Reishi for Cats

The mushroom in healthy-aging formulas, the new cat research, and how to make sense of extracts

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 

The difficult part of choosing reishi often starts after the recommendation. One bottle says organic mushroom powder, another says extract, and a third advertises a percentage of polysaccharides. They can all look like versions of the same thing while delivering quite different preparations.

Reishi is a mushroom studied for compounds that interact with immune signalling. There is now a controlled study in cats involving a reishi-containing blend, as well as research in dogs and laboratory cells. Together, those findings make the ingredient worth understanding. They also make the details matter: which mushroom preparation, what else was in the blend, and what actually changed in the animals.

Reishi is a mushroom containing several compound families, including polysaccharides. A 2026 controlled study in 20 adult cats tested a blend of three mushroom extracts and bovine colostrum; it did not establish reishi-alone benefits for infections, anxiety or lifespan. Hollywood Elixir contains 25 mg reishi powder extract standardized to 35% total polysaccharides per standard 2.5 g sachet, plus a separate yeast beta-glucan ingredient. Total polysaccharides are not the same declaration as beta-glucans, and research blend amounts are not home serving instructions.

What reishi is

Reishi, also called lingzhi, is a woody mushroom commonly identified in supplement discussions as Ganoderma lucidum. Its compounds include polysaccharides, a broad group of carbohydrates, and triterpenes, a different chemical family. 2 4

These are part of the reason reishi is studied and used in supplements. They are also the reason the preparation matters. A whole mushroom powder, a concentrated extract and a multi-mushroom blend cannot be assumed to deliver the same compounds simply because reishi appears on each label.

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

“Immune support” needs a more useful explanation

The immune system recognises signals, responds to threats and regulates those responses. More activity is not automatically better in every setting. Research on beta-glucans has investigated how immune cells respond after exposure to these compounds; one canine study did that work in cultured blood cells. 3

That is a mechanism to investigate, not proof that oral reishi prevents illness in cats. It helps explain why the ingredient appears in immune-related formulas without reducing the immune system to something that should always be turned up.

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

What the 2026 cat study tested

Researchers studied 20 healthy adult cats in a randomized, blinded, placebo-controlled experiment. After a three-week wash-in, treatment lasted 12 weeks. The active group received 900 mg a day of a blend containing water extracts of turkey tail, red reishi and lion’s mane, plus bovine colostrum. 1

That last detail is central. The trial tested the blend, not reishi alone or Hollywood Elixir. Its amount cannot be copied onto a bottle of a different mushroom powder or divided into an assumed effective reishi dose.

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

What changed—and what was not demonstrated

The study reported some changes in gut microbial or metabolic measures and lower serum triglycerides with the blend. Fecal quality measures did not improve, and the authors reported no observed adverse health effects in that study setting. 1

Those findings add useful feline data. They do not demonstrate fewer infections, longer life or relief of anxiety. A laboratory measure can help researchers understand what a formula does without yet establishing the daily-life benefit an owner hopes to see.

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

Why the dog study remains a separate result

A different experiment in 40 adult beagles tested a reishi preparation specified as at least 70% beta-glucans over 28 days. At the highest amount, one post-vaccination antibody-response measure increased more than in controls. 2

That is not the same preparation or endpoint as the feline blend trial. Our reishi guide for dogs explains it in its canine context. Keeping the studies separate prevents a positive result in one species from silently becoming proof of a different claim in another.

The new feline study tested three mushroom extracts plus colostrum; it did not test reishi alone.

Where reishi fits in Hollywood Elixir

Hollywood Elixir contains 25 mg reishi powder extract per standard 2.5 g sachet, standardized to 35% total polysaccharides. It also contains a separate 50 mg yeast beta-glucan ingredient. 5

We include these alongside NR, CoQ10 and reduced glutathione in a formula designed around healthy aging. Reishi contributes to the immune-related part of that design; it is not being used as another name for an NAD+ precursor. The Hollywood Elixir label shows the complete combination and current cat directions. 12

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

Why bring immune and energy ingredients together?

