As winter approaches, it means shorter days and a dwindling amount of sunlight. This seasonal change can bring on symptoms ofseasonal affective disorder(SAD), which affects about one in 20 Americans.

Some social media influencers claim that you can counteract these symptoms with a combination ofvitamin D3andvitamin K2 supplements.

“You need to buy vitamin D before seasonal depression hits, before the sun goes away for months on end,” said TikTok user Cirena Wilson. “And make sure you get the one with K2.”

SAD symptoms often overlap with those of depression. Common signs include persistent feelings of sadness or depression, a loss of interest in activities you once enjoyed, andexcessive sleeping.

Can Vitamin D and Vitamin K Help With Seasonal Depression?

Vitamin D and vitamin K are key nutrients that everyone needs to stay healthy.But is there evidence that vitamin D and vitamin K can actually help with symptoms of SAD?

A recent study published inNutrientsexamined whether vitamin D can help alleviate symptoms of SAD. While the findings were inconclusive, the authors suggested that vitamin D deficiency, specifically, may increase the risk of developing SAD.

“Vitamin D is involved in the pathways of production of melatonin and is believed to play a key role inserotonin activity, which further links serotonin, melatonin, and light exposure, but mainly deficiency of vitamin D and SAD,” the study authors wrote.

Certain health organizations, including the U.K.’s National Health Service and the U.S. National Institute of Mental Health, do list vitamin D as a treatment option for people with SAD but don’t mention the addition of vitamin K.

There has been some evidence that vitamin D may help people living very far north where there is little sun exposure in the winter, saidMaya Vadiveloo, PhD, RD, FAHA, an associate professor of nutrition at the University of Rhode Island College of Health Sciences. But generally, the research doesn’t support vitamin D supplements for SAD.

“Broadly, I think that while there isn’t a strong evidence base to support dietary supplementation for prevention/treatment of SAD, there is good support to adhere to diets rich in fruits and vegetables, whole grains, nuts, seeds, legumes, and heart-healthy oils while limiting less healthy foods high in added sugars, salt, and saturated fats,” Vadiveloo said.

Also, the studies that have shown positive results with vitamin D supplements and SAD aren’t very strong,Taylor Wallace, PhD, CFS, an adjunct associate professor at the Friedman School of Nutrition Science and Policy at Tufts University said.

“There are some studies [and small clinical trials] that show vitamin D may affect mood in this regard,” Wallace said. “But they are mostly observational and the effects haven’t held true in larger clinical trials.”

It’s not clear that vitamin K would be beneficial in helping boost vitamin D in terms of stopping SAD symptoms, said Wallace, and cautioned that people should be careful not to take too much of either vitamin D or K. Instead, Wallace recommended most people stick with a daily multivitamin.

Understanding Vitamin K2 and Its Health Benefits

What Are Other Treatments for SAD?

If you’re looking forproven treatments for SAD, the good news is there are several that work. You can try light therapy, where you sit in front of a speciallight boxthat filters out harmful UV.Most people only need about 20 minutes a day to see results.

You can also speak with a mental health professional or consider selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant medication that helps with SAD symptoms.

Also, eating a nutrient-dense diet and making an effort to go outside more to soak up sunlight can make a big difference in your overall mood.

Beat Seasonal Depression With These 3 Tips That Experts Swear By

What This Means For YouTaking vitamin D and vitamin K supplements to ward off seasonal affective disorder probably isn’t the best approach. Instead, eat nutrient-rich foods, get outside as much as possible during the day, and reach out to a mental health professional, if necessary.

What This Means For You

Taking vitamin D and vitamin K supplements to ward off seasonal affective disorder probably isn’t the best approach. Instead, eat nutrient-rich foods, get outside as much as possible during the day, and reach out to a mental health professional, if necessary.

