Vitamin B2 (Riboflavin) for Dogs

How B2 helps cells use food energy—and how to read its place in your dog’s diet

By La Petite Labs Editorial 12 min read

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Hollywood Elixir® Senior Dog Supplement

Contains 0.5 mg Riboflavin (B2)

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Contents

Riboflavin helps your dog use the energy in food. Cells turn this vitamin into FMN and FAD, small helpers that enable enzymes to do their work. 7

Complete food is the foundation for meeting that need. An additional formula is a choice about the combination of ingredients you want alongside the everyday diet.

Canine feeding research has measured the need for B2 through enzyme activity. In a separate trial, additional vitamins did not improve healthy coats.

The vitamin behind the name riboflavin

Riboflavin is vitamin B2, a water-soluble nutrient. 1 Dogs need it in their diet; complete-food guidelines include a recommended concentration. 2

When you notice the name on a label, begin with the kind of product in your hand. Complete food is intended as the daily diet; treats and supplements usually are not. 3

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How B2 becomes FMN and FAD

An enzyme is a protein that speeds up a chemical reaction. Some enzymes need a smaller helper, called a cofactor. Riboflavin supplies the flavin part of two such helpers: flavin mononucleotide, or FMN, and flavin adenine dinucleotide, or FAD. 7

Cells make FMN from riboflavin, then use FMN to build FAD. These are working forms involved in transferring electrons during metabolism. The vitamin on the label is the starting material for that chemistry. 7

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From food energy to usable ATP

Breaking down food transfers energy to carriers such as NADH. Inside mitochondria, NADH hands electrons to a large enzyme assembly called Complex I. Its FMN helper receives them, and a series of further handoffs carries them to CoQ in the inner mitochondrial membrane. 8 10

Energy released as electrons move through the respiratory machinery drives protons across that membrane. This creates a difference between the two sides. As protons return through ATP synthase, the enzyme uses that flow to make ATP—the immediately usable energy supply for cellular work. 10

B2’s contribution is part of this controlled conversion of food energy. Calling it an energy vitamin describes its place in the machinery.

See how cells make, use and recycle NAD+ in our NADome and NADomics guide.

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B2 also helps recycle glutathione

Energy metabolism is only part of the picture. An enzyme called glutathione peroxidase uses reduced glutathione to convert hydrogen peroxide into water. Glutathione becomes oxidized in the process. 13

A different enzyme, glutathione reductase, restores the reduced form. It uses NADPH as the electron donor and contains FAD, the cofactor made from B2. This allows glutathione to be used again. 9

The distinction matters: one enzyme uses glutathione to deal with peroxide; the other helps replenish it. B2 contributes to the recycling machinery. The fuller glutathione explanation follows both parts of that cycle.

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One B vitamin can help another work

FMN helps convert B6 into its active coenzyme form. The two vitamins have connected roles. 1

The B6 guide explains that vitamin’s jobs in amino-acid metabolism in more detail.

Vitamin B2 helps your dog’s cells turn energy from food into ATP, the usable energy that powers their work.

Where riboflavin is found in food

Eggs, lean meat and organ meats such as liver contain riboflavin. 1 Their presence in a meal is useful nutritional information, but it does not tell you whether the whole day’s feeding is balanced.

For a dog eating a complete diet, keep added foods within the allowance for extras. AAHA recommends at least 90% of calories from complete nutrition and no more than 10% from treats and other foods. 12 Choose an extra because it fits the meal, rather than trying to deliver a vitamin dose through a piece of liver.

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Read the main food’s adequacy statement

Look for the nutritional adequacy statement and the life stage it names. In the United States, a “complete and balanced” claim can be substantiated through AAFCO nutrient profiles or feeding-trial procedures. It does not mean every food has been through a feeding trial. 3

Adult maintenance differs from growth and reproduction. Match that statement to the dog you are feeding before choosing an additional vitamin. This is a more useful first check than searching the ingredient list for one nutrient in isolation. 3

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How much B2 does a dog need?

