What supplements can cause nervousness? Identifying the culprits behind anxiety and jitters

According to a 2025 review, a significant number of individuals using certain dietary supplements reported side effects like increased anxiety. This article explores what supplements can cause nervousness and identifies the common triggers to be aware of for better health management.

Quick Summary

This comprehensive article reveals several dietary supplements, including potent stimulants, high-dose B vitamins, and specific herbal remedies, that can unexpectedly trigger feelings of nervousness, anxiety, and restlessness due to their impact on the nervous system and neurotransmitter balance.

Key Points

• Stimulants are primary culprits: Supplements with caffeine, guarana, or bitter orange (synephrine) can cause nervousness by overstimulating the nervous system.

• Herbal remedies can be deceptive: Herbs like Yohimbe and St. John's Wort are known to disrupt neurotransmitter levels and trigger anxiety, despite their 'natural' label.

• High-dose B-vitamins are a risk: Excessive intake of B6, B12, or folate, especially in concentrated forms, can act as metabolic stimulants and induce restlessness and anxiety.

• Glandulars affect hormones: Supplements derived from animal glands can cause unpredictable hormonal fluctuations that lead to a heightened stress response and nervousness.

• Individual sensitivity matters: A person's genetic makeup, existing anxiety disorders, and medication use can increase their vulnerability to supplement-induced nervousness.

• Dosage and interactions are key: To minimize risk, start with low doses, read labels closely, and be aware of dangerous interactions with other medications.

The usual suspects: stimulant-based supplements

Many supplements aim to boost energy, but this can lead to anxiety and nervousness by activating the body’s 'fight or flight' response.

Caffeine pills and pre-workout formulas

Caffeine blocks brain receptors that promote relaxation. While moderate caffeine is safe, high doses from pills or pre-workouts can cause anxiety, increased heart rate and blood pressure, difficulty sleeping, and tremors. Adults should generally limit caffeine intake to 400 mg daily.

Bitter orange (synephrine)

Bitter orange contains synephrine, similar to the stimulant ephedra, and is found in weight-loss supplements. It stimulates the nervous system, potentially causing nervousness, agitation, increased heart rate, palpitations, and elevated blood pressure, especially when combined with caffeine.

Herbal remedies with unexpected side effects

Some herbal supplements can affect brain chemistry, and individuals prone to anxiety should use them cautiously.

Yohimbe

Derived from tree bark, yohimbe is used for weight loss and sexual performance. It works by increasing norepinephrine release, which can overstimulate the nervous system and result in high anxiety levels, rapid heart rate, high blood pressure, and in some cases, panic attacks.

St. John's wort

Used for mood support, St. John's wort can also trigger anxiety and agitation. It affects serotonin levels, and combining it with antidepressants can risk serotonin syndrome. Potential side effects include increased anxiety, irritability, restlessness, sleep problems, and serious drug interactions.

Ginseng

Ginseng may boost energy and focus but can act as a stimulant for some, potentially leading to jitteriness and a rapid heartbeat depending on dose and individual sensitivity.

Green tea extract and guarana

Both contain concentrated caffeine. Extracts can have high doses that cause jitters, anxiety, nausea, and insomnia in sensitive individuals, unlike a mild cup of green tea.

High-dose vitamins and glandular supplements

Certain vitamins and hormonal supplements, especially in large doses, can cause nervousness.

B-Vitamins (B6, B12, folate)

Essential for energy, high doses of B6, B12, and folate can be over-activating for some. Methylated forms are particularly noted for potentially causing over-methylation in sensitive people. Symptoms can include restlessness, agitation, insomnia, mood swings, and anxiety.

Glandulars and hormonal effects

Supplements from animal organs (glandulars) contain hormones that can disrupt the endocrine system. Increasing cortisol or thyroid hormone levels can mimic stress, leading to anxiety.

How supplements trigger nervousness: the mechanism

Nervousness from supplements often stems from disrupting neurochemical balance.

• CNS Overstimulation: Stimulants like caffeine and synephrine activate the nervous system, mimicking stress responses like increased heart rate and anxiety.
• Neurotransmitter Imbalances: Yohimbe increases norepinephrine, a hormone linked to alertness and anxiety. High-dose B vitamins can boost stimulating neurotransmitters like dopamine and norepinephrine. St. John's wort affects serotonin, and high levels can cause agitation.
• Hormonal Fluctuations: Glandulars introduce animal hormones that can cause an unpredictable stress response and anxiety by affecting cortisol and thyroid hormones.

Navigating supplement choices

To reduce the risk of nervousness from supplements:

• Consult a professional: Discuss new supplements with a doctor, especially if you have anxiety or take medication.
• Read labels carefully: Check for stimulants and be wary of proprietary blends with undisclosed amounts.
• Start with a low dose: Begin with the minimum dose to see how you react before increasing.
• Time your intake: Avoid stimulating supplements late in the day to prevent sleep disruption and worsening anxiety.

