven offers nutrition and supplement consults as part of integrative psychiatry, and how to choose an integrative psychiatrist explains how to check any clinician's training. Some people also ask about pharmacogenomic testing, which looks at medicines rather than supplements.
Frequently asked questions
Does fish oil help depression?
NCCIH says it is uncertain whether omega-3 supplements help depression. Its provider summary says they are generally safe and well tolerated, with mostly minor side effects such as stomach upset and a fishy aftertaste, but it raises a concern that they may extend bleeding time in people who take drugs that affect platelet function. If you want to try fish oil, tell your prescriber, especially if you take a blood thinner.
Should I take vitamin D for my mood?
A large trial of adults aged 50 or older found that vitamin D3 did not prevent depression over about five years compared with placebo. That does not answer what happens if you are actually deficient, which is a separate medical question. If you think your level may be low, ask a clinician whether testing makes sense. Which lab tests are used in integrative psychiatry explains vitamin D testing.
Are supplements checked by the FDA before they are sold?
No. NCCIH says the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed. The FDA says manufacturers are responsible for evaluating safety and labeling first, and the agency can act against unsafe or mislabeled products after they reach the market. That is why product quality can vary and why a label claim is not the same as evidence.
If a supplement is natural, can it still cause side effects?
Yes. NCCIH warns that natural does not always mean safe, and gives kava, which can cause liver disease, as an example. St. John's wort can weaken many prescription medicines, and SAMe may worsen mania in people with bipolar disorder. Side effects and interactions are possible with any product that has an effect on the body, so treat supplements like medicines when you talk with your care team.
Are mood supplements safe for children and teens?
NCCIH notes that many dietary supplements have not been tested in children, so there is often little safety information for young people. Talk with your child's pediatrician or psychiatric clinician before starting anything, and include supplements on any medication list you share.
Next: compare your options
A question list for the medication conversation, with why each question matters and where the answer is written down.
Sources
- NCCIH: 8 Things To Know About Depression and Complementary Health Approaches
- NCCIH: Depression and Complementary Health Approaches, What the Science Says
- NCCIH: St. John's Wort
- NCCIH: S-Adenosyl-L-Methionine (SAMe), In Depth
- NCCIH: Anxiety at a Glance
- NCCIH: Using Dietary Supplements Wisely
- FDA: Dietary Supplements
- FDA: Mixing Medications and Dietary Supplements Can Endanger Your Health
Reviewed by Dr. Beata Lewis, MD, Founder and Clinical Director, board-certified in adult psychiatry, child and adolescent psychiatry, and integrative medicine on November 8, 2026. Facts checked against the sources above on November 8, 2026. This guide is general education, not medical advice, a diagnosis or a treatment plan, and reading it does not make you a patient of Mind Body Seven. For advice about your situation, talk with a licensed clinician.