LOY-003 for Dogs

Loyal's daily pill for big dogs: what it does, which dogs it's for, and where FDA review stands.

By La Petite Labs Editorial 8 min read

As Seen On

Woman hugging a golden retriever while holding a Hollywood Elixir box
Contents

LOY-003 isn't available yet, and Loyal hasn't announced a price or release date. It's a once-daily pill being developed by the veterinary biotech company Loyal to help large and giant dogs live longer, healthier lives by lowering two growth hormones, GH and IGF-1. On September 16, 2026, Loyal announced that the FDA had accepted the drug's reasonable expectation of effectiveness (RXE) section, one of three main sections needed for conditional approval. Safety and manufacturing are still to come.

Here's who LOY-003 is for, how it differs from Loyal's injection, and what has to happen before your vet could prescribe it.

La Petite Labs publishes this guide and makes Hollywood Elixir, a dog supplement. We're not affiliated with Loyal.

Is LOY-003 available? Where can I buy it?

No, you can't buy LOY-003 yet, from Loyal, a vet or any online store. It isn't approved, so it can't be legally sold, and there are no authorized sellers.1 When it does launch, it will be a prescription drug, available through veterinarians.

LOY-003 for Dogs at a glance

What it is
A daily prescription pill for large dogs, in development
Who it's for
Dogs 5+ years and at least 60 lb, per Loyal's overview (its FAQ says 7+ and 40 lb)
How it works
Lowers growth hormone (GH) and IGF-1
FDA progress
Effectiveness (RXE) accepted, announced Sept 2026 · Safety and manufacturing to come
Release date
Not announced; a February 2025 Loyal guide targeted 2027
Price
Not announced
Where it came from
Licensed in 2023 from Crinetics Pharmaceuticals, which developed it for a human growth-hormone disorder

Loyal’s three dog longevity drugs, compared

LOY-003LOY-001LOY-002
ForLarge dogs, 5+ years, 60 lb+Large dogs, 7+ years, 40 lb+Senior dogs, 10+ years, 14–179 lb
FormatDaily pillInjection every 3–6 monthsDaily pill
TargetGrowth hormone and IGF-1IGF-1Insulin and metabolism
FDA progressRXE accepted (2026)RXE accepted (2023)RXE + safety accepted; manufacturing next

Competitor label and pricing facts checked November 6, 2026. Sources are listed in the References section below.

Woman holding a Hollywood Elixir box beside a pug, a terrier and a food bowl

How much will LOY-003 cost?

Loyal hasn't announced a price. The one thing it has said is that a daily pill is cheaper to make and distribute than an injection, which it expects to mean lower costs for owners than for LOY-001.3 The "around $100 a month" figure you may have seen in the news was reported for LOY-002, a different drug, not LOY-003.12

As a prescription medicine, LOY-003 would also mean an initial vet visit and whatever check-ups your vet recommends.

Woman in sportswear holding a Hollywood Elixir box beside a black-and-tan dog outdoors

When will LOY-003 be released?

There's no confirmed release date. When Loyal licensed the drug in 2023, it aimed to launch it "as soon as 2026".3 Its February 2025 guide for vets moved that to conditional approval in 2027.4 Treat 2027 as an old target. LOY-003 still needs its safety and manufacturing sections accepted, and Loyal's senior-dog pill, LOY-002, has already slipped from its own early dates.

Our read of the public record: LOY-003 is unlikely to reach clinics before LOY-002, which has two of its three sections accepted and expects its last review in 2027.9

Woman holding a Hollywood Elixir box above her forehead beside a Bernese mountain dog outdoors

What is LOY-003?

LOY-003 is a flavored daily pill that Loyal is developing to extend healthy lifespan in large and giant dogs.4 It's the third of Loyal's three drugs, after LOY-001 and LOY-002.7

The compound came from Crinetics Pharmaceuticals, a human drug company. In August 2023, Crinetics gave Loyal an exclusive worldwide veterinary license to it.3 Crinetics had developed it for acromegaly, a human condition in which the pituitary gland makes too much growth hormone. Loyal keeps the full chemical identity confidential while the drug is in development,1 but its scientists have described the drug class: LOY-003 is an oral, non-peptide drug that activates the somatostatin 2 (SST2) receptor, which turns down the growth-hormone system.14

Golden retriever nuzzling a woman holding a Hollywood Elixir box on the grass beside a food bowl

Which dogs is LOY-003 for?

That depends on which part of Loyal's site you read. Its overview of the two large-dog drugs says LOY-003 is for dogs 5 and older weighing at least 60 lb, and its newer guide for vets agrees.15 But the FAQ further down the same page groups LOY-003 with LOY-001, at 7 and older and at least 40 lb.1 If yours is too small or too young, here's what to do.

