Volume IV: Equine Skin, Wounds and Topical Applications

Volume IV: Equine Skin, Wounds and Topical Applications

Volume IV: Equine Skin, Wounds and Topical Applications

Purpose

This volume covers research most directly connected to topical cannabinoid products in horses.

Equine studies have investigated:

  • Cannabinoid receptors in normal horse skin
  • Topical CBD on experimental distal-limb wounds
  • Topical THC-rich and CBD-rich oils in one clinical case

This area is directly relevant to topical products, but the evidence remains limited.

Study 1: Cannabinoid Receptors in Equine Skin

The Cannabinoid Receptors System in Horses: Tissue Distribution and Cellular Identification in Skin

Published: 2022
Type: Equine tissue study
PubMed:
https://pubmed.ncbi.nlm.nih.gov/35801813/

What researchers examined

Researchers examined healthy equine skin for the presence and location of cannabinoid receptors.

What researchers found

CB1 and CB2 receptor expression was identified in multiple components of equine skin, including epidermal and dermal cells. The findings support the existence of a functioning cutaneous endocannabinoid system in horses.

Why this matters

Skin cannabinoid receptors could theoretically participate in:

  • Skin homeostasis
  • Inflammatory signaling
  • Sensation and itching
  • Hair-follicle activity
  • Immune responses
  • Wound repair

What this does not establish

The study did not test a cream or balm. Receptor identification alone does not prove that a topical cannabinoid product is effective.

Responsible conclusion

Healthy equine skin contains cannabinoid receptors, giving researchers a biological reason to investigate topical cannabinoids for skin conditions and localized discomfort.

Study 2: Topical CBD on Equine Distal-Limb Wounds

Effects of Topical Treatment of Cannabidiol Extract in a Manuka Honey Carrier on Second-Intention Wound Healing in Horses

Published: 2020
Journal: Australian Veterinary Journal
Animals: Six Standardbred horses
PubMed:
https://pubmed.ncbi.nlm.nih.gov/32096215/

Study design

Researchers created standardized full-thickness distal-limb wounds under controlled research conditions.

Treatments included:

  • One-percent CBD compounded in manuka honey
  • Manuka-honey controls
  • Saline control

Treatments were applied daily for 42 days.

What researchers found

The study did not find a significant difference in measured wound-healing outcomes between the topical CBD treatment and the comparison groups.

Why this result matters

A negative or inconclusive result is still valuable.

It demonstrates that:

  • A topical CBD product does not automatically improve healing
  • Product formulation matters
  • Study design matters
  • Systemic absorption or cross-treatment effects may complicate results
  • Marketing claims can be stronger than the actual evidence

Responsible conclusion

In a small controlled equine wound study, topical one-percent CBD did not produce a measurable advantage in wound healing. Further formulation-specific research is needed.

Study 3: Topical Cannabis in an Equine Palliative-Care Case

Oral and Topical Chronic Administration of THC-Rich and CBD-Rich Cannabis Oils in a Horse

Published: 2026
Type: Single equine case report
PubMed:
https://pubmed.ncbi.nlm.nih.gov/42311392/

What was used

A rescued senior horse received THC-rich and CBD-rich full-spectrum oils:

  • Orally
  • Topically on a chronic wound
  • As one part of a wider palliative-care program

Treatment continued for approximately 10 months.

What was reported

The authors associated the multimodal treatment period with improvements in appetite, body condition, pain and mobility. The horse also received other veterinary care, so the independent contribution of the cannabinoids could not be determined.

Why this matters

This case is directly relevant because it involved:

  • A living horse
  • Topical cannabinoids
  • THC-rich and CBD-rich products
  • A chronic wound
  • Chronic pain
  • Long-term administration

Major limitation

One case cannot establish effectiveness or general safety. It does not prove that the same treatment would benefit another horse.

Responsible conclusion

One equine case report has documented long-term oral and topical cannabis use during palliative care. The observations justify controlled studies but do not establish a standard treatment.

Can a Topical Reach a Joint?

That question remains unanswered in horses.

A standard balm may interact with receptors in:

  • The epidermis
  • Dermal tissue
  • Hair follicles
  • Superficial nerves
  • Nearby soft tissue

However, evidence is still needed to establish whether an equine topical formulation can penetrate deeply enough to reach:

  • Tendons
  • Ligaments
  • Joint capsules
  • Synovial tissue
  • Articular structures

A topical cream and a specially engineered transdermal product should not be treated as equivalent.

Current Status of Equine Topical Research

Demonstrated

  • Equine skin contains CB1 and CB2 receptors.
  • Topical CBD has been formally tested in an equine wound model.
  • One equine case report involved topical THC-rich and CBD-rich oil.

Not demonstrated

  • Reliable relief of equine arthritis from topical THC
  • Deep-joint penetration
  • Standard topical dosing
  • Long-term skin safety
  • Safety if the horse licks or ingests the product
  • Effectiveness for tendon or ligament injuries
  • Effectiveness for rain rot, sweet itch or dermatitis
  • Consistent wound-healing benefits

Evidence-based statement

Equine skin contains cannabinoid receptors, but clinical research on topical cannabis products remains limited. One controlled wound study did not demonstrate improved healing, while one complex palliative-care case reported encouraging observations that require controlled confirmation.