LOY-001: IGF-1-lowering long-acting injection for large and giant breed dogs (Loyal)
LOY-001 is Loyal's long-acting injectable intended to extend healthy lifespan in large and giant breed dogs aged 7 years or older weighing at least 40 lb by lowering IGF-1, given every three to six months. The FDA accepted its reasonable-expectation-of-effectiveness technical section in 2023. No trial design or results have been published.
Record
| Design | company regulatory program |
|---|---|
| Status | ongoing |
| Intervention | LOY-001, a prescription long-acting injection that reduces IGF-1 levels |
| Intervention class | drug |
| Dose regimen | injection administered by a veterinarian every three to six months |
| Breed | large and giant breeds |
| Age | 7 years and older, weighing at least 40 lb |
| Primary outcome | healthy lifespan extension |
| Lead organisation | Loyal (San Francisco) |
| Sponsor or funder | Loyal |
| Tags | lifespan, drug, igf-1, large-breeds, fda-conditional-approval, loyal |
Notes: Company- and press-sourced only; trial size, design and results undisclosed as of 2026-10-01.
Sources and verbatim quotes
Loyal: for dog owners (company page) (2026), snapshot loyal-for-dog-owners (company)
LOY-001 is a prescription long-acting injection, while LOY-003 is a prescription daily pill.
LOY-001 is intended for dogs 7 years and older, weighing at least 40 lb, whereas LOY-003 is developed for dogs 5 years and older, weighing at least 60 lb.
Both drugs target the over-expression of IGF-1, a growth hormone that we believe is associated with large dogs’ shorter lifespan relative to small dogs.
LOY-001 received a Reasonable Expectation for Effectiveness (RXE) technical section complete letter in 2023
Loyal drug LOY-001 to extend lifespan of giant dog breeds (Gizmodo) (2023), snapshot gizmodo-loy-001 (press)
LOY-001 reduces the levels of IGF-1 in large and giant dog breeds, extending healthy life spans.
The drug is an injectable that would be administered by a vet every three to six months.
Reproduce: canine_trial_search(trial_id="loyal-loy-001-large-dogs") in dog-geroscience-mcp; dataset canine-trial-registry.