Vitamin B2 (Riboflavin) for Cats

How food supplies B2, what cells do with it, and where a daily supplement fits

By La Petite Labs Editorial 14 min read

Woman cuddling an orange-and-white cat and a silver tabby while holding a Hollywood Elixir box
Hollywood Elixir® Daily longevity system · adult & senior cats Starting at $63/month 

Riboflavin, or vitamin B2, helps cells use the nutrients in a meal. The body turns it into small molecules that help enzymes transfer electrons—part of the chemistry behind usable energy. 5

B2 also contributes to the enzyme that restores glutathione after it has been used. 9 A suitable complete food supplies this vitamin as part of everyday nutrition. 2

Riboflavin supplies FMN and FAD, cofactors involved in electron transfer. 5 A model cat-food experiment found that most measured B2 remained after processing, with some loss. 10 Feline food guidelines express its requirement as a concentration in the whole diet. 4 Hollywood Elixir combines B2 with NR, CoQ10 and reduced glutathione in a food-mixed powder. 16 15

What riboflavin does

Vitamin B2 and riboflavin are two names for the same water-soluble vitamin. Its importance comes from what cells make from it: FMN and FAD, molecules that work with enzymes. 1

An enzyme carries out a chemical reaction. A cofactor is a component it needs for that work. B2 supplies cofactors that carry electrons between reactions. 5

Your cat needs B2 as part of nutrition. That does not mean every cat needs a separate B2 bottle: complete food appropriate to life stage is intended to supply the required nutrients. 2

Woman kneeling with two long-haired tabby cats while holding a Hollywood Elixir box beside a food bowl

Why it appears on a food label

Riboflavin listed among added vitamins can be part of making a food nutritionally complete. The ingredient list tells you what went into the recipe; the nutritional-adequacy statement tells you whether it is intended to serve as the daily diet. 3

In the US, a “complete and balanced” claim is supported by meeting an AAFCO nutrient profile or by feeding trials using AAFCO procedures. It is not individual AAFCO approval of the product. 3

A complementary food has a different role: it must be combined with other foods to provide the full daily ration. A short ingredient list or “additive-free” description does not change that distinction. 4

Woman exercising beside a tabby cat, with a Hollywood Elixir box and food bowl on a small table

From the meal to working cofactors

Eggs, organ meats and lean meats are among the foods that contain riboflavin. 1 That does not make one ingredient a complete recipe; a homemade diet needs the right amounts and proportions of all required nutrients. 2

Some dietary riboflavin is associated with proteins. Digestion breaks those proteins down, freeing riboflavin for absorption. Cells then convert the vitamin to FMN and use FMN to make FAD. 5

Orange-and-white cat reaching toward a woman holding a Hollywood Elixir box while sitting in a chair

How B2 helps turn food into usable energy

Breaking down nutrients supplies electrons to carriers including NADH. In mitochondria, NADH passes those electrons into a chain of proteins. An FMN-containing protein helps with the first handoff; the electrons then travel onward to coenzyme Q, or CoQ. 6

This electron movement powers the pumping of other charged particles across an internal membrane. As those particles flow back through an enzyme, it uses the flow to make ATP—the molecule that powers much of a cell’s work. 7

B2 is therefore part of how the cell makes a meal useful. The NAD+ guide for cats follows the electron carrier’s wider roles and how cells replenish it.

Gray-haired man holding a Hollywood Elixir box while two cats rest beside him in an armchair

Restoring glutathione for another use

Cells use glutathione to help handle hydrogen peroxide by converting it to water. An enzyme called glutathione peroxidase performs the reaction using glutathione in its reduced form. The glutathione becomes oxidized as it participates. 8

A second enzyme, glutathione reductase, restores the reduced form using electrons supplied by NADPH. That enzyme contains FAD, made from riboflavin. This is the direct B2 connection: the vitamin supplies a cofactor for the machinery that makes glutathione available again. 9

NADPH here is distinct from the NADH in the energy example. The glutathione guide explains how making new glutathione differs from using and restoring it. 9

B2-derived FAD belongs to the enzyme that restores glutathione for another use.

