This Overlooked Ingredient Protects Your Pet’s Mobility

A surprising ingredient from the egg industry offers support for aging joints and cartilage. Osteoarthritis is one of the most common causes of chronic pain, stiffness, and declining mobility in pets, particularly as they enter their senior years. If you share your life with an aging pet, you’ll probably notice subtle changes long before a diagnosis is made. Maybe he’s a little slower getting up after resting, isn’t jumping into the car with the same enthusiasm, hesitates before climbing stairs, or takes longer to warm up on walks. These changes can be early signs of underlying degeneration in joints, tendons, bones, and cartilage.

Osteoarthritis isn’t simply a disease of worn-out cartilage. It is a complex, progressive inflammatory process involving cartilage, the synovial membrane, underlying bone, and the biochemical signaling pathways that regulate inflammation and tissue breakdown. Once inflammation becomes established within a joint, it can create a destructive cycle in which inflammatory signals stimulate cartilage-degrading enzymes. Those enzymes damage the extracellular matrix, and the resulting tissue breakdown generates additional inflammatory signals.

This is why protecting your pet’s mobility is about much more than simply managing pain after it appears. Ideally, we want to support healthy cartilage metabolism, maintain the integrity of the extracellular matrix, regulate excessive inflammation, and preserve comfortable movement for as long as possible.

A June 2026 study¹published in the peer-reviewed veterinary journal Animals sheds light on eggshell membranes for preserving canine joint health. Researchers investigated eggshell membrane peptides (ESMPs) in canine chondrocytes, the specialized cells responsible for maintaining cartilage, using real canine cartilage cells, not rodent cells, to measure markers of inflammation, cartilage breakdown, and cartilage repair to understand how the peptides worked.

What they discovered is interesting; the eggshell membrane peptides did not simply appear to “lubricate” the joint. They interacted with cellular inflammatory signaling and helped preserve the machinery responsible for maintaining the cartilage extracellular matrix.

In other words, the research points toward an important concept: supporting the health of cartilage cells is just as important as supporting the structures surrounding joints.  The study found that ESMP reduced activation of NF-κB, a major inflammatory signaling pathway, while decreasing inflammatory mediators and a cartilage-degrading enzyme called MMP-13. At the same time, ESMP helped preserve two important components of healthy cartilage, type II collagen and aggrecan, a primary structural component of cartilage that helps cartilage retain water and withstand compression.

Osteoarthritis Is More Than Wear and Tear

When I talk with pet parents about osteoarthritis, I try to correct the idea that it is naturally a result of cartilage being worn down from years of use. It’s much more complicated than that.

Healthy cartilage is an extraordinary biological material, not an inert piece of padding. It contains specialized cells called chondrocytes that continually monitor their environment and regulate the production and breakdown of the extracellular matrix surrounding them. That matrix is what gives cartilage much of its structural and functional integrity. It provides a smooth, resilient surface over the ends of bones, allowing joints to move with less friction while absorbing mechanical forces generated during walking, running, jumping, and playing.

Interestingly, cartilage doesn’t have a direct blood supply like many other tissues. Instead, its health depends heavily on the activity of chondrocytes, the resident cells embedded within the cartilage matrix. These cells continuously balance the production and breakdown of extracellular matrix components. In a healthy joint, this turnover is tightly regulated. Chondrocytes produce substances such as type II collagen and aggrecan that give cartilage its strength, structure, and ability to retain water.

Osteoarthritis disrupts this balance. Inflammatory signals can cause chondrocytes to shift from a maintenance and repair state toward a catabolic state, meaning they begin producing more enzymes and mediators that contribute to tissue destruction. One of the inflammatory signals commonly used to model this process in laboratory research is interleukin-1 beta, or IL-1β, a signaling protein produced by immune cells that acts as an alarm system for inflammation.

When chondrocytes are exposed to IL-1β, they respond as though the joint is under inflammatory attack. They increase the production of inflammatory mediators and cartilage-degrading enzymes while decreasing the production of important structural components. Over time, this imbalance can contribute to progressive loss of cartilage integrity.

The new study used this type of model. Researchers exposed canine chondrocytes to IL-1β and then evaluated whether eggshell membrane peptides could counteract the resulting inflammatory and cartilage-damaging response.

Interesting New Research on Cats

I love it when the research world turns its attention to cats, because so much of our feline nutrition science has historically been an afterthought compared to canine studies. A July 2026 study published in Animal Nutrition and Metabolism offers a well-designed look at what eggshell membrane, alone and in combination with sodium hyaluronate, does for a cat's skin and coat.²

Researchers followed 24 healthy young Ragdoll cats over eight weeks, and what they found reinforces that eggshell membrane isn't just a "pretty coat" ingredient; it genuinely supports the skin barrier from the inside out. Cats supplemented with eggshell membrane showed smoother, more compact hair cuticle structure under the microscope, better coat compliance, and measurably lower trans-epidermal water loss, meaning their skin was retaining moisture more effectively, not just looking shinier. That's a functional improvement in barrier integrity.

