Healthspan Flexi-Joints is one of the better-known joint supplement ranges for dogs. If you are comparing it with other products, however, the brand name and headline claims only tell part of the story.
The useful questions are more practical: which ingredients are included, how much does your dog receive each day, what type of support is the formula designed to provide, and how easily will it fit into your daily routine?
Healthspan sells both Flexi-Joints for Dogs and a higher-strength product called Flexi-Joints Plus for Dogs. The figures examined below are for Flexi-Joints Plus, as published by VetVits by Healthspan at the time of writing. Formulas and feeding instructions can change, so always check the current packaging and manufacturer’s website before buying.
What is in Healthspan Flexi-Joints Plus?
Each tablet contains:
| Ingredient | Amount per tablet |
|---|---|
| Glucosamine hydrochloride | 500 mg |
| Chondroitin sulphate 90% | 100 mg |
| Green-lipped mussel powder | 200 mg |
| Vitamin C | 50 mg |
| Vitamin E | 30 IU (20 mg α-TE) |
| Manganese | 0.4 mg |
| Brewers’ yeast | 165 mg |
The product follows a recognisable joint-tablet format. Glucosamine and chondroitin form the centre of the formula, supported by green-lipped mussel, vitamins C and E, manganese and brewers’ yeast.
That does not make it a poor formula. It does mean that it takes a different approach from products built around collagen peptides, botanical ingredients or an oil-based daily serving.
What does each ingredient contribute?
Glucosamine hydrochloride
Glucosamine is a naturally occurring compound associated with cartilage and other joint structures. It has been used in canine joint supplements for many years and is commonly paired with chondroitin.
The label specifies glucosamine hydrochloride. When comparing products, look at the exact form and the amount supplied in the complete daily serving, rather than relying on the word “glucosamine” alone.
Chondroitin sulphate
Chondroitin is another structural component associated with cartilage. It is frequently combined with glucosamine in traditional joint-support formulas.
Flexi-Joints Plus lists 100 mg of chondroitin sulphate 90% per tablet. The “90%” describes the stated concentration of the ingredient; it is worth noticing when comparing the declared quantities on different labels.
Green-lipped mussel powder
Green-lipped mussel is a marine ingredient used in many joint products for dogs. It naturally supplies a range of nutrients, including lipids and naturally occurring compounds associated with joint nutrition.
Flexi-Joints Plus provides 200 mg per tablet. Because it comes from molluscs, it is also relevant to owners avoiding particular animal or marine ingredients.
Vitamins C and E
Vitamins C and E have antioxidant roles within the body. They appear here as supporting nutrients rather than as the central feature of the joint formula.
Manganese
Manganese is a trace mineral involved in normal connective-tissue and bone metabolism. The quantity is small because minerals are required in much lower amounts than the principal ingredients.
Brewers’ yeast
Brewers’ yeast is commonly used as a nutritional and palatability ingredient and can provide naturally occurring nutrients. Healthspan declares gluten and sulphites among the potential allergens associated with this ingredient.
Why the daily serving matters more than the per-tablet figure
The amount shown on the label is per tablet, but Healthspan’s directions vary the number of tablets according to the dog’s size:
| Dog | Published daily serving | Green-lipped mussel per day | Glucosamine per day |
|---|---|---|---|
| Puppy, 5–20 kg | 1 tablet | 200 mg | 500 mg |
| Small dog, up to 9 kg | 1 tablet | 200 mg | 500 mg |
| Medium dog, 10–19 kg | 2 tablets | 400 mg | 1,000 mg |
| Large dog, 20–39 kg | 3 tablets | 600 mg | 1,500 mg |
| Giant dog, 40 kg+ | 4 tablets | 800 mg | 2,000 mg |
This is important. A medium dog receives twice every listed per-tablet amount, while a large dog receives three times the amount. Cost per day and pack duration therefore change with the dog’s weight too.
For example, a 120-tablet pack lasts approximately 120 days at one tablet daily, 60 days at two tablets, 40 days at three tablets or 30 days at four tablets.
