how to read a dog supplement label.

to read a dog supplement label properly, ignore the front of the pack and find one number: how many milligrams of each active ingredient your dog actually gets in a full daily dose - not per tablet, not per "serving", but per day at your dog's weight. that single figure decides whether a supplement can support what it says it supports, and it is the number a lot of labels are built around not showing you.

everything else - the hero ingredient names, the "clinically proven" badge, the photo of the labrador looking delighted - is marketing until you have done the sum. this guide covers the conversion to active mg per daily dose, how much epa and dha should be in there, what "clinically proven" legally means, and what "complementary pet food" tells you. we will be honest about what a supplement can and can't do, because the uk label rules are honest about it too.

the only sum that matters - active mg per daily dose

brands can declare an ingredient amount three ways, and two of them flatter the product. "per tablet" and "per serving" both sound like your dog's dose. they usually aren't. a "serving" might be three chews, while the feeding guide tells you to give your 12 kg dog one. so the headline number gets quietly divided by three before it reaches your dog, and nobody mentioned it.

the fix is one calculation. take the amount declared, then multiply by the number of chews your dog's weight calls for in the feeding guide. that gives active mg per daily dose, which you compare to a published range for the ingredient. and if the label won't give you enough to finish the sum - if it names an ingredient but won't state the amount - treat the missing number as the answer.

how much epa and dha should be in there

omega-3 is the cleanest ingredient to practise on, because the science is specific about the two fractions that do the work: epa and dha. "fish oil" and "salmon oil" are not the number that matters. epa+dha is. a label that boasts "1,200 mg salmon oil" while staying silent on epa+dha has told you the size of the bottle, not the strength of the dose.

published intakes are usually expressed per kilogram of body weight - the table below gives the landmarks. these are numbers vets work from, not targets to chase off a label, and the upper end of the range is only ever used under veterinary supervision. note the safe upper limit: more is not automatically better, and stacking several products can quietly push a dog past it (see can i give my dog several supplements at once).

epa+dha landmark	figure	source
published intake, lower end	~50 mg per kg body weight	today's veterinary practice
published intake, upper end - vet-supervised only	~220 mg per kg body weight	today's veterinary practice
vet-supervised ceiling (metabolic body weight)	~310 mg per kg to the power 0.75	colorado state university
safe upper limit	~280 mg per 100 kcal of diet	national research council

now the worked example. a bottle says "1,200 mg salmon oil per serving", a serving is three capsules, and the directions say one capsule per 10 kg. your 20 kg dog gets two capsules, so 800 mg salmon oil a day - and nowhere does the label say how much of that is epa+dha, which is exactly the figure you needed. the label won't let you finish the sum, and that silence is the finding.

spotting the fairy dust

"fairy dusting" is the trade name for adding just enough of a fashionable ingredient to print it on the label, and not enough for it to do anything. it is legal, common, and easy to spot once you know the tell: a hero ingredient named on the front with no amount declared anywhere.

here the uk rules are quietly on your side. the fediaf code of good labelling practice says that if a label draws particular attention to a substance for its functional effect, the amount of that substance has to be declared. so a chew that makes a feature of green-lipped mussel or a named probiotic, yet won't tell you the milligrams or the cfu count, is withholding the one thing the code says a functional claim should come with. our green-lipped mussel dosage guide gives the published ranges to check a declared figure against, and are the probiotics in your dog's chew already dead covers why a cfu count only counts if it survives to the mouth.

even a declared number needs a second look, because form matters as much as amount. one systematic analysis of glucosamine and chondroitin products (santos and colleagues, 2017) found the declared quantities broadly accurate, but the glucosamine in a different chemical form from the one the label implied. mg on the pack is necessary; it is not always sufficient.

what "clinically proven" is actually allowed to mean

less than you would hope. in the uk, the advertising rules (cap code rule 3.7) require a marketer to hold documentary evidence for any objective claim before it is published, and the asa treats "clinically proven" as a claim that needs clinical trial data behind it. the gaps are in the detail.

"clinically proven" does not have to mean the finished product was tested. the asa has repeatedly criticised evidence that leans on the ingredient rather than the end product, on trials that are small or lack a control group, or on studies that don't translate to the animal in front of you. a trial on one ingredient, in another species, at a dose higher than the chew delivers, can sit behind a "proven" badge and tell you almost nothing about the tub in your hand. the honest questions: proven to do what, in whom, at what dose, and was it this product. if the brand can't answer, the badge is decoration.

label features worth a second look

none of these disqualifies a product on its own - each is a prompt to do the sum first.

• amounts "per serving" or "per tablet" when the feeding guide gives your dog a fraction of a serving - always convert to per daily dose.
• proprietary "blends" that give one combined weight for eight ingredients but no individual amounts. you cannot check a single dose.
• "up to" and "with added" - "up to" is a ceiling, not a promise, and "with added x" says nothing about how much.
• disease claims - a uk supplement is not allowed to say it treats, prevents or cures anything (more on why below). a product that does is breaking the rules, which is not a sign of strength.

what "complementary pet food" means on a uk label

if the pack says "complementary pet food", that is not a downgrade or a red flag - it is the correct legal category for almost every supplement sold in britain. under assimilated regulation 767/2009, a complementary feed is one designed to be fed alongside your dog's normal diet rather than to replace it. a daily chew is complementary by definition: it tops up, it doesn't feed. our all-in-one dog supplements guide goes into what one chew can and can't stand in for.

the same regulation shapes what the label may claim. supplements can make function claims - supporting normal joint function, helping maintain a healthy coat, supporting normal digestion - but they may not reference particular diseases or claim to treat or prevent them. the veterinary medicines directorate is blunt about this: in guidance updated in january 2026 it confirmed non-medicinal products may be presented only for "maintaining health in healthy animals", and said it had received over 400 complaints about unlawful medicinal claims in a single year. so when a label sticks to "supports normal joint function", that is not weak wording - it is the law working as intended, and a brand that respects it is worth more trust than one promising to cure things it legally cannot.

this is also the honest limit of the whole category. a supplement supports normal function in a healthy dog. it does not fix a damaged joint, and no amount of label maths changes that. if something is actually wrong, the sum you need is a vet's, not a milligram count.

reading a label well takes about ninety seconds once you know the sum: find the active, convert it to mg per daily dose at your dog's weight, and compare it to a published range. a brand that makes that easy has decided you are allowed to check its work. that is the idea behind our proof page, where every active is set out and each dose is published as it is confirmed - the label on your pouch is the definitive record, with more on our faq. do the maths on ours, then do it on everyone else's.