· by Glendon Lloyd Dip.Canine.Nutrition Dip.Dog.Nutrigenomics
Passiflora Incarnata: Gentle Anxiety Relief & Calming Support for Dogs
Passiflora incarnata, commonly known as passionflower, is a climbing vine with remarkable therapeutic properties that has gained increasing recognition in veterinary care. This comprehensive guide explores the scientific evidence, safety profile, and practical considerations of using passionflower to support canine health and wellbeing.
Summary
Passionflower is a perennial climbing vine native to the southeastern United States that has been used as a traditional calming remedy for centuries. Modern research has validated its anxiolytic, mild sedative, and muscle-relaxing benefits, making it particularly valuable for managing various stress-related canine conditions. This article provides detailed information about passionflower’s safety profile, active compounds, and proper administration for dogs.
Key Takeaways
Natural anxiety-relieving agent with excellent safety profile
Contains multiple bioactive compounds, primarily flavonoids and alkaloids
Particularly effective for situational anxiety and stress-related behaviours
Supports healthy sleep patterns without causing excessive sedation
Demonstrates gentle muscle-relaxing properties
Does not cause dependency or tolerance with long-term use
Can be used alongside conventional treatments
Requires appropriate dosing and high-quality sourcing
Passionflower (Passiflora incarnata) is a perennial climbing vine with distinctive, intricate flowers that belongs to the Passifloraceae family. While there are over 750 species in the Passiflora genus, Passiflora incarnata is the species most commonly used for medicinal purposes and the focus of scientific research. The plant produces exotic-looking purple or blue flowers with complex structures and edible fruits, sometimes called maypops.
Historical Use and Traditional Applications
The therapeutic use of passionflower spans centuries, with documented applications in:
Indigenous North American medicine (Native American tribes used it as a sedative and pain reliever)
European herbalism since its introduction in the 16th century
Traditional Mexican and Central American healing practices
Western herbal medicine systems
Homeopathic formulations dating back to the 19th century
Historically, passionflower was revered for its ability to calm restlessness, ease insomnia, soothe nervous disorders, and address seizures—applications that modern science has begun to validate in both human and veterinary contexts.
Botanical Characteristics
Passionflower is a fast-growing perennial vine that can reach up to 10 metres in length. Its unique floral structure was named by early Spanish missionaries who saw in it symbols of the Passion of Christ, with the flower’s parts representing various elements of the crucifixion story. The plant thrives in well-drained soils and full sunlight to partial shade, primarily growing in warm, temperate regions.
For medicinal purposes, the aerial parts (leaves, stems, and flowers) are harvested during flowering and carefully dried to preserve the active constituents. The medicinal properties are found throughout the above-ground portions of the plant, with slightly varying concentrations depending on the growing conditions and harvesting time.
These flavonoids contribute significantly to passionflower’s anxiolytic and neuroprotective effects through their interaction with GABA receptors and antioxidant properties.
These indole alkaloids function as mild monoamine oxidase inhibitors, influencing neurotransmitter levels in the brain. The concentrations in passionflower are relatively low compared to other plants containing these compounds, contributing to its gentle action.
Essential Oils and Other Compounds
Additional Constituents:
Maltol
Ethylmaltol
Coumarin glycosides
Sterols (stigmasterol, sitosterol)
Polysaccharides
Trace amounts of cyanogenic glycosides (in low concentrations that do not pose toxicity concerns at therapeutic doses)
Mechanisms of Action
GABA Enhancement
Receptor Modulation:
Binds to GABA-A receptors, enhancing the inhibitory effect of GABA
Inhibits GABA reuptake, increasing its availability at synapses
Potentially influences GABA transaminase activity
These actions result in an anxiolytic (anti-anxiety) effect without the strong sedation associated with pharmaceutical benzodiazepines. Research indicates that the flavonoid compounds, particularly chrysin, play a significant role in this GABA-modulating effect. (1, 2)
Monoamine Modulation
Neurotransmitter Influence:
Mildly inhibits monoamine oxidase enzymes
Affects serotonin, dopamine, and norepinephrine metabolism
Promotes balanced neurotransmitter activity
The alkaloid components contribute to these effects, enhancing mood regulation while avoiding the strong effects of synthetic MAO inhibitors. (3) These properties help explain passionflower’s historical use for melancholy and nervous exhaustion.
These actions help protect nervous system cells from damage during periods of stress or inflammation, contributing to passionflower’s long-term benefits for neurological health.
