Dealing with your frizzy curly hair can become a problem. We know how you feel as you dream of having smooth, shiny, straight hair. Many straightening and smoothing options are available, from keratin treatments to the Japanese straightening technique.
But which one will work best for you, and how do they differ? Which is better? We’re here to shed some light on the keratin treatment vs Japanese straightening technique, and both offer the same results.
These are two popular methods for straightening hair that are available today.
Keratin Treatment vs Japanese Straightening Comparisons
If you don’t have time to read our full article, a shorter version is available here: keratin vs Japanese straightening comparison table that summarizes the differences.
Feature | Keratin Treatment | Japanese Hair Straightening |
Main Purpose | Smooths frizz, adds shine, softens curl pattern | Permanently straightens the hair |
Chemical Process | Uses formaldehyde (or an alternative) to coat the hair | Uses ammonium thioglycolate and heat to restructure bonds |
Results | Smooth, shiny, and slightly straighter hair | Pin-straight, sleek hair |
Duration | 2 to 4 months (temporary) | 6 to 12 months (permanent, but new growth needs touch-ups) |
Hair Type Compatibility | Suitable for all hair types, especially frizzy/wavy hair | Best for healthy, strong, and relatively loose curls |
Hair Texture After Treatment | Natural movement, soft texture preserved | Very straight with less natural movement |
Time Required for Treatment | 1.5 to 3 hours | 3 to 5 hours |
Post-Treatment Maintenance | No washing or tying hair for 48–72 hours (varies) | No washing, tying, or styling for 72 hours |
Damage Level | Minimal to moderate (if overdone) | Moderate to high (can cause dryness or breakage) |
Coloring Hair | Can be done before or after treatment (safer after) | Better done after therapy due to harsh chemicals |
Styling Flexibility | Allows for waves and curls with heat tools | Hair stays straight—difficult to curl afterward |
Fade Over Time | Gradually fades, hair returns to its natural state | Grows out—new hair will show natural texture |
Cost Range (USD) | $150 – $400 | $300 – $600+ |
Ideal For | Frizz control, shine boost, easier styling | Long-term straightening with no daily flat ironing |
Maintenance Products Needed | Sulfate-free shampoo, keratin-safe products | Protein-rich, hydrating products to prevent dryness |
Great, now let’s explore them in detail one by one.
What is a Japanese Hair Straightening Treatment?

The Japanese straightening treatment is also known as the Japanese straight perm, thermal reconditioning, or the Yuko system. While we don’t provide this service at our hair wellness spa, it’s a popular and effective hair straightening method.
One thing is for sure: it provides a permanent hair treatment to make your frizzy, wavy, or curly hair straight and sleek, similar to a keratin hair treatment. The process offers permanent hair straightening by restructuring the internal bonds of your hair.
During the treatment, stylists use a chemical solution combined with heat, like a flat iron, to achieve long-lasting straightening results. The therapy straightens hair and gives it a smooth and glossy texture.
Great, but what are the steps of the Japanese straightening process?
Steps For a Japanese Straight Perm
1. Hair Consultation & Analysis
Before undergoing a Japanese straightening treatment, we recommend consulting a professional stylist to help assess your hair type, condition, and desired results. To customize a treatment for you, the stylist will analyze your hair to determine its thickness, texture, and whether you have had any previous chemical treatments.
2. The Application and Straightening Process
After consulting with your stylist, the first step is to apply a product to break down your hair’s natural bonds to help soften and straighten the hair follicles. The application will stay on your hair for a while, allowing the solution to do its job.
The solutions are rinsed, and your hair is blow-dried. Then, your stylist will use a flat iron to help straighten each section of your hair. The iron reshapes your hair’s internal structure during this step to achieve the straightened effect.
3. Neutralization, Rinsing, and Blow-Dry
Your stylist will then apply a neutralizing solution to set your hair’s new structure and prevent it from reverting. Your hair is then rinsed to remove the chemicals and blow-dried to reveal the straightened results.
The entire process can take between 3 and 5 hours, depending on the thickness and length of your hair.
A thermal reconditioning treatment lasts until your hair grows out. A worthy note is that while it leaves you with a permanent treatment, your new roots will grow in your natural texture.
