Below is a full review of my in-salon keratin straightening treatment from how the treatment works, the process, steps to maintain and my experience from start to finish when the treatment faded from my hair.

Keratin straightening is something I had considered over 15 years ago, in my early 20s, and the hairdresser I had gone to back then said it damages the hair and the fumes are harmful; so I did not get it done and did not really think about it again. About 7 months ago my regular hairdresser got in touch with me and asked if I would be willing to get a keratin straightening treatment at a discount so she could have some before and after photos to show clients using a new brand that she had just gotten. Keratin treatments are expensive, costing between $250 to $450, and time consuming, taking anywhere from 2 to 4 hours, depending on formula, hair texture and hair length. If I recall correctly, my hairdresser was charging $125 per hour. The whole process took 3-1/2 hours; 30 minutes to do a clarifying wash and blow dry and 3 hours from the time the product was applied to my hair to the last blow dry (and my hair was rather short).
A bit on keratin treatments, from my own reading, mostly from here; as I understand, a keratin treatment is a semi-permanent straightening treatment that smooths, reduces frizz and adds shine to the hair by using formaldehyde, formaldehyde derivative or ingredients that release formaldehyde, along with a flat iron, to cross-link bonds in the hair, resulting in smoother, straighter hair. Treatments containing formaldehyde last longer and get the hair very shiny and sleek/straight (like the Brazilian Blowout).
Glyoxylic acid is a gentle formaldehyde-free ingredient and provides more of a smoothing treatment rather than straightening, however, according to Cosmetics Business, releases formaldehyde at high heat, allowing it to smooth the hair. Glyoxylic acid is the ingredient in the at-home smoothing treatment O’Wow.
A keratin treatment is different than the Japanese hair treatment and relaxer that permanently break the bonds in the hair using ammonium thioglycolate and sodium hydroxide (these are more effective on very curly/coiled hair, but more damaging with noticeable grow-out).
I have also read that keratin treatments work by “injecting” the porous parts of the hair with protein so it feels smoother and healthier and/or sealing the hair with a coating of protein. I suspect this is not referring to keratin straightening, but rather a product using protein and amino acids like HairWellness from Noir Wild to reduce frizz and help repair damaged hair, with results lasting 2 to 4 weeks. Keratin is also an ingredient in the in-salon treatments, so likely helps in this way as well.
I skimmed an article that said formaldehyde is released bit by bit from the hair over time, causing the treatment to fade; I wanted to read more about this, but cannot find the article now.

The following can help maintain the keratin treatment:
- Before the treatment, start with clean, clarified, dry hair.
- After the treatment, do not get hair damp or wet for 72 hours.
- Do not dent the hair for 72 hours. This includes up-dos, ponytails, braids, hairbands, sunglasses on the head, hair accessories and tucking the hair behind the ears.
- Wash less frequently using lukewarm/cool water.
- Do not use shampoos with sulfates or salts.
- At night, use a silk pillowcase or tuck the hair in a silk bonnet.
- If coloring the hair, this should be done before the keratin treatment, as it seals in the color and provides a protective coating to help hair color from fading. If coloring after, wait at least 3 weeks, as the color will not penetrate the hair as well. To add some confusion, I also read that color should be done after a keratin treatment as the treatment can cause fading.
- No swimming in chlorinated water for 2 weeks.
- Use heat protectant and do not use high heat.
- Use a boar bristle brush to smooth the hair.