Supplement Comparison for Nervousness Risk

Supplement	Primary Active Ingredient(s)	Risk of Nervousness	Key Mechanism
Caffeine Pills	Caffeine	High	Blocks adenosine receptors, activates "fight-or-flight" response.
Bitter Orange	Synephrine	High	Sympathomimetic agent, stimulates nervous system.
Yohimbe	Yohimbine	High	Increases norepinephrine release, overstimulates.
St. John's Wort	Hypericin, hyperforin	Moderate	Affects serotonin levels, can cause agitation.
B-Complex (High Dose)	B6, B12, Folic Acid	Moderate	Acts as a metabolic stimulant, increases stimulating neurotransmitters.
Ginseng	Ginsenosides	Low to Moderate	Mild stimulant effect, can cause jitteriness in some.
Green Tea Extract	Caffeine, EGCG	Low to Moderate	Contains concentrated caffeine; risk depends on dose and sensitivity.
Glandulars	Animal Hormones	High	Directly affects hormonal balance, mimics stress response.

Conclusion

While often seen as harmless, supplements can cause nervousness, particularly at high doses or in sensitive individuals. This is often due to nervous system overstimulation, neurotransmitter imbalances, and hormonal changes. Recognizing ingredients like caffeine, synephrine, yohimbe, St. John's wort, and high-dose B vitamins is crucial for making safer choices. Always consult a healthcare professional and pay attention to your body's reactions. For more information, visit the National Center for Complementary and Integrative Health (NCCIH) at nccih.nih.gov.

Potential Triggers of Supplement-Induced Anxiety

Nervous System Overstimulation: Supplements with high levels of caffeine or stimulants like synephrine can overactivate the central nervous system, causing anxiety, restlessness, and a rapid heart rate.

Neurotransmitter Imbalances: Herbs such as Yohimbe and St. John's Wort impact brain chemicals like norepinephrine and serotonin, potentially leading to mood issues and anxiety.

High-Dose B-Vitamins: Large amounts of B6, B12, or folate can be metabolically stimulating and trigger anxiety symptoms in some people.

Hormonal Disruptions: Supplements with animal glands can introduce hormones that disrupt the endocrine system, mimicking a stress response and causing nervousness.

Individual Sensitivity: Factors like genetics, pre-existing anxiety, and other medications can make individuals more sensitive to supplement side effects.

Interaction with Medications: Combining supplements like St. John's Wort with antidepressants or other stimulants can cause dangerous interactions and increase nervousness.

Managing Supplement Side Effects

Immediate Action: If you feel nervous after taking a supplement, stop use and monitor symptoms. See a healthcare provider if symptoms continue or worsen.

Safe Supplement Use: Always read labels, follow dosage instructions, and consider starting with a lower dose to see how you tolerate it.

Choosing Non-Stimulant Options: If sensitive to stimulants, choose supplements labeled as non-stimulating and avoid those with caffeine, guarana, or bitter orange.

Frequently Asked Questions

Can pre-workout supplements cause anxiety?

Yes, many pre-workout supplements contain high doses of stimulants like caffeine, guarana, and synephrine, which can overstimulate the nervous system and lead to nervousness, jitters, and a rapid heartbeat.

Why do B-vitamins cause nervousness in some people?

High doses of B-vitamins, especially B6, B12, and folate, can act as metabolic stimulants and increase the release of stimulating neurotransmitters like dopamine and norepinephrine, leading to restlessness and anxiety in sensitive individuals.

Is St. John's wort safe for people with anxiety?

St. John's wort can cause anxiety and agitation, and it should be used with extreme caution. It can interact negatively with many medications, including antidepressants, and can potentially lead to serotonin syndrome.

What is synephrine and why is it linked to nervousness?

Synephrine is an active ingredient in bitter orange and is a stimulant similar to ephedra. It can increase heart rate, blood pressure, and cause nervousness by stimulating the nervous system.

Are all green tea extracts safe for anxious individuals?

While regular green tea is generally mild, green tea extracts can be highly concentrated sources of caffeine. In high doses, this can trigger anxiety, irritability, and insomnia, especially for those sensitive to caffeine.

How can I tell if a supplement is causing my nervousness?

Symptoms like increased heart rate, jitters, insomnia, or heightened anxiety that appear shortly after or during the regular use of a supplement could indicate a link. To confirm, consider eliminating the supplement under medical supervision.

Which supplements are generally safer for people prone to nervousness?

Supplements like magnesium, omega-3 fatty acids, and some adaptogenic herbs (when used correctly) have been studied for potential calming effects, but it's essential to consult a healthcare professional before starting any new supplement.