I challenged Marta Ferreira, from the Blog The skin I live, writing with me articles on the Hair Schedule and the Curly Girl Method analyzed in the eyes of science, in a series of 4 publications.

The first article in this series can find here, the second here, the third here it's the room here.

Can hair finishing be done with conditioner or just finishing creams?

Both of these products have the function of facilitating the act of combing the hair, through the lubrication of its shaft and can leave some residue on the hair when used.

In terms of composition, these products are apparently similar.

However, caution is needed when using the conditioner to finish the hair due to the possibility of having preservative ingredients in certain quantities that are not allowed by the EU in non-rinse products (such as methylchloroisothiazolinone and methylisothiazolinone) as they may contain a greater concentration of these ingredients and may lead to contact allergy. In the case of styling creams that are not rinsed, the concentration of ingredients that may leave residue on the hair will be slightly reduced and will be able to be left on the hair as they are formulated for this purpose. (1)

What ingredients protect hair from UV rays?

For the summer, at a time of greater sun exposure, using a product with UV protection should be useful to prevent hair from being damaged by the sun's rays - the sun increases the porosity of the hair and can even modify the natural color.

The most common ingredients in hair care products are: Octylmethoxycinnamate (ethylhexyl methoxycinnamate or octinoxate), Cinnamidopropyltrimonium chloride, Benzophenone-3, Benzophone-4 and Quaternium-95.

However, it will be difficult to determine in these products leave in what is the concentration of these ingredients, if they effectively protect the hair completely from UV rays and if they will be evenly spread over the hair depending on the amount applied, since the concept of sun protection factor does not apply to hair. It is necessary to bear in mind that although the cream protects from sunlight, it does not mean that the hair does not look dry due to heat dehydration.

A good way to protect your hair from lightning is to wear a hat with a denser fabric that can cover much of the sunlight.

Humectants / Anti-Humectants in hair on damp days - Glycerin and other humectants in finishing creams on rainy and humid days cause more frizz?

First of all, it is important to clarify that the “anti-humectant” concept does not exist. This term is sometimes used to refer to emollient and occlusive ingredients, as they limit the permeability of hair to water, but these ingredients not only do not prevent wetting, but also improve its durability. Humectant means it attracts water, however, this category can involve many categories of ingredients, including salts, glycerin, plant extracts, hyaluronic acid, hydrolyzed proteins, sodium PCA, lactic acid, urea, and other ingredients, but not all are the same , and may behave differently on the hair. (2)

On the other hand, and since humectants are very soluble in water, it is not clear that these ingredients try to be highly effective in rinsed products, since a large part can be eliminated during rinsing.

Regarding creams leave in, it is impossible to draw this kind of generalist conclusion: nobody knows what percentage there is in a product, even by reading the list of ingredients.

Why is a hairdressing product more expensive than a supermarket product?

In terms of ingredients, the price should not be much different, since the suppliers of raw materials are the same for all companies. And although there may be slightly lower prices for those who buy in large quantities, but there can be no better glycerin than the other, for example. Glycerin is exactly the same molecule regardless of origin, and the purity is similar at all suppliers.

Just like white and commercial brand drugs - Benuron's Paracetamol must be the same as any other that contains Paracetamol.

Brands also pay for the extra formulation: the packaging, the label, the marketing, the level of the supermarket shelf, where they sell and if they just want to be sold at hairdressers and pharmacies, etc. This logically increases the price of the product. On the other hand, some more expensive brands may have exclusive patents that make products more expensive. However, the fact that a patent exists does not mean that the product containing it is necessarily better. It just means that there is innovation.

In terms of safety, any formulated product must comply with legislated safety rules. Just think that many of the supermarket brands belong to the same pharmacy or hairdressing companies, that is, we can see that whoever formulates, produces and controls these products has a very solid and reliable structure.

For example, L’Oreal owns brands like Kérastase, Lancôme, Redken, Garnier, etc. Does this mean that all formulas of these products are similar to each other? Not necessarily, but some will be almost the same! A good way to understand this is to read the label to get more knowledge of the product they are about to buy.

Is it possible to know whether one anionic surfactant is stronger or not than another? Which anionic ingredients are the most and least aggressive for the scalp?

Yes, there are more detergent anionic surfactants than others.

However, as mentioned in previous publications, it is not possible to determine whether a shampoo is more detergent or not just by the surfactants it contains. Shampoos are essentially a combination of surfactants that serve to dissolve oils as well as grab dirt particles.

Therefore, choosing or refusing products simply because they contain “Sodium Laureth Suphate” does not make sense, and we may be paying more for an “Sulfate Free” product unnecessarily.

What ingredients are heat protectors in the hair?

