Glucosamine Dose Checker

How it works

First, how much your dog eats. Daily energy need (maintenance energy requirement, MER) from body weight in kg (BW), activity a from 0 to 1, and a factor for neutering:

MER = (95 + 90 × a) × BW^0.75 × f    f = 0.88 neutered, 1.00 intact

Then the food that meets it, from the food's metabolizable energy (ME, kcal per kg):

food (g/day) = MER ÷ (ME ÷ 1000)

Then the glucosamine in that food, with 20% taken off for extrusion:

glucosamine (mg/day) = food (g/day) ÷ 1000 × glucosamine (mg/kg) × 0.8

And last, the comparison: a floor of 15 mg per kg of body weight a day and a full clinical dose of 30 mg per kg a day. The percentage is the delivered amount against the full dose.

Where the 15 and 30 mg/kg come from, and why we call it human dosing

There is no dose for dogs that research has settled. Dog studies have given glucosamine at very different amounts, from about 10 mg per kg of body weight a day to several times that, with mixed results.

The figures most dog supplements and guides use trace back to people. The standard human dose is about 1,500 mg a day, the amount used in the large human trials. For an adult of 70 to 75 kg that works out at about 20 mg per kg of body weight. That per-kg figure was carried over to dogs as it is: around 15 to 20 mg/kg a day to keep a dog on, and up to about 30 mg/kg as a higher, starting dose. We use 15 as the floor and 30 as the full dose.

That carrying over is what makes it human dosing. Between species, doses usually scale with metabolic body weight (BW^0.75), not body weight itself, because a smaller animal burns energy, and clears many substances, faster per kg. Scaled that way, a dog's dose per kg would come out higher than a person's, and more so the smaller the dog. A simple mg per kg ignores this, so read the comparison as a rough guide and ask your vet for your dog's dose.

Read the result as an estimate

• The dose targets come from human dosing (see above). Food intake scales with metabolic weight (BW^0.75), so from the same food a small dog gets more glucosamine per kg of body weight than a large dog. The right scaling for dogs is not settled.
• The label figure is a minimum. "Glucosamine (min)" promises at least that much; the bag may hold more.
• The 80% is an assumption. How much glucosamine survives extrusion varies by recipe and process. Foods from our list are counted as kibble unless they are wet food; for a label you enter, untick the box if the food isn't extruded.
• Every dog is different. Two dogs of the same weight can need quite different amounts of food. If you feed less than the calculation says, your dog gets less glucosamine too.

This tool is information, not veterinary advice. If your dog has joint problems, ask your vet about the dose and whether a separate supplement makes sense. More on the evidence: Is glucosamine necessary in your dog's diet?