How PerGram Works
PerGram is a price comparison engine for dietary supplements. We normalize every product to its cost per gram of active ingredient so you can compare real value — not just bottle prices.
We Scrape Real Prices
Our automated scrapers collect prices directly from retailer websites — Amazon, iHerb, Swanson, BulkSupplements, and more. Prices are refreshed regularly so you see current pricing, not stale data from weeks ago.
We Extract Supplement Facts
For each product, we read the Supplement Facts label to determine the active ingredient, its dosage per serving, the number of servings per container, and the total amount of active ingredient in the package. We use a combination of HTML parsing and AI-powered image analysis for accuracy.
We Normalize to Cost Per Gram
This is the core of PerGram. We take the price and divide it by the total grams of active ingredient to get a universal metric: dollars per gram.
This lets you compare a 60-capsule bottle against a 1 kg powder, or a premium brand against a bulk supplier — on equal footing.
We Rank and Compare
Products are ranked by their normalized cost per gram within each supplement category. You can browse by category, search across all products, filter by formulation (capsules, powder, liquid) and package size, and compare products side by side.
Data Quality
- Sanity checks. Every price update is checked against historical data. Large deviations are flagged for review before being published.
- Human review. Our extraction pipeline includes a human-in-the-loop review queue where supplement facts are verified against label images.
- Confidence scoring. Each extraction receives a confidence score. Low-confidence data is filtered from public rankings until verified.
Last updated: April 2026