Hair smoothening has become a go-to solution for those struggling with frizz, dullness, and unmanageable hair. While many love the glossy, sleek results, few understand what actually happens during the smoothening process. Is it just a surface-level cosmetic fix or does it change the structure of your hair What makes smoothened hair behave so differently
In this article, we will dive into the science behind hair smoothening, exploring how it works, the chemistry involved, and what makes it different from other hair treatments like straightening or keratin therapy.
What Is Hair Smoothening
Hair smoothening is a semi-permanent hair treatment designed to eliminate frizz, add shine, and make hair more manageable. Unlike rebonding or permanent straightening, smoothening does not entirely alter the structure of the hair. Instead, it relaxes the bonds in the hair shaft slightly, allowing the hair to become smoother and softer while retaining its natural texture.
Popular smoothening treatments include:
- Keratin Treatment
- Cysteine Treatment
- Hair Botox
- Taninoplasty
Each of these methods uses a slightly different approach and set of ingredients, but the core scientific principles remain the same.
Understanding the Structure of Hair
To understand how smoothening works, it is important to understand what hair is made of.
Each hair strand is made up of three layers:
- Cuticle – The outermost layer, made of overlapping cells like roof shingles. This layer protects the inner parts of the hair.
- Cortex – The middle layer, containing proteins mainly keratin and melanin which gives hair its color. This layer determines strength, elasticity, and shape straight, wavy, or curly.
- Medulla – The innermost layer, often absent in fine hair.
The hair’s texture and strength are determined by protein bonds in the cortex. These include:
- Hydrogen bonds – Weak and easily broken by water or heat.
- Salt bonds – Affected by pH changes.
- Disulfide bonds – Strong chemical bonds that maintain the shape of your hair.
Smoothening treatments mainly affect disulfide bonds, but unlike straightening, they do so more gently and temporarily.
How Hair Smoothening Works Step by Step
Step 1 Hair Cleaning Clarifying Shampoo
The process starts with washing the hair using a clarifying shampoo to remove dirt, oil, and product buildup. This helps open the cuticle layer, allowing the treatment to penetrate the hair more effectively.
Step 2 Application of the Smoothening Solution
Next, the chosen treatment solution keratin, cysteine, and others is applied to damp hair. This formula typically contains active ingredients that:
- Break or loosen the disulfide bonds slightly
- Add smoothing agents or proteins like keratin or cysteine
- Coat the hair strand to seal in moisture and reduce frizz
This step is where the chemistry happens.
Keratin-Based Smoothening
Keratin is a protein naturally found in hair. When applied as a treatment, keratin and conditioning agents fill the gaps in the hair shaft, making it smoother and shinier. While some traditional keratin treatments used formaldehyde to lock the keratin in place, newer formulas are formaldehyde-free and safer.
Cysteine-Based Smoothening
Cysteine is an amino acid that bonds with the hair’s natural protein structure. It works by temporarily rearranging the disulfide bonds, offering a gentler alternative to keratin treatments. Cysteine is ideal for enhancing natural texture without flattening curls completely.
Step 3 Heat Activation Blow-Drying and Flat Ironing
After the solution sits on the hair for 20 to 30 minutes, it is blow-dried and flat-ironed at high temperatures usually around 200 to 230 degrees Celsius. This heat serves several purposes:
- Activates the product and helps it bond to the hair
- Seals the cuticle, trapping the smoothening ingredients inside
- Realigns the hair’s keratin structure into a smoother, straighter form
The heat is critical because without it, the ingredients will not bond properly, and the smoothening effect will not last.
Step 4 Rinse and Final Blow-Dry
Depending on the treatment type, hair is either rinsed immediately or after a few days. Some treatments require a 72-hour wait before washing to allow the product to fully settle. After rinsing, a neutralizing conditioner may be applied to rebalance the pH and further seal the hair cuticle.
What Makes Smoothened Hair Look and Feel Different
After smoothening, hair appears shinier because a smooth cuticle reflects more light. It feels softer because gaps in the hair shaft have been filled. It becomes more manageable due to reduced frizz and tangling. Most importantly, it retains a natural look because it is not overly straightened.
The disulfide bonds are not permanently broken, unlike in rebonding. This means your hair gradually returns to its natural state over three to six months.
How Long Does Hair Smoothening Last
The longevity of results depends on:
- Hair type and porosity
- Product used such as keratin or cysteine
- Aftercare routine use of sulfate-free products and heat styling habits
- Environmental exposure sun, chlorine, saltwater
On average, hair smoothening lasts between three to five months. Proper maintenance can extend results up to six months.
Common Misconceptions Debunked
Myth 1 Smoothening Damages Hair Permanently
Fact Modern smoothening treatments, especially formaldehyde-free ones, are designed to be gentle. With proper care, they do not cause long-term damage.
Myth 2 Smoothening and Straightening Are the Same
Fact Straightening like rebonding permanently alters hair bonds for a pin-straight look. Smoothening is semi-permanent and enhances natural texture while reducing frizz.
Myth 3 Only Straight Hair Can Be Smoothened
Fact Wavy, curly, or frizzy hair can also benefit from smoothening treatments designed to enhance natural texture, not erase it.
Important Aftercare Tips
To maintain the effects and protect your hair:
- Use sulfate and paraben-free shampoos and conditioners
- Avoid washing your hair for at least 72 hours if required by the treatment
- Limit heat styling and always use a heat protectant
- Avoid swimming in chlorinated pools without protection
- Apply weekly deep conditioning masks to maintain moisture
Final Thoughts
Hair smoothening is more than just a beauty treatment. It is a carefully designed chemical and physical process rooted in hair science. By understanding how smoothening works, what it does to your hair structure, and how to care for it, you can make informed choices that lead to better results and healthier hair.
So, the next time you admire your smooth, shiny hair, remember that it is not just a makeover. It is a result of well-understood science and thoughtful care.
