Are Lansinoh Bags Reusable? I Learned the Hard Way

If you pump breast milk, you’ve likely seen Lansinoh bags. They’re thin, simple to use, and sold almost everywhere—like Target and Amazon. I grabbed my first box at 2 a.m. during a late-night newborn feed.

But here’s the question I kept asking—and maybe you are too: Are Lansinoh bags reusable?

It’s a fair thing to wonder. You go through a lot of bags each day. Tossing them after one use can feel wasteful. And let’s be honest—the cost adds up fast.

In this post, I’ll give you a clear answer straight from Lansinoh. I’ll also explain why these bags are single-use only. Plus, I’ll share safer, budget-friendly ways to store your milk. Because when it comes to feeding your baby, you deserve smart, safe, and low-stress options.

Quick Answer: Are Lansinoh Bags Reusable?

No, Lansinoh breast milk storage bags are for one-time use only. Once opened, they’re no longer sterile. And that matters when feeding your baby.

Lansinoh says these bags are pre-sterilized. They aren’t made to be washed or reused. If you try, you could break the seams or weaken the plastic. Even worse, germs could get in—and no one wants that near baby’s milk.

I get it. When you use a few bags a day, tossing them feels wasteful. And the cost adds up fast—especially during those long pumping days. I’ve been there. But trust me, reusing bags can lead to more stress later on.

Why Lansinoh Bags Are Single-Use Only

Lansinoh breast milk bags are pre-sterilized and made for one-time use. That’s not just advice—it’s how they’re built.

The plastic is thin and flexible. The seams are strong enough for one use, but not more. These bags come ready to go, so you don’t need to boil or clean them first. That’s great for busy moms—but it also means they aren’t safe to reuse.

Washing the bags can stretch the plastic or wear down the edges. The seams may look okay, but they can fail during freezing or thawing. That’s a big risk when every drop matters.

Then there’s the hygiene problem. Even if you rinse the bag, milk can hide in the folds. Bacteria feed on protein—and leftover milk gives them the perfect place to grow.

Lansinoh makes this clear on their website:

“No, the Breastmilk Storage Bags are for one-time use only.” — Lansinoh FAQs

It may feel wasteful to throw a bag away. But it’s one way to help keep your baby’s milk safe.

What Could Happen If You Reuse Them

Here’s what might go wrong if you reuse a bag:

Contamination risk is real

Once opened, a bag is no longer sterile. Even rinsed, germs can stick around—especially in the seams. That can spoil milk or make your baby sick. And you might not see or smell anything wrong.

The seal could fail

The zipper and plastic wear out fast. They’re not built for hot water, scrubbing, or pressure. Your milk could leak—or worse, the bag might burst in the freezer. (Been there. It’s heartbreaking.)

Soap isn’t enough

Even after washing, milk proteins can stay on the plastic. You might not see the film, but bacteria love it. It’s not like cleaning a bottle or silicone bag.

What experts say: The CDC and FDA both recommend single-use bags—or containers made for reuse. Lansinoh bags don’t fit that second group.

And if you’re thinking, “But I only reused it once…” — remember: one weak bag is all it takes.

Common Myths About Reusing Breast Milk Bags

Let’s clear up some myths I’ve heard (and once believed myself). Reusing bags may seem safe—but the truth is a bit more messy.

“They’re BPA-free, so they must be safe to reuse.”

Yes, Lansinoh bags are BPA and BPS-free. That’s great! But being BPA-free doesn’t mean they’re made for reuse. It just means they don’t contain one specific chemical. The bag still wears down with heat, pressure, or washing.

“If I rinse with hot water, it’s fine.”

Hot water feels clean, but it doesn’t sterilize. Milk proteins stick to plastic. Rinsing won’t remove all of it—especially in the seams. Scrubbing weakens the bag faster.

“I reuse Ziploc bags—what’s the difference?”

Ziplocs might seem similar, but they’re not built for frozen milk. Breast milk bags are thinner and made to hold liquid under pressure. Ziplocs aren’t sterile either—but you’re not using them for baby milk. And when it’s your baby’s health, even small risks feel big.

