Zylkene vs Anxitane vs Composure: Which Calming Supplement is Best for Your Dog?
A veterinarian-informed comparison of the three most recommended calming supplements for anxious dogs.
Quick Verdict
Best Overall: Zylkene — Most clinically-studied, works for multiple anxiety types, minimal side effects.
Best for Fast Relief: Anxitane — Works in 30-60 minutes, ideal for thunderstorms and travel.
Best for Daily Use: Composure — Tasty chews dogs love, good for mild ongoing anxiety.
Zylkene
Alpha-casozepine from milk protein. Clinically proven for general anxiety, vet visits, and major life changes.
Anxitane
L-Theanine from green tea. Works in 30-60 min. Best for noise phobias and situational anxiety.
Composure
L-Theanine + Colostrum + Thiamine. Tasty chews dogs love. Good for mild daily anxiety.
In This Article
If your dog struggles with anxiety—whether it's separation anxiety, thunderstorm phobia, travel stress, or general nervousness—you've probably heard about calming supplements. But with so many options, how do you know which one actually works?
In this comprehensive guide, we compare the three most veterinarian-recommended calming supplements: Zylkene, Anxitane, and Composure. We'll break down their ingredients, how they work, what the science says, and which is best for different types of anxiety.
Quick Comparison Table
| Feature | Zylkene | Anxitane | Composure |
|---|---|---|---|
| Active Ingredient | Alpha-casozepine (milk protein) | L-Theanine (green tea) | L-Theanine + Colostrum + B1 |
| Time to Work | 1-2 days (full effect) | 30-60 minutes | 30-45 minutes |
| Format | Capsules (open & sprinkle) | Chewable tablets | Soft chews (chicken flavor) |
| Palatability | ⭐⭐⭐ (neutral taste) | ⭐⭐⭐ (beef flavor) | ⭐⭐⭐⭐⭐ (highly palatable) |
| Clinical Studies | ⭐⭐⭐⭐⭐ (most studied) | ⭐⭐⭐⭐ (well-studied) | ⭐⭐⭐ (moderate) |
| Best For | General anxiety, vet visits, moving | Thunderstorms, fireworks, travel | Mild daily anxiety, nervous dogs |
| Price (30-day supply) | $25-40 (medium dogs) | $30-50 (medium dogs) | $15-25 (medium dogs) |
| Works for Cats | Yes (same product) | Yes (cat version) | Yes (cat version) |
| Side Effects | Rare (mild GI upset) | Rare (mild drowsiness) | Rare (soft stool) |
How Each Supplement Works
Understanding the science behind each supplement helps you choose the right one. Each works through a completely different mechanism, which is why they can sometimes be combined.
Zylkene
Mechanism: Alpha-casozepine binds to GABA-A receptors in the brain (the same receptors that anti-anxiety medications like Valium target), promoting relaxation without sedation.
Origin: Derived from casein, a milk protein. Mimics the calming effect that nursing puppies experience.
Anxitane
Mechanism: L-Theanine increases alpha brain waves (associated with calm focus) and boosts GABA, serotonin, and dopamine levels.
Origin: Naturally found in green tea leaves. Known for promoting "calm alertness" without drowsiness.
Composure
Mechanism: Multi-ingredient approach: L-Theanine for calm, Colostrum Calming Complex (C3) for stress response, Thiamine (B1) for nervous system support.
Origin: Combination formula designed for synergistic effect.
Zylkene: Complete Review
Zylkene by Vetoquinol
The gold standard in veterinary calming supplements, with the most clinical research behind it.
What Makes Zylkene Special
Zylkene contains alpha-casozepine, a bioactive peptide derived from the casein protein in cow's milk. This compound has a similar molecular action to benzodiazepines (like Valium) but without the side effects, dependency risk, or prescription requirements.
The science behind it is fascinating: when puppies nurse, they ingest casein which breaks down into alpha-casozepine in their digestive system. This contributes to the deep relaxation puppies experience after feeding. Zylkene delivers this same compound directly.
Clinical Evidence for Zylkene
- 2007 Study: Dogs given Zylkene showed significant reduction in fear-related behaviors (trembling, hiding, vocalizing) compared to placebo.
- 2017 Study: 83.9% of dog owners reported improvement in anxiety behaviors after 56 days of Zylkene supplementation.
- Veterinary Endorsement: Recommended by Fear Free Certified veterinary practices worldwide.
- Safety Profile: No known drug interactions. Safe for long-term use. Can be used with prescription medications (consult vet).
Zylkene Dosing Guide
| Dog Weight | Capsule Size | Daily Dose |
|---|---|---|
| Up to 10 lbs | 75mg | 1 capsule daily |
| 10-22 lbs | 75mg or 225mg | 1-2 capsules or half of 225mg |
| 22-55 lbs | 225mg | 1 capsule daily |
| 55-110 lbs | 450mg or 225mg | 1 capsule (450) or 2 capsules (225) |
| Over 110 lbs | 450mg | 2+ capsules daily |
Pro Tip: For predictable stressful events (vet visits, travel, boarding), start Zylkene 2-3 days before and continue through the event. The capsules can be opened and sprinkled on food.
