Although research has found a strong connection between vitamin D deficiency and depression, there’s a lack of research on whether vitamins can improve the symptoms of seasonal affective disorder.

Many people take vitamins for seasonal depression — aka seasonal affective disorder (SAD) — but there’s still relatively little research on whether supplements can help with these seasonal symptoms.

The symptoms of SAD can be debilitating. But certain treatments can improve your symptoms and boost your mood. Antidepressant medications may help some people, as can talk therapy and light therapy.

Some research even suggests that certain natural supplements may help with the symptoms of depression. While there’s a lack of research on the topic, here’s what research tells us.

Seasonal affective disorder is a mental health condition where you experience depression during specific seasons. It’s also called seasonal depression or major depressive disorder (MDD) with seasonal patterns.

According to the American Psychiatric Association, SAD affects about 5% of adults in the United States.

The symptoms usually begin in the fall or winter (winter-pattern SAD), but some people experience SAD in summer and spring (summer-pattern SAD). The symptoms usually last 4–5 months.

The cause of SAD isn’t entirely clear, but it may occur because the shift in seasons affects your circadian rhythm. The circadian rhythm, which affects your sleeping patterns and mood, is affected by sunlight.

When seasons change, the number of hours of daylight changes — and this change may affect your mood.

Symptoms of seasonal affective disorder

The symptoms of seasonal affective disorder may include:

Symptoms of winter-pattern SAD may also include:

The symptoms of summer-pattern SAD may include:

Vitamins can play a major role in helping maintain a positive mood and good sleep patterns. However, research has not been able to show whether vitamin supplements should be recommended for improving seasonal depression symptoms.

Vitamin D

Serotonin, a hormone that plays an important role in regulating your mood and sleeping patterns, is dependent on vitamin D. It’s not surprising, therefore, that research has found a strong association between vitamin D deficiency and seasonal affective disorder.

What’s unclear is whether vitamin D supplements can help relieve SAD symptoms.

While a 2020 research review of 7,534 people found that vitamin D supplements reduced negative emotions in people with major depressive disorder, research that specifically links vitamin D supplements and seasonal depression is inconclusive.

Although there needs to be more research specifically on vitamin D as a treatment for seasonal affective disorder, anyone with a vitamin D deficiency could benefit from taking supplements or getting more sunshine. You can reach out to a healthcare professional if you believe you might have a deficiency.

St. John’s wort

Also known as Hypericum perforatum, St. John’s wort is often marketed as a supplement that can improve depression, anxiety, and sleep issues. Yet, it’s not well studied.

A large review of studies in 2017 looked at the research on using St. John’s wort for depression. Although some research suggested it could reduce symptoms of depression, the review concluded that there’s not enough evidence to support treating depression with St. John’s wort.

The National Center for Complementary and Integrative Health states that there’s “not enough reliable evidence” to know whether St. John’s wort can improve seasonal affective disorder.

St. John’s wort is considered safe for consumption, but it can have side effects. It can also interact with certain medications, including:

  • antidepressants
  • birth control pills
  • cyclosporine
  • some medications for heart disease, cancer, and HIV
  • blood thinners, especially warfarin

It’s essential to talk with a medical professional before using St. John’s wort.


Melatonin is a hormone that is naturally produced by your brain’s pituitary gland. At night, your body produces melatonin, which gets your body ready for sleep. As such, melatonin is used as a natural sleep aid.

Seasonal changes may affect your circadian rhythm, which affects your body’s sleep-wake cycle.

Research in 2020 suggests that poor sleep plays a role in both summer-pattern and winter-pattern SAD. Since sleeplessness and poor sleep can worsen your mood, quality sleep could improve the symptoms of depression.

Using melatonin supplements may improve your sleep. But it’s important to be aware of the side effects of melatonin. Even though melatonin can be bought over the counter, it’s a good idea to speak with a doctor before using it, especially if you use it long-term.


Magnesium is important for various bodily functions, including brain function and mood regulation.

According to 2020 research in animals, your magnesium levels may be lower during the winter. Stress can also deplete magnesium levels.

Some research — like this recent review — suggests that magnesium supplements may reduce symptoms of depression.

Magnesium may also improve sleep, which may indirectly improve depressive symptoms. If you have low magnesium levels, a supplement may improve your mood, but more research is needed to understand the connection between magnesium and SAD.

Many people take vitamins and supplements because they believe it’s a natural way to enhance their health. But just because something is natural doesn’t mean it’s always safe.

It’s possible to take too much of a certain vitamin. If you take too much vitamin D, for example, you may experience nausea and vomiting.

Here are some tips for using supplements safely:

  • Read about the correct dosage and side effects: The packaging should tell you how much of a certain supplement you should take every day. You can always double-check this with your doctor or a pharmacist. Do not exceed the recommended dosage.
  • Get blood tests first: There’s no use supplementing with a vitamin if you already have optimal levels of that vitamin. So before you buy, it can help to get a blood test. Although blood tests can be expensive, vitamins can be too — and taking them unnecessarily may be both expensive and dangerous.
  • Speak with a doctor first: While this isn’t always possible, it may be necessary. Certain vitamins and supplements can interact with medications you’re taking, causing uncomfortable or dangerous side effects. Even if it’s just over the phone, check in with a healthcare professional before starting a new supplement.
  • Choose high quality supplements: No matter which supplements and vitamins you use, only purchase quality supplements made by reputable companies.

Before trying a new supplement, you may also want to try adding more foods with the vitamins mentioned above. For instance, adding more tryptophan to your diet can help your body make more serotonin.

Prescription medications like antidepressants can also help with seasonal depression. If you’re hesitant to take prescription medication, other natural treatments for seasonal affective disorder include talk therapy, sun exposure, and light therapy.

Potential side effects of taking vitamins

It’s possible to overdose on vitamins and supplements. This can be dangerous in some cases, depending on the person and the vitamin. Excessive vitamins may cause serious side effects.

Certain vitamins and supplements can also interact with medications, which can weaken the effects of your medication or cause side effects. If you use any medication — whether for chronic or acute conditions — it’s important to ensure that your supplements won’t interact with them.

To be safe, consider speaking with a doctor before trying a new supplement.

With the right support and treatment, the symptoms of seasonal affective disorder can be managed.

There are many possible treatments for seasonal depression, including antidepressants, talk therapy, and light therapy.

Although certain vitamins are marketed as helpful for treating seasonal affective disorder, there’s not enough evidence at the moment to know whether they’re truly beneficial.

Reaching out to a healthcare professional can help you determine if a supplement is right for you.