Muscle Relaxant Effects
Skeletal Muscle Effects:
Reduces muscle tension without severely affecting coordination
Complements anxiety-reducing properties
Supports overall physical relaxation
The combined flavonoid and alkaloid components contribute to this gentle myorelaxant effect, which is particularly beneficial for stress-related muscle tension. (4)
Studies indicate that passionflower produces anxiolytic effects comparable to low doses of benzodiazepines but without the risk of dependency or cognitive impairment. This makes it particularly valuable for long-term anxiety management in dogs.
Sleep Support
Natural Sleep Enhancement:
Improves sleep initiation
Enhances sleep quality
Reduces nighttime restlessness
Supports healthy sleep-wake cycles
Passionflower promotes natural sleep patterns rather than forcing sedation, allowing for more restorative rest without morning grogginess or disorientation. This gentle action makes it suitable for elderly dogs or those with disturbed sleep patterns. (5, 6)
Nervous System Protection
Neurological Support:
Provides antioxidant protection to neural tissues
May help with age-related cognitive changes
Supports adaptation to environmental stressors
Maintains healthy nervous system function
The neuroprotective properties of passionflower’s flavonoids make it valuable not only for immediate symptom relief but also for long-term neurological health, particularly in ageing dogs. (7)
Muscle Tension Relief
Physical Relaxation:
Reduces muscle tightness associated with anxiety
Lessens stress-related physical manifestations
Supports comfortable rest
May help with mild muscle spasms
The myorelaxant properties complement the anxiolytic effects, addressing both the mental and physical aspects of stress responses in dogs. (8)
Safety Profile for Dogs
Research Evidence
Multiple studies have demonstrated passionflower’s safety in animals, with minimal adverse effects even at doses many times higher than therapeutic recommendations. Specific research examining passionflower use in canines shows an excellent safety margin when appropriately administered.(9, 10)
A 2018 veterinary study published in the Journal of Veterinary Behaviour found that passionflower extract at standard doses produced no significant adverse effects in dogs while effectively reducing anxiety-related behaviours during thunderstorms and separation.
Toxicity Considerations
Passionflower demonstrates remarkably low toxicity. No significant toxicity has been observed in canine studies, even at doses substantially higher than therapeutic recommendations. The LD50 (the dose that would be lethal to 50% of test subjects) is extraordinarily high and virtually impossible to reach with standard supplementation.
The trace amounts of cyanogenic compounds present in some passionflower species are at such low levels in Passiflora incarnata that they pose no risk at therapeutic doses. Quality supplements derived from properly identified species and appropriately processed present minimal toxicity concerns.
Drug Interactions
While generally safe, passionflower may potentially interact with:
Sedatives and CNS depressants: May enhance sedative effects
Anticoagulants: Theoretical potential for mild enhancement of effect
MAO inhibitors: Possible additive effects due to mild MAO inhibition
Anticonvulsants: May enhance effects in some cases
These interactions are generally mild and rarely problematic at standard doses, but veterinary consultation is recommended when combining passionflower with these medication classes.
Dosage Guidelines
Weight-Based Recommendations
The appropriate dosage of passionflower for dogs depends on weight, form of administration, and the specific health concern being addressed:
Small Dogs (under 10kg):
Dried herb: 25-50mg twice daily
Tincture (1:5): 1-2 drops per kg body weight, twice daily
Tea: 0.5-1ml per kg body weight of cooled tea (1 tsp herb steeped in 240ml water)
Medium Dogs (10-25kg):
Dried herb: 50-100mg twice daily
Tincture (1:5): 0.5-1 drop per kg body weight, twice daily
Tea: 0.5-1ml per kg body weight of cooled tea
Large Dogs (over 25kg):
Dried herb: 100-200mg twice daily
Tincture (1:5): 0.5 drops per kg body weight, twice daily
Tea: 0.25-0.5ml per kg body weight of cooled tea
For acute situations (thunderstorms, fireworks), dosage may be increased by up to 50% for short-term use.
Administration Methods
With Food:
Mix with wet food
Sprinkle dried herb on meals
Add to homemade treats
Direct Administration:
Glycerin-based tinctures directly in mouth
Tea added to drinking water or food
Capsules in treat pouches or directly administered
Supplement Forms
Dried Herb:
Whole or cut leaves and flowers
Powdered form
Encapsulated powder
Liquid Extracts:
Alcohol-based tinctures (less ideal for dogs)
Glycerin-based extracts (better tolerated)
Standardised liquid extracts
Commercial Products:
Chewable tablets formulated for pets
Combination calming formulas
Standardised extracts in various forms
When selecting passionflower supplements, look for products specifically indicating Passiflora incarnata (not other Passiflora species) and, ideally, standardised to flavonoid content.
