Not all inserts and boosters are created equally. As well as the multitude of shapes and sizes, covered here, you might also need to consider what your inserts and boosters are made from. For brevity from here on in I’m just going to talk about inserts, but the same is true of boosters too.

There are a few common fabrics used in nappy inserts. Each one has it’s own pros and cons. Sometimes they are blended together in an insert so you can get the benefit of each, whilst hopefully counteracting the disadvantages.

Below is a rough guide to the main fabrics, although remember that within each category inserts will be of varying quality and so it’s not simply the case that X will always be better than Y.


Certainly the cheapest fabric to manufacture, and therefore often included in some of the more affordable nappies.

Microfibre is entirely synthetic, created from fossil fuels. It requires water, energy and chemicals to produce. It will not biodegrade after use.

Microfibre cannot be placed directly against your baby’s skin as it will pull the natural moisture from their skin and make the area very sore. The microfibre fibres are also little hooks meaning they will scratch the skin’s surface which is why it feels a bit funny on your hands. Either stuff microfibre in a pocket, or place something else (either another booster or a liner) between the microfibre and your baby.

It is quick to absorb and holds up to 7 times its own weight in liquid. Great for flooders. It’s prone to compression leaks but, this can be overcome easily by adding a natural fibre to counteract the leak.

Microfibre inserts do not require any prepping before use, just one wash to remove manufacturing residues and you’re good to go. It will also dry very quickly.

It sheds micro plastics during the wash process. These micro plastics pollute water courses and oceans. But the shedding of fibres also means that over time (and I’m talking a significant number of washes here) the insert will lose absorbency as there is simply less fabric.


Cotton is a natural (plant based) fibre. Also a very affordable option.

Cotton is easy to care for. For boosters or anything without elastics/PUL you can wash at higher temperatures, tumble dry, or place directly against heat sources. Those in hard-water areas will find it goes crispy after multiple washes. It will instantly soften once your baby wets the nappy, but if this bothers you then you can shake the nappy or rub it against itself once dry to soften it up. Due to the natural oils it will require multiple washes to bring it up to full absorbency, up 10 washes in some cases.

It is the fastest absorber, you only need to try clear up some spilt water to see just how readily and easily cotton absorbs. This makes it perfect for flooding. It can also hold 27 times it’s own weight in fluid.

Available in a range of different weaves (such as Birdseye, Terry towelling, or waffle) and weights to offer different thicknesses. It can suffer from wear and tear, especially on edges of fabric (edgewear) where more friction will occur. Depending on weave and design of nappy they may not last more than one child. Bobbling is common too on flat weaves, although this tends to be more of a cosmetic issue.

Very intensive to produce. Cotton cultivation accounts for 16.5% of global pesticide usage, and yet is only grown on 2.4% of arable land. Organic cotton is produced using less pesticides (some natural and synthetic pesticides are still used but in moderate quantities). But the lower yield quantities means organic cotton requires significantly more water. Opt for unbleached versions where available, and if you can afford to. These lessen the environmental impact.

Overall I think cotton is very underrated from an absorbency perspective, although predominantly cotton nappies may not last for multiple babies due to wear and tear.


Bamboo, a man-made fibre, has ever-increasing popularity in the cloth nappy market right now. It is a type of rayon.

Bamboo can be grown without pesticides or herbiciders, and is the fastest growing plant on the planet.

Although it is derived from a plant, due to the manufacturing required it is considered a semi-synthetic or man-made fibre. There are three methods of bamboo production:

  1. Bamboo fabric can be created by using a mechanical process by crushing the fibres, adding natural enzymes, and spinning into yarn (similar to linen production), but this is expensive and time-consuming so rarely done. The environmental impact of this method is far less.
  2. The vast majority of bamboo production is a chemical process; taking bamboo chips and adding chemicals (caustic soda and carbon disulphide) to create a liquid pulp. This pulp is then pushed through a spinneret (fine sieve) and spun into yarn. This chemical method is split into two categories:
    1. Standard production, the cheapest option for a manufacturer and the worst for the environment. The vast majority (around 75-80%) of bamboo textiles are produced via this method. After processing the chemicals are discarded, and not always correctly. The chemicals used have known links to many health issues, irresponsible dumping causes issues not just for factory workers but people, animals and plant life in the surrounding area.
    2. Closed loop (or lyocell method) follows the same manufacturing process but the water and chemicals from the processing are recovered and reused (around 99.5% of chemicals can be captured). A far smaller, but thankfully growing, method which presents far less negative environmental impact.

