What’s The Shelf Life of Activated Charcoal and Does It Expire?

Activated charcoal is one of the best cleansers and most absorbent substances in the world. What's interesting about it is that it's not powerful because of some chemical property, but rather because of the structure of the charcoal itself.

Imagine you have a piece of paper. If you fold that piece of paper and open it back up, the crease in the paper can accumulate some dust or sand or something you pour over it. It will absorb – or catch – a little of the substance, but not much. If you fold the paper up back and forth a lot, in an accordion pattern, then pour your sand over it, it will catch and hold a lot more.

This is sort of how activated charcoal works. At a microscopic level, activated charcoal has a ton of holes and divots that attract and catch particles of other things, like dirt and oil. It does this essentially at a molecular level, far smaller than our paper example.

If you buy some activated charcoal, you want it to be an effective cleanser, whether you're using it on your skin, as part of a tooth brushing habit, or as something you eat to detox your insides. The question is, how long is it good for? What's the shelf life, the expiration date for your charcoal?

Can Activated Charcoal Expire?

So the first question is, can activated charcoal expire at all?

The answer is, pretty much no. See, various other treatments you might use as part of your beauty routine are made up of molecules that tend to be large and complex.  They also aren't always super stable. All kinds of things can go wrong.

  • Oils, if they're organic, can go rancid.
  • Creams and suspensions can separate and be difficult to recombine.
  • Organic molecules can decompose.
  • Alcohols can evaporate out of a suspension, or denature into component chemicals.

Charcoal is not any of these things. Charcoal is basically what remains after thoroughly burning some kind of organic compound, usually something like wood, sawdust, or coconut hulls. It's basically just ash that has been burned and burned and burned until nothing but the carbon remains.

The "nothing but the carbon remains" part is very important. Charcoal without the "activated" part can actually be dangerous to your health. That's why you can't just go buy some charcoal briquettes from the store and grind them down to use. In fact, that can cause cancer, among other health issues.

The "activation" of activated charcoal is basically just burning it at a very high temperature (we're talking 1,100 to 1,600 degrees F, or 600-900 C) to get rid of anything that isn't carbon. It's sometimes then processed with chloride salts to give it an even more porous structure and washed with an acid to get rid of any elements that remain other than the carbon. In some cases it's then even processed with something like carbon dioxide to create even deeper pores, enhancing its absorbent properties.

Charcoal isn't going to go bad. Carbon doesn't decay into anything else, not really. There's just one thing you might have to worry about.

How Does Activated Charcoal Degrade?

Activated charcoal doesn't decay, but it can lose potency if it's not stored properly. The reason is that porous structure and absorbent nature.

Once you open a package of activated charcoal, the timer starts ticking. See, the air itself is full of all kinds of stuff. There's moisture, there are little particles of everything from smoke to chemical fumes to bathroom residue. There are bacteria and viruses and mold spores. 99% of this stuff is harmless in the kinds of quantities you find in the air normally, but when the concentration builds up, that's when you get smog. That's why people working in wildfire zones use respirators with carbon filters, for example.

When the charcoal is exposed to air, it starts absorbing those particles. Anything that isn't just air can get trapped in the charcoal.

Now, this isn't going to cause a chemical reaction or break down the charcoal. The charcoal itself doesn't change. What changes are the pores themselves in the charcoal.

Imagine you have a yard, and there are 100 holes dug into the yard. Periodically throughout the day, someone walking buy notices the holes and drops some stuff into them. Initially, that's not going to do much; you have a lot of holes and a lot of space to fill. Over time, though, those holes start to fill up. A few weeks or months later, some of those holes might be partially or even completely full.

If you go to use the holes for whatever your intended purpose was, and they're partially full, you won't be able to use them to their fullest extent. If you wait too long, the holes will all be completely full, and you can't use it at all.

Charcoal is the same way. It has tons of tiny holes that can absorb things, but the longer it's exposed to the air, the more stuff it will passively absorb. It becomes less effective at absorbing stuff when you want to use it because it's already partially full.

This is also why charcoal filters in respirators need to be replaced from time to time. Forcing air through them while you breathe fills them up with stuff from the air, which clogs the filter and makes it harder and harder to pass air through it. Eventually, you aren't able to breathe through it and need to replace it.

Does Activated Charcoal Work on Everything?

We, and many other people who sell activated charcoal products, might make it sound like it's a miracle absorbent, that it can suck in basically anything until it's full. This isn't quite true, though, and it's only useful for certain kinds of substances.

