How lactase actually works — and why most supplements dose it wrong

Lactase is one of the most-hyped enzymes in the supplement industry. It is also one of the most mis-dosed. Here is the dosage math behind 600 LACU — and why “strong enzyme formulas” often ship half of what the published literature actually asks for.

When we reviewed 12 competing multi-enzyme products before formulating Markzyme-Pro, the single most common failure mode was under-dosed lactase alongside wildly over-dosed filler protease. The math is simple: 8-oz of milk contains roughly 12 g of lactose. To hydrolyze that load, published activity studies suggest 300–600 LACU of fungal lactase per serving.

Most competitor formulas ship 100–200 LACU. That’s a third of what a single glass of milk actually requires. But because “lactase” sounds expensive to the consumer, those doses get marketed as “clinically-studied.”

What LACU actually measures

LACU stands for Lactase Unit. It measures the rate at which a given preparation of lactase hydrolyzes a standard substrate (o-nitrophenyl-β-D-galactopyranoside) at a fixed pH and temperature. Higher LACU = more enzyme activity per capsule.

What LACU does not tell you: how well the enzyme survives stomach acid, whether the preparation is acid-stable, or whether the enzyme has the right pH profile for the stomach environment (pH 2–4) versus the small intestine (pH 6–8). This is why single-ingredient lactase products often disappoint — they spec the enzyme on paper but lose most of the activity before the enzyme reaches the food.

Why we paired lactase with probiotics

The capsule delivers the enzyme for this meal. The probiotic delivers the mechanism for next week’s meal. L. acidophilus, for example, produces its own beta-galactosidase in the gut — an ongoing second mechanism of lactose support. Published activity: 1,301–2,053 Miller units per study.

Taking lactase in a capsule is like bringing a fire extinguisher to a fire. Having lactase-producing bacteria living in the gut is like building the walls with less-flammable material in the first place. You want both.

Part of the Dispatch — field notes from Nutriva Labs. Read about Markzyme-Pro →