Zylkene Pros and Cons
Pros
- ✓ Most clinical evidence of any supplement
- ✓ No sedation or drowsiness
- ✓ Safe for long-term daily use
- ✓ Works for both dogs and cats
- ✓ No known drug interactions
- ✓ Can double dose for acute stress
Cons
- ✗ Takes 1-2 days to reach full effect
- ✗ Capsule form (not a chew)
- ✗ Contains milk-derived ingredients
- ✗ Higher price than some alternatives
- ✗ Not ideal for acute/sudden anxiety
Anxitane: Complete Review
Anxitane by Virbac
L-Theanine supplement that works quickly for situational anxiety and noise phobias.
What Makes Anxitane Different
Anxitane's active ingredient, L-Theanine, is an amino acid found naturally in green tea. It's the compound responsible for the "calm alertness" that tea drinkers experience—relaxation without drowsiness.
L-Theanine crosses the blood-brain barrier within 30 minutes and directly increases alpha brain wave activity. Alpha waves are associated with wakeful relaxation (the mental state during meditation). It also boosts levels of calming neurotransmitters like GABA, serotonin, and dopamine.
Clinical Evidence for Anxitane
- 2010 Study: Dogs receiving L-Theanine showed significant reduction in storm phobia behaviors compared to control group.
- 2016 Study: L-Theanine reduced anxiety-related behaviors in shelter dogs, improving adoption readiness scores.
- Human Research: Extensive studies in humans show L-Theanine reduces stress and anxiety within 30-40 minutes of ingestion.
- Safety: FDA GRAS (Generally Recognized as Safe) status. No withdrawal effects or dependency.
Anxitane Dosing Guide
| Dog Weight | Product Size | Daily Dose |
|---|---|---|
| Up to 22 lbs | S (50mg tablets) | 1 tablet, 1-2x daily |
| 22-55 lbs | M (100mg tablets) | 1 tablet, 1-2x daily |
| 55-110 lbs | L (200mg tablets) | 1 tablet, 1-2x daily |
| Over 110 lbs | L (200mg tablets) | 2 tablets, 1-2x daily |
Pro Tip: Give Anxitane 30-60 minutes before a stressful event (thunderstorm predicted, car ride, vet visit). Can be given twice daily for ongoing anxiety. The beef-flavored tablets can be given as a treat or hidden in food.
Anxitane Pros and Cons
Pros
- ✓ Fast-acting (30-60 minutes)
- ✓ Excellent for noise phobias
- ✓ No sedation ("calm alertness")
- ✓ Chewable tablet format
- ✓ Well-studied in veterinary research
- ✓ Can be given as-needed
Cons
- ✗ Higher price per dose
- ✗ Some dogs dislike the taste
- ✗ Effects wear off in 4-6 hours
- ✗ May need twice-daily dosing
- ✗ Not ideal for deep-seated anxiety
Composure: Complete Review
Composure by VetriScience
Multi-ingredient calming chews that dogs actually enjoy eating. Great for daily use.
What Makes Composure Different
Composure takes a multi-pronged approach with three calming ingredients working together:
- L-Theanine (Suntheanine®): Same amino acid as Anxitane. Promotes alpha brain waves and increases calming neurotransmitters.
- Colostrum Calming Complex (C3): Bioactive proteins from bovine colostrum that support a healthy stress response. Contains proline-rich polypeptides (PRPs) that help regulate cortisol.
- Thiamine (Vitamin B1): Essential for nervous system function. Deficiency is linked to anxiety and irritability. Supports healthy brain chemistry.
The combination approach means Composure works through multiple pathways simultaneously, which some dogs respond to better than single-ingredient supplements.
Composure Products
Composure (Regular)
Original formula. Chicken liver flavored soft chews. Best for daily maintenance of mild anxiety.
Composure Pro
Higher dose formula with added calming herbs. Best for moderate anxiety or during stressful events.
Composure Dosing Guide
| Dog Weight | Daily Dose | Stressful Events |
|---|---|---|
| Up to 12 lbs | 1 chew daily | 2 chews |
| 13-24 lbs | 2 chews daily | 4 chews |
| 25-50 lbs | 3 chews daily | 6 chews |
| 51-100 lbs | 4 chews daily | 8 chews |
| Over 100 lbs | 5+ chews daily | 10+ chews |
Pro Tip: Dogs LOVE the taste of Composure chews—many will take them as treats. For stressful events, give 30 minutes before. Can be safely doubled during high-stress periods.
Composure Pros and Cons
Pros
- ✓ Highly palatable soft chews
- ✓ Most affordable option
- ✓ Multi-ingredient synergy
- ✓ Works in 30-45 minutes
- ✓ Safe for daily long-term use
- ✓ Easy to dose (just add more chews)
Cons
- ✗ Less clinical research than Zylkene
- ✗ May not be strong enough for severe anxiety
- ✗ Large dogs need many chews (cost adds up)
- ✗ Contains animal-derived colostrum
- ✗ Soft chews require cool storage
Which Supplement Should You Choose?
