Is ‘Over’ Bonding Real? We Find Out Whether You Should Put Down the K18
Main image – Esthergalvan/Stocksy
It’s the year 2025 and us beauty addicts have never been so spoilt thanks to the abundance of ingredients, treatments and products available. But when it comes to our hair, does being spoilt for choice mean we are overdoing it?
Cue: Bond building technology. A way to repair and strengthen the internal structure of the hair using products like Olaplex, K18 and Epres.
Thanks to their promise of ‘transforming’ hair from the inside out, these products have become more and more popular – despite their rocketing price tags – and now you can find ‘bonding’ claims in everything from shampoos to leave-in conditioners.
Image – Leandrocrespi/Stocksy
But are we now at risk of ‘over-bonding’ our hair, as I keep seeing people claim on my FYP? Particularly when combining repairing protein and bonding ingredients, which some have claimed can overload the hair and cause damage.
Here, lead trichologist and brand president at Philip Kingsley, Anabel Kingsley, and cosmetic chemist, Milan Scott, discuss the benefits of hair bonding, how it works and whether it’s actually possible to overdo it.
What are hair bonds?
Kingsley sets it out clearly. “Our hair is made of protein fibres known as Keratin,” she says. “Keratin is a powerful protein formed by the combination of eighteen different amino acids. Amino Acids are an essential component of healthy hair as they combine to form proteins used by the body to build tissue cells.” Clever huh?
So, what do these proteins do? “They form the building blocks of your hair, keeping it strong and healthy,” Kingsley continues. Unfortunately though the bonds can get easily damaged by, “for example, heat styling, colouring, perming [and] also UVB [which] can affect protein loss in the hair,” she says.
There are three main types of hair bonds; “Hydrogen bonds are the weaker bonds that can temporarily get broken by water and heat, like when we wet or flat iron our hair,” explains Scott.
“Salt or iconic bonds are also temporary bonds,” Kingsley continues. “They contribute to the strength and elasticity of hair and are broken by changes in pH or strong acidic or alkaline solutions. They can be reformed by returning the hair to a neutral pH.”
And finally, “disulfide bonds are the permanent bonds and they determine the shape of your hair,” Scott says. “They can get broken by chemical treatments like bleach or relaxers. They can also be broken by heat but not as easily.”
Kingsley adds, “Disulphide bonds are one of the strongest naturally occurring bonds. They also give your hair its elasticity and strength.”
So how does bond repair work?
Products like Olaplex and K18 help to fix broken bonds within the hair shaft. “When the hair’s outer layers are compromised (lipid layer and cuticle) this can expose the hair’s cortex (where the bonds are found) causing them to become damaged, weaken and break,” explains Kingsley.
Image – Studiofirma/Stocksy
“A bond builder helps to repair disulphide bonds in the hair’s cortex, reinstating hair’s strength and resilience to damage and breakage.” And Scott adds, “K18 mimics the natural keratin structure and helps realign the internal protein chains.”
Does it really work – and how long does it last?
Scott says its efficacy all depends on your hair’s level of damage, “so I think it’s important to manage your expectations,” she says. “They can definitely improve the strength, look, and feel of compromised hair but they aren’t a magic fix for severely damaged hair.”
And if you’re wondering if using bond repair products is good enough to replace a trim, you might be disappointed. “You cannot cure a split end, only temporarily seal them to stop them travelling further up the hair shaft creating shorter breakage,” Kingsley says.
Image – Leandrocrespi/Stocksy
“[Bond repair products] repair the bonds in the cortex (inner structure of the hair shaft – the cuticle is the outer) which prevents split ends from forming,” she adds. “The only way to cure a split end is to chop it off in way of a trim.”
How long the results last when using a bonding product is, again, down to the level of damage. “Some bond builders claim to have longer effects, but nothing is permanent,” Scott says. “If you’re still using high heat and frequently colouring your hair, you’ll likely get the best results when using those products consistently.”
