Let me explain this in terms anyone can understand.
Picture each of your dachshund's 26 intervertebral discs as a jelly donut squeezed between two firm plates.
Your glucosamine chews, your fish oil capsules, your joint supplements? They are like throwing water at a fire burning inside a sealed room. They reach the door. They run underneath it. They never actually get to where the damage is happening.
The inflammation is not just around the disc. It has built a TWO-PATHWAY ASSAULT, a dual biochemical cascade that synthetic glucosamine is structurally incapable of blocking, and that has been degenerating your dachshund's disc tissue every single day the chews are sitting in the bowl uneaten.
Trying to stop IVDD progression with glucosamine chews is like trying to put out a fire by painting the wall next to it.
You are treating the surface. The inflammation underneath keeps burning.
Here is what the published science actually says.
1. The Filler Problem makes most of the chew medically useless.
When you buy a bag of joint chews, between 60% and 80% of everything in that bag is filler. It has to be. Without it, the chew would not hold its shape, would not be palatable enough for your dog to eat, and would not last 18 months on a shelf. The active ingredient, glucosamine sulfate, is listed eighth or lower on virtually every major brand.
Studies show that synthetic glucosamine sulfate absorbs at approximately 12% bioavailability in dogs, meaning 88 cents of every dollar you spend on glucosamine supplements is excreted before it can reach the disc tissue.
Your 58 dollar bag of chews hits the gut and stops. The disc tissue stays unprotected underneath, degenerating every single day.
2. The Palatability Problem means your dog may be swallowing zero active ingredient.
The dog does not just refuse the chew once. They refuse it systematically. Dachshunds are reported as one of the breeds most likely to eat around a supplement hidden in food and leave it untouched in the bowl.
Nearly half of all negative reviews for joint chews cite one specific problem: the dog will not eat them. You are not a dissatisfied customer. You are a subscription that renews forever because the product was never designed to fix the underlying problem.
3. The Absorption Problem means most of what your dog does eat never reaches the spine.
Here is the number the supplement industry hopes you never look up.
Synthetic glucosamine sulfate, the form used in virtually every commercial joint supplement on the market, has a bioavailability in dogs of approximately 12%. Intervertebral discs are among the least-vascularized structures in any mammal. Getting any therapeutic compound to the disc nucleus is a delivery challenge under the best circumstances. With 12% absorption, you are not getting anything to where it needs to go.
Your dachshund's disc has become a defenseless structure. The inflammation is thriving because nothing you are giving them is capable of reaching it.
4. The Wrong Pathway Problem means glucosamine cannot stop what is destroying the disc.
Even when you do give glucosamine, and even when the dog eats it, and even when some fraction absorbs, it still cannot stop what is actually destroying the disc. IVDD is driven by two inflammatory pathways. The COX pathway and the LOX pathway. Both produce the compounds that drive the pain, the swelling, the nerve damage, and the progressive degeneration that takes a Grade 2 to a Grade 4. NSAIDs block COX.
Glucosamine blocks neither pathway.
I have published this in the peer-reviewed literature. I have presented it at three international conferences. The mechanism is not in dispute.
Here is their playbook, stated plainly:
Chews your dog refuses to eat. A second brand when the first fails. Fish oil that misses the LOX pathway. NSAIDs you cannot use long term because of the liver. A new bag of the same glucosamine you started with. Repeat forever until you end up in my surgery suite.