Glucosamine / Chondroitin Sulfate
2-amino-2-deoxy-beta-D-glucopyranose / chondroitin polysulfate
Also known as: Cosequin · Dasuquin · Restor-A-Flex · ProMotion · Seraquin · chitosamine · NSC-758 · 2-amino-2-deoxy-beta-D-glucopyranose · G6SD-glucosamine · amino monosaccharide · chondroitin 4-sulfate · chondroitin sulfate A/B/C · CSA · sodium chondroitin sulfate · chondroitin polysulfate · CDA · CSCSC · GAG · galactosaminogluconoglycan sulfate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of chronic pain | 13-15 mg/kg (of the chondroitin component) PO once daily (q24h) | PO | q24h | — | 🌎 NA |
| Adjunctive treatment of cancer pain | 15-30 mg/kg (of the chondroitin component) PO once daily (q24h) for 4-6 weeks then half the dose | PO | q24h | 4-6 weeks then half dose | 🌎 NA |
| Adjunctive treatment of chronic pain | 13-15 mg/kg (of the chondroitin component) PO once daily or every other day (q24-48h) | PO | q24-48h | — | 🌎 NA |
| Dietary Supplement (Cosequin Regular Strength) - Small Dogs <25 lbs | under 10 lb.: 1/2 to 1 capsule daily; 10-24 lb.: 2 capsules daily (1 in AM; 1 in PM). Maintenance Administration (after initial 4-6 week period): under 10 lb. can often have their dosage reduced to 1/2 capsule daily or 1 capsule every other day. 10 to 24 lb. can often have their dosage reduced to 1 capsule daily. | PO | q12h-q24h | Initial 4-6 weeks, then maintenance | 🌎 NA |
| Dietary Supplement (Cosequin DS) - Medium/Large Dogs >25 lbs | 25-49 lb.: 2 capsules daily (1 in AM; 1 in PM); 50-100 lb.: 3 capsules daily (2 in AM; 1 in PM); over 100 lb.: 4 capsules daily (2 in AM; 2 in PM). Maintenance Administration (after initial 4-6 week period): dogs can have their total daily dosage gradually lowered until maintenance level is reached. | PO | Divided daily | Initial 4-6 weeks, then maintenance | 🌎 NA |
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of cancer pain | 15-30 mg/kg (of the chondroitin component) PO once daily (q24h) for 4-6 weeks then half the dose | PO | q24h | 4-6 weeks then half dose | 🌎 NA |
| Adjunctive treatment of chronic pain | 15-20 mg/kg (of the chondroitin component) PO once daily or every other day (q24-48h) | PO | q24-48h | — | 🌎 NA |
| Dietary Supplement (Cosequin For Cats) | Initially: under 10 lb.: 1 capsule sprinkled on food daily; over 10 lb.: 2 capsules sprinkled on food daily (1 in AM/1 in PM). Maintenance Administration (after initial 4-6 week period): once desired response is obtained, capsules may be administered every other day. | PO | q24h or divided | Initial 4-6 weeks, then maintenance | 🌎 NA |
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Navicular syndrome | 16.5 grams (5 scoops) in feed twice daily | PO | q12h | — | 🌎 NA |
| Dietary Supplement (Cosequin Concentrated Powder) | Initially: for horses under 600 lb., 2 scoops in AM and 2 scoops in PM; horses 600-1,200 lb., 3 scoops in AM and 3 scoops in PM; horses over 1,200 lb., 4 scoops in AM and 4 scoops in PM. Suggested Maintenance Administration: horses under 600 lb., 1 scoop daily; horses 600-1,200 lb., 1-2 scoops daily; horses over 1,200 lb., 2 scoops daily. | PO | Divided AM/PM | Initial 2-4 weeks, then maintenance | 🌎 NA |
- Navicular syndrome: Using Cosequin Concentrated Powder
- Dietary Supplement (Cosequin Concentrated Powder): Transition Period: Do not lower amount until horse has begun to respond. Reduce total daily amount by one level scoop each week.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Glucosamine and chondroitin sulfate are widely used nutraceuticals (nutritional supplements) primarily utilized as an adjunctive treatment for osteoarthritis and other painful joint conditions in dogs, cats, and horses. They are also occasionally used to support bladder health in cats with Feline Lower Urinary Tract Disease (FLUTD) due to the presence of glycosaminoglycans in the protective lining of the urinary tract.
