The front of a supplement tub is marketing. The back is the product. Here is how to tell, in about ninety seconds in a shop aisle, whether what you are holding will do anything at all.
1. Find the milligrams. If you cannot, put it down.
The single most useful thing on any label is a number next to each active ingredient. Not a percentage, not a position in a list — a milligram figure.
If instead you see the words proprietary blend followed by one combined number, you are being told there is glucosamine in the tub without being told how much. That is legal, common, and it makes the product impossible to evaluate. A blend listing “1,200 mg of a proprietary joint complex” could be 1,150 mg of rice flour and 50 mg of the thing you came for.
2. Check the amount against the daily dose, not the chew
A chew with 300 mg of glucosamine sounds reasonable until you read that a 50 lb dog is supposed to get one a day. Two labels can look identical and deliver very different daily amounts.
Do this arithmetic before you compare prices:
| Product A | Product B | |
|---|---|---|
| Glucosamine per chew | 300 mg | 500 mg |
| Chews per day, 50 lb dog | 1 | 2 |
| Daily glucosamine | 300 mg | 1,000 mg |
| Days per 60-count tub | 60 | 30 |
Product A lasts twice as long, which feels like value, and delivers less than a third of the active. Those are not the same product at a different price. They are different products.
3. Look at the form, not just the name
“Zinc” on a label can mean zinc oxide, which is cheap and absorbed poorly, or a chelated zinc, which costs more and actually gets in. The same distinction runs through most of the category:
| Ingredient | Cheaper form | Better absorbed |
|---|---|---|
| Minerals | Oxides | Amino-acid chelated |
| Omega-3 | Flaxseed (ALA) | Marine oil (EPA/DHA) |
| Collagen | Hydrolyzed, high dose | Undenatured type II (UC-II) |
| Turmeric | Ground root powder | Extract standardized to curcuminoids |
The flaxseed one catches most people. Dogs convert plant ALA into usable EPA at a very low rate, so a chew advertising “1,000 mg of omega-3 from flaxseed” delivers a small fraction of that as the omega-3 that does the work on skin.
4. Check when the potency was measured
This one is specific to probiotics, and it is the most common sleight of hand in the category. Nearly every label states CFU count at time of manufacture. Live cultures die in heat and humidity, so by the time a tub has crossed an ocean, sat in a warehouse and lived on your counter for a month, that number can be a fraction of what it was.
What you want is a guarantee through the end of shelf life, and packaging that makes it plausible: a sealed jar with a desiccant, not a scoop-and-go tub or paper sachets.
Things that are not evidence
“Veterinarian formulated.” Unregulated phrase. It can mean a vet was consulted once, years ago.
Press logos. Very often paid placements on sponsored-content pages, not editorial coverage.
Star ratings on the brand’s own site. Worth something only if the platform verifies purchase and the brand cannot delete individual reviews.
“Clinically studied ingredient.” Read carefully — this usually means the ingredient has been studied somewhere, at some dose, not that this product was studied at this dose.
The ninety-second version
- Turn the tub over. Find milligram amounts per active. No amounts, no sale.
- Multiply by the daily serving for your dog’s weight. Compare daily amounts, not tub prices.
- Check the form of the two or three ingredients you actually care about.
- For probiotics, check whether CFU is guaranteed at expiry.
- Ask the company for a certificate of analysis for your batch. A brand that tests will send it. A brand that does not will change the subject.
Written by the Furry Friend Labs team. We make dog supplements, so we have an obvious interest here — which is exactly why everything above is a test you can run on our labels too. Every active in our products is declared in milligrams, and we will send you the lab report for your batch code if you email us. This article is general information about reading labels, not veterinary advice; anything about your specific dog belongs with your vet.