Do Calming Chews Work for Dogs? An Honest Look at the Evidence

If you are reading this, you have probably watched your dog pace before a storm, shadow you from room to room, or sit by the door long after you have left. You want to help, and a calming chew looks like an easy place to start.

It is a fair question to ask whether they actually work. Here is an honest answer, including the parts that do not suit anyone selling calming chews, us included.

Do calming chews work for dogs?

Calming chews can help some dogs with mild, everyday stress, but they do not work for every dog and the research is mixed. Some ingredients have small, controlled dog studies with positive results. Others have weak evidence, and at least one well-run trial found no effect in mildly anxious dogs.

A science writer at McGill University's Office for Science and Society reviewed the field in 2025 and described the research on common calming chew ingredients as unimpressive, with many studies lacking placebo groups or enough dogs. That critique is worth taking seriously. It does not mean no chew can help. It means you should judge a chew by its ingredients and doses, give it a fair trial, and keep realistic expectations.

What does the research say about each calming ingredient?

Evidence depends on the ingredient, not the word "calming" on the pack. This table summarises the dog studies we could verify.

Ingredient What the dog research shows Strength of evidence L-theanine In a placebo-controlled lab study (Araujo et al., 2010), dogs fearful of people showed less fear after 8 weeks. An open-label study in storm-sensitive dogs (Pike et al., 2015) reported owner-rated improvements, but had no placebo group. Small, promising, limited Ashwagandha A randomised, placebo-controlled trial in 24 stressed dogs (Kaur et al., 2022) reported lower cortisol and lower fear and anxiety scores after 4 weeks, with no adverse events reported. One small trial, positive L-tryptophan A randomised, placebo-controlled trial in 138 mildly anxious pet dogs (Bosch et al., 2009) found no change in anxiety-related behaviour over 8 weeks. A 2024 evidence summary concluded tryptophan alone is not enough to reduce anxiety in anxious adult dogs. Mixed, not enough on its own Chamomile Long history of traditional use. We could not find a controlled trial of chamomile for anxiety in dogs. Traditional use only Magnesium and B vitamins Both are essential nutrients for normal nerve function. We could not find controlled trials of them as calming supplements in dogs. Nutritional role, little dog trial data

Two things stand out. First, almost every positive study used daily dosing for four to eight weeks, not a single chew before a stressful event. Second, the tryptophan result is a useful reminder that an ingredient making sense on paper does not guarantee a measurable effect.

How long do calming chews take to work?

The published dog studies measured results after four weeks (ashwagandha) and eight weeks (L-theanine and tryptophan) of daily use. That is the most honest guide we have.

A fair trial looks like this: give the chew every day at the label dose for your dog's weight, for about four weeks, and keep simple notes. Write down how your dog handles the triggers you already know, such as storms, visitors, car trips or being left alone. Comparing notes from week one and week four tells you far more than a gut feeling on day three.

We cover the difference between daily and as-needed use in more detail in our guide to daily versus as-needed calming supplements.

Which dogs are calming chews most likely to help?

Calming chews make the most sense for dogs with mild, predictable stress, for example:

• Dogs who get unsettled during storms or fireworks
• Dogs who are a little clingy or restless when routines change
• Dogs who find car trips, visitors or grooming stressful
• Dogs settling into a new home

They are least likely to be enough on their own for dogs with severe fear, aggression, self-injury, or anxiety that is getting worse. Those dogs need a vet, and often a behaviour professional.

How do calming chews compare with other options?

Chews are one tool among several. This comparison shows where each fits.

Option What it does Best suited to Needs a vet? Calming chews Daily nutritional support for a calmer baseline Mild, everyday or predictable stress Check first if your dog is on medication or has a health condition Behaviour training Changes how your dog responds to triggers over time Almost every anxious dog A vet or qualified trainer can guide you Managing triggers Reduces exposure, such as a safe den during storms Predictable triggers like fireworks No Exercise and enrichment Burns energy and gives the brain a job Restless, under-stimulated dogs No Prescription medication Treats diagnosed anxiety under veterinary care Moderate to severe anxiety Yes, always

The pattern in the research and in practice is the same: chews work best as part of a plan, not as the whole plan. If storms are the big trigger, our guide to thunderstorm and fireworks anxiety covers the other pieces.

What should I look for in a calming chew?

• Named ingredients with amounts. A "calming blend" without doses tells you very little.
• Ingredients with some dog research, such as L-theanine or ashwagandha, if evidence matters to you.
• A dose by weight. A 5 kg dog and a 35 kg dog should not get the same amount.
• Made for dogs. Never give a dog a human sleep or stress product. Some contain ingredients that are unsafe for dogs.
• Honest claims. Be wary of promises of instant, guaranteed or "cures anxiety" results.
• A guarantee, so a fair four-week trial does not cost you if it does not suit your dog.

Our calming chews buying guide goes into ingredients and labels in more depth.

Where do Hero Calming chews fit?

Our Hero Calming chews are a daily chew made in Australia and vet reviewed. They combine magnesium, L-tryptophan, vitamin B1, ashwagandha, chamomile and Jerusalem artichoke (a prebiotic fibre). Of those, ashwagandha has the most direct dog trial evidence. Tryptophan, as the table above shows, has mixed results on its own, which is one reason we use it as part of a combination rather than alone.

We designed them for daily use as one part of a calmer routine, not as a sedative and not as a replacement for training or veterinary care. They come with a money-back guarantee, so you can give them the fair four-week trial described above. If you are not sure whether your dog's behaviour points to anxiety, start with our dog anxiety hub.

When should I see a vet about my dog's anxiety?

See your vet if your dog's anxiety is severe, appeared suddenly, or is getting worse, or if you notice:

• Destructive behaviour or attempts to escape that risk injury
• Self-injury, such as constant licking or chewing of the skin
• Aggression, or growling and snapping that is new
• Changes in eating, sleeping or toileting
• No improvement after a fair trial of training and routine changes

A sudden change in behaviour can sometimes have a medical cause, such as pain, which is another reason a vet check comes first. Our guide to the signs of anxiety in dogs can help you describe what you are seeing.

The bottom line

Calming chews are not magic, and anyone who tells you they are is overselling. For dogs with mild, everyday stress, a well-formulated chew given daily for a few weeks, alongside training and routine, may help take the edge off. Judge it fairly, keep notes, and bring your vet in whenever the anxiety is more than mild.