Immune-cell behaviour and metabolism are connected research questions. Beta-glucan experiments in canine cells have examined changes in both responses and metabolic activity. 3 Separately, NAD-related reactions and CoQ help transfer energy from nutrients, while glutathione-dependent enzymes handle reactive molecules. 6 7

That gives a broader formula a coherent biological purpose: ingredients associated with different cellular jobs, rather than several copies of the same claim. It does not show that reishi raises a cat’s NAD level or that the finished combination reproduces a laboratory effect. For the energy side, see NAD+ for cats. 8

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

A powder can already be an extract

“Powder” describes a physical form. An extract can be dried into a powder and placed in a capsule or mixed into a sachet. Whole mushroom powder and powdered extract are therefore not interchangeable descriptions.

Check how the manufacturer identifies the preparation before comparing quantities. A smaller amount of an extract is not automatically weaker, and a larger amount is not automatically preferable. Without preparation details, the milligram number alone leaves too much of the comparison unresolved.

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

Total polysaccharides are not all beta-glucans

Beta-glucans are one class of polysaccharide. A declaration of total polysaccharides does not establish that every milligram in that total is beta-glucan. 2

Hollywood Elixir’s reishi specification is 35% total polysaccharides. Its yeast beta-glucans are declared separately. 5 The formula includes two distinct sources: a mushroom extract and a specified yeast ingredient. Read them as separate entries when comparing it with a product that declares reishi beta-glucans alone. 12

Ask what was used, then what was measured

For a stand-alone mushroom product, useful questions include the species, the part used, the extraction process and the assay behind any stated percentage. “Fruiting body” and “mycelium” identify different source material; neither phrase replaces the rest of the specification.

If a detail is absent, ask the manufacturer rather than filling it in from another brand’s page. Our ingredient guide identifies the preparation we disclose. It should not be read as confirmation of additional extraction or assay details that are not stated there.

Powder describes a format. It does not tell you whether a mushroom ingredient has been extracted.

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 →
Woman holding a Hollywood Elixir box toward a brown cat perched on the back of a sofa

How much can a cat have?

Use the current directions for the exact cat product, with individual veterinary advice when appropriate. The 900 mg amount in the feline study was the whole experimental blend, including other mushrooms and colostrum. 1

It is not a universal reishi serving. Nor is a quantity reported by another owner enough to choose an extract for your cat. When comparing products, keep the amount, preparation and complete ingredient list together. Increasing a mixed formula to chase one ingredient increases the other ingredients too.

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

Do you need to brew it in hot water?

Do not assume a manufactured extract needs to be prepared like mushroom tea. Follow the instructions for the actual product. Adding an extra heating step because another preparation used hot-water extraction confuses how the ingredient was manufactured with how the finished supplement should be served.

Hollywood Elixir uses a declared reishi powder extract in a food-mixed formula. 5 If the directions for a product are unclear, ask the manufacturer before changing the preparation. The aim is a repeatable serving the cat accepts, not a kitchen extraction experiment. 12

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

Watch the cat, not only the label

Monitor appetite, stool and any new signs after adding a formula. Stop the addition and contact your veterinarian if a concerning change appears. Keep the label, serving and timing available so the whole product can be reviewed.

The healthy-cat study provides a limited observation period, not a guarantee for a cat with a different health history. And if the supplemented food is refused, offer the usual food without it. Appetite loss deserves attention in its own right. 11

What about liver warnings and long-term use?

Human reishi references discuss safety concerns and potential interactions, including with anticoagulant or immune-suppressing medicines. 4 Those warnings are a reason to review a cat’s medical plan; they do not establish a universal feline rule that reishi becomes harmful after a particular number of days.

Bring the complete formula to that discussion. Avoid both extremes: assuming a natural ingredient cannot cause problems, or converting a human report about one preparation into a precise safety threshold for every cat product.

Cancer or FIV changes the question

The recent feline blend study enrolled healthy cats. It does not establish a treatment for cancer, FIV or another diagnosed disease. 1

If you are considering reishi because of such a diagnosis, discuss the reason with the treating veterinarian. Ask how the addition fits the current plan, what outcome is being sought and whether its ingredients complicate treatment. “Immune support” is too broad a phrase to resolve those questions on its own.

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

An unknown mushroom is a different situation

A cat eating an unidentified mushroom needs prompt veterinary or poison-control advice. Wild mushrooms can be difficult to identify, and some exposures are dangerous. 9

Do not use a reishi supplement article to decide that an unknown mushroom is safe, and do not use wild-mushroom poisoning reports as though they measured the effects of a labelled reishi extract. They are different questions with different evidence and different next steps.