Loyal says its drugs will be labeled for the kinds of dogs studied in their efficacy trials, so the final label will settle it.1 It's meant only for adult dogs that have finished growing, not puppies.4

LOY-003 isn't available yet, and Loyal hasn't announced a price or release date.

Why do large dogs die younger?

Big dogs have much shorter lives than small ones. Loyal puts a Great Dane's average life expectancy at 6 to 8 years, against up to 20 for a Chihuahua.2

Loyal's explanation is hormonal. Large dogs can have anywhere from about 2 to 30 times as much IGF-1 as medium and small dogs, and higher levels are linked both to bigger adult size and to shorter lifespans.26 Loyal believes these hormones stay high in adulthood and speed up aging.1 See your own breed's numbers in our dog lifespan by breed guide, for example the Great Dane.

Overhead view of a black-and-white dog beside a food bowl and Hollywood Elixir box

How does LOY-003 work?

LOY-003 lowers two linked hormones. Growth hormone (GH) is released by the pituitary gland and prompts the liver to make IGF-1 (insulin-like growth factor 1), which carries the growth signal to tissues.13

The idea comes from decades of aging research. Lowering GH and IGF-1 signaling has extended lifespan in lab animals, starting with roundworms in 1993.2 Genetics points the same way in dogs: a 2007 study in Science found one version of the IGF1 gene common to all small breeds and nearly absent from giant ones.8 LOY-003 targets the same pathway as LOY-001, but as a pill rather than an injection.2

It does that by activating SST2, the receptor that somatostatin, the body's own brake on growth hormone, works through. Human drugs that act on SST2, such as octreotide, are peptides that are usually given by injection. LOY-003 is designed to work when swallowed.14

Woman smiling beside a golden retriever, a green food bowl and a Hollywood Elixir box

Will LOY-003 make my dog smaller?

No. LOY-003 is meant only for dogs that are skeletally mature, meaning fully grown, so it isn't expected to change adult size.4 The aim isn't growth at all. It's to lower the hormone levels that stay high in big dogs after they've finished growing.

Man holding a Hollywood Elixir box while sitting on an outdoor sofa with a golden retriever

What evidence is there for LOY-003 so far?

Two things are public. First, the FDA has accepted the RXE section, meaning it agrees LOY-003 can reasonably be expected to work as intended, based on data Loyal submitted but hasn't published.2

Second, Loyal and Crinetics scientists presented a short study in July 2025. Forty laboratory Beagles were given LOY-003 by mouth every day at several dose levels. IGF-1 fell by about 40 to 46% within eight days and stayed down through day 22, and fasting blood sugar and insulin also dropped after the first dose.14 It was published as a conference abstract, not a full paper.

So the drug does what it's designed to do to the hormones, in lab Beagles over a few weeks. Whether that adds healthy years to large pet dogs is still untested.

How many years could LOY-003 add?

Nobody knows yet. The only published dog data measured hormones over a few weeks, not lifespan, and Loyal hasn't given a number. RXE is a preliminary standard: it isn't evidence of a specific gain in years. For LOY-001, Loyal plans a large, long-term efficacy trial, similar to STAY, to support full approval.4 It hasn't announced a trial of that kind for LOY-003 in the sources we checked.

LOY-003 lowers the growth hormones that stay high in big dogs after they've finished growing.

Spotted gray dog beside a Hollywood Elixir box held in a person's hand

Is LOY-003 safe?

The safety data isn't public yet. Loyal says safety data is still being gathered for LOY-003.4 Full safety data will go to the FDA as part of its application for conditional approval, and Loyal plans to share it closer to launch.1 The 2025 Beagle abstract reported hormone, blood sugar and insulin changes but no side-effect data.14 Until the safety data is out, side effects and drug interactions aren't known publicly. They'll appear on the final label, and your vet will weigh them against your dog's health.

Golden retriever nuzzling a man holding a Hollywood Elixir box beside a food bowl

LOY-003 milestones so far

  • August 2023: Loyal licenses the compound from Crinetics and names it LOY-003, aiming for "as soon as 2026".3
  • February 2025: Loyal's guide for vets targets conditional approval in 2027.4
  • July 2025: Loyal and Crinetics scientists present a 40-Beagle study: daily LOY-003 cut IGF-1 by about 40 to 46%.14
  • September 16, 2026: Loyal announces that the FDA has accepted LOY-003's reasonable expectation of effectiveness section, Loyal's third RXE.2
  • Next: the target animal safety and manufacturing sections, then a possible conditional approval.
Golden spaniel eating from a green bowl beside a Hollywood Elixir box

LOY-003 vs LOY-001 vs LOY-002

More on LOY-001 · More on LOY-002 · All dog longevity drugs

Pill or injection: LOY-003 or LOY-001?

