Keratin, Cysteine, Thermal Reconditioning, & More!
We’re revisiting one of our most popular posts, Cysteine vs. Keratin: Which Is the Better Hair Straightening Treatment? In this expanded post, we’ll give you a broader comparison.
Before Straightening, Please Note
Everyone’s hair is different, so remember the saying, “Your mileage may vary!” For this post, we’re providing a simple breakdown of each service. This breakdown includes application time, longevity and upkeep, as well as the average cost. Different people may have different outcomes. For best results, consult with a stylist beforehand. Then, you can decide which straightening system is right for your hair and lifestyle before undertaking a treatment. Finally, follow the after-care instructions provided by your stylist. After all, proper aftercare ensures the health of your hair and the longevity of the service!
How It Works
Hair is constructed from a strong protein called keratin. Keratin contains sulfides, which, when they bond together, create a disulfide bond (chemical side bond), which is responsible for the wave patterns and curls in a person’s hair structure. Therefore, the curliness of your hair and its curl/wave pattern is determined by the number of its disulfide bonds. Disulfide bonds can’t be broken by water or heat. In contrast, physical side bonds (such as hydrogen and salt,) can be broken by water and heat. Thus, the main difference between heat straightening and chemical straightening is which kinds of side bonds you break.
The easiest, least-permanent hair straightening system is heat straightening. This can be achieved with a blow dryer and/or flat iron. Here, the physical side bonds (hydrogen and salt) are broken when the hair is washed (salt), dried, and flat-ironed (hydrogen.)
Application Time: Variable, depending on your hair length, curl pattern, and tools used.
Lasts: Until the next time hair gets wet (including rain and humidity)
Average Cost: Equipment costs or salon visit for styling service. Flat iron or hair dryer, variable cost. Generally, $35-150
- Least chemically damaging
- Not permanent, so you can change your style
- Can be done with or without a professional
- Least costly, as tools are a one-time expense
- Can cause heat damage to the hair when done often
- Doesn’t get hair as straight or tame frizz as uniformly as chemical straightening
- Requires constant upkeep
Chemical Straighteners (Relaxers)
Chemical straighteners (sometimes called perms or relaxers) use chemicals different from the hair’s rebonding counterparts to change the curl/wave pattern of hair. This straightening system doesn’t fully straighten the hair, but rather softens and loosens the curl pattern. To achieve a fully straight look, additional heat styling is often required. There are two basic kinds of chemical relaxers. The first uses a lye base, such as sodium hydroxide. The second uses a non-lye base, such as guanidine hydroxide. Because this procedure requires more frequent touch-ups, it’s easy to damage hair from overlapping chemicals.
Application Time: 1-2 hours, variable to the length and density of hair
Lasts: 6-8 weeks
Average Cost: In salon: $50-$150+; At home: $15-$50
- Faster than other chemical straighteners
- Can be performed by a professional or at home
- Doesn’t fully straighten hair
- Can cause burning or scalp irritation if left on too long
- Chemicals used can leave hair dry and brittle
- Requires frequent touch-ups
- Ongoing styling required
Thermal Reconditioning/Rebonding (Japanese Straightener)
In a thermal reconditioning/rebonding treatment (also called the Japanese Straightener,) the chemical bonds of your natural curl pattern are broken, re-structured into a different pattern, then re-bonded via a neutralizing agent. This is considered a permanent straightener, as treated hair will not revert to the original curl pattern. However, it requires maintenance, because new growth will come in with the original curl pattern.
Application time: Up to 8 hours
Lasts: Permanent effect on treated hair, must be applied to new growth every 6-9 months
Average Cost: $500-$1,000+
- Sleek, glassy effect
- Permanently alters treated hair
- Will not revert to the natural curl pattern
- Requires no additional styling
- Fades colored hair or highlighted hair
- Color treatments must be performed before rebonding service
- Hair won’t hold a curl after treatment, so it’s a commitment
- Long application time
- Must be performed by a professional in a salon setting
- Higher cost
Cysteine Hair Straightening
Cysteine is a nonessential amino acid naturally occurring in keratin and other proteins. Chemically, cysteine is more gentle than keratin treatments. Additionally, it doesn’t use formaldehyde or derivatives in its formulation. Depending on the hair’s natural curl pattern, length, and density, cysteine straighteners can reduce curl by 60-70%. However, it requires a 2-month wait time between other chemical treatments, such as color or highlights. This straightening system is considered semi-permanent.
Application Time: 90 minutes-4 hours, subject to the hair’s length and density
Lasts: 3-4 months
Average Cost: $125-$400
- No formaldehyde
- Can be used with color treated hair or after other hair relaxing services, but other chemical treatments must be performed BEFORE straightening treatment or with a 2-month interval following
- Considered safer and gentler than keratin treatments
- Semi-permanent process
- Not recommended for home application
- Frequent shampooing reduces efficacy
- Requires sulfate-free shampoo to be effective
- Cannot be used with henna or hair color containing metallic dye salts
Keratin Hair Straightening (Brazilian Blowout)
As mentioned earlier, keratin is a naturally-occurring protein found in hair. Here, there is a slight distinction between a keratin treatment and a keratin straightening service (Brazilian Blowout.) In a keratin straightening service (Brazilian), a clarifying treatment opens the cuticle. Next, keratin is applied to the activated cuticle. Finally, the shape of the hair is set with a flat iron, sealing keratin into the hair shaft. It’s important to note that in this service, formaldehyde is often a main ingredient. Proper ventilation is required, and the service must be performed in a salon setting.
On the other hand, most keratin treatments (such as Goldwell’s Kerasilk Control, Keratin Complex treatment, Cezanne Perfect Finish, and Trissola Solo) do NOT contain formaldehyde. Keep in mind, formaldehyde-free formulations won’t provide the same sleek, glossy effect as keratin treatments with formaldehyde, nor will they last as long. Formaldehyde-free keratin treatments average around 2-4 months, while Brazilian Blowouts generally average 4-6 months. Always ask your stylist for ingredient specifics if you have a particular concern.
Application Time: 90 minutes-4 hours
Lasts: Keratin treatment (semi-permanent) 2-4 months; Keratin straightener (Brazilian blowout) 3-9 months
Average Cost: Varies from $300-$850+
- Glassy, sleek finish
- Shortens blow-dry time by 40% to 60%
- Lasts 3-9 months
- Can safely use with color-treated hair, including lightened hair
- Unlike Japanese Hair Straightening, the chemicals used in this service don’t open or break the hair cuticle.
- Can wash hair immediately after treatment
- No risk of damage with repeat applications
- Contains formaldehyde
- Can fade hair color
- Requires sulfate-free shampoo for maintenance
- No more than 3 applications recommended per year
Now that you’re a straightening system pro, ready to get your hair sleek & skinny? Use Vagaro to find a salon in your area in your area that offers the perfect straightener for your hair!
Header Image: Studio B Films