Cats getting eggshell membrane had significantly lower levels of IL-31, a key itch-signaling molecule involved in allergic skin disease, than the control group. This is beneficial for inflammatory, itch-prone skin, not just dry or dull-coated skin. Alongside that, these cats showed improved antioxidant markers, including higher glutathione peroxidase and catalase activity, and increased zinc and vitamin E levels in both blood and hair, nutrients your cat's body needs for proper keratinization and structural hair protein synthesis.

There was even a gut connection here. Supplemented cats showed shifts in their fecal microbiota toward more Blautia and other beneficial short-chain-fatty-acid-producing bacteria, and those same bacterial shifts correlated with the improved antioxidant and skin markers. This is the gut-skin axis showing up yet again, this time in cats, reinforcing that what we do for the microbiome doesn't stay in the gut.

The most consistent benefits in this study came when eggshell membrane was paired with sodium hyaluronate rather than used alone, which tells me these two ingredients are likely working through complementary mechanisms, hyaluronate primarily supporting hydration, and eggshell membrane providing more structural and antioxidant support. This is exciting to me, and it's exactly the kind of foundational research I hope we see more of in cats in the future.

What Exactly Is Eggshell Membrane?

It’s important to distinguish eggshell from eggshell membrane. When you crack an egg open, there is a thin membrane attached to the inside of the shell. This membrane is a protein-rich biological material containing collagenous proteins and other bioactive compounds, including Type I collagen, Type V and Type X collagen, elastin, and glycosaminoglycans like glucosamine and chondroitin sulfate.

For this study, researchers didn’t simply grind up eggshells and add them to cells. The eggshell membrane peptides were processed into smaller peptide fragments. This distinction is important because different eggshell membrane products can have substantially different compositions, processing methods, peptide profiles, concentrations, and biological properties. Small peptides are of particular interest in nutritional research because their size can influence digestion, absorption, transport, and biological activity.

Eggshell membrane and its hydrolyzed components have attracted scientific interest because of their potential effects on joint health.³ Previous studies⁴ have reported improvements in joint discomfort, stiffness, and function following eggshell membrane supplementation in human subjects, while animal research has suggested effects on inflammatory markers and extracellular matrix degradation.

Eggshell Membrane Targets Key Inflammatory Signals

The researchers examined several inflammatory markers after exposing canine chondrocytes to IL-1β. The inflammatory stimulus increased expression of IL-6, inducible nitric oxide synthase, or iNOS, and cyclooxygenase-2, or COX-2. ESMP significantly reduced these inflammatory responses. The researchers also measured inflammatory mediators in the cell culture environment and found reductions in IL-6, nitric oxide, and prostaglandin E2 following ESMP treatment.

Why are these molecules important? Because inflammation inside an osteoarthritic joint is not merely an unpleasant side effect. It can actively contribute to changes in cartilage metabolism.

For example, nitric oxide can influence chondrocyte behavior and has been associated with reduced expression of factors involved in cartilage matrix production. PGE2 is another inflammatory mediator involved in pain and inflammatory signaling.

This does not mean that every increase in these molecules automatically causes arthritis. Biology is rarely that simple. But in the context of an inflammatory cartilage model, reducing their excessive production is biologically meaningful.

The researchers also looked at whether ESMP could influence the balance between cartilage breakdown and cartilage maintenance.

The Inflammatory Switch: NF-κB

The NF-κB pathway can sound intimidating if you are not accustomed to molecular biology. Still, it is actually easier to understand when you think of it as part of the body's communication system. Cells constantly receive information from their environment.

Inflammatory molecules act like messages telling cells that something is wrong. NF-κB is part of the machinery that helps translate some of those messages into changes in gene expression. When inflammatory signaling is activated excessively or chronically, NF-κB can contribute to sustained expression of inflammatory mediators and tissue-degrading enzymes.

In osteoarthritis, this can perpetuate the cycle of inflammation and cartilage breakdown. The 2026 study found that IL-1β caused NF-κB p65 to accumulate inside the nuclei of canine chondrocytes. ESMP reduced that accumulation.

Weight Management Matters

There is another component of joint health that no supplement can replace. Body composition. Every additional pound your pet carries increases the mechanical and metabolic burden placed on the musculoskeletal system.

But weight management is not simply about reducing mechanical load. Adipose tissue is metabolically active and can produce signaling molecules involved in inflammation. This means excess body fat can contribute to a systemic inflammatory environment in addition to increasing physical stress on joints.

Maintaining an ideal body condition is one of the most powerful forms of preventive joint care. A lean, appropriately muscled pet has a very different long-term joint trajectory than an overweight one carrying excess body fat for years.