FEDIAF’s 2025 adult-dog guidance lists 1.74 or 1.50 mg of B2 per 1,000 kcal, depending on the assumed energy intake. A dog eating fewer calories needs more nutrient-dense food. These figures describe complete food, not an extra dose. 2

For a hypothetical 500-kcal day, a concentration of 1.50 mg per 1,000 kcal would supply 0.75 mg in the day’s food. That is arithmetic for understanding the units; it is not a prescription to add 0.75 mg to dinner. 2

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What a dog feeding study tells us

In a 1996 experiment, 20 adult dogs received diets with five different riboflavin concentrations. Researchers followed a measure of glutathione reductase activity in red blood cells through day 112. Dogs on the lowest-B2 diet showed poorer biochemical B2 status than those on higher levels. 4

This gives the recycling connection a direct canine example: an enzyme system helped researchers assess whether the diet supplied enough riboflavin. The study estimated a maintenance requirement. It did not test an energy boost in dogs already eating an adequate diet. 4

Persistent weakness calls for veterinary assessment; anemia is one possible cause, and its origin needs investigation. 15

Does more B2 mean a better coat?

A separate study followed 64 privately owned dogs given diets with graded vitamin concentrations. They had no history of skin or coat problems, and assessments took place at the start and after 122 days. The diets did not improve hair or coat condition; riboflavin blood concentrations were also unaffected by treatment. 6

Several vitamins changed together, so this was not a B2-only experiment. It also did not test treatment of dogs with riboflavin deficiency. For an owner hoping to improve an already healthy coat, it provides no reason to expect extra B2 to add shine. 6

B2 requirements describe what your dog’s whole diet needs to provide. They are not extra doses to sprinkle over a complete meal.

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

Case provided by JoAnna Pendergrass, DVM

Rex, a 7-year-old Labrador Retriever, was brought in after his owner noticed he was slower to rise, hesitant on stairs, and less able to play as before. Examination showed stiffness and reduced hip mobility; radiographs confirmed degenerative joint changes.

His care required weight management, veterinary-guided pain control, nutritional support, and rehabilitation — a comprehensive plan, but one started only after visible decline appeared.

Clinical takeaway: Rex’s case reflects the value of proactive aging support: maintaining lean body condition, monitoring mobility early, and supporting cellular resilience, antioxidant defense, and healthy inflammatory balance before decline becomes obvious.

Single-case vignette. Not generalizable. Veterinary oversight is essential for pain, stiffness, or suspected joint disease.

Explore Hollywood Elixir Research →
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Why B2 comes up in liver research

In a 2025 study, researchers compared 66 dogs with chronic liver disease with 50 healthy controls. The liver-disease group had lower serum riboflavin. Dogs with recent vitamin supplementation or unbalanced diets had been excluded, so the finding was not simply a comparison of good and poor feeding. 5

That makes B2 status a worthwhile research question in liver disease. The study did not give riboflavin as treatment or establish whether supplementation improved the dogs’ health. For a dog with a diagnosed condition, the result belongs in a veterinary nutrition discussion; it does not supply a home treatment dose. 5

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For home-prepared meals, use the whole recipe

A B2-containing ingredient answers one nutrient question. A balanced home-prepared diet has to bring all the required nutrients together. 1 3

Work from the exact weighed recipe and the specific vitamin-and-mineral preparation its formulator names. Before replacing that preparation with a B-complex or another formula, ask the professional who developed the recipe to check the substitution. Keep the recipe, ingredient amounts and supplement label together so that the question can be answered for the food you actually make.

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Why riboflavin is yellow

Riboflavin is yellow, and people can excrete absorbed excess in urine. That does not tell you why your dog’s urine looks bright or whether a supplement is helping. 1

If a colour change follows a new product, keep its label available for your veterinarian. Mention changes in the amount passed, discomfort or other unusual signs too. Colour alone is not a way to choose the next dose.

Keep light and storage in mind

Visible and ultraviolet light can inactivate riboflavin and its derivatives. 1

Keep the packaging’s storage instructions with the food or supplement. Avoid leaving a clear container on a sunny shelf. Use the storage conditions specified for that particular product.

