What Are Weighted Blankets Filled With? Glass Beads vs. Poly Pellets vs. Sand, Explained

Key Takeaways

• Micro glass beads or poly pellets are the most common fillings for weighted blankets, while sand, rice, and grain are more budget-friendly and older. Cleveland Clinic also describes weighted blankets as filled with plastic pellets or glass beads.

• Glass beads have a higher density than poly pellets, and therefore less volume per pound. That results in a flatter, quieter blanket which won't lose its shape when washed. 

• Poly pellets are cheaper, but heavier, warmer, and slightly rustle. Sand and grain absorb moisture, and the World Health Organization links damp, mouldy indoor spaces to a higher risk of respiratory symptoms and asthma flare-ups.

• The cover changes how warm a blanket feels: TENCEL™, bamboo and cotton suit warm Indian nights, while microfibre suits winter and air-conditioned rooms.

• Pick a weight of about 10% of your body weight; Cleveland Clinic advises no more than 10%.

• Studies on weighted blankets are limited and have not compared fills, so consider a weighted blanket as a comfort product rather than a medical treatment. 

Choosing a weighted blanket is about more than selecting the right weight. The material inside the blanket affects how evenly pressure is distributed, how quiet it feels when you move, how warm it feels when you sleep, and how well it holds up after months or years of regular use. Two blankets with the same weight can feel very different simply because they use different filling materials.

Most modern weighted blankets are filled with either micro glass beads or poly pellets, while some older or budget options use sand, rice, or other grain-based fillers. Each material has its own strengths and drawbacks in terms of comfort, durability, maintenance, and suitability for different climates. The blanket's internal construction also plays an important role in keeping the weight evenly spread across the body.

This guide explains what weighted blankets are filled with, how each filling material compares in real-world use, and which option is best for Indian conditions. We also look at how the blanket's construction influences comfort, longevity, and overall sleeping experience, so you can choose a blanket that fits your needs.

What's in a Weighted Blanket?

There are two basic components to a weighted blanket:

• The weighted inner: small fill particles (usually glass beads or poly pellets) sealed in stitched pockets, with soft padding or batting to keep it comfortable.

• The outermost layer: the material that you touch, like cotton, bamboo, or microfibre. It can be easily taken off for washing.

Cotton, wool, or down is used to fill ordinary blankets. A weighted blanket replaces some of that fluffy fill with dense particles, and that's what creates its gentle, even pressure, which it reports as being a “hug”. 

How a Weighted Blanket Is Built and What Makes It Heavy

Weighted blankets are divided into small stitched squares or channels. There is a certain amount of filling in each pocket. The particles are stitched onto the blanket so they will not slide to one corner of the blanket.

With each pocket being filled with the same amount of fill, the pressure is distributed throughout your body rather than on a single area. The smaller the pockets, the more even the weight and the less the shifting.

There are layers of fabric and soft padding between the fill and skin. These keep the beads from poking through, insulate, and smooth the blanket. Tight, double-stitched seams ensure that the fill won't leak over time.MysaSleep’s weighted blankets work on the same principle with a 7-layer construction.

So what makes a weighted blanket heavy?

 The weight is from the fill. The total is just the fill x number of pockets plus the weight of the fabric and padding. That's how manufacturers weigh a weighted blanket: They measure the fill per pocket very carefully to ensure the blanket will weigh the appropriate amount evenly. The amount of filling required depends on the density of the filling. The blanket can be thinner with dense materials such as glass because it takes less volume to reach that target weight. 

Micro glass beads: why they are used in premium blankets

The micro glass beads are tiny, round, and dense, with a size comparable to that of fine salt grains. The uniformity of the shape of the beads ensures that they form a very tight formation when placed in a pouch; as a result, they lie evenly against the body and do not form any texture on the body surface.

Also, glass beads have an inert property. They are resistant to moisture absorption and chemical degradation; moreover, they retain their shape even when exposed to heat and washing. A blanket that uses glass beads of the appropriate certification level will be evenly distributed after multiple washes, just like when it was used for the first time. The sound effect is almost silent since glass beads glide smoothly on one another and on the fabric without any rubbing sounds or clicks.

For Indian buyers specifically, glass beads have a useful thermal property: they stay at room temperature rather than holding warmth against the skin. Paired with a breathable fabric like bamboo or TENCEL, MysaSleep's bamboo weighted blanket can stay comfortable through summer months in a way that blankets with plastic fill often cannot.

The downside is cost. High-quality micro glass beads are more expensive than plastic pellets, which shows up in price. Cheaper glass bead blankets sometimes use irregular or recycled glass that does not pack as cleanly, which is why certification matters. MysaSleep's weighted blanket range uses non-toxic micro glass beads alongside OEKO-TEX Standard 100 certified outer fabrics, meaning every component has been independently tested against over 1,000 restricted substances before it reaches the buyer.