What food processing changes

A 2023 experiment measured B vitamins before and after retort processing—the heat treatment used for sealed foods—in a chicken-based model cat food. 10

Riboflavin concentration fell by 18.3%, leaving 81.7% of the measured amount. The recipe was deliberately fortified well above ordinary production levels so the vitamins could be measured reliably. This was a food-processing experiment, not a feeding trial in cats. 10

The result explains a reason for planned vitamin additions during manufacture. It does not mean an owner should replace an assumed percentage after opening every can. 10 At home, discarding cooking water can also discard some water-soluble riboflavin; that is a different process from heating a sealed recipe. 1

Tabby cat looking up at a Hollywood Elixir sachet held above it, with the product box on a small table

How much belongs in the whole diet?

FEDIAF’s 2025 B2 recommendations use milligrams per 1,000 kcal of usable food energy. Adult maintenance is 1.05 mg at the lower assumed calorie intake, or 0.80 mg at the higher intake. Growth and reproduction use 0.80 mg. 4

Eating fewer calories calls for more concentrated nutrition. These are whole-diet concentrations, not extra supplement doses. 4

The food’s life-stage statement matters too: growth and adult maintenance are different formulation categories. 3

Hand gently petting an orange-and-white cat beside a food bowl and Hollywood Elixir box

What deficiency research found in cats

In a 1959 experiment, Gershoff and colleagues produced riboflavin deficiency using purified diets. They reported skin changes; some cats receiving amounts slightly below their minimum requirement developed cataracts. The study also varied fat and carbohydrate: higher-carbohydrate, lower-fat diets appeared to spare the requirement in that setting. 11

Those findings establish that a sustained nutritional shortfall can matter. They do not turn a dull coat into a B2 test or show that adding riboflavin treats cataracts. Nor do they show that changing flavors of complete food causes deficiency. 11

Man holding a Hollywood Elixir box beside a black cat, an orange tabby and a food bowl

A favorite flavor can still be complete

A cat does not need a different flavor for each vitamin. If the accepted food is complete for the right life stage, liking only one or two flavors does not itself create a vitamin gap. 2

Compare the feeding statements on the actual foods. A complete-and-balanced chicken food can supply the main ration; a chicken treat has another purpose. 3 That distinction matters more than the number of flavors in the cupboard.

When your cat is eating less

Eating a favorite complete food is different from leaving most of a meal untouched. Appetite loss has many possible causes and does not identify a particular vitamin deficiency. If your cat stops eating, contact your veterinarian promptly rather than waiting for a supplement to restore interest in food. 12

Describe how much was actually eaten and when the change began. A vitamin powder cannot replace the food left in the bowl.

Sasha’s kidney-disease workup below illustrates why changes in an older cat deserve attention.

One favorite complete food can supply the vitamin B2 a cat needs.

Silver tabby sitting beside a food bowl and a Hollywood Elixir box held in a person's hand

DVM Voice: Clinical Vignette of a Common Pattern in Senior Cat Aging

Case provided by JoAnna Pendergrass, DVM

Sasha, a 12-year-old cat, was brought in after her owner noticed increased thirst and urination, lethargy, vomiting, and a generally unkempt appearance. Examination showed weight loss, elevated blood pressure, and reduced vitality.

Diagnostic testing revealed elevated kidney markers, poorly concentrated urine, and protein loss in the urine — findings consistent with chronic kidney disease, one of the most common chronic conditions in senior cats.

Her care required a kidney-focused diet, blood pressure management, targeted supplementation, medication support, and regular monitoring — a necessary plan, but one started after clinical signs were already visible.

Clinical takeaway: Sasha’s case reflects why senior-cat wellness should begin before obvious decline. Earlier monitoring, body-condition tracking, hydration awareness, antioxidant support, and daily cellular resilience may help support quality of life as cats age.

Single-case vignette. Not generalizable. Veterinary diagnosis and monitoring are essential for increased thirst, urination, vomiting, lethargy, weight loss, or suspected kidney disease.

Explore Hollywood Elixir Research →
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Will extra B2 make a cat more energetic?

A nutrient can be essential without extra amounts improving an already adequate diet. 2 The research discussed here does not establish a visible energy boost or a household response timetable for extra B2 in well-fed cats.