Different ingredients, connected cellular jobs

Riboflavin supplies FMN and FAD. NR provides a route to making NAD, a different family of cofactors. 7 14 CoQ accepts electrons downstream of FMN, while FAD helps the enzyme that restores glutathione. 8 9

Those connected jobs give B2 a clear place in Hollywood Elixir’s 17-active NAD+ longevity system. The formula brings B vitamins, NAD+ precursors, mitochondrial cofactors and antioxidant ingredients together, with riboflavin among the nutrients connecting energy metabolism and antioxidant recycling. 16 Choose it for that wider cellular-nutrition purpose: one prepared formula, rather than a collection of isolated vitamin choices.

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What 0.5 mg on the label means

The current standard 2.5 g sachet supplies 0.5 mg of riboflavin. 16 A serving quantity differs from a whole-food concentration. 2

Read the complete ingredient list to see what accompanies the B2.

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Fit the serving into the usual meal

Use the applicable Hollywood Elixir serving directions, mix the powder into your dog’s usual food and serve immediately. 16

One powder brings the selected ingredients to the bowl together.

B2, B-complex or a combined formula?

Start with the job the product needs to do. If a veterinarian has identified a specific riboflavin need, follow that recommendation. A B-complex supplies several B vitamins, so check which ones and in what amounts. 1

For broader healthy-aging nutrition, Hollywood Elixir puts B vitamins beside NAD+ precursors, mitochondrial cofactors and antioxidant ingredients. 16 Choose the complete system for those connected functions, then follow its serving directions alongside the main food’s label. The ingredients come together in one daily powder; the meal can stay the one your dog knows.

For a human preparation, check the entire label: some chewable vitamins contain xylitol, which is toxic to dogs. 11

B2 helps cells restore glutathione after it has been used. That lets this antioxidant keep helping protect cells from chemical damage.

Educational content only. This material is not a substitute for veterinary advice. Always consult your veterinarian about your dog’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

FMN and FAD: Cofactors made from riboflavin that help enzymes carry out electron-transfer reactions.

ATP: A molecule that supplies usable energy for cellular work.

Glutathione reductase: The FAD-containing enzyme that uses NADPH to restore reduced glutathione.

Nutritional adequacy statement: Label wording that identifies a food’s intended nutritional use and life stage.

Related Reading

Aging & Senior Dog Guidance
• Dog Age Calculator
• Dog Lifespan by Breed
• Dog Dementia
• Lethargy in Dogs
• My Dog Won't Eat
• Dog Pacing At Night
• Dog Licking Paws
• Can Dogs Dehydrate

Healthy Aging Support
• NAD+ for Dogs
• NMN for Dogs
• Antioxidants Supplements for Dogs
• Best Senior Dog Supplements & Vitamins
• Dog Longevity Drugs
• Rapamycin for Dogs