Poly pellets: what the trade-off looks like in practice

The Poly Pellets are formed from polypropylene, which is a type 5 plastic that can be found in items such as food containers and in medical devices. The Poly Pellets are bigger in size compared to glass beads; the size of the Poly Pellets is equivalent to that of a small lentil. This implies that since the Poly Pellets are lighter in weight, the blanket will need more of them to achieve the required weight.

This does not mean poly pellets are unsafe. Virgin polypropylene is a tried and tested material, and a high-quality poly-pellet blanket is washable and durable. However, the practical issues encountered are much more subtle. Poly pellets tend to migrate towards the corners of baffles more easily than glass beads, especially in bigger compartments, thus creating soft spots over time. Also, poly pellets make an imperceptible rustling noise when the blanket is moved, although it is not very loud.

Plastic also holds warmth differently than glass. A poly pellet blanket can feel warmer through an Indian summer or monsoon night compared with a glass bead blanket at the same weight. In air-conditioned rooms, this is a minor point. For anyone sleeping without AC, it is worth knowing before buying.

Steel Beads and Other Less Common Fillers 

In addition to glass and poly, you might run into a couple of additional fillers when looking for weighted blanket materials:

Steel/Metal beads: Very dense and require very few beads per ounce of weight. They are resilient and may be smooth, but they can be small and have a shiny texture, which can produce a subtle clicking sound. They also do not occur in mainstream blankets.

Fills with crystal or gemstone: Sells primarily as a “wellness” option. The effect of the crystals on sleep is primarily a subjective one and is not scientifically proven to be effective; it is more often than not a charge adjuster.

Most buyers will continue to have only two realistic options: glass beads or poly pellets. For most buyers, glass beads and poly pellets remain the two practical choices.

Sand, rice, and older grain fillers

Sand and grain fillers appear mostly in older blankets and DIY guides. The practical problem with all of them is the same.

Grains and sand absorb moisture. In India's monsoon months, where humidity stays high for weeks at a stretch, a blanket whose fill cannot dry properly becomes a risk for mould inside the pockets. Sand-filled blankets generally cannot go through a standard washing machine cycle without the fill retaining water and developing a damp smell that never fully airs out.

Not only is this a health point, but it is also a comfort one. According to the WHO guidelines on indoor dampness and mould, the epidemiological evidence is enough to state that people who live in damp or mouldy buildings are at more risk of having respiratory symptoms, respiratory infections, and asthma exacerbations. The ability to retain moisture makes a good argument for avoiding it in a wet climate for general use. 

Weight distribution is the second problem. Sand and grain particles are irregular in size, so they clump in some pockets and leave gaps in others. A 2024 review in Frontiers in Psychiatry, indexed on PubMed Central, found that the calming response produced by deep pressure touch depends on that pressure being consistent and distributed across skin receptors, not concentrated or variable. A fill that bunches undermines that distribution regardless of the blanket's total weight.

Most commercial manufacturers moved away from sand and grains years ago. For a blanket you plan to use regularly in India, they are not a practical choice.

Fill materials at a glance

What Else Is a Weighted Blanket Made Of?

The fill is only half the story. The material around it alters the feel of the blanket and how warm or hot it'll keep you:

• Cotton: A  cotton weighted blanket is comfortable, breathable, and clean. An all-rounder that is dependable for the Indian climate.

• Fabrics made from bamboo: Bamboo fabric weighted blankets are typically soft and typically said to feel cooler, favorites among warm sleepers.

• Microfibre/minky: Microfibre fabric is very soft and plushy, but warmer. More suitable for cooler rooms or winter.

• Padding and inner liner: It is a thin batting layer that is placed between the fill and the cover, which provides comfort and prevents the particles from coming through the cover.

• Removable duvet cover: Makes it easier to care for the blanket because you can wash only the cover that will come into contact with your bed. 

Here is how the main cover fabrics compare: 

Choosing the right fill for your situation

For most buyers looking at a weighted blanket for regular nightly use in India, glass beads are the stronger long-term choice. The pressure is more even, the noise profile is quieter, the blanket stays cooler, and the fill holds its distribution better through years of washing. The higher upfront cost is the real trade-off, and it is a genuine one.

Poly pellets are a reasonable option if price is the deciding factor and the blanket will be used in an air-conditioned room where warmth is less of a concern. Confirm the pellets are virgin polypropylene and that the blanket is rated for machine washing before buying. Sand and grain fills are not worth considering for regular use.

Once you have settled on a fill type, the fabric choice determines how warm or cool the blanket feels. The guide on choosing the right fabric for your weighted blanket walks through how TENCEL, bamboo, cotton, and microfibre each perform across Indian seasons. 

MysaSleep's weighted blanket range uses non-toxic micro glass beads in a 7-layer construction across five fabric options.

