Mylar Bags for Cannabis: Sizes, Types, and How to Choose

Written by Lia Thompson, packaging specialist at Creative Labz. Last updated October 3, 2026.

Mylar bags are the most widely used cannabis packaging for a simple reason: they protect flower better per dollar than almost anything else. They're light, cheap to ship, smell-resistant, and come in a size for every quantity from a single gram to a full pound. But "Mylar bag" covers a lot of options, and picking the wrong size or style can mean crushed buds, failed compliance, or a bag that looks cheap on the shelf.

This guide covers what Mylar bags are, the sizes and types available, and how to choose the right one for your product.

What Is a Mylar Bag?

Mylar is a polyester film, usually laminated with a metallized or foil layer. That combination creates a barrier that blocks light, oxygen, moisture, and odor far better than standard plastic. Most cannabis Mylar bags add a resealable zipper and a strip above it that can be heat sealed for an airtight, tamper-evident closure.

Why Mylar Bags Work So Well for Cannabis

• Light protection. Opaque Mylar blocks the UV light that breaks down THC and terpenes.
• Odor control. A sealed Mylar bag contains strong smells. Learn more in Mylar Bags Are Smell-Proof, But Are They Dog-Proof?
• Moisture and oxygen barrier. Flower stays at its packed humidity instead of drying out or absorbing damp air.
• Light and flat. Bags ship cheaply and store flat until you fill them.
• Printable. The flat surface is ideal for branding and labels.

Mylar Bag Sizes for Cannabis

Cannabis Mylar bags are sized by the weight of flower they're designed to hold:

Flower density varies by strain and trim, so dense, compact buds take up less room than fluffy ones. If you're between sizes, size up slightly so the zipper closes without crushing buds.

Types of Mylar Bags

• Standard resealable bags: a press-to-close zipper plus space to heat seal. The everyday choice.
• Child-resistant bags: special zippers that are hard for children to open. Often required for retail cannabis. Check your state's rules.
• Tamper-evident bags: a heat seal and tear notch that show whether the bag has been opened.
• Clear-front or window bags: let customers see the product. Store them away from light.
• Pre-designed bags: ready-made artwork, so you can sell without a custom print run. See Pre-Printed vs. Custom Cannabis Packaging.
• Bag-and-box combos: a resealable bag inside a printed outer box, like our 3.5g cereal box combos.
• Specialty bags: sized for edibles, disposable vapes, pre-rolls, and mushrooms.

How to Choose the Right Mylar Bag

1. Match the size to the weight using the chart above.
2. Check your state's rules for child resistance, opacity, and labeling.
3. Decide how you'll brand it: pre-designed, plain with custom stickers, or fully custom printed.
4. Plan your seal: use a heat sealer for airtight, tamper-evident closures. Our guide on how to heat seal Mylar bags walks through it.
5. Add humidity control for longer storage with a two-way humidity pack.

Frequently Asked Questions

Are Mylar bags reusable?

Yes. A good zipper holds up to many openings. For retail, use a fresh bag for each sale so customers get an intact seal.

How long does weed last in a Mylar bag?

Sealed and stored cool and dark, flower can keep good quality for many months. Read Can Weed Expire in a Mylar Bag?

Mylar bags or jars?

Mylar is lighter, cheaper, and blocks light completely. Jars protect buds from crushing and feel premium. Many brands use both. See our guide to resealable cannabis packaging.

Shop Mylar Bags

Creative Labz carries Mylar bags in every size from 3.5g to 448g, in child-resistant, tamper-evident, and pre-designed styles, plus heat sealers and labels to finish them.