Bamboo offers good levels of absorbency, although not particularly quickly. It is reasonably priced. Available in a range of different weaves, with bamboo Terry (pictured) being the most common.

Care must be taken not to dry bamboo against direct heat, such as a heated airer or radiator as this can damage the fibres. Bamboo inserts will require to up 5 washes to reach full absorbency. Bamboo is very soft to touch, although it will go crispy in hard-water areas this is not to the extent of other fabrics. It is also important to use a non-bio detergent if you have bamboo nappies as the enzymes in some bio detergents can eat away at the bamboo fibres over time, resulting in balding.

It is widely reported that bamboo offers antibacterial properties and is biodegradable. Whilst this information is true when bamboo is in its natural plant form, is it less likely post processing. For example it is the natural oils than contain the antimicrobial properties, the more you process the bamboo pulp the more you remove these natural oils. Under Canadian law companies are no longer allowed to make these claims without supporting evidence.


Hemp is a natural (plant based) fibre. is the most absorbent fabric and locks that moisture in well. It also boosts some excellent eco-credentials.

The most expensive fabric. Normally blended with cotton (at around a 45:55 hemp:cotton ratio). When blended with cotton, hemp will outperform bamboo for quick absorption (those graphics floating round the internet saying that hemp is the slowest absorber are wrong).

It is a natural material but a lot less resource intensive to grow compared to cotton, and less resource intensive to produce compared to bamboo. It is grown organically. Is biodegradable and compostable – the fabric will return to the earth once it reaches the end of its lifespan. Plus antibacterial, anti-fungal, and anti-allergen.

Prone to shrinkage from washing, ensure you reshape inserts whilst damp especially during the prewashing stage. Because of how well hemp holds onto liquid you will need to ensure you have your wash routine nailed as without sufficient washing it is more likely to have ammonia build-up. I’ve never personally had an issue despite using hemp heavily for years. Due to the natural oils hemp inserts can take up to 10 prewashes to reach their maximum absorbency. The downside of good absorption is a slower drying time.

Although hemp is excellent from an eco perspective you have to bear in mind that it contains a significant amount of cotton and therefore holds some of the environmentally negative aspects of cotton production.


A synthetic fibre with a lot of greenwashing.

Charcoal booster.

Generally these are made of a few layers (2-3 maybe) of standard microfibre, wrapped in an outer grey fleece. Because the microfibre layers are covered in fleece these inserts can go directly against your baby’s skin and will provide a stay-dry layer.

The outer fleece is made from bamboo nanoparticles with are heated to an extremely high temperature to burn them. Hence charcoal bamboo.

Manufacturers can get away with calling them ‘charcoal bamboo’ because that is a correct (albeit slightly misleading) description of the outer fleece. But this fleece does not have any of the properties you might typically associate with bamboo, such as good absorbency, because it’s a fleece (fleece cannot hold liquid).

Often marketed as a bamboo insert with odour reducing properties (which isn’t actually true). Their only real benefit is that they can hide stains, but then if you’re having persistent stains you need to troubleshoot your wash routine, not hide them.

In reality these inserts are often just microfibre. Of course microfibre has it’s place, but if you’re purchasing charcoal bamboo and expecting bamboo qualities then you may be disappointed.

There are of course actual charcoal bamboo inserts available. These have the same charcoal bamboo fleece (remember it’s just a grey fleece, there’s still no odour reducing properties), but inside the insert are layers of bamboo not microfibre. These will perform in the same way as a normal bamboo insert. It benefits from having a soft stay-dry layer but this also adds an extra bit of bulk so consider whether you need inserts that are able to go directly against the skin.

If the manufacturer or retailer doesn’t explicitly state the content of bamboo under the fleece, then assume these are microfibre.


Tencel , a man-made fibre, is the brand name of lyocell, produced by Austrian textile company, Lenzing.

Tencel and hemp inner from Kit and Kin.

Tencel is a natural fibre derived from wood pulp (eucalyptus trees) in sustainably harvested forests. Fabrics made from wood pulp come under the name rayon, so for example bamboo is also rayon.

The processing of Tencel is closed-loop, meaning the chemicals and water used in production get reused rather than dumped. It also uses less-toxic chemicals (amine oxide rather than caustic soda) than standard rayon production which is better for the factory employees and those living in the local area.

It is 50% more absorbent than cotton. And due to the fibre structure it is more absorbent than bamboo too.