The declaration line by line
Labels usually give amounts per capsule and additionally per daily serving. At two capsules daily every figure doubles. The most common misreading comes from confusing the per-serving column with the per-capsule column.
Declared per capsule are glucosamine sulphate, MSM, horsetail extract standardised to seven per cent silicon, and vitamin C at fifty per cent of the nutrient reference value, plus excipients and the capsule material.
Raw material is not active substance
For glucosamine sulphate the figure given is usually the raw material. For stability that raw material often contains a salt, commonly potassium chloride, so the share of pure glucosamine is lower than the declared number.
A statement such as "equivalent to x mg glucosamine" makes that difference visible. Without it the actual amount cannot be calculated and an exact comparison with other products is impossible.
Excipients and capsule shell
Excipients such as magnesium salts of fatty acids and silicon dioxide are processing aids that keep the powder flowing and the capsules evenly filled. They are permitted and unremarkable at the amounts used.
The capsule material matters more for your choice. Gelatine is usually bovine or porcine and therefore neither vegetarian nor vegan. Anyone who cares needs a statement such as hydroxypropyl methylcellulose or an explicit "vegan capsule shell".
Allergens and origin
Glucosamine from crustaceans must be declared as an allergen in the EU. For anyone with a shellfish allergy that is the decisive line. If no origin is stated at all, assume the animal source and ask before buying.
Also check traces statements indicating possible contamination from the same production line. With a diagnosed allergy that line matters more than any efficacy statement.