Damage to the hair fiber begins (denaturation of the hair protein) after 100ºC. High temperatures can cause 3 types of hair damage: decomposition of the hair pigment that leads to a change in its color, damage to the surface of the hair fiber that causes the hair to become rough and without natural shine and weakening of the proteins inside the hair wire, leading to breakage.

There are 3 theories to explain how these products work:

- uniform heat distribution - products that leave a layer in order to prevent direct contact between the hair and the utensil. This protective layer helps to minimize the effects of excessive heat.

- reduced heat conduction - any product that makes the hair more malleable can say that it protects from heat, because if the straightening irons slide more easily and quickly through the hair, there is less chance of damage - this effect can reduce the high temperature momentarily and decrease the damage.

- oxidation prevention - at least one study suggests that thermal decomposition of capillary protein is caused by a reduced oxidation action. (3)

There are hundreds of products that claim to protect hair from thermal actions, of those studied, the literature talks about PVP / DMAPA acrylates copolymer, Hydrolyzed Wheat Protein and Quaternium 70 that had good results in hair in creams leave in and when listed at the top of the list of ingredients. (4)

However, it is necessary to realize that a product is formed by a set of ingredients in a formula and not by just one, being that it will be very unlikely in the same way to predict the quantity of these ingredients in the products and their effectiveness, since there is no legislation for this type of products.

Is it possible to have “excess protein” in hair derived from hair products / masks and lead to breakage?

Hydrolyzed proteins that have a weight of 1000 Daltons or less are those that bind best to hair. Smaller than 500 Daltons can penetrate the hair. (5)

Despite this, hair keratin is irreparable when it comes to its shape and hair protection properties, and the use of amino acids in hair products does not replace or restore any damaged molecular structure. Especially because the damage does not consist only of the loss of molecules, but of entire scales of the hair cuticle.

The bottom proteins are conditioning ingredients that help reduce friction and frizz and can help improve the overall look of the hair.

Larger proteins function more as ingredients that will deposit in the hair, than in the more porous hair it will fill in the gaps and improve its surface. This type of protein will help to attract hydration to the hair and this helps it not to break down so easily.

On the internet there is a reference that you should not use products with protein very often because they may lead to breakage of it.

It is believed that this myth emerged from the African American community, which, when relaxing, obtained a more porous hair and when using these products with a large amount of emollients it made the hair “stiff” and brittle. That is why specific products for people started to be formulated after certain chemical procedures on the hair. (6)

Hydrolyzed protein can have several functions, such as forming a film around the hair and even reducing the loss of hydration in the hair. (7)

For this reason, there is no basis that justifies hair breakage due to excess protein.

There are products that are “heavier” in terms of consistency than others, can we see that by looking at the composition before buying it?

It may be beneficial to notice if the list of ingredients has a large or small amount of the ingredients that can cause accumulation in the hair: silicones, mineral and vegetable oils, butters, waxes and cationic surfactants. Usually the ingredients are in order of quantity (greater to lesser quantity) and this may give an indication of how much residue the product can leave on the hair, but as we have seen it cannot be taken in any way as a guarantee, since the finish of the The product depends on the interaction between all these ingredients with the rest of the formulation, and not on its presence.

Thus, it will be more interesting which type of hair the product is intended for, which its texture (creams tend to be heavier than sprays, for example) and which finish the brand proposes (wet, light, texturizing effect) , etc.).

Can I do Co Wash exclusively?

Co Wash can be interesting for those who wash their hair daily, for example, but should alternate with a shampoo with a more detergent action to clean the hair thoroughly from the possible accumulation of residues. Most shampoos are anionic while conditioners are highly cationic and will therefore be attracted to the most damaged parts of the hair (which have a more negative charge because they lose disulfide bonds). For this very reason, conditioners are not good at grabbing dirt, dead cells and oil from the scalp and hair. The conditioner was formulated to leave residue on the hair, even if a good massage is done on the scalp: it always leaves some residue.

If used every day, the day may come when it will start to accumulate too much residue on the scalp, on the hair and become “heavy”, without natural curls. It may also attract more dirt from the air. Frequent washing with conditioner can lead to dandruff and other types of inflammation on the scalp.

In this sense, exclusive washing with Co Wash is not recommended for those who have normal or oily scalp, wash their hair infrequently, or use finishing products without rinsing after washing.

Does overuse of sulfates really do harm?

There are some studies that mention that shampoos with a very detergent action are often used in a routine that can lead to hair becoming drier and with irritation on the scalp. (8)

If a shampoo contains sulfates, but if they are present in a reduced concentration or if the product also contains several oils, non-ionic surfactants or even some silicones; this product is likely to have a mild washing action. And in fact, we will only know this by experimenting, and checking how the hair looks after washing, or by the amount of foam it can make (which can, however, also be a misleading experience, since there are ingredients that increase the formation foam without giving more divergence to the product). (9)

Do No Poo / Low Poo - Should I use a sulphate shampoo?

