There are numerous kinds of shampoo, including vitamin-enriched, fruit-enhanced, color-reviving, therapeutic, and so on. Shampoo that simply promises to clean hair, however, has seen declining sales, has little or no advertising, and has been phased out by most manufacturers. Shampoo that makes no other promise than to clean hair is in the stage of its product life cycle.

Decline stage of the product life cycle

Explanation:

A decline stage of a product's life cycles is when the sale of that particular product starts to fall.

At the decline stage of a product's life cycle, the product is not longer desirable or appealing to consumers.

A decline stage of a product's life cycle is the final stage in the life cycle of that product.

At the decline stage of a product's life cycle, manufacturers of that product can try to :

a.  make the product look better  by better branding or advertising, take for example, a shampoo as used in this question, the packaging of the shampoo can be changed, the colour of the bottle can be made to look more attractive

b. The cost of buying the product ( shampoo) can be reduced so that people can be interested in buying it again

c. The product can be sold to another company who maybe willing to improve the product in a better way.