If a veterinarian identifies a nutritional problem, the treatment and follow-up should address that problem. For an optional addition, the immediate practical questions are whether your cat takes it and whether the combination fits the feeding routine.

Woman leaning toward a fluffy orange cat beside a Hollywood Elixir box and green food bowl

Forms and other B vitamins

A label may list riboflavin or riboflavin 5′-phosphate: both are B2 preparations. 1 A different form name alone does not promise a better result for your cat.

B2 supplies flavin cofactors; it is distinct from niacin and NR. 5 The niacin guide explains that B3 relationship.

FMN also participates in converting B6 to an active coenzyme form. 1 The B6 guide follows its work with amino acids. For the whole family, see B vitamins for cats.

Tabby cat licking its nose beside a food bowl and Hollywood Elixir box

Why Hollywood Elixir includes B2

Using food energy and restoring glutathione both involve B2-derived cofactors. 5 9 NR supplies starting material for NAD. 13 Its reduced form, NADH, can pass electrons through FMN-containing machinery toward CoQ. 6 Reduced glutathione helps handle peroxide. 8 FAD belongs to the enzyme that restores it for reuse. 9

Hollywood Elixir supplies riboflavin, NR, CoQ10 and reduced glutathione. 16 For an adult or older cat, those ingredients come in one daily powder. 15 The appeal is supporting these normal functions through a single meal addition, without managing separate products for each ingredient.

The studies here did not test whether the finished formula increases a cat’s activity or glutathione levels.

The B2 amount in a Hollywood Elixir portion

The panel declares 0.5 mg of B2 per standard 2.5 g sachet. 15 The ingredient guide names the preparation as “Vitamin B2 (as Riboflavin) USP.” That is the manufacturer’s form description, not independent certification of the complete product. 16

Current product directions specify half a sachet below 7 lb, one sachet at 7–30 lb and two above 30 lb. Use the applicable portion for your cat. 15

One vitamin or a combined powder?

If your veterinarian has specified riboflavin treatment, use the exact preparation and amount in that plan. A mixed supplement is not automatically an equivalent substitute.

For an optional daily addition, compare what you want to include with what is already on the shelf. Hollywood Elixir’s B2, NR, CoQ10 and reduced glutathione may overlap with separate products. 16 The choice may be to use one combined powder in place of several additions, with the amounts checked before making a replacement. That is a more concrete decision than buying another product because its name sounds different.

Tabby cat sitting at a table with a food bowl and Hollywood Elixir box

Safety depends on the preparation and amount

A 2024 EFSA assessment found no target-animal safety concern for a specified riboflavin fermentation additive under its proposed feed-use conditions. No cat tolerance trial was supplied; the assessment used other toxicology data and calculations. It did not evaluate every household B2 product. 14

A human bottle also has its own concentration and accompanying ingredients. Use applicable cat-product directions, or the preparation specified for a medical nutrition plan, rather than scaling a human dose.

Woman cuddling a silver tabby and a cream-colored cat while holding a Hollywood Elixir box

Mixing and storing the daily portion

Hollywood Elixir’s directions are to mix the chosen daily serving into the usual food, serve immediately and repeat daily. 15 Notice whether your cat eats the portion. Powder left in the bowl has not become part of the meal consumed.

Riboflavin is yellow and light-sensitive. Follow the storage instructions on the actual package; color alone cannot tell you how much active vitamin remains. 1 Keep the package and its directions available for whoever feeds your cat.

Choosing what belongs beside the usual food

As a cat grows older, a familiar meal can remain the anchor of its daily routine. An optional addition can focus on the normal energy and antioxidant functions described here. 7 9 Make that addition easy to give consistently. Hollywood Elixir mixes into the usual food. 15 After checking the full combination against anything already given, use the appropriate portion and see whether your cat accepts it with the meal.

B2 supplies working cofactors; the meal supplies the fuel they help cells use.

Educational content only. This material is not a substitute for veterinary advice. Always consult your veterinarian about your cat’s specific needs. These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease.

Glossary

Riboflavin: Another name for vitamin B2.

Cofactor: A component an enzyme needs to carry out its reaction.

FMN and FAD: Working cofactors made from riboflavin.

ATP: An energy-carrying molecule used for cellular work.

