Heat styling is the most popular way to straighten and shape your hair. Unfortunately, it can also be very bad for you. This article explains why high temperature styling is bad for hair and tells you where to buy products with the best ingredients to protect your hair from heat.
Why heat is bad for hair?
Heat exposure causes three types of hair damage: 1) decomposition of hair pigment (melanin) which cause changes in hair coloration; 2) damage to the fiber surface which makes the hair feel rough and look dull, and 3) weakening of internal hair proteins which can result in increased breakage. These effects are greatest when hair is exposed to temperatures above 130C. Blow dryers, curling, and flat irons are all capable of inflicting significant heat damage.
How do heat protection products work?
No one knows for sure, but here are three possible theories to explain how heat protection products work:
Uniform heat distribution
Products that leave a “buffering” layer on hair can prevent direct contact between the heating appliance and the hair surface. This protective layer can help minimize local overheating effects.
Reduced heat conduction
Almost any product that makes the hair more slippery can claim heat protection because if the flat iron or curling iron slides through the hair more quickly there is less likelihood of damage. This effect can reduce heat conduction and therefore decrease damage.
At least one study suggests that the thermal decomposition of hair protein is caused by an oxidation reaction. Since oxidation and reduction are opposite chemical reactions, a reducing chemical like sodium bisulfite or ascorbic acid may stop the damaging reaction.
How is heat protection measured?
Heat protection can be measured using a variety of experimental techniques. Three common methods are: 1) Combing analysis to measure increases or decreases in hair surface roughness, 2) Fluorescence spectroscopy to analyze the breakdown of hair protein (usually tryptophan), and 3) Texture analysis to show changes in the mechanical properties of hair tresses.
(Reference: J. Cosmet. Sci., 49, 245-256 (July/August 1998) Thermal degradation of hair. II. Effect of selected polymers and surfactants R. McMULLEN and J. JACHOWICZ, InternationalSpecialty Products,Wayne, NJ 07470.)
Which ingredients really work?
There are dozens (hundreds? thousands?) of products that claim to protect hair from heat damage. Do they really work? The scientific literature shows only a few chemical compounds that have been studied and shown to provide a real, measurable benefit. For best results, look for leave-in treatment products that have these ingredients in listed toward the top of the ingredient list (in the first 5 ingredients, or so):
- PVP/DMAPA acrylates copolymer
- Hydrolyzed wheat protein
- Quaternium 70
(This doesn’t mean these are the ONLY ingredients in the universe that really work, but these are the only ones that have published data. Strong reducing ingredients that work by the oxidation-prevention mechanism described above are not recommended because they may cause other types of hair damage.)
What about “heat activated?”
One final note: be careful not to confuse “heat protection” with “heat activation.” Activation simply means the product undergoes some kind of change when heat is applied. Typically this refers to setting agents (in technical jargon, thermoplastic resins) which melt at the temperature of blow dryers or irons, and therefore form tighter bonds with the hair.
What Products Should You Buy?
If you’re looking for a hair protectant that contains ingredients that really work, click here to buy Ouidad Climate Control Heat & Humidity Gel; it contains 2 of the 3 proven ingredients.
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