Sand ---- Sand is unfortunately being marketed as the "proper" substrate, because bearded dragons come from the desert, and it's easy to market sand as a desert substrate. In reality, their natural substrate would be a mixture of hard packed dirt, clay, and rocks. Sand is a bad idea because bearded dragons are messy eaters, so if you feed them in their terrarium, they'll inevitably ingest some sand. Since they can't digest sand, it creates the risk of impaction, where it clogs up their digestive system and they will lose the use of their limbs and die. Even if you don't feed them in their terrarium, bearded dragons will 'explore' with their tongues. Mine will still lick things in his enclosure that have been there ever since I set it up. Another issue is that sand is extremely difficult to keep clean. If fecal matter is left behind, the sand will readily harbor bacteria, causing the terrarium to smell and your reptile to be exposed to a greater risk of infections/parasites. **Calcium-Sand** There's a newer type of "sand" being pushed that is supposed to be good for bearded dragons. The idea is that if bearded dragons are going to eat some of the substrate, then it might as well have calcium in it to make it better for them. The bad part is that it's not actually sand but calcium carbonate found in limestone and chalk, [and is actually a leading ingredient in TUMs][1]. The side-effects of this will mean that your bearded dragon will have a harder time digesting their food because of the effect it has in neutralizing stomach acids. And if the bearded dragon feels like it needs more calcium in its diet and eats more of the sand, the effect will only get worse. **Colored-Sand** Included with the calcium-sand is sand that has been dyed different colors. The problem with the dye is that it permanently stains the bearded dragon's skin. I do not know of any health concerns that have been linked to the dyes though. Reptile Carpet ---- Reptile carpet is a good alternative. It comes in a roll of felt fabric that you can lay down at the bottom of the terrarium. The positive side of reptile carpet is that it's easy to clean; you can simply take is out and rinse it off. The downside is that bearded dragons' claws have been known to get caught in the fibers. Paper Towels ---- You can use paper towels, and then you wouldn't have to worry about their claws getting caught like you would with the felt carpet, but as soon a paper towel is soiled you're going to have to replace it. This can get fairly pricey depending on the cost of paper towels at your store. Slate Tiles ---- What I personally think is the best substrate (the one I use), is slate tile. It's easy to clean, has no risk of impaction, it holds heat well, and it even helps keep their claws worn down naturally so you'll never have to worry about trimming them yourself. Simply pick whatever shade of gray/brown you want the floor to be (you can probably find sand colored tiles if you prefer the look of sand), and have it cut to fit the floor of the terrarium. Some people go so far as to add grout, I opted not to so that I could take the tiles out in order to clean them, but having grout does have the benefit of keeping dirt from getting in between the tiles. It's really up to you on which method you prefer. Compacted Soil ---- As I mentioned with the sand, a more natural substrate for bearded dragons is compacted soil. I've heard of people mimicking this substrate type by using a mixture of about 50/50 topsoil and sand (the kind you get for children's sandboxes). The benefit of this is that the compacted dirt is less likely to get ingested, and even if it does, dirt is organic and less likely to cause impaction (as opposed to sand which is tiny rocks). It also provides them with a substrate that they can dig in if they want. Although it has the same sanitary issues as sand does as a substrate. [1]: https://www.tums.com/about/calcium-carbonate/