What research says about weighted blankets

Weighted blankets are popular, but the evidence is still developing. Cleveland Clinic says current studies are small and have limitations, though there is no evidence against them either. In a 2020 randomised trial in the Journal of Clinical Sleep Medicine, 120 adults with insomnia and a psychiatric condition slept for four weeks under either an 8 kg weighted chain blanket or a light control blanket. Remission of insomnia was reached by 42.2% of the weighted-blanket group versus 3.6% of the control group (study on PubMed Central). A 2024 pilot trial of 102 adults with insomnia in BMC Psychiatry also reported better sleep quality after one month (study on PubMed Central), although the authors say larger studies are needed.

Neither trial compared filling materials, so there is no evidence that one fill works better than another for sleep. What the fill does change is the day-to-day experience: how even the pressure feels, how quiet and warm the blanket is, and how well it survives washing. 

Quick checklist before you buy

• Weight: about 10% of body weight (slightly less if unsure) or 6 kg for a 60 kg person. Cleveland Clinic advises no more than 10%. Use the MysaSleep size guide to check the appropriate weight.

• Noise: Ensure that the fill is fine and well-stitched.

• Heat: Check the fill and cover fabric.

• Safety: Check for non-toxic, certified fill.

• Care: Make sure that the cover can be removed and the blanket is washable. 

Find the Right Weighted Blanket for Your Sleep

Glass beads, poly pellets, or fillers with sand all have unique comfort, sound, heat, cleaning, and durability characteristics. Glass beads work best in moist, warm environments; poly beads are inexpensive; and sand or grain is best for a single project. Regardless of the fill you choose, the blanket’s weight and cover fabric can play a role in how it feels, just as much as the fill.

Fill, fabric, and construction all go hand in hand: examine each before purchase. Start with the fill, match the fabric to your climate, and choose a weight that is about 10% of your body weight. Here is where to go next:

• Weighted blankets for adults – micro glass beads in a 7-layer build, in TENCEL™, cotton, microfibre and bamboo

• TENCEL™ weighted blanket – our best seller for year-round comfort

• Bamboo weighted blanket – a silky option for warm sleepers

• Weighted blankets for kids – lighter weights made for smaller bodies

• Size guide – check your weight and size before you buy

Still unsure about fill, weight, or fabric? Contact the MysaSleep team, and we will help you choose.

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Frequently asked questions

What is inside a weighted blanket? 

Weighted blankets generally contain either glass beads or polypropylene plastic balls that are enclosed in separate compartments on the blanket. Traditionally, blankets made using materials such as sand, rice, or gravel have been used. The material inside the blanket provides the weight of the blanket and controls how evenly the weight will be distributed on the user's body, how the blanket sounds when it is being moved, and its durability.

Are glass beads better than poly pellets in a weighted blanket? 

For most consumers in India, glass beads work better on average. Being denser, they mean that less of the filling is needed for the same weight to be achieved, which will result in a smaller thickness of the blanket and also help to keep the pressure even. They are also less noisy, colder, and durable enough to remain in place after multiple washes. Poly beads are less expensive and functional, but are bulkier, warmer, and slightly noisy.

Can you use sand in a weighted blanket?

While sand was one of the materials used in early weighted blankets, this material was not ideal; hence, manufacturers stopped using it. First, sand can easily absorb water. As such, washing the blanket becomes quite hard. In the humid climate of India, there is a high likelihood of mold in the pockets of the blanket filled with sand. Secondly, sand does not distribute weight evenly. The WHO links damp, mouldy indoor environments to a higher risk of respiratory symptoms and asthma flare-ups, which is another reason to avoid moisture-holding fills. 

Are the glass beads in weighted blankets safe and non-toxic? 

Absolutely, provided that they are made by an officially certified manufacturer. Glass beads used for making glass bead blankets consist of completely harmless glass that doesn’t present any chemical danger to users if manufactured correctly. The difference between a glass bead blanket, which is safe to use, and another one that is less expensive is the certification of the former. MysaSleep employs non-toxic glass beads and  OEKO-TEX certification to ensure that the blankets are safe to use.

Why do glass bead blankets feel quieter than poly pellet blankets? 

The glass beads are small, round, and dense, and hence they move freely without much friction being experienced due to their interaction with each other and with the cloth. The poly pellets are relatively big and made up of hard plastic, and give off a small noise whenever the blanket moves. This noise produced by the poly pellets is slight but constant. For a quiet, padded feel, you can try the TENCEL™ weighted blanket. 

Do glass beads make a weighted blanket feel hot in Indian summers? 

The glass beads do not hold any thermal energy as the plastic does; hence, they do not contribute to the heat felt apart from that contributed by the fabric itself. Whether the glass bead blanket will be hot or cold is largely dependent on the fabric. 

What is the difference between a 7-layer weighted blanket and a regular one?

With a total of seven layers, the fill layer is sandwiched between the padding layer, which protects the beads from pressing on the skin, and the outside stitching from being pressed by the beads. It ensures that there is no sharpness from the beads felt on the thin fabric. In addition, the beads will not escape through the stitch lines. This is made possible through the even distribution of weight during washing.