Do Calming Chews Work for Dogs? Evidence, Expectations and Safety

Every pet shop shelf has them now: calming chews, calming bites, calming treats, all with a dog looking suspiciously relaxed on the packet. So, do calming chews work for dogs? The honest answer is “a bit, for some dogs, and not by themselves”, and the evidence is thinner than the packaging suggests.

We sell calming supplements at Calmshops, so weigh what follows accordingly. But we’d rather you bought them with realistic expectations than feel let down, so here is what the research says, what to expect, and how to use them safely.

What’s in calming chews?

Most contain a mix of the following:

• L-tryptophan, an amino acid the body uses to make serotonin.
• Alpha-casozepine, a milk protein extract.
• L-theanine, an amino acid found in tea.
• Herbal ingredients such as chamomile and valerian root.
• CBD, in some products. This is a separate question we won’t cover here.

What does the research say?

It varies by ingredient, and it’s less solid than you might expect.

Tryptophan. A 2024 review in the journal Veterinary Evidence (Sofyan) looked at whether tryptophan in the diet reduces signs of anxiety in adult dogs. It reviewed two placebo-controlled studies. One found no significant overall effect on anxiety and fear-related behaviour. The other found owners reported less anxiety-related behaviour, but the cortisol (stress hormone) measurements didn’t differ significantly. The review concluded that tryptophan alone is not enough for anxious adult dogs.

A blend of tryptophan, alpha-casozepine and CBD. A 2025 study from the Waltham Petcare Science Institute in Frontiers in Veterinary Science (Flint and colleagues), funded by Mars Petcare, tested treats containing CBD, tryptophan and alpha-casozepine against a placebo. Only the treat with the 2 mg/kg CBD dose plus tryptophan and alpha-casozepine differed from placebo, with a smaller rise in cortisol after a short car journey, and the authors described the effect as mild. Most other measures showed no significant effect. The paper also notes that earlier studies of tryptophan have given mixed results.

Valerian and chamomile. The same paper says more scientific evidence is needed to support how well these work in dogs. That’s a fair summary of the position.

In short: some signals, mostly small, and no strong proof that any of these ingredients calms an anxious dog on its own. L-theanine wasn’t covered in the papers we read, so we can’t tell you what the evidence says about it.

What can you realistically expect?

Take the edge off, perhaps. Not cure anything. That fits how we use them: a calming treat can take the edge off a specific stressful evening, but it won’t replace training or fix the cause. We keep Calmdogs in the cupboard for fireworks and long car journeys, as extra support rather than a switch.

That also means a chew is a poor answer to some problems. The Dogs Trust says non-prescription products lack scientific evidence for separation anxiety, and that only a vet and a behaviourist should decide whether medication is appropriate. If your dog is showing real fear, a chew is not the plan.

When a chew might be worth trying

• A predictable, short-lived event: fireworks, a vet visit, a long car journey, a house full of visitors.
• Alongside a routine that already does the real work: exercise, a safe space, training. Our guide to calming your dog naturally covers that part, and our post on dog aromatherapy is another gentle option.
• A dog whose vet has said a supplement is fine to try.

Safety checks before you buy

1. Talk to your vet first if he is on any medication, has a health condition, is pregnant or nursing, or is a puppy. Don’t assume “natural” means harmless.
2. Read the label. Check the active ingredients and the dose for your dog’s weight, and follow the feeding guidance. Avoid giving several products with overlapping ingredients.
3. Treat it as a complementary feed, not a medicine. No chew should claim to treat, prevent or cure a medical condition. If one does, be wary.
4. Count the calories. Chews are extra treats. Adjust his meals if you use them regularly.
5. Introduce one thing at a time so you can tell what’s working, and watch for tummy upsets.
6. Don’t ignore a sudden change. If the anxiety is new, speak to your vet first. Pain and illness can look like stress.

Our guide to which vitamins to give your dog covers the basics of supplements more generally, and our vets guide can help you find one to ask.

If you do want to try one

We keep Calmdogs calming supplements in the cupboard. They are a complementary feed, so they won’t do the training for you, and they shouldn’t replace a conversation with your vet if your dog is struggling. If you’d like support with a dog who is fearful or hard to settle, our dog trainer directory lists reward-based trainers. And if the problem is mainly your dog being wound up before bedtime, our guide to crate training has a good routine for helping a dog switch off.

Written by Georgiana & Figo.