Frequently Asked Questions
How is the product data collected?
We use a hybrid approach. Automated scripts periodically discover protein product ASINs (Amazon Standard Identification Numbers), including different flavors and sizes. We use Amazon’s Creators API to fetch current price, title, brand, images, and product information. The feed runs daily so prices and availability stay as current as practical.
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). Products are included in value rankings only when all three inputs are available. Products with incomplete label data are excluded rather than assigned an estimated value.
How often is the data updated?
The core product data, especially prices, fetched through Amazon’s Creators 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.