The right supplement depends on your dog's specific type of anxiety and your needs. Here's our recommendation for common scenarios:
🏠 Separation Anxiety
Best Choice: Zylkene
Separation anxiety requires consistent, daily support. Zylkene's sustained effect and research specifically on separation behaviors makes it ideal. Start 2-3 days before leaving dog alone for first time.
⛈️ Thunderstorm/Firework Phobia
Best Choice: Anxitane
Noise phobias require fast-acting relief. Anxitane works in 30-60 minutes, perfect for when you hear thunder approaching. Keep on hand during storm season.
🚗 Travel Anxiety
Best Choice: Anxitane or Composure
Both work quickly enough to give before car rides. Anxitane if your dog has severe car anxiety; Composure for milder nervousness.
🏥 Vet Visits
Best Choice: Zylkene (start 2-3 days before) + Anxitane (day of)
Combination approach works best. Zylkene builds up calming effect; Anxitane provides extra support for the actual visit.
😟 Mild/General Nervousness
Best Choice: Composure
For dogs who are generally nervous but don't have specific severe triggers, Composure's daily chews offer gentle support at a reasonable cost.
📦 Moving/New Home
Best Choice: Zylkene
Major life transitions need sustained calming support. Start Zylkene 1-2 weeks before the move and continue for 2-4 weeks after settling in.
Can You Combine These Supplements?
Yes—many veterinarians recommend combining calming supplements, especially for moderate to severe anxiety. Because each works through a different mechanism, they can be safely used together.
Safe Combinations
- Zylkene + Anxitane: Zylkene for daily baseline, Anxitane added before stressful events. This is the most commonly recommended combination.
- Zylkene + Composure: Works well because Zylkene (casein) and Composure (L-Theanine + colostrum) use completely different pathways.
- All Three: For severe anxiety cases, some vets recommend all three with behavioral modification. Always consult your vet first.
Important Note
Composure and Anxitane both contain L-Theanine, so combining these two gives a higher L-Theanine dose. While generally safe, consult your vet before using both together, especially at higher doses.
Frequently Asked Questions
Which calming supplement is best for dogs?
Zylkene is the most clinically-studied option and works best for general anxiety and stressful events. Anxitane (L-Theanine) is best for quick-acting relief during thunderstorms or travel. Composure is best for daily maintenance and has the most palatable chew format.
Can I give my dog Zylkene and Composure together?
Yes, most veterinarians consider it safe to combine these supplements since they work through different mechanisms. Zylkene uses alpha-casozepine while Composure uses L-Theanine and Colostrum. However, always consult your vet before combining supplements.
How long does Zylkene take to work in dogs?
Zylkene typically takes 1-2 days to reach full effectiveness when given daily. For predictable stressful events, start giving it 2-3 days before the event. Some dogs show improvement within 24 hours, but maximum benefits are seen after 1-2 weeks of daily use.
Is Anxitane the same as L-Theanine?
Anxitane is a brand name for a veterinary-grade L-Theanine supplement made by Virbac. L-Theanine is the active ingredient. You can find generic L-Theanine supplements, but Anxitane is specifically formulated and dosed for pets.
Which supplement works fastest for dog anxiety?
Anxitane (L-Theanine) works fastest, typically showing effects within 30-60 minutes. Composure also acts relatively quickly at 30-45 minutes. Zylkene takes longer (1-2 days for full effect) but may provide more sustained anxiety relief.
Are calming supplements safe for puppies?
Yes, all three supplements are generally safe for puppies. Zylkene is especially popular for puppy socialization periods. Always use appropriate dosing for your puppy's weight and consult your vet for puppies under 12 weeks.
Can these supplements replace anti-anxiety medication?
For mild to moderate anxiety, supplements alone may be sufficient. For severe anxiety, supplements typically work best alongside prescription medication and behavioral modification. Never stop prescribed medications without veterinary guidance.
Assess Your Dog's Anxiety Level
Take our free 2-minute quiz to understand how anxious your dog is and get personalized product recommendations.
Take the Dog Anxiety QuizFinal Thoughts
All three supplements—Zylkene, Anxitane, and Composure—are legitimate, veterinarian-recommended options for helping anxious dogs. They're not miracle cures, but they can make a meaningful difference when used appropriately.
Our Final Recommendations:
- Start with one supplement and give it 2-4 weeks before deciding if it works
- Keep a log of anxiety behaviors to objectively assess improvement
- Combine with other strategies like exercise, training, and environmental management
- Consult your vet if anxiety is severe or doesn't improve with supplements
- Consider combining supplements for moderate-severe cases (with vet guidance)
Remember: supplements are most effective when combined with proper training, environmental management, and in some cases, veterinary behavioral consultation. If your dog's anxiety significantly impacts their quality of life, don't hesitate to seek professional help.