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

What would a useful daily routine look like?

It should fit feeding comfortably and have a purpose you can explain. If you are interested in a healthy-aging formula, record the routines that concern you and discuss new changes with the clinic. Do not interpret every quiet afternoon as a calming effect or every healthy week as proof of stronger immunity.

Keep the main food and amount eaten in view: cats still need an adequate diet, whatever optional formula accompanies it. 10 Record new changes in appetite or behaviour separately instead of assuming they are effects of the mushroom.

Choose reishi with the rest of the formula in view

For a stand-alone recommendation, match the exact preparation and instructions. For a broader daily healthy-aging routine, look at the combination: which ingredient is present, why it is there and what else the cat will receive.

Hollywood Elixir places reishi alongside separate yeast beta-glucans, NR, CoQ10 and reduced glutathione. Its case is a measured formulation connecting immune-related, energy and antioxidant ingredients. That is more specific—and more useful—than asking one mushroom to promise a calmer, longer or illness-free life.

Hollywood Elixir declares reishi total polysaccharides and separate yeast beta-glucans; they are not the same measurement.

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

Reishi: A mushroom also called lingzhi, commonly identified as Ganoderma lucidum in supplement discussions.

Polysaccharides: A broad group of carbohydrates made from linked sugar units.

Beta-glucans: A class of polysaccharides; the term is more specific than total polysaccharides.

Extract: A preparation made by drawing selected constituents from a source material.

Mycelium: The fungal network, distinct from the mushroom fruiting body.

Biomarker: A measured biological feature; a change does not automatically establish a clinical benefit.

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. Milan G. Broughton, Patrícia M. Oba, Julio C. Mioto, Laura L. Bauer, Samantha A. Koziol, Chinmayee Panda, Shirin Pourafshar, Ryan N. Dilger, Brett R. Loman, Kelly S. Swanson. Effects of a Mushroom-Based β-Glucan Blend on the Gastrointestinal Health and Immune Function of Healthy Adult Cats. 2026· DOI 10.1093/jas/skag259Species/context: CatsEvidence boundary: Twenty healthy cats received a mushroom-and-colostrum mixture or placebo. The modest changes in gut measurements did not include altered stool characteristics.↩ 1 · ↩ 2 · ↩ 3 · ↩ 4
  2. Emanuela Kayser, Paola L. Castaneda, Katiria Soto-Diaz, Andrew J. Steelman, Alayna Murphy, Maria Spindola, Fei He, Maria R. C. de Godoy. Functional properties of Ganoderma lucidum supplementation in canine nutrition. 2024Species/context: DogsEvidence boundary: Forty adult beagles were assigned to a control group or a defined Ganoderma preparation for 28 days. The vaccine-antibody result does not establish prevention or treatment of disease; the ingredient supplier funded the study.↩ 1 · ↩ 2 · ↩ 3
  3. Simon Paris, Ludivine Chapat, Marion Pasin, Manon Lambiel, Thomas E. Sharrock, Rishabh Shukla, Cecile Sigoillot-Claude, Jeanne-Marie Bonnet, Hervé Poulet, Ludovic Freyburger, Karelle De Luca. β-Glucan-Induced Trained Immunity in Dogs. 2020Species/context: Cultured canine blood cellsEvidence boundary: This laboratory study explains beta-glucan-induced changes in canine immune cells. Its main preparation came from Euglena, and it did not test feeding reishi.↩ 1 · ↩ 2
  4. Memorial Sloan Kettering Cancer Center. Reishi Mushroom. 2026Species/context: Human herbal guidanceEvidence boundary: Reference on reishi constituents and potential human medicine interactions. It does not establish feline interaction rates or a universal cat serving.↩ 1 · ↩ 2
  5. La Petite Labs. Hollywood Elixir: current supplement facts. 2026Species/context: Manufacturer ingredient label for dogs and catsEvidence boundary: Current Hollywood Elixir ingredient quantities per standard 2.5 g sachet, including niacin, NR, CoQ10, glutathione, reishi and yeast beta-glucans.↩ 1 · ↩ 2 · ↩ 3
  6. Reactome. Complex I oxidises NADH to NAD+, reduces CoQ to CoQH2. ReactomeStudy design/context: Curated human respiratory-chain reactionSpecies/context: human biochemical pathwayEvidence boundary: This curated reaction explains a normal role of CoQ10 in cellular energy metabolism. It is not a supplementation trial.↩
  7. Reactome. Detoxification of Reactive Oxygen Species. Accessed 2026Species/context: Conserved cellular pathways; human curated recordEvidence boundary: Glutathione peroxidases help convert hydrogen peroxide to water. This describes normal antioxidant chemistry rather than the effects of an oral supplement.↩
  8. Rachel S. Fletcher, Joanna Ratajczak, Craig L. Doig, Lucy A. Oakey, Rebecca Callingham, Gabriella Da Silva Xavier, Antje Garten, Yasir S. Elhassan, Philip Redpath, Marie E. Migaud, Andrew Philp, Charles Brenner, Carles Canto, Gareth G. Lavery. 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 pathway study using mouse muscle cells and genetic modelsSpecies/context: mouse, mouse cellsEvidence boundary: The experiments explain NAD precursor metabolism in mouse cells and models. They do not establish a supplement benefit in dogs or cats.↩
  9. ASPCA Poison Control. The Fungus Among Us: Mushroom Toxicosis. 2026Species/context: Companion animalsEvidence boundary: Wild mushroom ingestion requires a different assessment from using a labelled supplement, because some species are toxic and identification can be difficult.↩
  10. Cornell Feline Health Center. Feeding Your Cat. Accessed 2026Species/context: CatsEvidence boundary: Cornell explains the nutritional requirements of cats and the role of complete and balanced food. A targeted supplement does not replace that dietary base.↩
  11. Cornell Feline Health Center. Anorexia. n.d.Species/context: Feline clinical guidanceEvidence boundary: Food refusal can become serious promptly and calls for veterinary assessment of its cause.↩
  12. La Petite Labs. Hollywood Elixir: ingredient forms. Evidence boundary: The detailed ingredient guide identifies reishi powder extract standardized to 35% total polysaccharides, separate yeast beta-glucans and reduced glutathione. It describes ingredient identity and formulation.↩ 1 · ↩ 2 · ↩ 3

