Brittle or Peeling Nails
This does get into some technical details - but some people do want a detailed explanation for nail peeling or brittleness...
Nail Plate Composition
The nail plate is the hard part of the nail that grows out and is composed of three primary layers (but actually a much larger number of layers) of compacted dead cells (dorsal, intermediate and ventral nail plates). Without getting TOO technical the "toughness" of the nail plate relates to the alignment of the keratin fibers and to disulfide cross-links.
Nails Peeling:
To simplify, nail peeling is when the bonds between the layers of nails break. When these separated nail layers grow to the end of the fingers they are able to peel apart and fray.
Although there can be medical reasons for peeling nails - one significant cause is the result of a repeated series of the nail drying out and then being hydrated.
The stress of this repeated cycle of drying out / hydrating can cause the different layers of the nail to actually separate from each other. You can't apply anything to the nail to cause these separated nail layers to "fuse" back together. If you are starting with peeling nails, breaking the cycle of nail damage starts with stopping these layers from separating and then growing out the already damaged nail while helping to prevent layer separation on newer nail growth.
then wetting of the nails and then drying out etc. Without a proper protective layer on the nail plate it can dry out (especially in dry conditions like winter or in a hot dry climate). Repeated exposure to chemicals, nail polish, acetone nail polish remover and even just water can also help cause the issue. The repeated cycle eventually allows the different layers to separate from each other. As they separated layers grow out to the ends of the fingers it results in the frayed and peeling nail.
Nail Brittleness
Damage to the nail's protective coating can cause the nail to "dry out". This causes the nail to become brittle.
- harsh nail products (nail polish / acetone remover)
- gluing / application of fake nails or gel nails etc
- harsh drying climates (hot or cold)
- excessive exposure to water
- other chemicals (alcohol hand sanitizer etc)
- cutting cuticles (they act as a seal - skin to nail plate)
- poor nail care (pulling hang nails, biting nails)
What to do?
Try and avoid as many of the above issues as you can.
These things all strip out the protective elements of the nail plate and lead to the nail plate drying out which leads nail brittleness and possibly also to nail peeling. Environmental factors however can be difficult to change and that is why a simple 25 second daily application of FlexiNail helps. It works to penetrate the nail plate and help maintain the correct "moisture" content for the nail. Remember that too much "moisture" (think of the weak nails after coming out of a bath) is just as bad as not enough (dry, brittle, cracking and splitting).
If you are still reading... then you are REALLY interested in the human nail. Stop reading now if you aren't a chemistry geek.
The main chemical composition of the nail is keratin. There are alpha-keratin (helical) filaments and cystine rich (non-helical) keratins. The nail contains different amino acids and bunch up to form polypeptide chains in the keratin. There are covalent disulfide cross-links and linkages that are said to be responsible for nail hardness. In addition to these disulfide cross links there are also secondary bonds (polar linkages, peptide linkages, hydrogen linkages etc) within the keratin structure. All of this contributing to the unique structure of the nail. Chemistry is the primary determinate of how a product can penetrate (even a little tiny bit each time) into the nail plate. A proper protective nail plate coating will help the the water content of the nail stay in the 15 to 18% range. This is important and plays a role in the flexibility or elasticity of the nail.
The name "FLEX" in FlexiNail comes from the desired flexibility or elasticity in a healthy nail. You can chemically alter a nail to become hard (with formaldehyde for example) but a hard chemically altered nail is not what you want (not to mention you would have to apply formaldehyde!) Achieving and then MAINTAINING the correct balance of "moisture" in the nail plays a critical role in natural nail care.