Developed during World War II when natural latex was in short supply, synthetic latex is a man-made, rubber-like product that may be used in either the support layer or the comfort layer of a mattress—or both. In most cases, synthetic latex is produced with the use of petrochemicals, which is a less environmentally-friendly process than harvesting and manufacturing all-natural latex. But it’s also typically much less expensive, which makes synthetic latex mattresses a more affordable option.
The chemical composition of synthetic latex is very close to that of natural latex, but the two products have somewhat different feels in a mattress. For example, synthetic latex is generally a bit less elastic than natural latex. That means that when you push your hand — or body — into synthetic latex, it doesn’t push back quite as readily. This gives it a slightly stiffer feel, and to the extent that it doesn't conform as well to your body's curves, it can be slightly inferior to natural latex for support.
The lower elasticity of synthetic latex could also cause it to pack down more easily over time. But on the other hand, synthetic latex has more uniform properties than a natural product, which some say gives it even greater durability overall.
Regardless of the type of processing used, synthetic latex has many of the same basic performance properties as all-natural latex. Both materials are highly elastic, which makes them both springy and responsive, and supportive under key pressure points.
Like all-natural latex, synthetic latex is neutral in temperature, which is a plus if you are concerned about “sleeping hot.” And like all-natural latex, synthetic latex is long-lasting, especially when compared with other types of mattress foam materials such as memory foam or polyurethane foam.