And if your pet already has osteoarthritis, achieving and maintaining an ideal body condition is one of the most important interventions you make.

Movement Is Medicine

As your pet ages, it’s common for them to become more sedentary. It’s a predictable pattern that starts innocently enough. At the first signs of morning stiffness, we ease up on long walks. With less activity, muscle mass begins to slip away. Muscles aren’t just for movement, though; they support and stabilize joints and tendons. As muscles disappear, the body’s natural scaffolding for mobility becomes more difficult, and the sedentary spiral begins.

Appropriate movement, tailored to your pet, can help preserve muscle mass, joint range of motion, balance and functional capacity. Develop a strategy for your pet's age, orthopedic condition, fitness level and pain status.

For some dogs, this may involve shorter walks, swimming, underwater treadmill therapy, therapeutic exercises, balance work or other rehabilitation techniques. The goal is maintaining function.

Nutrition Provides the Foundation

Both dogs and cats need adequate protein and essential nutrients to maintain muscle and connective tissues. They also need appropriate energy intake so that excess body fat won’t accumulate.

Omega-3 fatty acids, particularly EPA and DHA, have been studied extensively in canine joint nutrition for their role in supporting healthy inflammatory balance for dogs and cats with osteoarthritis.

Antioxidant-rich whole foods⁵ also contribute to overall nutritional resilience.

Appropriate hydration matters. Your pet’s body can’t build and maintain healthy tissues without adequate water. The bigger picture is that mobility and joint health are influenced by far more than one ingredient. Eggshell membrane complements a broader strategy, but it’s not a magic bullet.

A fresh, species-appropriate diet provides the amino acids, minerals, fatty acids, antioxidants, and other nutrients required for tissue maintenance.

A Proactive Approach to Mobility and Joint Health

Joint health and mobility are multifactorial, which means our approach should be multifactorial, too. For pets with joint disease, consider their body composition, amount of exercise, muscle condition, diet quality, omega-3 status, previous injuries, environmental factors, pain management, sleep health, and overall ability to manage stress.

Eggshell membrane contains several naturally occurring components associated with connective tissue biology. The 2026 canine cell study suggests that its enzymatically derived peptides can influence inflammatory signaling and cartilage matrix metabolism in a way that is consistent with joint protection.

The best integrative veterinary strategies combine the strengths of multiple approaches to health and longevity. Protecting your pet's mobility and joint and tendon health is a lifelong project. The earlier you support healthy movement and nutrition, the more opportunities to preserve longevity and quality of life.

And sometimes, an ingredient that seems almost too ordinary to notice, such as the membrane inside an eggshell, turns out to contain a fascinating collection of biological compounds worth paying attention to. While it’s perfectly fine to peel the membrane from your morning egg and give it to your pet, it’s nearly impossible to obtain a therapeutic amount this way; a small dog would need the membrane from more than a dozen eggs every day to reach commonly supplemented amounts. Think of fresh eggshell membrane as a healthy bonus, not the therapeutic dose. If you’re using ESM specifically for joint support, a standardized eggshell membrane supplement provides a practical, consistent way to deliver an appropriate amount.

Sources and References:

• ¹ Mao, X.; Xu, L.; Cao, Y.; Wang, M.; Wang, W. Eggshell Membrane Peptides Alleviate IL-1β-Induced Inflammatory Responses and Extracellular Matrix Degradation in Canine Chondrocytes by Inhibiting the NF-κB Signaling Pathway. Animals 2026, 16, 1939.
• ²  Chen Q, Wang W, Wang H, Ma M, Miao C, Zhang Y, Lei S, Pan L, Liu Y, Chang X, Wang J and Xiong W (2026) Dietary sodium hyaluronate and eggshell membrane improve skin barrier function and coat health in Ragdoll cats. Front. Vet. Sci. 13:1882271.
• ³ Ragetly GR, Martins Â, Ober CA, Boiocchi S, Nicolas CS. Efficacy of a joint supplement containing eggshell membrane among other ingredients to improve the mobility of dogs with osteoarthritis: a multicenter double-blind randomized placebo-controlled study. Front Vet Sci. 2025 Jun 2;12:1561793.
• ⁴ The Veterinary Journal, November 2019
• ⁵  Muršec, A.; Poljšak, B.; Nemec Svete, A.; Erjavec, V. Antioxidant Strategies for Age-Related Oxidative Damage in Dogs. Vet. Sci. 2025, 12, 962.

About Karen Shaw Becker, DVM, CVH, CVA, CCRT

Veterinarian Dr. Karen Shaw Becker believes biologically appropriate food and an animal's immediate environment are essential in determining health, vitality, and lifespan. She has spent her career as a wildlife and exotic animal veterinarian and small animal clinician, empowering animal guardians to make intentional lifestyle decisions to enhance the well-being of their animals.