Loyal is developing both so owners and vets have a choice. In Loyal's words, a long-acting injection offers convenience and better compliance, while some owners may prefer a daily pill.1 The injection would be given by your vet every three to six months.4 The pill would be given at home every day, and Loyal expects it to cost less to produce.3 Neither is approved, so there's nothing to choose between yet.

How FDA approval works for LOY-003

LOY-003 is going through the FDA Center for Veterinary Medicine's expanded conditional approval pathway. Three main sections have to be accepted: reasonable expectation of effectiveness (done), target animal safety and manufacturing.1

With all three in place, the FDA can grant conditional approval. The drug could then be sold, with a label saying it is "conditionally approved by FDA pending a full demonstration of effectiveness." Conditional approval lasts one year and can be renewed each year, for up to five years in total, while the company gathers the stronger evidence needed for full approval.10

Woman holding a Hollywood Elixir box beside a dapple dachshund and green food bowl on a sofa

What you can do for a large dog now

You don't have to wait for a drug to help a big dog age well:

  • Keep them lean. In a lifelong study of 48 Labradors, dogs fed 25% less than their littermates lived a median of 1.8 years longer.11 For a large dog, staying lean also takes load off the joints. Ask your vet for a target weight before cutting food.
  • Protect their joints. Watch for stiffness or slowing on stairs, and raise it with your vet early.
  • Book regular check-ups, especially as your dog reaches the age when its breed's health problems tend to start.
  • Keep them moving, with exercise matched to their age and build.

Our dog age calculator shows when a large dog counts as senior.

Woman cuddling a brown-and-white spaniel while holding a Hollywood Elixir box

What to ask your vet about LOY-003

  • Would my dog be a likely candidate, given their age, weight and health?
  • Which baseline records are worth keeping now, such as weight, body condition and routine bloodwork?
  • How would LOY-003 compare with LOY-001 for my dog, if both are approved?
  • What can we do today for healthy aging in a large breed?

Where daily nutrition fits

We make Hollywood Elixir, a daily nutrition powder for adult and senior dogs. It's built around nicotinamide riboside, an NAD+ precursor, with CoQ10, glutathione and 14 more actives, and every active amount is printed on the label. It's a supplement, not a drug. It doesn't target growth hormone or IGF-1, isn't designed to do what LOY-003 is being developed for, and hasn't been tested for lifespan. Its case is practical: one scoop in the food bowl instead of a cupboard of separate supplements, with the serving set by your dog's weight, which matters for a big dog. If that suits your dog, discuss it with your vet. See the full formula and serving guide.

For a large dog, staying lean is the best-supported way to add healthy time today.

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

Growth hormone (GH): a hormone made by the pituitary gland that drives growth and prompts the liver to make IGF-1.

IGF-1: insulin-like growth factor 1, which carries growth signals to tissues; large dogs tend to have more of it.

Acromegaly: a human condition in which the pituitary makes too much growth hormone.

Skeletally mature: fully grown, with growth plates closed.

SST2: somatostatin receptor 2; drugs that activate it turn down growth-hormone release.

RXE: reasonable expectation of effectiveness, the FDA's preliminary effectiveness standard.

Conditional approval: FDA permission to sell an animal drug for up to five years while full effectiveness evidence is collected.

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

Sources and further detail

  1. Loyal, *For veterinarians* (program status, eligibility, pathway and FAQ; checked November 2026)
  2. Loyal (16 Sept 2026), Longer lives for bigger dogs? Loyal earns third RXE acceptance from the FDA
  3. Loyal (11 Aug 2023), Announcing our partnership with Crinetics Pharmaceuticals
  4. Loyal (Feb 2025), Product brief for veterinarians (v6)
  5. Loyal, Product brief for veterinarians (v7)
  6. Greer KA, Hughes LM, Masternak MM. *Age* (2011). Connecting serum IGF-1, body size, and age in the domestic dog
  7. Loyal, *Products in development*
  8. Sutter NB, Bustamante CD, Chase K et al. *Science* (2007). A single IGF1 allele is a major determinant of small size in dogs
  9. dvm360 (13 Jan 2026), Lifespan extension drug in development for senior dogs reaches a new milestone
  10. FDA, *Conditional approval explained: a resource for veterinarians*
  11. Kealy RD, Lawler DF, Ballam JM et al. *JAVMA* (2002). Effects of diet restriction on life span and age-related changes in dogs
  12. Entrepreneur, This $100-a-month pill can extend the life of your dog
  13. Michigan State University Veterinary Diagnostic Laboratory, *Growth hormone and IGF-1 in dogs*
  14. Tovar AP, McMahon JE, Graves JL et al. *Journal of the Endocrine Society* (2025), ENDO 2025 abstract MON-620. Sub-chronic dosing of a non-peptide somatostatin 2 receptor agonist reduces IGF-1 and acutely impacts glucose and insulin homeostasis in dogs

FAQ

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

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