Nearly all the useful information about a dog supplement is printed on the tub, just not on the side most buyers look at. The front carries a photograph of a contented retriever, a count of ingredients and two or three reassuring adjectives. The back carries the composition, the additives, the analytical constituents and the feeding guide, in the smallest type the packaging allows. Learning to read that panel takes a few minutes, and it changes what a shelf of near-identical products looks like.
None of what follows requires trusting any manufacturer, which is rather the point. A feed label is a regulated document with a predictable structure, and once that structure is familiar the right questions ask themselves. How much of each named ingredient is in one chew. How many chews is this dog meant to have. And, most revealing, what has the maker chosen not to print.
The two words that decide what you are holding
Under the feed law applying in the UK and across the EU, every pet food product sits in a defined category, and two of them matter to a shopper. A complete feed is formulated to supply, in the daily ration alone, every nutrient a dog is known to require for the life stage stated on the pack. That is the legal meaning of complete on a bag of kibble, and it is a substantial claim.
A complementary feed is defined by what it does not do. It is not designed to meet a dog’s requirements on its own and must be fed alongside other food. Every supplement chew, powder, oil and paste sold for dogs falls here, and the phrase complementary feed, or complementary pet food, will appear somewhere on the pack, usually near the feeding guide.
This is not a technicality. It marks the legal border between food and veterinary medicine. A licensed medicine has been through an authorisation process, carries an authorisation number and may make claims about disease. A complementary feed has done neither and may do neither. It is food, sold to support normal function, and no wording on its label can lawfully promise to act on an illness. A dog that is limping, itching or losing weight needs a veterinary appointment, not a different tub.
Active ingredients per chew: the number everything else hangs on
Take a product such as 8 in 1 Dog Treats, a multi-ingredient soft chew of the sort sold in tubs of sixty – the label should state, for a single chew, how many milligrams of each named ingredient it contains. Glucosamine at perhaps a hundred milligrams, a similar quantity of MSM and of collagen, thirty or so milligrams of chondroitin sulphate, a measure of salmon oil, a small vitamin blend and a named probiotic strain. Where those figures are printed, two tubs can be compared in about ten seconds. Where they are missing, meaningful comparison is impossible and the price is effectively being set by the packaging.
Some labels quote amounts per hundred grams rather than per chew. That is lawful and close to useless, because it cannot be interpreted without knowing what a chew weighs. If a pack gives a figure per hundred grams and never states the chew weight, the arithmetic has been made deliberately awkward.
When a blend has no numbers
The most common evasion is the proprietary blend: a line reading something like joint complex, 450 mg, followed by ingredients in brackets. The list runs in descending order by weight, so the first item is the largest, but nothing indicates whether the second is two hundred milligrams or two. The expensive ingredients tend to sit at the quiet end.
Manufacturers defend this on grounds of commercial confidentiality: the formula is hard-won and worth protecting. It is a reasonable-sounding position with an awkward consequence, since it shields the recipe from competitors and from the customer at once, and only one of them is paying for the tub.
Per chew or per day: the trap in the feeding guide
The second number to find is the feeding guide, usually scaled to bodyweight. A typical pattern is one chew for dogs under ten kilograms, two for ten to thirty kilograms and three above that. Nothing about that is unreasonable. It simply means the same tub delivers three different daily intakes depending on which dog is eating from it.
The trap runs both ways. A brand can quote a striking per-chew figure while the feeding guide quietly requires three chews for the large dog in the photograph, so the tub lasts twenty days rather than sixty. Or it can quote a daily total that looks generous until divided by the chews needed to reach it, at which point the per-chew content turns out to be modest.
Neither presentation is dishonest on its own. The fix is to convert everything to one basis before comparing: milligrams of each named ingredient per day for the actual dog, and cost per day at that feeding rate.
Analytical constituents, and the questions they cannot answer
Feed labels must declare a short list of analytical constituents: typically crude protein, crude fat or oils, crude fibre, crude ash and moisture. Crude fibre measures indigestible plant material. Crude ash is the mineral residue left when a sample is incinerated, so it indicates total mineral content rather than the filler the word suggests. Moisture matters for soft chews, because water content affects texture and shelf life.
