Photographs are useful for recognizing a product, but they are a poor way to estimate its amount. Bottles can be photographed at different scales, and similarly named products may be supplied in different formats.
Read the stated net contents
Rosemary & Keratin Volumizing Shampoo is listed as 220 ml. Rosemary & Keratin Daily Shampoo is listed as 100 ml. Compare those written amounts, then read each formula and method. Shared ingredients in a name do not prove they are the same product in two sizes.
Keep the units consistent
Some products are described in milliliters and others in grams. Milliliters indicate volume, while grams indicate mass, so do not treat the numbers as directly equivalent. With sets, read the package information to understand the stated contents rather than assuming each bottle contains the total shown in the title.
Plan around your actual use
Consider the number of people using the bottle, available storage space, and how the product's method fits your routine. Do not estimate a guaranteed number of applications without knowing the amount used each time. Check any package directions about storage and use after opening.
Check the method before deciding
The 220 ml volumizing shampoo lists a gentle 3–5-minute massage before rinsing. The 100 ml daily shampoo lists gentle massage without that stated time. Choose the bottle you intend to use, not just the larger number.
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