A bit about my hair, from left to right (check out my hair story here):
- Grow-out from a previous cut and color; the hair felt and looked quite healthy. This is my natural wave.
- Decided to go blonde; it started to look progressively worse as time went on.
- Stopped bleaching and let it grow. The hair was breaking and dry, my nice waves were gone and nothing I did improved the hair.
- Cut out a lot of damage and went back to brunette. This photo was taken just after getting it cut and colored at the salon.
My hair is thin, dry, frizzy and feels coarse. It has no shine or softness. I cannot just leave my hair air dried or blow dried, as it poofs into a frizzy, wavy dome around my head. I either need to tie it back or flat iron and/or curl; styling took me about 45 minutes in the morning. My hair gets frizzy and poofy in rain, snow and humid weather. It tangles easily with shampooing or on a windy day. Previous to the treatment I was washing my hair once a week, as it was so dry and took a while to feel oily. My hair was breaking off at the underside at the back hairline and I was loosing a lot of hair in the shower.
My hairdresser used Professional Keratin by Macpaul. Macpaul uses a formaldehyde-free formula (I could not find the ingredients) with three in-salon services in one bottle; straightening, smoothing and frizz reduction, with processing time and number of flat iron passes differing depending on the treatment chosen.
Straightening treatment:
- Processing time – 60 minutes on thin hair and up to 90 minutes on curly hair.
- 10 to 12 flat iron passes.
- 4 levels of curl reduction.
- Lasts 3 to 6 months.
Smoothing treatment:
- Processing time – 50 minutes.
- 7 to 9 flat iron passes.
- 3 levels of curl reduction.
- Lasts 1 to 3 months.
Frizz reduction treatment:
- Processing time – 30 minutes.
- 4 to 6 flat iron passes.
- 2 levels of curl reduction.
- Lasts 1 month.
Macpaul Professional Keratin steps:
- Start with an in-salon clarifying wash and dry.
- Section hair and apply treatment from roots to ends with a brush and comb through.
- Allow treatment to process on the hair (I had 90 minutes).
- Lightly rinse 50-70% of the product and towel dry.
- Blow dry straight section by section with a round brush.
- Flat iron thin sections of the hair section by section at 230.C (446.F), with a lower temperature for colored or damaged hair (I had the high temperature).
- Rinse and blow dry.
I got the keratin straightening treatment one week after getting the cut and color from a different stylist; the cut was not great and did not look good straight, and the color was a shade darker than my natural hair (which I did not ask for and did not like).
When my hairdresser applied the keratin treatment, she parted my hair in a mid part (how I usually style it); this helps the hair fall where it is supposed to when air drying, blow drying or styling. This was particularly helpful for my bangs (fringe) falling into the right place rather than them being parted in the middle (where they wanted to lay previously).
When the treatment was on my hair it had a floral/fruit scent and had no stinky fumes when flat ironing. My scalp was itchy for a few minutes as it was processing. The treatment itself, as it was processing on the hair, lightened my hair a shade and the flat iron lightened it a further shade; strange since the keratin treatment is supposed to seal in color. I was not particularly upset by this, as my hair was too dark anyway; however, I do not really like the auburn tones in my hair.
For the photos below, I used the same products for each; Briogeo Be Gentle, Be Kind Smoothie shampoo and conditioner, a leave-in conditioner on wet hair and Olaplex No. 7 oil on wet hair. When blow drying, I used the Briogeo Blossom and Bloom Volumizing Spray. After the hair was dry (blow dry or air dry), I applied the Olaplex oil (a necessary step to smooth the hair) .
I experimented with a couple different hair products; heavier products like the Kevin Murphy Hydrate Me shampoo and conditioner felt quite heavy on my keratin treated hair, likely because of the heavier hydrating ingredients and silicones.
My hair got oilier much faster because of the straight, frizz-reduced hair and I had to go from washing once a week to twice a week and even then, I probably could have washed my hair every second day. Before the keratin treatment my hair did not have much volume; with the treatment I had even less volume and a volumizing spray was a necessary step. Rain and humidity had no effect on my hair; it did not get frizzy or poofy.
I noticed that my hair was pretty much impossible to tangle; with wind, using drying or clarifying shampoos or blow drying the hair did not make my hair tangled or knotty and it was easy to get a wide-tooth comb through it, wet or dry.

In the before photo, my hair is air dried and is wavy and frizzy. It feels dry and coarse and has no shine. Directly after the keratin treatment, the hair feels heavy, a bit sticky, weighed down and there is not a lot of movement. I could not wait to wash my hair.

I got the treatment done the day after the above before photo, so the poof and frizz has calmed down.

Week 1 (blow dried) – The hair is shiny, straight and feels soft. The fringe is laying where it is supposed to.
The hair air dries twice as fast after the keratin treatment and a rough blow dry takes about 2 minutes. I do not use a round brush while blow drying; just dry my hair upside down, directing the hair dryer from root to tip a couple times. The hair is straighter with less frizz on blow drying as opposed to air drying. There are fly-aways and a bit of poof and the hair is not slick-straight even after blow drying. To help with this and to touch up the bangs, I use Olaplex No. 7 oil after the hair is dry.
After air drying, since the hair has some wave and poof, I use a flat iron on a low temperature with large sections of hair and a straight look is achieved with one pass.
My hair stopped breaking off at the back and there was not as much hair in the shower.

Week 3 (air dried) – So impressed with how the bangs look after being air dried. Previously, they would curl, wave and frizz up all over the place. The hair has some wave.

3 months (blow dried) – Second day hair. I sleep with my hair tucked up into a silk bonnet to reduce friction.

5 months (blow dry) – The hair has a bit of wave and the bangs have begun to curl (I trim these about every 2 to 3 weeks). There is some fly-away hair.

5 months (air dry) – More wave; still has some shine and still feels soft.
The Macpaul Professional Keratin lasts up to 6 months. By 6 months my hair still felt soft, did not have much frizz, and I was not certain it had completely faded.

7 months (blow dry). No hair oil applied. My hair looks and feels quite different compared to 2 months ago. It feels more coarse, has more frizz and poof and is not as shiny. The treatment has now faded. I am surprised it dried pretty straight.

7 months (blow dry) – Before and after applying Briogeo hair oil.

7 months (air dry). No hair oil applied. A lot of wave and frizz now.

7 months (air dry). Before and after Briogeo hair oil.
Now that the treatment has faded from the hair (I forgot how annoying and frizzy my hair actually is), I am still left with softer, healthier-looking and healthier-feeling hair than previous to the treatment. I would get a keratin treatment again, but will likely try the two above-mentioned home treatments before getting one done in the salon.
Thank you for reading.