Activated charcoal cannot absorb certain kinds of substances, or if it can absorb them, it doesn't do a very good job of it in the body. Metals, for example, don't get absorbed by charcoal very well. Substances like methane also don't get absorbed, because they're basically already just made of hydrogen and carbon. Caustic substances don't absorb well, and while alcohol can absorb, it's also absorbed by the body just as well, so charcoal can only do so much.

At the same time, activated charcoal can absorb things you might not want to absorb. If you're taking activated charcoal as part of your diet, for example, it can start absorbing medications and nutrients. It will absorb some nutrients from the food you eat, which prevents your body from using it. It can even absorb some of the medications that you may take, making those medications far less effective.

We generally recommend that you avoid taking activated charcoal internally. It's not going to kill you, and it probably won't hurt you, but it can interfere with other medications you may be taking. Instead, just use it topically. You can use it as a toothpaste, or as a skin cream, with no real issues.

How to Properly Store Activated Charcoal

There are generally two risks to handling activated charcoal. The first is that, whenever it's exposed to air, it's passively absorbing stuff from the air itself, and thus slowly using itself up. It will take quite a while for it to become useless, depending on the quality of the air, the amount of surface area exposed, and other factors, but it will slowly degrade over time.

The other risk is, well, it's messy! Anyone who has ever used activated charcoal is by now familiar with the black stains it leaves on basically everything. It will happily stain clothing, tile, skin, and everything in between. It's not a permanent stain, but depending on the surface, it can be very hard to get it completely clean.

Therefore, proper storage of activated charcoal comes down to two things: ease of handling and a proper seal.

Activated charcoal comes in a lot of different forms. For example, you can get capsules that are designed to dissolve. The charcoal inside is protected from the air and will be perfectly fine so long as the capsules don't degrade. You can also get activated charcoal as tablets, often individually packed in blisters that are sealed against the environment. These will also last indefinitely so long as the seal isn't punctured.

Other times, you'll find activated charcoal in jars or bottles, where it's nothing more than a loose powder. In these cases, it's easier for air to get in and out and access the charcoal. You'll want to make sure your charcoal is sealed as completely as possible.

Some people also put their charcoal in a suspension. They'll mix the charcoal with something like glycerin or oil, to make a solution. This isn't all that useful for directly using the charcoal, such as for toothpaste, but it works well when you want to use it as an ingredient in something like soap making. That's more for using it as a color than an active ingredient.

In general, it's best to keep your activated charcoal in a cool, dry space, sealed against the elements as much as possible. The more exposure it has to air, the more it's going to absorb stuff from that air, and the less effective it will be later.

How to Tell if Charcoal is Used Up

Let's say you have an old container of activated charcoal. How can you tell if it has been "used up" or is less effective than it was when you got it? When should you throw it away and get new charcoal instead?

First, look at the packaging it's in. Is the package sealed or air-tight? Keeping activated charcoal in blister packs or capsules is good. Keeping it in jars with tight seals is also good. Keeping it in a bottle with a screw cap isn't as effective, and keeping it in something without a solid seal is worse.

Does the container still have a seal, or does it look like it has been opened in the past? If they are capsules, are the capsules still solid or do they look to have degraded, melted, or stuck together? These can be signs that the charcoal has been exposed and isn't quite good anymore.

Second, look at the consistency. What consistency should it have, and what does it have now?

If you have a jar of charcoal powder, it should remain a powder. If it has been exposed to air, it will generally clump up and turn more solid as water and other stuff from the air binds the charcoal together. Conversely, if it was in tablet form to begin with, check if those tablets still crumble the way they should or if they're more solid than you would expect.

How To Dispose of Expired or Used Activated Charcoal

If you've used up your charcoal in something like a water filter, or if you've decided that the activated charcoal you have on a shelf has expired, you need to dispose of it. But how?

First, don't just throw away your charcoal. Putting charcoal back into the environment means everything trapped in it is now free in that environment. You were using it to filter out toxins and crud, right? So you won't want that stuff going right back where it came from.

Generally, you will want to check with your city or state regulations to see if there's a process for disposing of spent carbon. There are some services that do it, but you may need to either mail it to them or deliver it to a drop-off point. These tend to be more for industrial-scale use than individual use, though, so they might not be able to work with you.

Technically, it's possible to re-activate charcoal by burning it again to destroy the non-carbon contaminants and return to nothing but carbon. This is dangerous, though, and you likely don't have the equipment or the chemicals necessary to do it safely. We don't recommend trying. Instead, just look for local recyclers or local regulations that tell you what to do with it.

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