10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Psychiatric Association.Seasonal affective disorder (SAD).National Institutes of Health.Beat the winter blues.National Institute of Mental Health.Seasonal affective disorder.National Institutes of Health Office of Dietary Supplements.Vitamin D: fact sheet for consumers.National Institutes of Health Office of Dietary Supplements.Vitamin K: fact sheet for consumers.Jahan-Mihan A, Stevens P, Medero-Alfonso S, et al.The role of water-soluble vitamins and vitamin D in prevention and treatment of depression and seasonal affective disorder in adults.Nutrients. 2024;16(12):1902. doi:10.3390/nu16121902NHS England.Dr Lowri’s top tips for getting through the ‘winter blues.’Yang Y, Zhang S, Zhang X, Xu Y, Cheng J, Yang X.The role of diet, eating behavior, and nutrition intervention in seasonal affective disorder: a systematic review.Front Psychol. 2020;11:1451. doi:10.3389/fpsyg.2020.01451Campbell PD, Miller AM, Woesner ME.Bright light therapy: seasonal affective disorder and beyond.Einstein J Biol Med. 2017;32:E13-E25.National Institutes of Health.Feeling SAD?.

10 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Psychiatric Association.Seasonal affective disorder (SAD).National Institutes of Health.Beat the winter blues.National Institute of Mental Health.Seasonal affective disorder.National Institutes of Health Office of Dietary Supplements.Vitamin D: fact sheet for consumers.National Institutes of Health Office of Dietary Supplements.Vitamin K: fact sheet for consumers.Jahan-Mihan A, Stevens P, Medero-Alfonso S, et al.The role of water-soluble vitamins and vitamin D in prevention and treatment of depression and seasonal affective disorder in adults.Nutrients. 2024;16(12):1902. doi:10.3390/nu16121902NHS England.Dr Lowri’s top tips for getting through the ‘winter blues.’Yang Y, Zhang S, Zhang X, Xu Y, Cheng J, Yang X.The role of diet, eating behavior, and nutrition intervention in seasonal affective disorder: a systematic review.Front Psychol. 2020;11:1451. doi:10.3389/fpsyg.2020.01451Campbell PD, Miller AM, Woesner ME.Bright light therapy: seasonal affective disorder and beyond.Einstein J Biol Med. 2017;32:E13-E25.National Institutes of Health.Feeling SAD?.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

American Psychiatric Association.Seasonal affective disorder (SAD).National Institutes of Health.Beat the winter blues.National Institute of Mental Health.Seasonal affective disorder.National Institutes of Health Office of Dietary Supplements.Vitamin D: fact sheet for consumers.National Institutes of Health Office of Dietary Supplements.Vitamin K: fact sheet for consumers.Jahan-Mihan A, Stevens P, Medero-Alfonso S, et al.The role of water-soluble vitamins and vitamin D in prevention and treatment of depression and seasonal affective disorder in adults.Nutrients. 2024;16(12):1902. doi:10.3390/nu16121902NHS England.Dr Lowri’s top tips for getting through the ‘winter blues.’Yang Y, Zhang S, Zhang X, Xu Y, Cheng J, Yang X.The role of diet, eating behavior, and nutrition intervention in seasonal affective disorder: a systematic review.Front Psychol. 2020;11:1451. doi:10.3389/fpsyg.2020.01451Campbell PD, Miller AM, Woesner ME.Bright light therapy: seasonal affective disorder and beyond.Einstein J Biol Med. 2017;32:E13-E25.National Institutes of Health.Feeling SAD?.

American Psychiatric Association.Seasonal affective disorder (SAD).

National Institutes of Health.Beat the winter blues.

National Institute of Mental Health.Seasonal affective disorder.

National Institutes of Health Office of Dietary Supplements.Vitamin D: fact sheet for consumers.

National Institutes of Health Office of Dietary Supplements.Vitamin K: fact sheet for consumers.

Jahan-Mihan A, Stevens P, Medero-Alfonso S, et al.The role of water-soluble vitamins and vitamin D in prevention and treatment of depression and seasonal affective disorder in adults.Nutrients. 2024;16(12):1902. doi:10.3390/nu16121902

NHS England.Dr Lowri’s top tips for getting through the ‘winter blues.’

Yang Y, Zhang S, Zhang X, Xu Y, Cheng J, Yang X.The role of diet, eating behavior, and nutrition intervention in seasonal affective disorder: a systematic review.Front Psychol. 2020;11:1451. doi:10.3389/fpsyg.2020.01451

Campbell PD, Miller AM, Woesner ME.Bright light therapy: seasonal affective disorder and beyond.Einstein J Biol Med. 2017;32:E13-E25.

National Institutes of Health.Feeling SAD?.

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