So, you’ll need touch-ups every six months or when you notice new hair growth. The touch-up process treats the regrowth near the roots to smooth your hairstyle.
Does The Japanese Straightening Treatment Cause Damage?
The hair straightening method contains chemicals that can damage hair if it is not done correctly or if it is already unhealthy.
For this reason, we recommend that all our clients have a professional hair consultation.
Yet, when done by a professional, it is considered safe compared to other chemical straightening treatments, such as rebonding or relaxers.
Pros and Cons of Japanese Straightening
Pros | Cons |
Ultra-Smooth Finish: Delivers sleek, naturally straight hair with a polished texture. | Chemical Exposure Risk: The process uses strong chemicals that can weaken hair if overdone. |
Long-Lasting Results: With proper care, effects last for many months, often up to a year. | Irreversible Straightness: Once treated, the straightness is permanent and will not fade naturally. |
Low Maintenance: Minimizes the need for daily heat styling or frizz control products. | Regular Root Touch-Ups: New growth retains its original texture and requires re-treatment every 6 months. |
Time-Saving Routine: Cuts down morning styling time, making it ideal for busy schedules. | Limited Styling Flexibility: The hair remains stick-straight, making it harder to re-curl or create volume. |
Cuticle Sealing Effect: Some notice healthier-looking hair post-treatment due to reduced breakage and sealed ends. | Color Compatibility Issues: Not ideal for color-treated hair with henna or red tones, which can shift or react unpredictably. |
Confidence Booster: Ideal for individuals who struggle with persistent frizz or unpredictable curls. | Upfront Investment: The treatment can be pricey and requires professional application for best results. |
What is a Keratin Treatment?

Now, we focus on what we do best here at Haste Urban Hair Spa, the Keratin treatment. So, what is the difference between Keratin and Japanese straightening?
The main difference is that a Keratin treatment is a semi-permanent smoothing method using a keratin-based formula. The formula coats the hair shaft, delivering smoother, straighter, and shinier hair.
If you’re looking for frizz reduction with improved manageability that doesn’t require permanent straightening, your hair needs this.
Our Steps For a Keratin Treatment?
1. Hair Analysis
As with Japanese straightening, we recommend a hair consultation and analysis to determine if a Keratin treatment is appropriate. We can then assess your hair’s health and learn about your hair routine and desires.
2. The Keratin Treatment Process
Once we determine your personalized treatment, we will wash your hair to remove buildup, which helps to open your hair shaft to absorb the keratin. We will then apply the keratin solution and let it process for up to an hour, depending on the type of hair and the product used.
After applying the treatment, we will blow-dry and flat-iron your hair to seal in the keratin and help it bond with your hair. Once completed, our stylists will provide you with post-treatment care.
The entire treatment can take between 2 and 3 hours. You will need to wait up to 72 hours before rewashing your hair. The results should last about three to five months, as they will fade over time.
We recommend repeating the process every three to five months to maintain your look.
Does a Keratin Treatment Cause Damage To Your Hair?
No, a keratin treatment does not damage your hair. Our treatments contain nourishing ingredients such as keratin proteins, vitamins, botanical extracts, and amino acids.
Still, it includes using a chemical solution to help smooth the hair and seal the formula. For this reason, we recommend you have it done by a professional who knows the procedures.
Pros and Cons of Keratin Treatment
Pros | Cons |
Smooths and softens hair, reducing frizz and creating a silkier, sleeker texture. | Chemical Exposure: Some formulas contain potent ingredients that may trigger sensitivities. |
Easier Styling: Cuts down blow-dry and flat iron time, making day-to-day hairstyling more straightforward. | High Cost: Professional treatments can be expensive and often need maintenance products. |
Semi-permanent results: Lasts between 3 and 5 months, offering a middle-ground commitment. | Not Suitable for Everyone: May cause reactions in individuals with allergies or sensitive scalps. |
Works on Most Hair Types: Compatible with straight, wavy, and lightly curly textures. | Gradual Fading: Unlike permanent methods, the effect wears off over time, requiring reapplication. |
Improved Hair Manageability: Makes hair feel more controlled, healthy-looking, and shiny. | Post-treatment care requires sulfate-free products and a specific aftercare routine to maintain the results. |
Which is Better: Keratin or Japanese Straightening

When it comes to keratin treatments vs Japanese straightening, it comes down to your personal preference. But if you’re undecided, then we can help you with your decision-making, as there are four differences between them:
- The duration differs as the Japanese straight perm is permanent, and the Keratin treatment is semi-permanent, lasting up to five months without permanently altering hair structure.