Clinical Pearl: Because these products are not FDA-regulated as pharmaceuticals, product quality, purity, and bioavailability can vary drastically between manufacturers. It is highly recommended to use products from reputable veterinary companies that have undergone independent quality testing and clinical trials (e.g., Cosequin®).
While clinical efficacy is sometimes debated and large-scale definitive studies are lacking, these supplements are generally considered very safe and are frequently used as part of a multimodal approach to joint health and chronic pain management.
Mechanism of action
These compounds work synergistically to support cartilage matrix synthesis and inhibit cartilage degradation:
- Glucosamine: Acts as a primary building block for cartilage. Chondrocytes utilize glucosamine to synthesize glycosaminoglycans (GAGs) and hyaluronan. It also regulates the synthesis of collagen and proteoglycans and exhibits mild anti-inflammatory properties by scavenging free radicals.
- Chondroitin Sulfate: Provides structural integrity to cartilage. It actively inhibits destructive enzymes (such as metalloproteinases) in joint fluid and cartilage. It also stimulates the production of GAGs and proteoglycans, and may reduce thrombi formation in the microvasculature of the joint.
Pathway: Exogenous Glucosamine + Chondroitin → Uptake by Chondrocytes → ↑ GAG & Hyaluronan Synthesis + ↓ Cartilage Degrading Enzymes → Improved Joint Fluid Viscosity & Cartilage Health.
Safety & warnings
Contraindications
- Known hypersensitivity to glucosamine or chondroitin
Adverse effects
- Mild gastrointestinal upset
- Flatulence
- Stool softening or mild diarrhea
- Hypersensitivity reactions (rare, as products are derived from natural sources)
Precautions
Use with caution in patients with bronchoconstrictive conditions (e.g., asthma), as glucosamine has been reported to exacerbate asthma symptoms in humans. Product quality varies widely; choose products with proven bioavailability. Products containing manganese could lead to manganese toxicity if given at very high dosages chronically.
Drug interactions
Glucosamine may induce resistance to this agent by reducing its inhibition of topoisomerase II.
Glucosamine may induce resistance to this agent by reducing its inhibition of topoisomerase II.
High doses of chondroitin/glucosamine may enhance coagulation effects and theoretically increase the International Normalized Ratio (INR).
High doses potentially could enhance the effects of heparin or other drugs that affect coagulation.
Monitoring
- Clinical efficacy (improvement in mobility, reduction in pain, or improvement in urinary signs for FLUTD)
Pharmacokinetics
Absorption
Both glucosamine HCl and glucosamine sulfate are absorbed in the gut after the salt is cleaved in the stomach. Purified, low molecular weight chondroitin appears to be absorbed from the gut. Reported bioavailability in horses is ~25% for chondroitin sulfate and ~2% for glucosamine. In dogs, bioavailability is ~5% for chondroitin sulfate and ~12% for glucosamine.
Overdose
Oral overdosage is highly unlikely to cause significant systemic problems. The LD50 for the combined compound in rats is greater than 5 g/kg.
- Clinical Signs: Massive ingestions may result in gastrointestinal effects (vomiting, diarrhea). Theoretical changes in coagulation parameters could occur but have not been documented.
- Toxicity Note: Products containing manganese could lead to manganese toxicity if given in very high dosages chronically above label recommendations.
Available products
Formulations
- Capsules
- Chewable tablets
- Powder
- Soft chews
Veterinary
- Cosequin®
- Restor-A-Flex®
- OsteO-3®
- Arthri-Nu®
- ProMotion®
- Seraquin®
- Oste-O-Guard®
- Caniflex®
- Equi-Phar Flex®
Human-labeled
- Various over-the-counter nutritional supplements (None as FDA-approved pharmaceuticals)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Check individual product labels for specific storage and expiration information. Chondroitin sulfate is extremely hygroscopic (absorbs moisture from the air). Generally, these products should be stored in tight containers at room temperature, avoiding direct sunlight.
Client information
- Patience is key: Onset of any noticeable clinical improvement may require 2 to 6 weeks of consistent daily treatment.
- Consistency matters: Do not switch brands from the one prescribed without first contacting your veterinarian, as over-the-counter supplement quality varies drastically.
- Administration: Tablets can be given as a treat or crumbled into food. Capsules can be opened and sprinkled onto wet or moistened dry food to ensure the pet consumes the full dose.
- Side effects: Adverse effects are very unlikely, but mild gastrointestinal upset (soft stool, gas) has been reported. If this occurs and is troublesome, contact your veterinarian.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.