“If lactose is the problem, lactase is the quiet little hero no one talks about.”
If you’re lactose intolerant like I am, you’ve probably stood in the dairy aisle holding a packet of lactase tablets thinking:
How much of this do I actually need?
One tablet? Two? The whole strip?
Lactase enzyme is often presented as a quick fix. Pop a pill, eat the cheese, move on with your life. But what is lactase really? How does it work? And why does the “right dose” feel like a guessing game?
Today I want to unpack this properly. Not just the marketing version. The biology, the practical side, and the real-life “mum trying to enjoy pizza without consequences” version.
Let’s get into it.
What is lactase enzyme?
Lactase is a digestive enzyme. Its full scientific name is lactase-phlorizin hydrolase, but thankfully no one expects you to say that in public.
It’s produced naturally in your small intestine. Specifically, by the cells lining the brush border of your intestinal wall. Its job is very simple:
Break down lactose.
Lactose is the main sugar in milk. It’s a disaccharide, which means it’s made up of two smaller sugars stuck together: glucose and galactose.
Your body cannot absorb lactose as-is. It’s too big. So lactase steps in and splits it into those two smaller sugars. Once separated, they can be absorbed into your bloodstream and used for energy.
When lactase is working well, dairy feels easy. When it isn’t, things get… uncomfortable.
What happens if you don’t have enough lactase?
If your body doesn’t produce enough lactase, lactose passes through the small intestine undigested. It then reaches the large intestine, where bacteria happily ferment it.
That fermentation produces gas, bloating, cramping and sometimes diarrhoea. In other words: the classic lactose intolerance symptoms. The scientific term for this is lactose malabsorption. When it causes symptoms, we call it lactose intolerance.
It’s not an allergy. It’s not inflammation. It’s not your immune system misbehaving.
It’s simply a shortage of an enzyme.
Why do some people stop producing lactase?
This part fascinates me.
Most mammals stop producing lactase after weaning. Humans are unusual because some populations developed lactase persistence — the ability to keep producing lactase into adulthood.
This genetic adaptation is common in people with Northern European ancestry. In many parts of Asia, Africa and South America, lactase persistence is far less common.
Globally, about 65–70% of adults have some degree of lactase non-persistence. In other words, lactose intolerance is biologically normal. You are not broken. You are statistically typical.
So what exactly is a lactase supplement?
Lactase supplements contain the lactase enzyme, usually derived from yeast or fungi.
When you take a tablet just before eating dairy, the enzyme mixes with the food in your stomach and small intestine. It helps break down lactose before it reaches your colon.
Think of it as temporarily outsourcing the job your small intestine isn’t doing efficiently.
But here’s where things get tricky.
Enzymes are proteins. They are sensitive to temperature, pH and timing. They don’t last forever in your digestive tract. And they only work on lactose present at that time.
This is why dosing feels inconsistent.
How much lactase do I actually need?
Here’s the honest answer: It depends.
I know that’s annoying. But it’s true.
The amount of lactase you need depends on:
- How lactose intolerant you are
- How much lactose you’re eating
- The form of dairy (milk vs aged cheese vs ice cream)
- Your gut transit time
- Whether you’re eating other foods at the same time
Most lactase supplements are measured in FCC units (Food Chemicals Codex units). You’ll commonly see tablets ranging from 3,000 to 9,000 FCC units.
General guide:
- 3,000–4,000 FCC units: small serve of dairy
- 6,000–9,000 FCC units: larger serve
- Higher doses: large milk-based meals or desserts
But this is not a precise science. It’s more like adjusting seasoning.
How much lactose is in common foods?
Understanding lactose content helps more than memorising enzyme doses.
Here’s a rough guide:
- 1 cup milk: 12–13 grams lactose
- 1 cup yoghurt: 4–8 grams (varies with fermentation)
- Ice cream (½ cup): 3–6 grams
- Fresh cheeses (ricotta, cottage cheese): moderate
- Aged hard cheeses (Cheddar, Parmesan): very low
- Butter: negligible
This is why many lactose intolerant people can eat aged cheeses comfortably. During cheese ageing, bacteria consume lactose. By the time a cheese is properly matured, very little remains.
That’s also why I always tell people: try aged cheese before writing off dairy entirely.
DEEP DIVE: My extensive lactose in dairy database →
Can you take too much lactase?
Lactase supplements are generally considered very safe. Because lactase works locally in the gut and is broken down like other proteins, excess amounts are unlikely to cause harm.
That said, taking more doesn’t always improve results. Once all the lactose is broken down, extra enzyme doesn’t do anything useful.
More is not always better. Enough is enough.
Why does lactase sometimes “not work”?
This is the question I get most often. Here are the most common reasons:
1. You took it too early
Enzymes don’t hang around. If you take lactase 20–30 minutes before eating, much of it may be degraded before food arrives.
Take it with the first bite.