NADPH: An electron donor used in reactions including glutathione restoration.

Complete food: Food intended to provide the full daily ration for its stated life stage.

Related Reading

Aging & Senior Cat Guidance
• Cat Age Calculator: Cat Years to Human Years
• Cat Lifespan by Breed
• Lethargy in Cats
• Senior Cat Not Eating
• Cat Drinking A Lot
• Why Is My Senior Cat Withdrawn?

Healthy Aging Support
• NAD+ for Cats
• NMN for Cats
• Vitamins For Older Cats
• Senior Cat Food

References

Numbered references identify the sources used for specific claims. Read the study design, species and evidence boundaries alongside each finding.

  1. NIH Office of Dietary Supplements. Riboflavin — Fact Sheet for Health Professionals. NIH Office of Dietary SupplementsStudy design/context: Nutrient referenceSpecies/context: Human nutrition; general chemistryEvidence boundary: Riboflavin identity, dietary sources, forms and light sensitivity.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5 · ↩ 6
  2. Cornell Feline Health Center. Feeding Your Cat. Cornell Feline Health CenterStudy design/context: Nutrition guidanceSpecies/context: CatsEvidence boundary: Complete food, life stage, food preferences and homemade diets.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5
  3. U.S. Food and Drug Administration. “Complete and Balanced” Pet Food. U.S. Food and Drug AdministrationStudy design/context: Nutritional-adequacy guidanceSpecies/context: Cats and dogsEvidence boundary: Explains complete-and-balanced claims and their substantiation.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  4. FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. FEDIAF · 2025Study design/context: Complete-food formulation guidelinesSpecies/context: Cats and dogsEvidence boundary: Feline dietary concentrations and complete/complementary food definitions.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  5. Reactome. Vitamin B2 (riboflavin) metabolism. ReactomeStudy design/context: Curated biochemical pathwaySpecies/context: HumansEvidence boundary: Digestion and conversion of riboflavin into FMN and FAD.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5 · ↩ 6
  6. Reactome. Complex I oxidises NADH to NAD+, reduces CoQ to CoQH2. ReactomeStudy design/context: Curated mitochondrial reactionSpecies/context: HumansEvidence boundary: Electrons pass from NADH through FMN-containing machinery to coenzyme Q.↩ 1 · ↩ 2
  7. Reactome. Respiratory electron transport. Reactome· DOI 10.3180/R-HSA-611105.7Study design/context: Curated respiratory pathwaySpecies/context: HumansEvidence boundary: Electron transfer, membrane particle movement and ATP synthesis.↩ 1 · ↩ 2
  8. Reactome. GPX1 catalyzes 2 glutathione, reduced + H2O2 => glutathione, oxidized + 2 H2O. ReactomeStudy design/context: Curated biochemical reactionSpecies/context: HumansEvidence boundary: Glutathione participates in converting hydrogen peroxide to water.↩ 1 · ↩ 2
  9. Reactome. GSR catalyzes glutathione (oxidized) + NADPH + H+ => 2 glutathione (reduced) + NADP+. ReactomeStudy design/context: Curated reaction and enzyme-complex recordSpecies/context: HumansEvidence boundary: Glutathione reductase uses NADPH and contains FAD.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5 · ↩ 6
  10. Amanda N. Dainton and colleagues. Effects of container type and size on thermal processing characteristics and B-vitamin retention of canned cat food. Frontiers in Veterinary Science · 2023· DOI 10.3389/fvets.2023.1175819Study design/context: Food-processing experimentSpecies/context: Cat-food recipe; no live catsEvidence boundary: Measured vitamin retention after retort processing in a fortified model recipe.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  11. S. N. Gershoff and colleagues. The Effect of the Carbohydrate and Fat Content of the Diet upon the Riboflavin Requirement of the Cat. The Journal of Nutrition · 1959· DOI 10.1093/jn/68.1.75Study design/context: Experimental dietary deficiencySpecies/context: CatsEvidence boundary: Purified diets examined riboflavin deficiency and dietary fat/carbohydrate context.↩ 1 · ↩ 2
  12. Cornell Feline Health Center. Anorexia. Cornell Feline Health CenterStudy design/context: Clinical guidanceSpecies/context: CatsEvidence boundary: Causes of appetite loss and the need for veterinary assessment.↩
  13. Rachel S. Fletcher and colleagues. Nicotinamide riboside kinases display redundancy in mediating nicotinamide mononucleotide and nicotinamide riboside metabolism in skeletal muscle cells. Molecular Metabolism · 2017· DOI 10.1016/j.molmet.2017.05.011Study design/context: Mechanistic cell and mouse studySpecies/context: Mice; mouse-derived muscle cellsEvidence boundary: NR metabolism and its contribution to NAD synthesis.↩
  14. EFSA FEEDAP Panel and colleagues. Safety of a feed additive consisting of vitamin B2/riboflavin produced with Eremothecium ashbyi CCTCCM 2019833 for all animal species (Hubei Guangji Pharmaceutical Co., Ltd). EFSA Journal · 2024· DOI 10.2903/j.efsa.2024.9073Study design/context: Specified feed-additive safety assessmentSpecies/context: Rats; cultured cells; target-feed assessmentEvidence boundary: Evaluated one fermentation preparation; no cat tolerance trial was supplied.↩
  15. La Petite Labs. Hollywood Elixir® Longevity System. La Petite LabsStudy design/context: Manufacturer declarationsSpecies/context: Adult/senior dogs and catsEvidence boundary: Supplement Facts, applicable portions and food-mixing directions.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5 · ↩ 6
  16. La Petite Labs. Hollywood Elixir Ingredients: NAD+ & Antioxidants. La Petite LabsStudy design/context: Ingredient declarationsSpecies/context: Dogs and catsEvidence boundary: Named B2 preparation and the complete ingredient combination.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4