What that panel cannot do is tell anyone whether the product is worth buying. Two chews with identical analytical constituents can hold wildly different quantities of glucosamine, or none at all, because the actives sit at levels far too small to shift a protein or fat percentage. The panel describes the biscuit. It says nothing about the reason the biscuit was bought.
The ingredients list is a weight order, not a highlight reel
Ingredients must be listed in descending order by weight. On a soft chew, the opening entries are almost always base and binder: glycerin, pea or potato flour, linseed, oat flour, a vegetable fat, a natural flavouring. The ingredients named on the front of the pack often appear towards the end.
That is not automatically damning, and this is where many label guides go wrong. A hundred milligrams of glucosamine in a four-gram chew is two and a half per cent by weight, so it will always sit low in the order however well the product is formulated. Position is a poor proxy for adequacy, which is why the declared milligram figures matter so much.
The list still earns its place. It flags anything a sensitive dog reacts to, and it exposes token inclusion: a headline botanical listed dead last, after the flavouring, with no quantity anywhere, is there in an amount chosen for the front of the pack rather than for the dog.
Words that sound like evidence
Much of supplement packaging consists of terms with no defined meaning in feed law that cannot be checked. They are not unlawful. They are simply not information.
- Natural. No agreed standard sits behind it for pet food, and it says nothing about quantity, quality or effect.
- Premium. A price bracket described as though it were a specification.
- Vet formulated. Occasionally meaningful. Ask whether a vet is actually named, with a qualification and a role, or whether one was consulted once and the phrase kept.
- Clinically proven. This belongs with a citation: species, number of animals, dose, duration and outcome measured. Without those, it is a slogan wearing a lab coat.
- Human grade. A sourcing standard for some ingredients, not a statement about their effect in a dog.
- Counts of active ingredients. Eight at token levels make a longer list, not a better product.
The useful habit is to ask what evidence could contradict the phrase. If nothing could, it is decoration.
Batch codes, dates and the address on the back
Three unglamorous items are worth locating. A batch or lot number is a legal requirement and is what makes a recall possible; a product without one cannot be traced. A best-before date matters more here than for many foods, because oils oxidise and turn rancid, and a heavily discounted tub is sometimes discounted for a reason. Storage instructions exist because heat and sunlight shorten the life of oils and live cultures alike.
The label must also carry the name and address of the feed business responsible for the product. A full UK trading address, with a telephone number and a named manufacturing site, gives a buyer somewhere to direct a question. A mailbox does not. Companies that make their own product tend to say where; those buying an off-the-shelf formulation and adding branding tend not to.
What full disclosure says about a manufacturer
Printing every quantity is a commercial decision as much as a regulatory one. It hands competitors the formulation, invites like-for-like price comparison, and removes any room to trim an expensive ingredient quietly when costs rise. A brand that publishes anyway has accepted all of that, which is a reasonable signal about how the product compares.
The reverse deserves the same weight. When a company that has plainly spent money on photography and copywriting declines to print a table of milligrams, that omission is a choice, not an oversight. Nobody hides a number that flatters them.
A checklist for the back of the pack
Run through this in the aisle, or on the product page before ordering.
- Does it say complementary feed, so the legal category is clear.
- Are quantities given per chew, in milligrams, for every named active.
- Is there a proprietary blend giving a total but no individual amounts.
- What does the feeding guide require at this dog’s bodyweight, and what daily total results.
- How many days does the tub last at that rate, and what is the true cost per day.
- Are probiotics named by strain, with a viable count, rather than by the word probiotic alone.
- Are calories per chew declared, which matters for a dog already carrying extra weight.
- Is there a batch number, a best-before date and a storage instruction.
- Is there a full trading address and a named company to contact.
- Do the claims support normal function rather than promising to fix a condition.
Using all this in a shop aisle
The practical version takes under a minute. Turn the tub around. Find the milligrams per chew, then the feeding guide, multiply, and work out what the dog would receive in a day and what that costs. If the milligrams are not printed, the comparison cannot be made, and the product has answered the question by refusing to answer it.
This will occasionally rule out a decent product from a small company that has not thought hard about its packaging. It will more often rule out an expensive one relying on a photograph and an adjective. That trade is worth making.
One further habit is worth building. Total up everything a dog eats in a day, across food, treats and every supplement in the cupboard, and look at that whole rather than at each label alone. Duplication is common, calories add up, and the answer to an undiagnosed health question is not on the back of a packet. It is at the practice.