The fact that the shampoo contains sulfates or not says little about its cleansing action or if it is too aggressive or not for the hair. In this sense, the search for SULFATE surfactants provides only an indication, and it does not always allow us to check if this product is suitable. It is therefore more pertinent to read the product label, in order to understand the type of scalp that shampoo brings the most benefits.

This option also differs from the routine of the person in question: if you have a tendency to wash hair daily, then the best for the health of the hair shaft will be to use a low detergent action shampoo, being indicated for dry scalp (the so-called low poo) or try the no poo / co wash. If the scalp is oily, the use of traditional shampoo or low poo will have to be frequent. If the routine of this type of hair goes through a long time without being washed, it is best to always use low poo between washes and to use sulfates sporadically, to remove all possible accumulation of product that may arise with the use of finishing creams.

At the end of the day, the decision will always be up to the person and what they think is pertinent to add to their hair routine, but no, sulfates are not the enemy if used well!

Explains the difference between soluble and non-soluble silicones and whether soluble should be compatible in the method.

In the world of curly hair, the difference between soluble and non-soluble silicones is mostly mentioned.

Fluid (insoluble) silicones can leave residue on the hair, and the amount of residue deposited will depend not only on the type of silicone, but also on the concentration it is in and the rest of the formulation.

Water-soluble silicones (such as silicones containing the prefixes peg, pg- and ppg and waxes such as emulsifying wax, emulsifying wax nf, peg 8 beeswax, peg-75 lanolin and peg-8 beeswax), do not mean that they come out with water, but rather that they dissolve in it and can also leave hair with some residue, since that is its function. Quaternary ammonium compounds (polyquaternium-X, bentrimonium chloride for example), are water-soluble but being able to make connections with the hair cuticle will not be rinsed (and thankfully!).

Some silicones that evaporate are for example Cyclomethicone, Cyclomethiconal, Cyclopentasiloxane and Hexamethyldisiloxane.

Once again, these ingredients are present in the products to facilitate styling, reduce frizz or make hair smoother; so the product that contains them should be chosen according to the condition of the hair shaft, adapting the amount of product applied and the products used in washing to the condition of the hair.

Can soluble silicones accumulate in hair?

It depends - but it is necessary to keep in mind that silicones are not alone in a formulation - they are accompanied by other ingredients in hair products and these ingredients may even accumulate more than the silicones themselves - the problem of the formula accumulating in the hair may not be due to fault of silicones, but of all the ingredients of that formula.

Silicones are more complex than they appear. There are for example some silicones that after rinsing the hair leave no residue, such as volatiles, and then there are other silicones that are heavier in weight and leave residue on the hair, such as dimethicone. These will lubricate the hair and help with frizz.

In the Curly Girl Method, any product with a certain ingredient is avoided, but a product with silicones at the beginning of the list of ingredients and another at the end, can it be said to have the same effect?

They may or may not have the same effect depending on the set of ingredients in the formulation. Comparing two products in which silicone is at the beginning of the list and another at the end, it indicates that the first product has more silicones than the last in theory, but, however, it is impossible to know the true concentrations of each ingredient in the formula. The first product may have silicone in first in the list and accumulate less residue in the hair than the second, for example, it will all depend on the set of the formula in question.

There are those who say that silicones never come out of the hair, being necessary to have a capillary transition, right?

The word silicones designates a class of molecules very diverse, and for that reason it does not allow us to make generalizations. Some silicones do not have the chemical capacity to permanently bond to hair, but others are modified specifically for this purpose, such as Amodimethicone. Some will have to leave with a shampoo, others will not, and others may be eliminated over several washes.

Will a more vigorous massage with conditioner (Co Wash) clean it in such a way that it is not necessary to use shampoo?

Co Wash / No Poo cannot replace the shampoo because it does not have enough micelles to foam and remove dirt from the hair. Most practitioners of this technique feel the need to alternate with a shampoo with anionic surfactants (which foam) to remove excess residue and dirt. Massage can help remove residue from the hair, and it is very important for Co Wash to be effective, as well as to prevent residues from accumulating in the product itself. However, this massage alone does not replace surfactants that cleanse the scalp more effectively.

Is this distinction on the part of people of products by their ingredients correct?

