How Perserving Works
Every price is scraped daily, normalized to a per-unit cost, and ranked — so you always see which Canadian retailer has the actual best deal, not just the lowest sticker price.
Daily price collection
Every 24 hours, a scraper visits each product page across our tracked Canadian retailers and records the current listed price in CAD. Prices are captured with a timestamp so you always know how fresh the data is.
We track prices from Amazon.ca, iHerb, Walmart Canada, and other major Canadian supplement retailers. Each listing links directly to the retailer so you can verify the price before buying.
Out-of-stock items are kept in the database but excluded from price rankings. A product that can't be purchased doesn't help you find the best deal.
Per-unit normalization
Sticker price alone is misleading. A $30 tub of creatine and a $45 tub of creatine aren't comparable without knowing how much product you're actually getting.
Perserving normalizes every price to a per-unit cost based on the active ingredient:
| Supplement type | Normalized unit |
|---|---|
| Creatine (powder, capsules) | Cost per 100g |
| Protein powder | Cost per 100g protein |
| Vitamin D | Cost per 1,000 IU |
| Omega-3 / Fish oil | Cost per 1g EPA+DHA |
| Magnesium | Cost per 100mg elemental |
Unit data comes from nutritional facts panels on each product. We extract serving size, servings per container, and active ingredient quantity to calculate the true cost per dose.
Ranking by value
Listings are ranked by per-unit cost, lowest first. The cheapest option per unit is always at the top — regardless of affiliate commission rates, brand deals, or any other commercial relationship.
Affiliate disclosure: Some links are affiliate links. When you buy through them, Perserving may earn a commission at no extra cost to you. This never affects ranking order — price determines rank, always.
Only real pages, indexed
The sitemap only includes product pages that have at least one active, in-stock listing. If a product has no current pricing data, it doesn't appear in search results. This keeps the index clean and ensures every page in the sitemap has useful, current information for shoppers.
Frequently asked questions
Are prices in CAD?
Yes. All prices are in Canadian dollars. iHerb prices are converted from USD using the current exchange rate at the time of scraping.
Why is the price on Perserving different from what I see on the retailer site?
Prices are updated once per day. Retailers change prices frequently, sometimes multiple times per day. If you see a discrepancy, the retailer's current price is the one that counts — always click through to confirm before purchasing.
How do I know if a product is in stock?
Out-of-stock products are flagged and excluded from the price ranking. If a listing appears in the comparison table, it was in stock at the time of the last price check.
Does Perserving sell supplements?
No. Perserving is a price comparison site only. We do not sell, stock, or ship any products. All purchases happen directly with the retailer.
How do I get a product or retailer added?
Perserving is actively adding products and retailers. The coverage grows regularly as new supplement categories and Canadian retailers are integrated into the scraper.