How Much Oxalate Is in Grape Seed Extract?
mg oxalate
per serving
Serving: 1 serving (100 g)
Verdict: 🟢 Safe
Per 100g: 0 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Grape Seed Extract: Safe (🟢), with 0 mg oxalate per serving — comfortably below the 25 mg safe cutoff. There's no need to limit it. Just keep your usual kidney stone basics in place: water throughout the day and calcium-rich foods at meals.
Putting Grape Seed Extract in context: it lands well below the category average of 21 mg. In the database, 89% of fruits (101 of 113) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical fruits here averages 21 mg oxalate per serving, so Grape Seed Extract runs 100% below that baseline. That places it among the lower-oxalate options in its category. Why this matters: the gap between two Safe foods can be wide — one may hold 5 mg oxalate while another sits at 24 mg. The lower one leaves more room in your day. See all fruits rated Safe for a full side-by-side.
Why does oxalate per 100g matter?
Per-100g values put every food on the same scale, which is handy when serving sizes differ a lot between foods — or when your portion doesn't match the standard serving. It lets you compare apples to apples on oxalate density. Applied to Grape Seed Extract: 0 mg oxalate per 1 serving — Safe per Harvard (2024).
How accurate is the oxalate measurement?
The measurements use ion chromatography, the accepted reference method for oxalate. That means real lab values for each food rather than inferred numbers. Some natural variation exists between samples, but this is the strongest published data set. For Grape Seed Extract, the measured oxalate value is 0 mg per 1 serving (Safe).
How does this compare to other foods?
The ratings split at 25 mg (Safe) and 100 mg (Avoid), with 25-99 mg in the Caution band. For context against similar foods, the category pages on OxalateWatch rank every item in that group by oxalate. For Grape Seed Extract, the measured oxalate value is 0 mg per 1 serving (Safe).