Safer, Greener Alternatives to Reusing Lansinoh Bags

If tossing a bag after one use makes you cringe (I’ve been there), good news—there are better, safer options.

Option 1: Reusable Silicone Milk Storage Bags

These are my personal favorite now.

• Pros: Tough, leak-free, freezer-safe, and easy to clean
• Cons: Cost more at first, and take up more room in the freezer
• Brands to try: Haakaa, ZipTop, Junobie (Target or Amazon)

Option 2: Glass Jars or Containers (For the Fridge)

Perfect if you’re storing milk for the short term.

• Pros: Easy to wash, no plastic, and lasts forever
• Cons: Can crack in the freezer if not handled with care
• Tip: Use 4 oz jars—they’re the perfect size and reduce waste

Option 3: Breast Milk Freezer Trays

Like ice cube trays—but for breast milk.

• Pros: Reusable, easy to portion, and quick to thaw
• Cons: You’ll need to move the frozen cubes to another bag or container
• Best for: Moms who pump often or freeze in small amounts

Yes, these options cost more up front. But they save money in the long run—and give you peace of mind.

Real Mom Talk: Why I Don’t Reuse Them

Okay, real talk. I reused a Lansinoh bag once. I rinsed it, let it dry, and filled it again the next day.

It looked fine—until it wasn’t.

The seam split in the freezer. I lost 4 ounces. I cried. Not just over the spill—but because I had pumped at 3 a.m. for that milk.

After that, I stopped reusing bags.

I get the urge. Bags aren’t cheap. Some days, I used five before noon. But after that mess, I saw the risks: spoiled milk, leaks, wasted effort. Saving a few cents didn’t feel worth it.

So I made a switch:

• I used Lansinoh bags only for freezing
• I stored fridge milk in glass jars
• I added a few silicone bags for backup

Was it perfect? Nope. But it was safer, less stressful, and easier on my budget.

Lansinoh Bags Best Practices (Single Use Done Right)

If you’re using Lansinoh bags the way they’re meant to be used—just once—a few small tips can save you time, milk, and stress.

Filling the Bag the Right Way

Don’t overfill. Stick to 4–6 ounces. Too much milk can break the seams, especially in the freezer.

Use a funnel or flange. Pouring from a pump bottle? Try a clean flange or silicone funnel to avoid spills.

Push out the air. Gently press out extra air before sealing. This helps prevent freezer burn.

Sealing and Storing Tips

Seal it tight. Close the double zipper all the way. Run your fingers across it once—then again to double-check.

Freeze flat. Lay the bag flat to freeze. Once it’s frozen, stand it up in a bin to save space. I used a dollar-store shoebox—it worked great!

Labeling Like a Pro

Write before filling. It’s hard to label a bag once it’s full and floppy. Add the date and amount first.

Add the time (optional). Some moms note AM vs. PM milk, since the milk can change. Totally up to you.

Use a fine-tip Sharpie. It won’t smudge or rub off in the freezer.

Storage Guidelines

Fridge: Up to 4 days (at or below 39°F)

Freezer:

Standard freezer: Up to 6 months

Deep freezer: Up to 12 months (best by 6 months)

Thawed milk: Use within 24 hours in the fridge. Never refreeze.

Storing breast milk doesn’t have to be hard. With a few good habits, even those 3 a.m. pumping sessions can feel a little easier—and a lot more in control.

Final Thoughts: Save Smart, But Store Safely

So, are Lansinoh bags reusable? No—and that’s how they’re meant to be. They’re made for one-time use to keep your milk clean and your baby safe.

But that doesn’t mean you have to waste money or toss plastic every day. You’ve got better options now.

For me, it came down to finding a balance. I used Lansinoh bags for freezing because they were easy and safe. For daily fridge milk, I switched to glass jars and silicone bags. It wasn’t perfect, but it gave me peace of mind—and that matters more than saving a few cents.

In the end, safety beats savings. Always. Your milk, your time, and your baby’s health are worth it. You deserve tools that make all three feel easier.

If you’ve found a tip that helped stretch your stash (or your budget), I’d love to hear it. We’re all learning as we go.

FAQs About Lansinoh Breast Milk Storage Bags