L-Lysine Powder Cat Supplement
Verified Aug 26, 2026
This is a powdered L-lysine supplement for cats, designed to be added to their regular food rather than fed as a complete diet. It provides a concentrated source of the amino acid lysine, with brewers yeast and chicken liver to improve palatability. It’s intended for cats who need additional lysine support alongside their normal balanced cat food.
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This is a targeted L-lysine supplement, not a complete cat food, and is meant to be used in addition to your cat’s regular diet. It offers a high level of lysine in a palatable powder form, which can be helpful when you and your vet decide extra lysine is appropriate. It’s suitable for most cats as long as their main diet is a complete and balanced cat food.
Computed from 3 of 3 applicable checks. Missing data is skipped, never counted against a food.
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At a Glance
Where these benefits come from
Benefits the manufacturer highlights in its own product marketing. KibbleLab lists them for reference and does not verify these claims.KibbleLab Review
Strengths
- Provides a concentrated source of L-lysine for cats that need extra amino acid support.
- Powdered format makes it easy to mix into wet food or a small meal portion.
- Includes chicken liver and brewers yeast to improve taste for picky eaters.
- Low moisture and ash suggest a stable, shelf-friendly supplement product.
Considerations
- This is a supplement only and should never replace a complete and balanced cat food.
- Chicken liver may be an issue if your cat has a known allergy to chicken or poultry proteins.
- Brewers yeast can be a problem for cats with a rare yeast sensitivity, so watch for any digestive upset when starting it.
- Always check with your veterinarian before adding any supplement, especially if your cat has other medical conditions or takes medications.
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
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.
02
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.
03
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.
04
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.
05
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
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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.
Manufacturer
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
No recall is listed for Under the Weather Pet L-Lysine Powder Cat Supplement.
Source: FDA animal food recall listings back to January 2019 · Checked daily, last on Aug 31, 2026
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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 track the FDA's animal food recall listings back to January 2019 and publish every pet food recall automatically. A filing that isn't pet food may not appear here.
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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 listings. Last verified dates reflect our most recent data check. We track the FDA's animal food recall listings back to January 2019 and publish every pet food recall automatically. A filing that isn't pet food may not appear here.
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