Dog Shedding: Causes, Duration, and Grooming Tips

What is the shedding season for dogs?

Shedding is the physiological process by which dogs systematically shed their old coat and grow a new one. For most dog breeds, this occurs twice a year—in the spring (when the winter coat is replaced by a lighter summer coat) and in the fall (when the summer coat is replaced by a thick winter coat). This process is primarily triggered by the length of daylight (photoperiod)—not by temperature.

The amount of shedding varies greatly depending on the breed: double-coated breeds (Husky, Samoyed, Bernese Mountain Dog, Labrador) shed heavily; short-haired single-coated breeds (Boxer, Doberman) shed very little. Dogs kept indoors under artificial lighting often shed moderately year-round rather than heavily during certain seasons.

Background + Scientific Context

Miller et al. (2013, Muller and Kirk's Small Animal Dermatology, Elsevier) described the phases of hair growth in dogs: The hair cycle in dogs consists of the anagen (growth), catagen (transitional), and telogen (resting) phases. Unlike humans—whose hair is in all phases simultaneously in a mosaic pattern—dogs exhibit synchronized cycles across large areas of their coat. This explains the periodic mass shedding. Signaling occurs via prolactin, melatonin, and thyroid hormones.

Credille and Slater (2001, Journal of Veterinary Internal Medicine, PubMed 11394408) investigated the effect of thyroid hormones on canine hair: Hypothyroidism leads to slowed hair growth, a brittle coat, symmetrical alopecia, and a prolonged telogen phase—recognizable by a dull, brittle coat that sheds easily without normal regrowth. Excessive hair loss outside of the normal shedding cycle therefore requires thyroid screening.

Watson (1998, Journal of Nutrition, PubMed 9772148) described links between nutrition and skin/coat quality: fatty acid deficiencies (particularly omega-3 and omega-6) lead to a dull, brittle coat and increased dandruff. Zinc deficiency impairs keratinization. A balanced diet that meets fatty acid requirements is the foundation of good coat quality—not biotin supplements without a diagnosis.

Vitomalia-Position

Shedding is a natural biological process—it cannot be cured, but it can be managed. Daily brushing during the shedding season is not a luxury, but rather basic pet care: Dead hair that remains trapped on the skin impedes airflow to the skin, promotes fungal infections, and causes discomfort. If you notice excessive hair loss outside of the shedding season, you should rule out any underlying medical causes.

When does a dog's seasonal shedding become an issue?

• Twice a year for double-coated breeds: Step up grooming
• If hair loss persists throughout the year: Check for thyroid issues, Cushing's syndrome, and dietary factors
• In cases of alopecia (patchy hair loss): unlike normal shedding — consult a veterinarian
• Regarding biotin supplementation: it is only advisable in cases of confirmed deficiency
• Regarding fatty acid supplementation: Omega-3/6 has been shown to improve coat quality

Practical application

Grooming routine during the shedding season:

Resources: - Undercoat brush (Furminator, Dematting Comb): for double-coated breeds - Rubber brush: for short-haired breeds with a single coat - High-pressure shower: Loosens dead hair and promotes new growth - Do not trim the hair of double-coated breeds: The undercoat protects against overheating and sunburn

Common Mistakes & Myths

• “Shearing shortens the shedding season.” Shearing the topcoat of double-coated breeds permanently alters the coat’s structure and impairs its thermoregulatory function. No cosmetic trimming for Samoyeds, Huskies, or Collies.
• “A high dose of biotin speeds up the shedding process.” Biotin improves coat quality only in cases of actual biotin deficiency—in dogs with adequate biotin levels, it has no demonstrable effect on the shedding process.
• “My dog sheds all year round—that’s a medical condition.” Moderate year-round shedding in indoor dogs is normal (due to changes in light exposure). Pathological hair loss manifests as alopecia, skin changes, or a brittle coat.

Current State of Research (2026)

Photoperiod as the primary trigger for coat shedding is well documented; melatonin as a signaling molecule is well established in veterinary dermatology. Genetic differences in the hair growth cycle among different breeds are being further investigated. There is solid evidence supporting the use of omega-3 supplementation to improve coat quality and reduce dandruff.

Frequently Asked Questions

How long does a dog's shedding season last?

For most breeds, 2–4 weeks per season. For double-coated breeds (Husky, Samoyed), this can last 4–6 weeks. Indoor dogs often shed moderately over several months rather than in a distinct seasonal surge.

What should I do if my dog is shedding heavily outside of the shedding season?

Visit to the veterinarian: Rule out thyroid issues (hypothyroidism), Cushing’s syndrome, nutritional deficiencies (fatty acids, zinc), and skin parasites as possible causes. Stress can also exacerbate hair loss (elevated cortisol). Normal off-season shedding is possible in indoor dogs, but persistent heavy hair loss warrants further investigation.

Is it a good idea to clip a dog's coat during the shedding season?

For short-haired and single-coated breeds: trimming may be an option. For double-coated breeds (Husky, Samoyed, Collie, Golden Retriever), this is strongly discouraged: Shearing damages the coat’s structure, impairs thermoregulation, and can lead to permanent changes in the coat.

Related terms

• Dog Grooming
• Biotin in Dogs
• Fatty Acids in Dogs
• The Thyroid Gland in Dogs
• Cushing's Syndrome in Dogs

Sources & Further Reading

1. Miller, W. H., Griffin, C. E., & Campbell, K. L. (2013). Muller and Kirk's Small Animal Dermatology (7th ed.). Elsevier Saunders. ISBN 9781416000082.

2. Credille, K. M., & Slater, M. R. (2001). The effects of thyroid hormones on the skin of Beagle dogs. Journal of Veterinary Internal Medicine, 15(6), 539–546. https://pubmed.ncbi.nlm.nih.gov/11394408/

3. Watson, T. D. G. (1998). Diet and skin disease in dogs and cats. Journal of Nutrition, 128(12), 2783S–2789S. https://pubmed.ncbi.nlm.nih.gov/9772148/