Quick answer: Melatonin is the hormone that tells a dog's body it is evening, and vets use it for noise fear, night-time restlessness in seniors, general anxiety and a couple of hair-loss conditions. Typical amounts are about 1 mg for a dog under 5 kg, 1.5 mg from 5 to 12 kg, 3 mg from 12 to 45 kg, and 3 to 6 mg for giants, up to three times a day, given 30 to 60 minutes before the trigger or bedtime. It is generally safe. The one thing that sends dogs to emergency clinics is human melatonin gummies and melt tablets sweetened with xylitol. Check the label, or use a dog product with a printed dose.
Dosage chart
- Under 5 kg (10 lb): about 1 mg per dose
- 5 to 12 kg (10 to 25 lb): about 1.5 mg per dose
- 12 to 45 kg (26 to 100 lb): about 3 mg per dose
- Over 45 kg (100 lb): 3 to 6 mg per dose
- Frequency: up to three times daily as needed; once at bedtime for sleep; once 30 to 60 minutes before a known trigger
These are the ranges commonly quoted in veterinary references and used in practice. Melatonin is not licensed for dogs, so there is no official dose; your vet may go higher or lower for a specific condition. Start at the low end and judge.
What it helps
- Noise phobia. Fireworks, storms, gunshots. Often combined with a botanical calming blend, and for severe cases with prescription Sileo or trazodone. See the fireworks prep plan.
- Sleep-cycle disruption in seniors. Older dogs, especially those with early cognitive decline, lose the clear day-night rhythm and start pacing, panting or barking at night. Melatonin before bed helps re-anchor the cycle. See senior dog restless at night.
- General anxiety and separation stress, as part of a routine rather than a rescue.
- Seasonal flank alopecia and alopecia X, two hair-loss conditions in which melatonin sometimes triggers regrowth. Vet-directed.
- Cushing's disease as an adjunct in some cases, under a vet.
What it does not do
It does not sedate a dog into stillness the way a prescription drug can, it does not fix separation panic on its own, and it does nothing during an event if it was not given beforehand. It is a timing signal and a mild calmer, not a tranquilliser.
Safety and interactions
- Common side effects: drowsiness, occasional stomach upset, rarely itching or a faster heart rate.
- Diabetic dogs: melatonin can affect insulin sensitivity; discuss with the vet.
- Breeding dogs: it can alter fertility and cycling.
- Drug interactions: sedatives, benzodiazepines, and serotonergic drugs such as fluoxetine and trazodone. Tell the prescriber before adding melatonin.
- Pregnancy and puppies: avoid unless a vet directs.
- Xylitol. Many human melatonin gummies, chewables and fast-melt tablets are sweetened with xylitol (sometimes listed as birch sugar), which causes dangerous drops in blood sugar and liver failure in dogs. Read every label, or use a dog-specific product.
Dog products vs human tablets
Human plain melatonin tablets without xylitol are used by many vets and are cheap, but supplement testing has repeatedly found that the melatonin content of over-the-counter products can differ widely from the label. A dog product that prints its dose and is made without sweeteners removes both problems. OcuLabs Calming + Anxiety Support Chews contain 4 mg of melatonin per two-chew serving, inside the range above for a mid-size to large adult dog, alongside chamomile 80 mg, valerian 50 mg, passion flower 30 mg, hemp seed oil, thiamine and L-theanine, with no added sugar and no xylitol. Two chews with dinner, or 30 to 60 minutes before a trigger. For a small dog, one chew delivers 2 mg. Do not stack with another melatonin product without adding up the totals. For how melatonin fits with the botanicals, read calming chews for dogs: ingredients explained.
Frequently asked questions
How much melatonin can I give my dog?
About 1 mg under 5 kg, 1.5 mg from 5 to 12 kg, 3 mg from 12 to 45 kg, 3 to 6 mg over 45 kg, up to three times daily. Confirm with your vet.
Is melatonin safe for dogs?
Generally yes. Watch for drowsiness and stomach upset; discuss diabetes, breeding and drug interactions with the vet; never give xylitol-sweetened human products.
What is it used for?
Noise phobia, senior night restlessness, general anxiety, two hair-loss conditions, and as a Cushing's adjunct.
How long does it take to work?
About 30 to 60 minutes, lasting several hours.
How much is in OcuLabs Calming Chews?
4 mg per two-chew serving, no xylitol, no added sugar.
This article is general information for dog parents and is not veterinary advice. Doses are commonly quoted ranges, not prescriptions. OcuLabs products are nutritional supplements and are not intended to diagnose, treat, cure or prevent any disease.