2. You underestimated lactose content
Milk-based sauces and desserts can contain more lactose than you realise.
3. You needed a second dose
If you’re eating dairy over a long meal, one tablet at the start may not cover everything.
4. Your symptoms aren’t only lactose-related
Some people react to other components in dairy, such as milk proteins or FODMAP content.
Lactase only breaks down lactose. It doesn’t solve every dairy issue.
How do I find my “right” dose?
This is where we move into practical, real-life territory. I recommend a structured approach:
Step 1: Test your baseline
Eat a known quantity of dairy without lactase (if safe to do so). Notice symptoms and timing.
Step 2: Start low
Try 3,000–4,000 FCC units with the same amount of dairy.
Step 3: Adjust gradually
Increase dose until symptoms are minimal or absent. Keep notes. Yes, it’s slightly nerdy. But it works.
Over time, you’ll develop intuition. I know exactly how much I need for pizza versus a creamy dessert.
Does lactase improve lactose tolerance over time?
Short answer: no.
Lactase supplements do not retrain your body to produce more lactase. They are a support tool, not a cure. However, small regular exposures to lactose may help some people tolerate modest amounts better. The gut microbiome adapts.
This doesn’t mean forcing yourself to be uncomfortable. But it does mean you might not need to eliminate dairy completely.
Should everyone with lactose intolerance use lactase tablets?
Not necessarily. Some people prefer to:
- Choose lactose-free milk
- Eat mostly aged cheeses
- Limit portion sizes
- Space dairy intake throughout the day
Others like the flexibility of lactase tablets for special occasions.
For me, it’s a mix. At home, I choose low-lactose options. At restaurants, I bring backup.
No drama. No deprivation.
Are lactose-free products better than lactase tablets?
Lactose-free milk contains lactase added directly to the milk. The lactose is already broken down into glucose and galactose. That’s why lactose-free milk tastes slightly sweeter.
From a digestive perspective, it works very well. The choice between lactose-free products and tablets usually comes down to convenience and cost.
If dairy is a daily staple, lactose-free milk may be simpler. If it’s occasional, tablets make sense.
What about children and lactase?
Children can also be lactose intolerant, though it’s less common before age five. Dosing in children should always be discussed with a healthcare professional. It’s not just about weight. It’s about total lactose intake.
And remember: calcium and protein are important for growing bodies. If dairy is reduced, nutritional planning matters.
Is lactose intolerance permanent?
Primary lactose intolerance (genetic lactase non-persistence) is lifelong. Secondary lactose intolerance, caused by gut illness or inflammation, can improve once the underlying issue resolves.
This is common after gastroenteritis or in conditions like coeliac disease. If symptoms suddenly worsen, it’s worth checking in with your GP.
My personal experience with lactase
I developed lactose intolerance in my twenties. It crept in slowly. First milk. Then soft cheeses. Then creamy sauces. I remember feeling frustrated. Cheese is not just food to me. It’s culture, comfort, connection.
Learning about lactase changed the tone of the conversation. Instead of “I can’t eat this,” it became “How can I manage this?”
Now I know:
- Aged cheese? Usually fine.
- Small yoghurt? Often fine.
- Ice cream? Tablet required.
It’s not about perfection. It’s about understanding your biology and making informed choices.
Signs you might need more lactase
- Bloating within 30–120 minutes
- Excess gas
- Loose stools after dairy
- Cramping
If symptoms are mild, you may simply need a slightly higher dose next time. If symptoms are severe, reassess lactose quantity rather than endlessly increasing enzyme units.
When lactase isn’t the full answer
Sometimes dairy discomfort isn’t just lactose.
It could be:
- Milk protein sensitivity
- Irritable bowel syndrome
- FODMAP sensitivity
- Fat intolerance
If lactase consistently fails despite high doses, broader investigation is reasonable. Don’t self-diagnose endlessly. A dietitian can help clarify patterns.
The bottom line: how much lactase do you need?
You need enough lactase to match the lactose you’re eating.
Not more. Not less.
For most adults, that falls somewhere between 3,000 and 9,000 FCC units per typical serve of dairy.
But your body is unique. Your gut is unique. Your tolerance is unique. And that’s okay.
A gentler way to think about it
Lactase isn’t a magic pill. It’s a tool. It gives you options. It gives you flexibility. It gives you back some food freedom.
If you’re navigating lactose intolerance, I want you to know this: you don’t have to choose between comfort and enjoyment.
You can understand the science. You can test your dose. You can find your rhythm.
And if you’d like more evidence-based, realistic conversations about cheese, digestion and living well without unnecessary restriction, come join my email list.
We talk science. We talk real life. And yes, we still talk cheese.
Because lactose intolerance doesn’t mean the end of joy. It just means understanding your enzymes.
Sabine is the creative force behind Cheese Scientist. She is a sustainable living advocate, a climate change protestor and is pro-choice. And, most relevantly, she is also a lactose intolerant cheese lover.
