L-Lysine Powder Cat Supplement
Verified Jun 9, 2026
This is a powdered L-lysine supplement for cats, providing a concentrated source of the amino acid lysine along with brewers yeast and chicken liver for palatability. It’s designed to be mixed with food for cats who may benefit from additional lysine in their diet, such as those with recurring respiratory or eye issues under veterinary guidance. The high protein content reflects its yeast and liver base rather than it being a complete diet.
Nutritionally, this is a straightforward lysine supplement built on a palatable base of brewers yeast and chicken liver, making it easy to give with food for most cats. It’s not a complete food, but as a supplement it provides a clear, single primary active (L-lysine) with minimal extra ingredients. This can be a reasonable option for cats whose veterinarians have recommended lysine support, especially if they accept powdered products well mixed into meals.
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At a Glance
KibbleLab Review
Strengths
- Simple, focused formula with L-lysine as the key active ingredient, supported by a high overall protein content from brewers yeast and chicken liver.
- Chicken liver improves palatability for many cats, which can make daily dosing easier when mixed with food.
- Limited ingredient list without artificial flavors or dyes, which helps reduce unnecessary additives in a supplement product.
- Calorie density is modest per serving, so it adds minimal extra calories when used as directed.
Considerations
- This is a supplement only and does not provide complete and balanced nutrition, so it always needs to be used alongside a regular cat diet.
- Contains chicken liver, which is a common allergen, so it would not be appropriate for cats with known chicken allergies or sensitivities.
- Brewers yeast can cause digestive upset in a small number of cats, so it’s sensible to introduce it gradually and monitor for loose stool or vomiting.
- Any lysine supplement should ideally be used under veterinary guidance, particularly for cats with ongoing respiratory or eye problems.
Full Ingredient List
Ingredients and analysis reflect manufacturer data at the time of our last update and can change without notice. Always check the actual product packaging before feeding.
Ingredient filtering helps identify compatible options but is not a substitute for a veterinary elimination diet.
Top 5 Ingredients Explained
01
Brewer's Yeast
Brewer's yeast (deactivated Saccharomyces cerevisiae) is commonly used in dog and cat foods as a flavor enhancer and supplemental source of protein, B‑complex vitamins, trace minerals and immunomodulating components such as beta‑glucans. It can support skin, coat and general nutritional status, but may cause gastrointestinal upset or allergic reactions in yeast‑sensitive pets, is not a live probiotic, and should be used cautiously in animals prone to purine‑related issues or those receiving antifungal medications.
02
Chicken Liver
Chicken liver is a nutrient-dense organ meat commonly used in pet foods and treats as a highly palatable protein source and flavor enhancer, providing concentrated vitamins (especially vitamin A and B-complex), iron, and copper that support energy metabolism, red blood cell formation, and skin/coat health in both dogs and cats. Because it is so rich, liver should be fed in moderation—excessive intake can cause vitamin A toxicity, and its high fat content and risk of bacterial contamination mean it should be properly sourced or cooked and limited for pets with pancreatitis or specific dietary restrictions.
03
L-Lysine
L‑Lysine is the biologically active form of the essential amino acid lysine used in pet foods and supplements to support protein synthesis, muscle maintenance, immune function and tissue repair, and is particularly useful when diets are low in animal protein or for growing, pregnant or convalescent animals. While generally safe when used to correct a deficiency, excessive supplementation can cause amino‑acid imbalances (notably affecting arginine in cats) and clinical benefits for conditions like feline herpesvirus are mixed, so dosing should follow a veterinarian’s guidance.
04
Mixed Tocopherol
Mixed tocopherols are a blend of natural vitamin E compounds (alpha, beta, gamma and delta tocopherols) used in pet foods primarily as a natural antioxidant and preservative to protect fats and fat‑soluble nutrients and extend shelf life. They also supply dietary vitamin E—an essential antioxidant for immune function, skin and coat health and cellular integrity in dogs and cats—and are generally safe at typical use levels, though they are not a substitute for a complete vitamin formulation and may be less effective in animals with fat‑absorption disorders.
Nutritional Breakdown
How to read As Fed versus Dry Matter
As fed shows the numbers straight off the label, water included. Dry matter removes the water so you can compare a wet food and a dry food fairly.What is calorie density
How many calories the food packs per unit. Denser foods mean smaller portions for the same calories.Product Details & Brand
Product Specs
Brand
Under the Weather Pet is a pet food and supplement brand offering freeze-dried bland diets, broth toppers, and wellness chews for dogs and cats. The brand targets health-conscious pet owners seeking convenient, vet-formulated solutions for digestive upset and recovery support.
Visit Under the Weather PetManufacturer
All Under the Weather products are manufactured in the United States in facilities that follow FDA and USDA guidelines. The company emphasizes quality control, sourcing premium human-grade ingredients, and producing small batches to ensure safety and nutritional integrity.
Manufacturing details are compiled from public sources and not independently verified; they may not reflect contract manufacturing or co-packing.
Recall History
Under the Weather Pet L-Lysine Powder Cat Supplement has no recalls since 2014.
Source: FDA Pet Food Recall Database · Monitored daily
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Frequently Asked Questions
Has Under the Weather Pet ever been recalled?
We have no recalls on record for Under the Weather Pet. We monitor the FDA Pet Food Recall Database daily.
How does KibbleLab rate foods?
Our scores are based on ingredient composition, nutritional profile, AAFCO compliance, and health considerations. We don't penalize by-products, grains, or synthetic preservatives. Brands cannot pay for higher scores.
Is KibbleLab a substitute for veterinary advice?
No. KibbleLab provides data-driven food analysis, not medical advice. Always consult your veterinarian before making dietary changes, especially for pets with health conditions.
KibbleLab provides informational content only. This is not veterinary advice. Always consult a qualified veterinarian before changing your pet's diet.
KibbleLab may earn affiliate commissions through product links. No one can pay for a higher score, or to change what we recommend for your pet.
Product data sourced from manufacturer websites, AAFCO statements, and FDA recall database. Last verified dates reflect our most recent data check.
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