All hairdressers know that keratin is a naturally occurring protein which forms the main component of hair – and has long been a buzzword in the industry. However, are you just as clued up on the three bonds that form the structure of the hair? Understanding these could be crucial in helping your clients achieve the healthy hair of their dreams…
The Three Bonds within Hair
There are three bonds, also known as side chains, within the hair: hydrogen bonds, disulfide bonds and salt bonds.
- Hydrogen Bonds These physical bonds account for about one-third of hair's strength and can be broken by water or heat. They can be reformed by drying or cooling the hair.
- Disulfide Bonds These chemical bonds are stronger and fewer than hydrogen and salt bonds and cannot be broken by water or heat – however they can be broken by chemicals, for example in colouring and perming. They are the key factors in supplying hair its strength and durability.
- Salt Bonds These physical bonds account for about one-third of hair's strength and can be broken by changes in pH or strong acidic or alkaline solutions. They can be reformed by normalising the hair's pH level.
Jez Barnett, Managing Director of Fabriq, says: “We’re often taught about hydrogen bonds when it comes to styling and blow drying, and hear about disulfide bonds when it comes to colouring and perming, however salt bonds are a rarer topic of conversation.”
What are Salt Bonds?
Jez breaks down the science behind salt bonds, explaining: “Salt bonds are ionic and as such, are often referred to as ionic bonds. This means they have a magnet-like attraction and form between the hair's positively charged and negatively charged amino acid side chains (these opposite charges are naturally attracted to each other). Salt bonds help stabilise the keratin protein chains, contributing to the hair’s strength and elasticity.
“Salt bonds can be semi-permanent or temporary. In styling they are temporarily disrupted by changes in water or heat (such as during blow drying and heat styling) and reform as the hair dries or cools.”
How do Salt Bonds Affect Hair?
The extent to which salt bonds are broken can determine the hair’s texture and manageability, as a significant portion of the hair’s strength is compromised when salt bonds are broken. Jez explains how different pH levels can affect salt bonds, and thus the health of hair, telling us: “Acidic conditions reinforce and strengthen salt bonds, while they are weakened or broken by alkaline conditions. Chemical services, excessive heat styling and general ageing make hair more alkaline and more negatively charged. This can result in even more damage and frizz.”
How to Repair Damaged Salt Bonds in the Hair
Protein-based masks and treatments can nourish and repair hair, including the salt bonds. This works thanks to the low pH level of these products and treatments, which strengthen the salt bonds by reinforcing the electrostatic attraction between the charged amino acids in keratin, leading to stronger, more stable salt bonds and hair.
Jez shares: “A 5–10-minute leave-in mask may deliver benefits that last a few washes, while a deeper penetrating protein treatment can give a full month of repair. With this repair comes improved manageability.” However, be sure to keep an eye out for clients that might be overdoing bonding treatments at home, as this can lead to protein overload.
For more long-term results, Jez says: “For permanent repair we have Fabriq Reset, a treatment which repairs and smoothes hair with low pH proteins that overload the positive charges to interrupt the salt bonds; this semi-permanently restructures the salt bonds and prevents curls and frizz from forming.”
Now that you’re clued up hair bonds, why not take a moment to find out more about the benefits of collagen on the hair?