Can using too many bonding products cause ‘over bonding’?
“Too much of any treatment can make your hair dry and heavy, especially if you’re lacking in moisture,” warns Scott. It’s a good point – imagine using a facial exfoliator daily when it’s only supposed to be applied once a week. Your skin would most likely become irritated and end up having zero glow.
“Overusing a product formulated to make hair stronger has been known to in-turn make hair brittle – when something is too strong, it can then also have the reverse effect and snap or break easily,” Kingsley says.
Image – Annatabakova/Stocksy
“However, this should not happen with a reputable, well formulated and clinically tested product.” She recommends following the instructions to a tee and applying one to two times a week.
This is why we love alternating between a moisturising treatment and a strengthening treatment each week. Live That Glow’s editor, Sally Underwood, has been using Phillip Kingsley’s moisture-boosting Elasticizer (£39 from Boots UK/ $53 from Phillip Kingsley US) once every two weeks, and then the brand’s Bond Builder Restructuring Pre-Shampoo Treatment (£30 from Phillip Kingsley UK/$43 from Phillip Kingsley US) every other week to try to restore her hair condition after prolonged anaemia – and she’s been thrilled with her results.
Can you use bonding products alongside protein treatments?
Kingsley says you can because they strengthen the hair in two different ways. “Bond repair products repair the disulphide bonds in the hairs cortex whereas protein treatments work to replenish the outer layer known as the hairs cuticle,” she explains.
However Scott suggests keeping an eye on how your hair is behaving. “If your hair is protein sensitive or already feeling hard, don’t layer them too closely,” she says. “Alternate them and listen to what your hair needs at the moment.”
So, which types should we use? “I would recommend using hydrolyzed proteins like hydrolyzed wheat, keratin, or silk and use them in moderation. These can penetrate the hair shaft without overwhelming it,” Scott says.
Does everyone need hair bonding products?
Kingsley says all hair types can use them, but to remember, “they are targeted to repair damaged hair,” she explains.
And Scott agrees, “not everyone needs bond builders,” she says. “If your hair is healthy and you’re keeping your routine low stress, you’re probably good without it.”
Basically, whilst everyone can use them, it doesn’t mean everyone necessarily needs to use them. And why spend the extra money if you’re hair isn’t damaged in the first place?
5 ways to get the most out of your hair bonding products
- “Use on clean hair so nothing blocks the active ingredients,” says Scott.
- “Pair with moisture so your hair stays hydrated,” she adds.
- “When it comes to thicker hair, usually you would need to use more of the product than it is suggested,” Kingsley explains. “This is to ensure that the ends of your hair are fully covered in the product so it can work to the best of its ability.”
- Judge your frequency of use with how much damage you usually cause your hair through styling. “For example, if you are heat styling daily, you will require treatments more regularly than someone who doesn’t,” she says.
- “Please don’t overdo it,” Scott adds.
The takeaway
So can you overdo it with hair bonding products? Well, it all depends on how often you treat your hair, after all, applying them too much can give the opposite results to what you’re using them for in the first place. Treating once or twice a week is what the experts recommend, with a side of following the instructions, listening to how your hair typically behaves, and taking into consideration your hair type.
If you don’t have damaged hair but what to enforce ongoing strength, by all means use hair bonding products – they can be applied on all hair types in moderation.
But first think about your budget – hair bonding isn’t always cheap. Consider whether you really want to spend money ‘fixing’ already-healthy hair unnecessarily with ingredients that are designed to repair damage. You know the saying – ‘if it ain’t broke, don’t fix it’ (or break the bank with it!)
Meet the experts
Anabel Kingsley is lead trichologist and brand president at Philip Kingsley.
Milan Scott, aka The Cosmescientist, is the powerhouse behind Keseana Cosmetic Labs, an innovative cosmetic R&D laboratory based in the Baltimore area.
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