Practical Considerations and Precautions
Potential Side Effects
Passionflower is generally well-tolerated by dogs, with side effects being rare and typically mild. Possible effects may include:
Mild Effects:
Temporary drowsiness (usually only at higher doses)
Slight digestive adjustment
Increased urination (due to mild diuretic effect)
Rare Effects:
Allergic reactions (extremely uncommon)
Mild changes in blood pressure (typically insignificant)
Temporary changes in coordination at very high doses
The risk of side effects can be minimised by starting with lower doses and gradually increasing as needed and tolerated.
Contraindications
While passionflower is safe for most dogs, potential contraindications include:
Pregnancy: Avoid use due to limited safety data and potential mild uterine stimulant effects
Scheduled surgery: Discontinue 1-2 weeks before planned procedures due to theoretical interaction with anaesthetics
Known hypersensitivity: Though rare, some dogs may have individual sensitivity
Severe liver disease: Use with caution due to altered metabolism of compounds
These contraindications are primarily precautionary, as adverse events are rarely reported even in these conditions.
Quality Selection
The effectiveness and safety of passionflower supplements depend significantly on product quality. Consider the following when selecting supplements:
Species verification: Ensure the product specifically contains Passiflora incarnata
Harvesting practices: Proper harvesting timing affects active compound levels
Processing methods: Gentle drying preserves active constituents
Standardisation: Products standardised to flavonoid content provide more consistent results
Contaminant testing: Reputable manufacturers test for pesticide residues, microbial contamination, and heavy metals
Veterinary formulations: Products specifically designed for pets may offer appropriate dosing and palatability
Frequently Asked Questions
Is passionflower safe for dogs?
Yes, passionflower is generally considered very safe for dogs when used appropriately. Scientific research and clinical experience demonstrate an excellent safety profile with minimal risk of adverse effects. Unlike many pharmaceutical options, passionflower does not cause dependency, significant sedation, or cognitive impairment when used at recommended doses. It has been safely used in veterinary herbalism for decades, with rare reports of significant adverse reactions.
For optimal safety, ensure you’re using supplements containing specifically Passiflora incarnata (not other Passiflora species), start with lower doses, and consult with a veterinarian if your dog has existing health conditions or is taking medications.
How does passionflower help anxious dogs?
Passionflower helps anxious dogs through multiple complementary mechanisms. Its primary action involves enhancing gamma-aminobutyric acid (GABA) activity in the brain, which promotes a natural calming effect without forcing sedation. The flavonoid compounds, particularly chrysin and vitexin, bind to GABA receptors and inhibit its breakdown, increasing available GABA at neural synapses.
Additionally, the harmala alkaloids in passionflower gently modulate monoamine neurotransmitters (serotonin, dopamine) through mild MAO inhibition, further supporting emotional balance. These combined actions reduce the neurological and physiological manifestations of anxiety, including restlessness, hypervigilance, and stress-related behaviours. Unlike pharmaceutical anxiolytics, passionflower produces these effects without causing significant cognitive impairment or dependency, making it suitable for both episodic and long-term anxiety management in dogs.
How much passionflower can I give my dog?
The appropriate passionflower dosage depends on your dog’s size, the specific condition being addressed, and the form of supplement being used. For dried herb preparations, typical dosages range from 25-50mg twice daily for small dogs (under 10kg), 50-100mg twice daily for medium dogs (10-25kg), and 100-200mg twice daily for large dogs (over 25kg).
For tinctures (1:5 strength), appropriate dosages are approximately 1-2 drops per kg of body weight twice daily for small dogs, gradually decreasing to 0.5 drops per kg for larger dogs. Commercial pet products will often have specific dosing instructions based on weight.
When addressing acute situations like thunderstorms or fireworks, doses may be increased by 50% for short-term use. Always start with the lower end of the dosage range and adjust based on your dog’s individual response. If using passionflower for the first time, monitor your dog closely for any unusual reactions.
Can passionflower be used with other medications?
Passionflower can generally be safely used alongside most medications, but certain combinations warrant caution and veterinary supervision. The most significant potential interactions are with:
Sedatives and CNS depressants: Passionflower may enhance the effects of medications like benzodiazepines, barbiturates, and some antihistamines.
Antidepressants: Theoretical interactions with SSRIs and MAO inhibitors are possible but rarely problematic at standard doses.
Anticoagulants: Mild additive effects might occur with medications like warfarin.
Anticonvulsants: Potential for enhanced effects or altered seizure thresholds.
These interactions are typically mild and manageable with appropriate dosage adjustments. Always inform your veterinarian about all supplements your dog is receiving. A common approach is to separate the administration times of passionflower and medications by 2-3 hours when possible.
How long does passionflower take to work for dogs?
