Does lactase help with dairy and lactose intolerance?
Yes — lactase is the clearest, most evidence-supported over-the-counter digestive enzyme. It replaces an enzyme your gut may not make enough of when digesting dairy.
Quick answer
Best suited for
- Lactose intolerance symptoms from dairy — gas, bloating, cramping, or diarrhea after milk, cheese, or other lactose-containing foods.
- People who still make some lactase but not enough to comfortably digest typical dairy servings.
It is unlikely to help with
- A general digestion or bloating aid unrelated to lactose — there's limited evidence for broader claims sometimes attached to combination products.
- A cure for lactase deficiency — it manages symptoms while you eat dairy, it doesn't restore the body's own lactase production.
- Persistent symptoms that don't improve with lactase, or symptoms that come with weight loss or greasy stools — that pattern can point to a different cause.
What to compare on the label
- Activity unit — Look for ALU (Acid Lactase Unit) at the labeled serving size — not just milligrams.
- Single-enzyme vs. blend — A lactase-only product is easier to dose for a dairy-specific issue than a broad multi-enzyme blend.
- Timing — Taken with or just before the lactose-containing food, not on a fixed daily schedule.
Where to find it
Nature's Way — Nature's Way Lactose Defense (Lactase Enzyme)
Single-ingredient lactase-only formula (not a broad multi-enzyme blend) — matches this guide's own comparison advice to prefer a lactase-only product for a dairy-specific issue. Activity is labeled in ALU, the unit this guide tells readers to look for. 690 mg (10,350 ALU) per 3-capsule serving is on the higher end for an OTC lactase product; people may find fewer capsules sufficient depending on how much lactase they still produce. This reflects the manufacturer's own published label (naturesway.com), not Enzyax's independent lab testing — we have not run our own potency assays on any product.
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How lactose intolerance works
Lactose intolerance happens when the small intestine doesn't produce enough lactase — the enzyme that breaks lactose (milk sugar) into simpler sugars the body can absorb. Undigested lactose passes into the colon, where gut bacteria ferment it, producing gas, bloating, cramping, and diarrhea.
Lactase production is highest at birth and typically declines with age; the degree of decline varies widely by ancestry and individual.
What the NIDDK guidance says
NIDDK's patient guidance describes lactase products as an option some people use to help manage symptoms when consuming dairy, alongside other management approaches like adjusting dairy intake or choosing lower-lactose products. It is described as an aid for managing lactose intolerance symptoms, not a cure for the underlying enzyme deficiency.
Where the evidence has limits
Individual response varies — dose needed depends on how much lactase a person still produces and how much lactose is consumed.
Lactase supplements address lactose specifically. They are not a general digestive aid, and there's limited evidence supporting broader digestion or bloating claims sometimes attached to combination products.
- Persistent symptoms that don't improve with lactase, or symptoms with weight loss or greasy stools, need medical evaluation rather than more supplementation — a different mechanism such as exocrine pancreatic insufficiency could be involved.
- Lactose intolerance is not the same as a milk protein allergy. An allergy involves the immune system and can be serious; lactase supplements do not treat a milk allergy.
Source: NIDDK — Lactose Intolerance. Last reviewed: July 28, 2026.