The Shockman Screen
Every product on this site was assessed against the same clinical screen before it was listed. One veterinarian runs it. Products that don't clear it don't go up.
Most pet supplement retailers list what distributors offer and what sells. The category has no gatekeeper, which is why a product can carry an impressive front label, a meaningless dose on the back, and no testing behind either. This is the screen I use instead.
Who runs it
I do. Elena Shockman, VMD — University of Pennsylvania, 16 years in veterinary practice, six of them in general practice and the rest in emergency and critical care, licensed in Pennsylvania and California. Not a buying team. Not a brand partnership. One veterinarian, product by product.
What gets assessed
Eleven areas. Ten of them are about the product. The eleventh is about the household — because a protocol nobody can sustain is not a protocol, it's a recommendation on paper.
1. Ingredient sourcing
Where the raw materials actually come from, and whether the company can document the supplier chain. A finished product is only as good as what went into it, and "proprietary sourcing" is usually a way of not answering the question.
2. Manufacturing standards
cGMP compliance, facility controls, batch records, and whether the company manufactures in its own facility or contracts it out — and if contracted, whether it will tell you to whom.
3. Third-party testing
Independent verification of identity, potency and contaminants. The question that separates most products isn't whether testing exists — it's whether the company will show you the certificate of analysis when you ask. Many won't.
4. Label accuracy
Active ingredients disclosed in milligrams per serving, not pooled into a proprietary blend. A blend tells you the ingredients are present. It does not tell you any of them are present in an amount that does anything.
5. Dose adequacy
Whether the amount delivered at the label directions matches the amount used in the research. This is the single most common failure I see. A product can contain exactly the right ingredient and still be useless at the dose on the back of the bottle.
6. Research base
What tier of evidence supports the claim, and whether any of it was generated in the species on the label. A randomized controlled trial in dogs is not the same as a rodent study, which is not the same as a mechanism and a hope. All three get sold the same way.
7. Formulation and bioavailability
Form, excipients, carrier, and whether the animal will actually take it. A supplement that the cat refuses is a supplement that doesn't work.
8. Safety profile
Contraindications, known drug interactions, and reported adverse events. This matters most for the animals already on medication, which is a large share of the animals whose owners are shopping for supplements.
9. Regulatory posture
NASC participation, how the company words its claims, and recall history. A company that makes disease claims on a supplement is telling you something about its judgment.
10. Clinical experience
How the product behaves in practice. Sixteen years of cases is a data source too — not a substitute for evidence, but a check on it.
11. Cost and sustained use
Whether a real household can afford it and keep it up. I look at cost per day at the effective dose, not the price on the shelf — a cheaper bottle that needs three times the serving isn't cheaper. And I look at whether the product survives contact with an actual week: twice-daily dosing for a cat who hides, a powder that has to be refrigerated, a chew that a dog with dental disease can't manage.
This is the area most screens skip, and it's the one I care most about. Medicine only works if it's accessible. A supplement that gets abandoned at week six because it costs $120 a month has not helped the animal — it has just cost the family money they may have needed for something else. When the cheaper product is the right answer, I say so.
About one in ten passes
That is the real number, and it's the most useful thing I can tell you about this category. Nine out of ten products I evaluate don't make it onto these shelves.
What I've learned doing this is that most failures aren't cynical. A few companies are knowingly selling underdosed products behind clever labels. But many are startups — founded by people who love animals, who assumed their contract manufacturer was handling quality, who didn't know that pooling four ingredients into a proprietary blend makes the product unevaluable, or that an ingredient safe in dogs can have a far narrower margin in cats, or that "reduces inflammation" on a supplement label is a drug claim with real regulatory exposure.
So a rejection here isn't a verdict on a company. When a product doesn't pass, I tell the company exactly why, in specifics: this ingredient at this dose, this claim on this panel, this certification missing. Several have come back having fixed it. That's a better outcome for animals than a quiet no.
A screen that only ever says no is a filter. A screen that tells you what to fix is a standard. I'm trying to build the second one.
Manufacturers: if your product didn't pass, or you'd like it assessed, get in touch. I'll tell you what I found.
Two examples
One that passed
A multi-strain probiotic capsule, listed.
It scored well because it does the unglamorous things properly. All seven probiotic strains are identified by their NCIMB numbers rather than described as "a proprietary probiotic blend" — which means I can look up what each one actually is. The dose is five billion CFU minimum per capsule, which meets standard therapeutic dosing, and the flat dose across body weights is defensible here: gut colonization doesn't scale with weight the way drug dosing does. The claim language is compliant structure-function throughout, with no disease claims anywhere on the package.
What gave me pause: titanium dioxide as a capsule whitening agent, and Enterococcus faecium — a strain that periodically draws concern in the literature about antibiotic-resistance transfer in clinical settings. I listed it anyway. The titanium dioxide controversy comes from high-dose human supplement use and doesn't apply at these levels, and NCIMB 30183 is a well-characterized strain with a long safety record in veterinary medicine. But I want you to know both of those are on the label, because a screen that never finds anything isn't a screen.
One that didn't
A joint chew from a direct-to-consumer brand. Rejected.
The ingredient list looks reassuring — green-lipped mussel, glucosamine, MSM, vitamin C, a few botanicals. Green-lipped mussel is genuinely one of the better-evidenced joint ingredients, with canine trials behind it. The product still didn't pass, for reasons that have nothing to do with how the front of the label reads.
- The green-lipped mussel is hidden in a proprietary blend. 368 mg pooled across green-lipped mussel, sea cucumber and polygonum, with no individual amounts. So the one ingredient with real evidence behind it is the one I can't verify a dose for. That is not an accident of labeling; it's a choice.
- Underdosed for the dogs most likely to need it. Glucosamine sulfate at 420 mg per serving works for a small or medium dog. A 100 lb dog needs roughly 900–1,575 mg a day and doesn't get there at label directions. The dogs with the worst arthritis are the big ones.
- Drug claims on the container. "Ease Discomfort." "Repair Flexibility." Those aren't structure-function claims, they're disease claims on a supplement — and they tell you something about a company's judgment beyond this one product.
- No certifications disclosed at all. No NASC, no NSF, no cGMP verification of any kind.
There's also a hypoglycemia caution buried on the label, which matters for diabetic dogs and which nobody reading the front of the package would see.
This brand could be re-evaluated. Disclose the blend, scale the dose, fix the claim language, get an independent audit, and the answer changes. That's the difference between a rejection and a grudge.
What this is not
This screen is not a guarantee of results in your animal. It's an assessment of whether a product is well made, honestly labeled, adequately dosed and supported by evidence worth the name. Whether it's the right choice for your dog or cat depends on the animal, and that's a conversation with your own veterinarian.
Nothing here treats, diagnoses or replaces veterinary care. If your animal is unwell, see your veterinarian first.
Questions about a specific product? Book a consultation.
