Can Vitamin K2 Cause Anxiety? Separating Anecdote from Evidence

October 30, 2025 •

3 min read

Studies in animal models suggest that vitamin K2 supplementation can actually help reduce anxiety-like behaviors, possibly by regulating blood glucose levels. The question of whether vitamin K2 can cause anxiety, therefore, arises from anecdotal reports of specific side effects that may mimic anxiety symptoms.

Quick Summary

This article explores the scientific evidence regarding vitamin K2's impact on mood and anxiety, investigates the potential side effects some individuals experience, and clarifies the consensus on its mental health effects.

Key Points

No Causal Link to Anxiety: Scientific research, particularly in animal models, suggests vitamin K2 may have anti-anxiety effects, not cause anxiety.
Anecdotal Reports of Palpitations: Some users, especially sensitive individuals taking higher doses, report heart palpitations, which can mimic or induce feelings of anxiety.
Works Synergistically with Vitamin D: K2 helps regulate calcium and works with vitamin D3 to potentially support mood-regulating neurotransmitters like serotonin.
Possible Side Effects are Generally Mild: Common side effects are typically mild gastrointestinal upset, though heart palpitations are a notable concern for some.
Lower K2 Levels Linked to Depression: Evidence from human studies suggests an inverse relationship between vitamin K status and depressive symptoms.
Consult a Doctor for Symptoms: Anyone experiencing anxiety-like symptoms or palpitations after taking K2 should consult a healthcare professional to identify the cause.

Exploring the Relationship Between Vitamin K2 and Mood

Vitamin K2, or menaquinone, is a fat-soluble vitamin primarily known for bone and cardiovascular health. However, research also indicates a potential role in mental well-being, often suggesting beneficial effects rather than causing anxiety.

What Research Says About Vitamin K2 and Anxiety

Scientific studies suggest that vitamin K2 may have calming effects. A 2016 study on rats with metabolic syndrome, a condition linked to anxiety, found that K2 supplementation reduced anxiety-like behaviors. This effect was partly attributed to K2's influence on blood sugar regulation. Furthermore, research consistently shows an inverse relationship between vitamin K status and depressive symptoms in humans and animals, suggesting a protective role for mental health.

The Synergy of Vitamin D3 and K2 for Mental Health

Vitamin K2 often works with vitamin D3, a nutrient linked to mood regulation. Vitamin D3 is important for neurotransmitter production, and K2 aids its utilization. The combination may enhance mood and emotional balance. Mood issues are more likely due to a deficiency in these vitamins than a side effect of correct supplementation.

The Anecdotal Evidence: Heart Palpitations and Anxiety

The most common reason for reported anxiety-like symptoms from K2 is heart palpitations, a documented but uncommon side effect for some individuals. These sensations can be mistaken for panic attacks.

Why Palpitations Might Occur

Some speculate that high doses of the MK-7 form of K2 may influence the nervous system or calcium regulation in sensitive individuals, triggering palpitations. The physical sensation can then induce stress and trigger anxiety. This suggests a physical reaction leading to anxious feelings rather than a direct cause of a psychological disorder. Some reports indicate that switching to MK-4 or lowering the dose resolved palpitations.

Other Reported Side Effects

Other reported side effects are generally mild, such as gastrointestinal upset. These are not directly linked to anxiety but can potentially increase stress.

K2 vs. K1: A Comparison

The table below outlines the differences between Vitamin K1 and K2:


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinones)
Primary Source	Leafy green vegetables	Fermented foods, animal products
Main Function	Blood clotting	Calcium regulation in bones and arteries
Absorption/Duration	Shorter duration	Longer duration
Mental Health Link	Less direct research	Emerging evidence suggests a link to reduced anxiety and depression

What to Do If You Experience Symptoms

If you experience anxiety or anxiety-like symptoms after taking vitamin K2, consider the following:

Stop or Reduce the Dose: Temporarily discontinue or lower the dose to see if symptoms improve.
Consult a Healthcare Provider: A doctor can assess your health and supplements to find the cause of your symptoms, especially if you have a heart condition.
Check Your Form: Discuss with your doctor if switching from MK-7 to MK-4 or lowering the dose is suitable, based on anecdotal reports.
Consider Synergistic Vitamins: Your practitioner may advise adjusting your intake of D3, calcium, or magnesium due to their interaction with K2.
Look at Other Factors: Anxiety has many causes; work with your doctor to rule out other possibilities.

Conclusion

While science suggests K2 may benefit mood and reduce anxiety, side effects like palpitations can be misinterpreted as anxiety. It's crucial to differentiate physical side effects from psychological causes. If you suspect K2 is affecting your mental state, stop use and consult a medical professional. For more on vitamin K and mood, see the systematic review in the MDPI journal: Exploring the Link Between Vitamin K and Depression.

Conclusion: Can Vitamin K2 Cause Anxiety?

Scientific evidence does not support the idea that vitamin K2 causes anxiety. Instead, studies suggest it may have anti-anxiety and mood-stabilizing effects. However, some individuals report palpitations, which can trigger anxiety. A balanced intake of D3 and K2 is often recommended, and any adverse reactions should be discussed with a healthcare professional to identify the true cause of symptoms. Anxiety is complex with various triggers, and while supplementation can be a factor, it's typically not the primary cause.

Frequently Asked Questions

Scientific research does not support the claim that vitamin K2 supplements cause anxiety. In fact, some animal studies show it may have anxiolytic (anxiety-reducing) effects, particularly when related to metabolic health.

The primary reason for reported anxiety is often due to the side effect of heart palpitations, which can occur in some individuals, particularly with higher doses of the MK-7 form. The physical sensation of a racing or fluttering heart can trigger or exacerbate feelings of anxiety.

Heart palpitations are a rare side effect of vitamin K2, but they are noted in some anecdotal reports from sensitive individuals. If you experience them, it is important to consult a healthcare provider to determine the cause.

Vitamin K2, especially when combined with vitamin D3, is speculated to support the synthesis of neurotransmitters like serotonin and dopamine, which are essential for mood regulation. A deficiency in vitamin K may therefore be linked to mood disturbances.

While more research is needed, some evidence suggests that low vitamin K levels may be linked to an increased risk of mood disorders, including depression and anxiety.

Some anecdotal evidence, primarily from online forums, suggests that the longer-acting MK-7 form may be more associated with side effects like palpitations in sensitive individuals compared to the shorter-chain MK-4. Discussing your specific supplement with a doctor is recommended.

You should see a doctor immediately if you experience significant heart palpitations, shortness of breath, or chest discomfort. For persistent but less severe symptoms like gastrointestinal upset, consulting a doctor can help determine if the supplement is the cause.

There is no scientific evidence to suggest that vitamin K2 directly increases adrenaline levels. While K2 influences various cellular pathways, an increase in adrenaline is not a known effect.