Could it be that if it were easy to know exactly how a product performs by analyzing the list of ingredients, there would be so many methods for the same purpose? How can a layperson understand a formulation of a cosmetic product, given that the European Commission's glossary of ingredients contains 26491 entries? How can we make this type of forecast without knowing the method of manufacture, the right concentrations, the existence or not of encapsulation of ingredients, among other characteristics that determine the performance of a cosmetic product? And above all, how does the list of ingredients tell me about the behavior of that product in MY hair? Both methods guide people to choose products best suited to their type of hair and scalp, however, this choice of ingredients does not include any of these factors, and there are ingredients whose preponderance that each of these methods give is not really relevant, as already mentioned in this article and in this article. (links) (10)

Difference between conditioner and Co Wash product.

Both of these products have very similar ingredients when looking at the compositions of the formulas, however, the product that you refer to as co wash may have a greater amount of cationic surfactants (or others) compared to the traditional conditioner to achieve a smoother and more effective cleaning, and leave less residue deposit on the scalp.

Can the water pressure in the shower smooth the curls?

When the hair gets wet, the only chemical bonds in the hair that are broken are the ionic, hydrogen and Van der Walls. For the hair to stay straight permanently, disulfide bonds (covalent) would have to be broken to lose its original shape and this is only possible with procedures that change these chemical bonds such as straightening.

If you notice a smoother root or less definition in the root, you can try different finishing techniques (fixing, kneading the hair, dedoliss, etc.) to try to stimulate the definition of curls in that area.

Can brushes straighten curls?

Hair has several types of chemical bond: covalent (disulfide), ionic, hydrogen and Van der Walls. When the hair is wet, most of these bonds are broken apart from the covalent ones, which are only broken when the hair is subjected to some chemical procedure such as straightening or discoloration. For a brush to permanently straighten the hair, it would have to break these covalent bonds, which does not happen. The brush breaks connections that when the hair gets wet again, these connections return to their original position, such as stretching the hair with a dryer. The act of brushing curly hair when dry should be avoided because it will lead to breakage due to its natural curvature and friction between the hair and the comb / brush that increases static electricity, and so the less we do it the better. The hair should be combed when wet and with conditioner or mask in order to decrease and break when untangling the hair. Another thing that can help is to change the brush for the comb (less bristles = less friction), or choose utensils with wider and more widely spaced teeth.

---

References

1. Cirs-reach.com. 2020. EU Public Consultation On Methylisothiazolinone (MI) Ban For Leave-On Cosmetic Products Launched – News And Articles – Chemical Inspection And Regulation Service | Enabling Chemical Compliance For A Safer World | CIRS. [online] Available at: <http://www.cirs-reach.com/news-and-articles/eu-public-consultation-on-methylisothiazolinone-mi-ban-for-leave-on-cosmetic-products-launched.html> [Accessed 2 June 2020].

2. Winter, R., 2009. A Consumer’s Dictionary Of Cosmetic Ingredients. New York: Three Rivers Press.

3. L Mc Mullen, R. and Jachowicz, J., 1998. Journal of cosmetic science, [online] (49(4):245-256). Available at: <https://www.researchgate.net/publication/289528396_Thermal_degradation_of_hair_II_Effect_of_selected_polymers_and_surfactants> [Accessed 2 June 2020].

4. Istrate, D., Popescu, C. and Möller, M., 2009. Non-Isothermal Kinetics of Hardα-Keratin Thermal Denaturation. Macromolecular Bioscience, 9(8), pp.805-812.

5. Bos, J. and Meinardi, M., 2000. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Experimental Dermatology, 9(3), pp.165-169.

6. Schueller, R., 2020. Can Hair Really Be Sensitive To Protein? Episode 139. [online] Thebeautybrains.com. Available at: <https://thebeautybrains.com/2016/06/can-hair-really-be-sensitive-to-protein-episode-139/> [Accessed 2 June 2020].

7. MITEVA, M., 2018. Alopecia Manual With Trichoscopic And Pathologic Correlations. [Place of publication not identified]: ELSEVIER – HEALTH Science.

8. de Cássia Comis Wagner, R. and Joekes, I., 2005. Hair protein removal by sodium dodecyl sulfate. Colloids and Surfaces B: Biointerfaces, 41(1), pp.7-14.

9. Cline, A., N Uwakwe, L. and J McMichael, A., 2018. No Sulfates, No Parabens, and the “No-Poo” Method: A New Patient Perspective on Common Shampoo Ingredients. Cutis, [online] 101(1):22-26. Available at: <https://pubmed.ncbi.nlm.nih.gov/29529111/> [Accessed 2 June 2020].

10. Eur-lex.europa.eu. 2020. EUR-Lex - 32019D0701 - EN - EUR-Lex. [online] Available at: <https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2019.121.01.0001.01.ENG&toc=OJ:L:2019:121:TOC> [Accessed 2 June 2020].