Frequently Asked Questions
How is the product data collected?
We use a hybrid approach. Automated scripts periodically scan Amazon search results and product pages to discover new protein product ASINs (Amazon Standard Identification Numbers), including different flavors and sizes. We also use the official Amazon Product Advertising API (PAAPI) to search for products by brand and to fetch the latest, most reliable data directly from Amazon — including price, product title, brand, images, and product descriptions. The data fetching process via the PAAPI is run daily to ensure prices and product availability are as up-to-date as possible.
How are the prices calculated?
Price Per Serving is calculated by dividing the current Amazon price by the number of servings. Price Per Gram of Protein — our primary ranking metric — is calculated by dividing the total product price by the total grams of protein in the container (Servings × Protein Per Serving). This gives the most accurate measure of value. Note: extracting serving size and protein per serving relies on parsing information from product titles and descriptions. While we use several patterns to capture this data accurately, inconsistencies in how manufacturers list information can sometimes lead to missing or estimated values.
How often is the data updated?
The core product data, especially prices, fetched via the Amazon Product Advertising API is updated daily.
What is the difference between protein types like Whey, Isolate, Casein, and Vegan?
Whey Concentrate is the most common type, derived from milk, containing protein with some lactose and fat. Whey Isolate is further processed to remove most lactose and fat, resulting in 90%+ protein content. Whey Hydrolysate is pre-digested for the fastest absorption. Casein is also from milk but digests very slowly, providing sustained amino acid release — often taken before bed. Vegan/Plant-Based proteins come from peas, rice, soy, hemp, and other plants, suitable for those with dairy allergies or dietary preferences.
How do I use the site?
The main table lists protein powders found on Amazon. You can sort by clicking column headers (like Price/Gram, Price/Serving, Protein/Serving), use the search bar to filter by name, brand, or flavor, and click on a product row to visit its Amazon page.
Why are some products missing?
Possible reasons include: the product was not discovered by our scanning process yet, the Amazon API did not return the product when requested, we could not reliably extract essential information (price, servings, protein grams) needed for calculations, or the product was manually excluded.
Is this site affiliated with Amazon?
ProteinPrices.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. As an Amazon Associate, we earn from qualifying purchases. This does not affect the price you pay.
Who can I contact?
For any questions or feedback, please email us at info@proteinprices.com.