Back to Intel
street9 min readMar 22, 2026

The Purity Gap: Why 75% and 93% Aren't Just Numbers

When someone says purity, they usually mean the number on the label. But purity has layers — and understanding what separates a 75% freebase from a 93% isolate changes how you shop.

S

Street Bureau

MGM Alkz

The label says 75%. Another label says 93%. The price difference is significant. Is it worth it?

That question has a real answer — but only if you understand what the numbers mean.

What the Percentage Actually Represents

Purity percentages in botanical alkaloid products refer to the concentration of the target compound — in this case, mitragynine — relative to total mass. A 75% freebase contains 750mg of mitragynine per gram. A 93% isolate contains 930mg per gram.

The remaining percentage isn't inert. It's a mix of other alkaloids, residual solvents (if process controls are poor), plant matter, and processing byproducts. In a high-quality 75% freebase, the remaining 25% is mostly minor alkaloids — speciociliatine, paynantheine, mitraphylline. In a poorly processed product, that 25% could include residual extraction solvents.

Freebase vs Salt Form

The form matters as much as the percentage. Freebase alkaloids are the base compound — fat-soluble, with certain absorption characteristics. Salt forms (lactate, HCl) are created by reacting the freebase with an acid, producing a water-soluble crystalline powder with different bioavailability profiles.

Neither is objectively superior. They're different tools with different characteristics.

The Real Question

For most users, 75% freebase is the right starting point. It preserves more of the natural alkaloid profile and is forgiving on dosing. For those who want precision — exact, reproducible outcomes — 93% isolate gives you that control. You're trading complexity for precision.

The gap between 75% and 93% isn't just 18 percentage points. It's the difference between a full-spectrum product and a targeted one.

purityfreebaseisolatecomparison