How to Reduce Lactose in Milk at Home

January 5, 2026 •

4 min read

An estimated 65% of the world's population has a reduced ability to digest lactose after infancy. For those with lactose intolerance, consuming regular milk can cause digestive issues, but there are simple and effective ways to reduce lactose in milk, allowing you to enjoy dairy again.

Quick Summary

Exploring effective methods for lowering milk's lactose content, including enzymatic treatment and fermentation. These techniques make dairy more digestible without sacrificing its nutritional value. The process is straightforward for preparing your own low-lactose products.

Key Points

Enzymatic Breakdown: Add lactase enzyme drops to milk and refrigerate for 24-48 hours to break down lactose into simpler, easier-to-digest sugars.
Fermentation Method: Use live cultures like kefir grains to ferment milk, where bacteria consume the lactose and create a tangy, lower-lactose product.
Slightly Sweeter Taste: Enzymatic treatment results in milk that is slightly sweeter than regular milk due to the conversion of lactose into glucose and galactose.
Customization: Adjust the amount of lactase drops or fermentation time to control the level of lactose reduction and flavor profile based on your personal needs.
Cost-Effective: Treating regular milk at home with lactase drops is often more budget-friendly than purchasing pre-made lactose-free milk.
Alternative Solutions: For those who cannot tolerate any lactose, non-dairy alternatives like soy or oat milk are also great options.

Understanding Lactose and Intolerance

Lactose is a disaccharide (a complex sugar) found in milk and dairy products. It is broken down into two simpler sugars, glucose and galactose, by the enzyme lactase in the small intestine. People with lactose intolerance produce insufficient amounts of lactase, leading to undigested lactose traveling to the large intestine where it ferments, causing gas, bloating, and cramps. Reducing the lactose content before consumption can prevent these symptoms.

The Enzymatic Method: Adding Lactase Drops

The most popular and straightforward method for making your own lactose-reduced milk is by adding commercially available lactase enzyme drops. This process mimics how manufacturers create store-bought lactose-free milk.

Steps for using lactase drops:

Purchase lactase drops: These can be found at most pharmacies, health food stores, and online retailers.
Add to milk: The typical ratio is about 5-10 drops per pint (or around 1 drop per 200ml) of milk, but always follow the specific instructions on the product packaging.
Refrigerate and wait: Gently shake the milk and let it sit in the refrigerator for 24-48 hours. This allows the enzyme time to break down the lactose.
Check for sweetness: As the lactose is broken down into glucose and galactose, the milk will develop a slightly sweeter taste. This indicates the process is working.

The Fermentation Method: Culturing Dairy

Fermentation is a traditional method that reduces lactose through the action of beneficial bacteria cultures. Some dairy products, like yogurt and kefir, are already lower in lactose because of this process.

Creating your own fermented, low-lactose milk product:

Use a starter culture: Add a specific culture containing bacteria that consume lactose to regular milk. Kefir grains are an excellent option for this.
Incubate: Allow the milk to ferment at the correct temperature for the culture you are using. This process can range from hours to days.
Monitor progress: Taste the milk periodically. The fermentation process increases acidity and decreases lactose, resulting in a tangy flavor.
Refrigerate: Once the desired tanginess is reached, refrigerate the product to slow fermentation and enjoy your cultured, lower-lactose dairy.

Comparing Lactose Reduction Methods


Feature	Enzymatic Method (Lactase Drops)	Fermentation Method (Yogurt/Kefir)
Equipment	Minimal: just drops and milk container	Requires starter cultures, possibly a yogurt maker
Process Time	24-48 hours of refrigeration	Hours to days of incubation and fermentation
Flavor Profile	Milk becomes slightly sweeter	Develops a tangy, more acidic taste
Lactose Reduction	Can achieve near-complete lactose removal	Reduces lactose, but not fully removed (tolerable for many)
Resulting Product	Liquid milk, same texture	Thicker, cultured dairy product (yogurt or kefir)
Cost	Cost-effective over time	Requires a one-time purchase of a starter culture

Important Considerations and Tips

While these methods are effective, here are some points to keep in mind:

Sweetness: The enzymatic method creates a sweeter-tasting milk. For those who dislike this, a filtration process combined with enzyme treatment (often used commercially) can create a more neutral taste, but this is much more complex for home use.
Expiration: Home-treated milk should be consumed within the same timeframe as regular milk and stored properly in the refrigerator.
Start small: When first trying these methods, it is best to start with a small batch to ensure you like the taste and your body tolerates it well.
Safety: Always use food-grade enzymes or cultures and ensure all equipment is clean to avoid contamination. For lactase drops, refrigeration after opening is often required.

Beyond Reducing Lactose: Other Strategies

If these methods don't suit your needs, there are other ways to manage lactose intolerance, such as using alternative milks or adjusting consumption habits.

Non-dairy alternatives: For a completely lactose-free option, consider milks made from soy, almond, oat, or other plants.
Lactase pills: Taking a lactase enzyme tablet just before consuming dairy can help your body digest lactose more effectively on the spot.
Pair with food: Consuming dairy with other foods can slow down digestion and minimize the impact of lactose.

Conclusion: Empower Yourself with DIY Dairy

Learning how to reduce lactose in milk at home provides a powerful solution for managing digestive discomfort without giving up dairy. By using either lactase drops or natural fermentation, you can customize your milk products to your tolerance level and taste preferences. This DIY approach is not only cost-effective but also empowers you to take control of your dietary needs, proving that a little knowledge can go a long way toward a healthier, more comfortable life.

Further Reading: For more in-depth scientific information on the processes and nutritional impacts, see this comprehensive review from the National Institutes of Health: Lactose-Free Dairy Products: Market Developments, Production, and Nutritional Consequences

Frequently Asked Questions

Lactose is broken down by adding the enzyme lactase to milk. This enzyme hydrolyzes the lactose into glucose and galactose, which are simpler sugars and easier for the body to digest.

Yes, you can easily make lactose-free milk at home by adding lactase drops to a container of regular milk and refrigerating it for 24-48 hours to allow the enzyme to work.

Lactase drops are a dietary supplement containing the lactase enzyme. They are designed to be added directly to dairy products to break down lactose before consumption, making the dairy easier to digest.

Yes, fermentation reduces lactose. During this process, beneficial bacteria in cultures like kefir or yogurt consume the lactose for energy, which significantly lowers its concentration in the final product.

No, heating milk, even to boiling, does not remove lactose. Lactose is a stable sugar molecule that is not broken down by heat. The only effective methods are enzymatic treatment or fermentation.

Lactose-free milk tastes sweeter because the lactase enzyme breaks down the lactose into glucose and galactose. These two simple sugars are perceived as sweeter by your taste buds than the original complex sugar, lactose.

For lactase drops to fully break down the lactose, you typically need to add them to milk and refrigerate for 24 hours. For a higher level of reduction, some brands recommend waiting up to 48 hours.