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 ODSStudy design/context: Nutrient referenceSpecies/context: Human chemistryEvidence boundary: Food and vitamin chemistry.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4 · ↩ 5 · ↩ 6 · ↩ 7
  2. FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. FEDIAF · 2025Study design/context: Formulation guidelineSpecies/context: DogsEvidence boundary: Whole-food concentrations.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  3. U.S. Food and Drug Administration. “Complete and Balanced” Pet Food. FDAStudy design/context: Label guidanceSpecies/context: Dogs and catsEvidence boundary: Nutritional adequacy.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  4. J. L. Cline and colleagues. The riboflavin requirement of adult dogs at maintenance is greater than previous estimates. Journal of Nutrition · 1996· DOI 10.1093/jn/126.4.984Study design/context: Maintenance feeding studySpecies/context: Adult dogsEvidence boundary: Requirement, not extra stamina.↩ 1 · ↩ 2
  5. Verena Habermaass and colleagues. Water-Soluble Vitamins (Riboflavin, Niacin, Pantothenic Acid) in Dogs with Chronic Liver Disease vs. Healthy Controls. Veterinary Sciences · 2025· DOI 10.3390/vetsci12090877Study design/context: Case-control studySpecies/context: DogsEvidence boundary: Serum observation; no treatment.↩ 1 · ↩ 2
  6. J. L. Tran and colleagues. Blood vitamin concentrations in privately owned dogs fed non-standardized commercial diets and after intake of diets with specified vitamin concentrations. Journal of Animal Physiology and Animal Nutrition · 2007· DOI 10.1111/j.1439-0396.2006.00639.xStudy design/context: Graded-vitamin dietsSpecies/context: DogsEvidence boundary: Healthy coats; multiple vitamins.↩ 1 · ↩ 2
  7. Reactome. Vitamin B2 (riboflavin) metabolism. ReactomeStudy design/context: Curated pathwaySpecies/context: Human pathwayEvidence boundary: Conserved mechanism.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  8. Reactome. Complex I oxidises NADH to NAD+, reduces CoQ to CoQH2. ReactomeStudy design/context: Curated reactionSpecies/context: Human pathwayEvidence boundary: Electron transfer.↩ 1 · ↩ 2
  9. Reactome. GSR catalyzes glutathione (oxidized) + NADPH + H+ => 2 glutathione (reduced) + NADP+. ReactomeStudy design/context: Curated reaction and complexSpecies/context: Human pathwayEvidence boundary: Glutathione recycling; no dose effect.↩ 1 · ↩ 2
  10. Reactome. Respiratory electron transport. Reactome· DOI 10.3180/R-HSA-611105.7Study design/context: Curated pathwaySpecies/context: Human pathwayEvidence boundary: Respiratory mechanism.↩ 1 · ↩ 2
  11. U.S. Food and Drug Administration. Paws Off Xylitol; It’s Dangerous for Dogs. FDAStudy design/context: Safety guidanceSpecies/context: DogsEvidence boundary: Human-product ingredients.↩
  12. American Animal Hospital Association. Feeding Plans for Healthy, Appropriate Weight Cats and Dogs. AAHA · 2021Study design/context: Feeding guidelineSpecies/context: Dogs and catsEvidence boundary: Whole diet and extras.↩
  13. Reactome. GPX1 catalyzes 2 glutathione, reduced + H2O2 => glutathione, oxidized + 2 H2O. ReactomeStudy design/context: Curated reactionSpecies/context: Human pathwayEvidence boundary: Peroxide handling.↩
  14. 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 studySpecies/context: Mice and muscle cellsEvidence boundary: NR pathway, not dog efficacy.↩
  15. Steven L. Marks. Anemia in Dogs. Merck Veterinary ManualStudy design/context: Veterinary referenceSpecies/context: DogsEvidence boundary: Nonspecific low-energy signs.↩
  16. La Petite Labs. Hollywood Elixir supplement facts, current product identity and directions. La Petite LabsStudy design/context: Manufacturer declarationsSpecies/context: Dogs and catsEvidence boundary: Composition and directions.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4

FAQ

What does vitamin B2 do for dogs?

Cells use B2 to make FMN and FAD, enzyme helpers involved in metabolism. A suitable complete diet is the starting point for supplying it.

Can riboflavin help a dog with low energy?

B2 participates in energy metabolism, but that does not establish an energy boost from adding more. Persistent low energy needs assessment: anemia, for example, can cause weakness and has several possible causes. Give your veterinarian the food and supplement labels along with a description of what has changed.

Is riboflavin safe for dogs?

Yes. Dogs need B2 as part of normal nutrition. For a supplement, check the amount and the full ingredient list; suitability depends on the whole product.

Can a B2 supplement upset my dog’s stomach?

If vomiting or diarrhea starts after a new product, stop that addition and contact your veterinarian for advice, especially if signs persist or your dog seems unwell.

Do puppies or pregnant dogs need extra B2?

They need food suitable for growth or reproduction; life stage alone is not a reason to add a separate dose. Hollywood Elixir guidance calls for veterinary direction for puppies and pregnant or nursing pets.

Does a large dog need more riboflavin?

The relevant amount depends on the whole diet and food intake. A large breed does not have a separate general rule for adding B2 on top of complete food.

Can I give my dog a human B2 supplement?

Have the dose and full ingredient list checked first. Some human chewable vitamins and supplements contain xylitol, which is toxic to dogs. If your dog may have swallowed a xylitol-containing product, contact a veterinarian or animal-poison service immediately.

Is B2 the same as B-complex or B12?

B2 means riboflavin. A B-complex combines several B vitamins, and B12 is a different vitamin. Read the label for the actual contents rather than treating the names as interchangeable.

Dalmatian looking toward a Hollywood Elixir box held in a person's hand

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