Words like biodegradable, compostable, and recyclable are all commonly used on products and packaging to indicate that a product is better for the environment.
But what does biodegradable mean? Is it the same as compostable? Which materials are biodegradable, and which are not?
If you're confused about the terminology, you're not alone.
A survey revealed that 49% of consumers have difficulty distinguishing between the terms “compostable” and “biodegradable” ("U.S. Consumer Perception of Compostable Packaging," Closed Loop Partners, 2022).
Below, we explain the meaning of biodegradable, what materials are biodegradable, and how biodegradation works. You'll also find out why choosing biodegradable products is important for the environment.
Contents
Merriam-Webster Dictionary defines the word biodegradable as:
biodegradable (ˌbaɪəʊdɪˈɡreɪdəbəl) (adj)(Environmental Science) (of sewage constituents, packaging material, etc) capable of being decomposed by bacteria or other biological means
But how does that definition actually apply in practice? Let's find out...
A material is considered biodegradable if it can be broken down naturally by living organisms such as bacteria, fungi, or other microorganisms.
Materials break down into simple, non-toxic substances like water, carbon dioxide, and biomass, within a reasonable time and under natural environmental conditions.
When a product is labelled 100% biodegradable, it means that every component (packaging and product) should break down to natural elements under the conditions where the product is typically disposed of.
Biodegradable does not necessarily mean no plastic, because there are some "biodegradable plastics" such as PLA (polylactic acid) that do break down in industrial composting facilities.
If you want to guarantee that a product does not contain any plastic, look for labels such as "plastic-free."
Biodegradable is not the same as eco-friendly.
Biodegradability is an indication of how the product will behave after disposal. It does not mean the product is made from sustainable materials or was manufactured in an environmentally responsible way.
Biodegradable is not the same as recyclable, although some materials, such as paper, may be both.
Recyclable materials are designed to be recovered and turned into new products through industrial processes. The idea is to keep them in circulation rather than sending them to waste.
Biodegradable items are meant to safely return to nature, and the two categories don’t always overlap. For instance, metals and glass are highly recyclable but will never biodegrade, while plant-based plastics like PLA can biodegrade but cannot be recycled in conventional systems.
The term biodegradable does not mean that biodegrading will immediately occur. The biodegradation process takes time; biodegradable products remain in the environment until biodegradation occurs.
Keep in mind that what biodegrades does not necessarily compost, and the two terms do not mean the same thing. Since biodegradable and compostable are often confused, let's clarify exactly how these two terms differ.
All compostable materials are biodegradable, but not all biodegradable materials are compostable.
Biodegradable materials can be broken down by microorganisms into water, carbon dioxide, and natural biomass. The term is broad and doesn’t guarantee how quickly the process happens or whether any harmful residues are left behind.
Compostable items must break down within a set timeframe under composting conditions, leaving no toxic residues and creating nutrient-rich compost.
The following table summarizes the key differences between the two terms.
| Feature | Biodegradable | Compostable |
|---|---|---|
| Definition | Breaks down naturally into water, CO₂, and biomass through microorganisms. | Breaks down into natural elements and contributes to healthy soil under composting conditions. |
| Conditions needed | May need specific conditions (heat, moisture, oxygen) and sometimes only degrades in industrial facilities. | Must break down in either home or industrial compost within a set timeframe (e.g., ASTM D6400 standard requires ~180 days). |
| End result | Can leave behind residues or microplastics if not properly designed. | Leaves no toxic residue; produces nutrient-rich compost. |
| Certifications | Rarely standardized; “biodegradable” can be vague. | Can be certified (e.g., ASTM D6400, BPI in the U.S., EN 13432 in Europe). |
| Practical example | A “biodegradable” plastic bag may take years to disappear in a landfill. | A certified compostable bag will fully decompose in a compost facility. |
Now that we understand the definitions, let's look at some examples of biodegradable products and how they differ from traditional plastics.
Choosing biodegradable products such as trash bags, laundry detergent, and baby wipes offers environmental benefits compared to non-biodegradable alternatives.
Biodegradable trash bags are made from plant-based materials such as cornstarch or sugarcane, so they reduce reliance on fossil fuels and help minimize plastic pollution.
Brands like Plastno make compostable trash bags that are suitable for curbside pickup, just like regular bags.
Organic plant-based liquid or powder detergents such as NaturOli Soap Nuts are fully biodegradable.
Non-biodegradable laundry detergents are problematic because their chemical ingredients persist in the environment instead of breaking down.
Examples include eco-friendly detergents made with coconut or paper laundry sheets. They deliver the same great cleaning power without contaminating the water supply and harming aquatic life.
Standard wipes are often made with polyester or polypropylene fibers, which do not biodegrade.