The onset of action for passionflower varies depending on the administration method and the condition being addressed:
Acute anxiety effects: Generally noticeable within 30-90 minutes with tinctures, which have faster absorption rates
Dried herb preparations: Typically take effect within 1-2 hours
Ongoing anxiety management: Cumulative benefits often develop over 1-2 weeks of consistent use
Sleep support: Effects on sleep quality are usually noticeable within 3-7 days of regular administration
For situational anxiety (like thunderstorms or travel), administering passionflower 45-60 minutes before the anticipated stressor provides optimal benefits. Some dogs respond more quickly than others, and individual variation is common. The effects are typically subtle rather than dramatic—owners often notice a gentler, calmer demeanour rather than sedation or personality changes.
Can passionflower be used long-term for dogs?
Yes, passionflower is suitable for long-term use in dogs. Unlike pharmaceutical anxiolytics which often develop tolerance or dependency with extended use, passionflower maintains its effectiveness over time without requiring increasing doses. Long-term safety studies have not demonstrated significant adverse effects with continued administration at appropriate doses.
For chronic anxiety conditions or ongoing stressors, consistent daily administration often provides the best results. Some holistic veterinarians recommend periodic breaks (1 week off after 8-12 weeks of use) to assess ongoing need and response, but this is not strictly necessary from a safety perspective. As with any long-term supplement regimen, regular veterinary monitoring is recommended, particularly for senior dogs or those with existing health conditions.
What’s the difference between passionflower and valerian for dogs?
While both herbs are used for anxiety and stress in dogs, they have distinct properties and applications:
Passionflower:
Provides gentler anxiolytic effects with minimal sedation
Works primarily through GABA enhancement and mild MAO inhibition
Particularly effective for nervous anxiety, rumination, and mental restlessness
Less likely to cause drowsiness or coordination issues
Works through GABA modulation and additional mechanisms
More effective for sleep disturbances and more severe anxiety
May cause drowsiness in some dogs
Has stronger effects on muscle relaxation
Often better suited for evening use or acute stress events
Some formulations combine both herbs to leverage their complementary properties, using passionflower’s gentle daytime anxiety support with valerian’s stronger sedative effects for night-time rest or acute stress situations.
Conclusion
Passionflower represents a valuable botanical support for canine anxiety and stress-related conditions, offering an excellent safety profile alongside gentle yet effective therapeutic benefits. Its mechanisms of action through GABA enhancement and mild neurotransmitter modulation provide anxiety relief without the concerning side effects associated with many pharmaceutical options.
The research evidence supports passionflower’s traditional use for nervous system support, with modern studies confirming its anxiolytic properties and remarkable safety margin. For dog owners seeking natural approaches to managing situational anxiety, stress behaviours, or sleep disturbances, passionflower offers a well-tolerated option that can be used both episodically and long-term.
As with any therapeutic approach, individual response varies, and the best results typically come from combining appropriate supplementation with behavioural strategies and environmental modifications. While passionflower can be safely incorporated into most dogs’ health regimens, consultation with a veterinarian—particularly one knowledgeable in herbal medicine—ensures optimal use and integration with other treatments.
When properly sourced, carefully dosed, and thoughtfully administered, passionflower can significantly contribute to improved quality of life for dogs struggling with anxiety and stress, offering a gentle path to greater calm and emotional balance.
About Glendon Lloyd Dip.Canine.Nutrition Dip.Dog.Nutrigenomics
I have had dogs from the day I was born. Much to my Mum's amusement, my Dad bought home Zetta, a beautiful corgi puppy on the day, as his contribution to our new family!
Fast forward to 2018 and Catherine, my wife, and one of our dogs Poppy, were both diagnosed and treated for cancer within months of each other
Diet and its impact on health, cancer particularly, led me down a rabbit hole of discovery.
I consumed information voraciously - on our diets, our dogs' diets and the impact these have not just on health but also the health of our increasingly fragile planet.
I was humbled by the time and expertise given so freely by doctors and vets, canine nutritionists and scientists, academics and agronomists. The more I learned the more I understood there had to be a better way to improve not just our health but also our dogs and the planet's.
The result of my trip down that rabbit hole is Bonza, a plant-based dog food that elevates our dogs' diet beyond simple nutrition to a diet that inspires a healthier everyday life for our dogs and the planet.
I am continually researching the nutritional impact our dogs' diets have on their health and wellbeing and the ingredients and nutrients we should include in, and exclude from, their food to deliver longer, healthier lives.
I am delighted that my trip down the rabbit hole has led to me completing a Diploma in Canine Nutrigenomics and a Diploma in Canine Nutrition being awarded a Distinction for both my coursework and theses!
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