What does the 33.5% protein figure mean?
The analytical constituents for Flexi-Joints Plus include 33.5% protein. This is a compositional measurement of the product; it does not mean that the tablets contain 33.5% collagen, nor does it identify the source or functional purpose of all that measured protein.
Analytical constituents are useful for describing the product as a whole, but they should not be confused with the declared quantity of a specific active or characterising ingredient.
What should you compare between dog joint supplements?
There is no single ingredient list that is automatically right for every dog. A fair comparison should consider the complete formula and the dog in front of you.
1. The purpose of the formula
Some supplements are built mainly around the traditional pairing of glucosamine and chondroitin. Others focus on collagen peptides, green-lipped mussel, botanical ingredients, oils or a combination of several nutritional approaches.
The longest ingredient list is not necessarily the best. What matters is whether the ingredients support the purpose for which the product has been formulated.
2. The complete daily amount
Do not compare one tablet with one scoop or one teaspoon. First calculate what your dog receives over a full day at the manufacturer’s recommended serving.
3. Ingredient forms and transparency
Look for clearly named ingredients rather than vague blends. Where quantities are declared, check whether they refer to one tablet, one scoop, 100 grams or the full daily serving.
4. Format and routine
Tablets suit many households because they are easy to store and count. They can be given whole or crumbled into food. Other dogs may accept a paste or oil-based format more readily, particularly when several tablets would otherwise be required each day.
The best supplement on paper is of limited value if it is difficult to give consistently.
5. Allergens and dietary restrictions
Flexi-Joints Plus contains ingredients derived from crustaceans and molluscs, while its brewers’ yeast declaration includes gluten and sulphites. It also contains beef flavouring. Owners managing known sensitivities should check the complete composition, not just the front-label ingredients.
6. Expectations
Joint supplements are nutritional products, not painkillers and not a replacement for veterinary diagnosis or treatment. Results vary between dogs, and a dog that is lame, painful, suddenly stiff or reluctant to exercise should be assessed by a vet.
How is FieldStrength Naturals Joint+ different?
FieldStrength Naturals Joint+ Collagen Paste is not intended to be a copy of a traditional glucosamine tablet. It takes a broader formulation approach built around:
- bovine collagen peptides Type I and III;
- green-lipped mussel;
- Boswellia serrata;
- rosehip;
- turmeric and black pepper; and
- linseed and coconut oils.
The most obvious difference is that Joint+ centres its structural support on collagen peptides, alongside green-lipped mussel and selected botanical ingredients. Flexi-Joints Plus centres its formula on glucosamine and chondroitin.
The format is different too. Flexi-Joints Plus is a beef-flavoured tablet, whereas Joint+ is a measured paste mixed into the dog’s daily food. Neither format is universally better; the practical question is which approach best suits your dog, its diet and the routine you can maintain consistently.
So, is Healthspan Flexi-Joints Plus a good choice?
It is an established, clearly labelled glucosamine-and-chondroitin product with added green-lipped mussel and supporting nutrients. For owners specifically seeking that familiar combination in tablet form, its formulation is straightforward to understand.
Owners looking for collagen peptides, Boswellia, rosehip, turmeric or an oil-based paste will be comparing a different type of formula. That is where reading beyond the headline becomes valuable: two products may both be described as joint supplements while taking substantially different nutritional approaches.
The right comparison is therefore not simply which product lists the most ingredients? It is:
What does my dog receive each day, why are those ingredients included, and can I use the product consistently as part of its normal routine?
If your dog has persistent stiffness, pain, lameness or a noticeable change in movement, speak to your vet before relying on any supplement.
Looking for a broader, collagen-led approach? Explore FieldStrength Naturals Joint+ Collagen Paste and see the complete ingredient list, feeding guide and available tub sizes.
Product information checked against the VetVits by Healthspan Flexi-Joints Plus product page on 7 September 2026. Formulas and directions may change. Further reading: VetVits Flexi-Joints Plus and PDSA guidance on joint supplements for dogs.