Brands like EcoPeaCo make biodegradable wipes from natural fibers like bamboo, organic cotton, or wood pulp. All these materials are biodegradable, provided they don’t contain plastic binders.
Some, like DYPER and EcoPeaCo, are also certified compostable.
Conventional disposable diapers are mostly plastic and take centuries to degrade. Eco-friendly alternatives use bamboo, wood pulp, and organic cotton liners that are partly biodegradable and compostable in commercial facilities.
Our guide to eco-friendly diapers includes brands like DYPER that offer a home pickup diaper composting service.
Biodegradable cat litter from brands like Tuft & Paw uses renewable materials like wood, corn, wheat, or recycled paper that naturally decompose over time.
These biodegradable cat litters are lighter, produce less dust, and in most cases are suitable for home composting. They offer a lower-impact alternative to clay or silica-based products.
In general, products are likely to completely decompose within the right conditions, provided their raw materials and substances are inherently biodegradable.
Examples of materials that are biodegradable include the following.
Each of these materials can be broken down by microorganisms into natural substances without leaving lasting pollution.
But many other common materials cannot break down naturally through biological processes.
Examples of materials that are not biodegradable include the following.
None of these materials breaks down naturally through microbial action, and when discarded, they persist in the environment for decades or even centuries.
The length of time materials take to fully decompose varies depending on the type of material and the conditions in which it’s discarded.
In some cases, we can only estimate the time it will take. For example, plastics haven't existed long enough for the decomposition process to have taken effect. Some studies conclude that it may never fully break down at all ("Microplastics in the marine environment," Andrady, 2011).
The following table compares a selection of materials along with an approximation of the time they take to biodegrade under typical outdoor conditions (like soil, air, and moisture).
| Material | Approximate Time to Biodegrade |
|---|---|
| Banana peel | 2–5 weeks |
| Paper bag | 1–5 months |
| Cotton T-shirt | 5–6 months |
| Wool sock | 1–5 years |
| Plywood | 1–3 years |
| Cigarette butt (with plastic filter) | 10–12 years |
| Leather shoe | 25–40 years |
| Tin can | ~50 years |
| Aluminum can | 80–200 years |
| Plastic bag (conventional) | 10–1,000 years |
| Glass bottle | >1 million years |
| Styrofoam (polystyrene) | Effectively non-biodegradable |
Sources: Science Learning Hub (NZ), Richland Center WI – “How Long Does It Take Garbage to Decompose?”, Ontario County Recycles (NY), Muncie Sanitary Recycling Facts, Ecomena – Recycling of Aluminium Cans
Note that times can vary depending on temperature, oxygen, and microbial activity.
Some materials require commercial facilities to decompose. Others, such as food scraps, can be added to your home compost bin.
You can put some biodegradable bags in your compost at home, but not all of them.
Many bags labeled "biodegradable" are actually designed to break down only in industrial composting facilities, where high heat and controlled conditions speed up the process. In a home compost pile, these bags often degrade very slowly or not at all.
If a bag is certified compostable under standards like ASTM D6400 or BPI-certified, then it is safe to add to compost and should fully break down.
If it only says "biodegradable" without certification, it’s best not to put it in your compost bin because it may leave fragments behind.
The complexity around biodegradable bags leads us to a broader question about biodegradable plastics in general.
Things like food waste will only release naturally occurring minerals, gases, and other natural materials. But any synthetic material, including plastic, is seldom environmentally friendly.
Biodegradable plastic sounds good in theory, and it certainly helps prevent plastic waste. But it's still not necessarily a good thing. Biodegradable waste can still contain harmful chemicals, toxic gases like methane, and microplastics, which are released when the biodegradable plastic decomposes.
However, compostable plastics are a better option.
Compostable plastics are generally found in things like food packaging. Eco-friendly packaging is often made from plants, and can therefore be put on your garden compost heap along with other compostable waste such as food scraps.
There are no real synonyms for biodegradable because no other term means exactly the same thing.
Many people confuse the terms compostable and biodegradable, and they have similar meanings but are not quite the same, as I described earlier.
When you think of biodegradable, what comes to mind? Chances are, you might think of something that is good for the environment - items that can break down and won't leave behind any toxic waste.
If you came to this article to find the meaning of the word biodegradable, you might have been surprised to learn that it isn't always a good thing.
Biodegradable doesn't always mean sustainable, and it's important to be aware of the differences between biodegradable, compostable, and degradable items.
In particular, biodegradable doesn't always mean that something will break down quickly or easily. In fact, some biodegradable material can take years or even centuries to decompose! So if you recognize the need to live sustainably, it's important to be mindful of the claims companies make about their products.
That being said, compostable products are, generally speaking, a much safer choice for the environment.