FAQ

Does a cat eating complete food need extra riboflavin?

A suitable complete food is intended to meet nutritional needs. A cat does not automatically need extra B2 because it prefers one flavor. An optional combined supplement is a separate choice from correcting a vitamin shortfall.

Which foods provide B2, and why is it added to cat food?

Eggs and meats can supply riboflavin. Manufacturers can add it to account for processing losses in the finished food. That is different from adding another vitamin serving at home.

How much riboflavin does a cat need?

FEDIAF’s whole-diet recommendations per 1,000 kcal are 1.05 mg for adults at the lower assumed energy intake, or 0.80 mg at the higher intake. Growth and reproduction use 0.80 mg. These are food concentrations, not extra supplement doses.

Can B2 deficiency affect a cat’s coat or eyes?

A controlled dietary-deficiency experiment reported skin changes and cataracts in some cats. Those findings do not make coat appearance a B2 test or establish that extra riboflavin treats eye disease. A persistent change needs its own assessment.

Will extra B2 improve energy, and how long would it take?

Being essential does not mean extra B2 improves an already adequate diet. The research discussed here supplies no reliable household response timetable. A diagnosed nutritional problem needs its own treatment and follow-up.

Can riboflavin be given daily or from a human vitamin bottle?

Daily use depends on the product and amount. Safety assessment of one riboflavin feed additive under proposed conditions does not establish a dose for an arbitrary human supplement. Follow applicable cat-product directions or a veterinarian’s specified preparation and amount.

Is riboflavin the same as niacin or a B-complex?

No. Riboflavin is B2 and supplies flavin cofactors. Niacin and NR belong to B3-related nutrition. A B-complex combines multiple B vitamins, including B2. The family name does not make their roles or amounts interchangeable.

What B2 form and amount does Hollywood Elixir contain?

The panel declares 0.5 mg per standard 2.5 g sachet. The ingredient guide specifies Vitamin B2 (as Riboflavin) USP. Use the applicable product portion and mix it into the usual food; the declared sachet amount is not a deficiency-treatment dose.

Orange-and-white cat beside a Hollywood Elixir box held in a person's hand

Discover LPL-01: How This Fits Into a Larger Feline Longevity System

Aging in cats unfolds quietly. It’s not driven by a single failure, but by gradual shifts across interconnected systems — cellular energy, oxidative balance, immune tone, and tissue integrity — each influencing the others over time.

This article explores one layer of that system. To understand what actually shapes long-term health, you need to step back and look at how these layers interact.

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