- Even the process differs, as the Japanese hair straightening involves a chemical process that breaks down the internal bonds of your hair. While the Keratin treatment uses a keratin-based formula, it provides a protective layer for your hair.
- With Japanese straightening, damage can result from the chemical solution used and from adding heat styling. At the same time, the Keratin treatment is less damaging, involves fewer chemicals, and is safer and healthier.
- The key ingredients in your Japanese straightening treatment are ammonium thioglycolate, compared to keratin, protein, and possibly formaldehyde in keratin treatments.
Hence, choosing the best treatment for frizzy hair depends on your desired look, the duration, and personal preferences. If you prefer low maintenance, then Japanese straightening is what you need, as you only need to retouch your hair every six months when the roots start to grow.
A Keratin treatment will gradually fade, bringing your hair back to normal, and you’ll need to get regular touch-ups every three to five months. Still, you do get less damage with a Keratin treatment.
Also, learn about hair botox treatment and how you can use it to restore your hair to health.
Keratin Treatment vs Japanese Straightening: Is It For Everyone?
Both treatments work well if you have frizzy, curly, or wavy hair and want to achieve smooth, straight hair.
Still, if you have hair with the following conditions, we recommend contacting a professional stylist before having any of these treatments:
- You dyed your hair red, bleached, or used henna tone colors within six months.
- If your hair is 70% gray or you’ve had it color-treated.
- You are concerned about the potential results or volume of the treatment if you have fine hair.
- You have African American Hair with different curl patterns and thickness.
When you visit our hair and scalp spa in Boston, we can provide a professional assessment to determine what works best for your hair.
Keratin Treatment vs Japanese Straightening After Care
You must follow proper aftercare to achieve the best results, regardless of which hair straightening treatment you choose. For both techniques, we recommend:
- Do not wash your hair for at least 72 hours after your treatment.
- Invest in sulfate-free hair products and wash your hair with lukewarm water.
- Use a sulfate-free conditioner and a wide-tooth comb when hair is damp.
- Refrain from using strong chemical treatments, such as coloring and bleaching.
- Schedule regular trims to help remove split ends.
- Also, use an anti-humidity product or styling serums to protect your hair against humid conditions.
Keratin vs Japanese Straightening: Pros & Cons
Treatment | Pros | Cons |
Keratin Treatment | – Smooths frizz, adds shine- Easier styling- Semi-permanent | – Wears off in 3–5 months- May contain strong chemicals |
Japanese Straightening | – Permanently straightens hair- Long-lasting, low-maintenance- Sleek, polished look | – Permanent result (no natural curl return)- Can cause damage if overdone |
Wrap-Up: Keratin Treatment vs Japanese Straightening
Choosing between a Keratin treatment and Japanese hair straightening depends on your hair goals, daily routine, and willingness to commit to long-term results.
If you want smoother, frizz-free hair while keeping your natural wave and flexibility, choose a Keratin treatment that offers low-damage, semi-permanent results with fewer risks.
Yet, if your goal is very straight hair with little styling, we recommend the Japanese straightening option. However, ensure your hair is healthy enough to handle the strong chemicals.
No matter which you choose, professional guidance is essential. At Haste Urban Hair Spa, we’re here to help you make the best decision for your hair’s health and personal style.
FAQ
Can I switch from a Japanese straightening to a Keratin treatment?
Yes, but you must wait 6–8 months after your last Japanese straightening session and consult with a stylist. Combining treatments too soon can damage your hair.
Will either treatment eliminate frizz?
Keratin significantly reduces frizz but doesn’t entirely remove it. Japanese straightening eliminates frizz by permanently straightening the hair.
Can I color my hair after getting either of these treatments?
Wait at least 2–3 weeks before coloring your hair post-treatment for best results. Japanese straightening can be more reactive to color, so it’s always best to consult a professional.
Which treatment is safer for damaged or color-treated hair?
Keratin treatments are safer for color-treated or mildly damaged hair, as they are less harsh and more conditioning than Japanese straightening.