The right capsule is the one you will take at the same time every day. If you already swallow a tablet each morning, adding another is simple. If you dislike large tablets, a two-capsule serving or a powder may suit you better than one big pill.
Holland & Barrett's powder format and its 120-tablet combination range show how differently the same category can be packaged. So decide the format first, then compare products inside it. If you have abandoned a supplement before, format was probably part of the reason.
A jar that suits your morning beats a stronger formula that sits in the cupboard.