FAQ

What is reishi?

Reishi, also called lingzhi, is a mushroom used in several supplement preparations. Its compounds include polysaccharides and triterpenes. The exact source material and preparation matter when comparing a powder, extract or mixed formula.

Has reishi been studied in cats?

A 2026 controlled study tested a blend including reishi, two other mushrooms and colostrum. It adds feline data, but does not isolate reishi or establish benefits for anxiety, infections or lifespan.

Is mushroom powder different from an extract?

Powder describes the format. An extract can be dried into a powder, so a powdered extract and whole mushroom powder may be different preparations. Read how the manufacturer identifies the ingredient rather than comparing milligrams alone.

Does 35% polysaccharides mean 35% beta-glucans?

No. Beta-glucans are one class within the wider polysaccharide group. Hollywood Elixir declares a reishi extract standardized to 35% total polysaccharides and a separate yeast beta-glucan ingredient. Read these as distinct entries when comparing mushroom products.

How much reishi is in Hollywood Elixir?

The formula declares 25 mg reishi powder extract per standard 2.5 g sachet, alongside separate yeast beta-glucans and other ingredients. Follow current cat directions. The amount in a different research blend does not establish a serving for this formula.

Must I prepare a reishi extract with hot water?

Follow the finished product’s directions. Manufacturing an extract is different from serving it; do not add a brewing or heating step because another product mentions hot-water extraction. Ask the manufacturer if the instructions are unclear.

Can cats taking medicines use reishi?

Have the full formula reviewed by the treating veterinarian. Human references flag potential interactions, including with immune-suppressing or clotting-related medicines, but do not supply universal feline rules. The cat’s condition, preparation and treatment plan need to be considered together.

What if my cat will not eat the supplemented food?

Offer the familiar food without the optional addition. Appetite loss deserves veterinary attention in its own right. Keep the label, amount and timing available if new signs appear; do not assume they are a normal adjustment or proof that the mushroom is working.

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.

Start with the underlying science:

Keep exploring

What would you like to understand next?

Search practical guides about healthy aging, cellular energy, ingredients, and daily support for cats.