Does benzophenone-4 build up on hair? The conditioner I use while co-washing includes benzophenone 4. I have learned that it's just an UVB absorber but not sure if it's safe for the CG Method and soluble in water.
Benzophenone-4 is a water-soluble UVA and UVB filter. According to Making Cosmetics, it is also readily soluble in propylene glycol, glycerin, ethanol, and isopropyl alcohol.
Read more: Protect Your Hair from the Sun
What is Benzophenone-4?
Benzophenone-4 is within a group of aromatic ketones that contain both UVB and UVA absorbing properties that filter block out harmful UV rays. They are often used in sunscreens but can be found in lip balms, perfumes, nail polishes, hair sprays, dyes, and even shampoos. While the water-soluble component may be good for using in a curly girl regimen, there are some other concerns about this ingredient. It also prevents the integrity of other ingredients from deteriorating under the sun.
Pros of Benzophenone-4
The FDA has approved the use of benzophenone-4 as a safe and effective OTC sunscreen ingredient for concentrations up to 10% while the EU Cosmetics Directive has said it was safe to use in OTC in concentrations up to 5%. It is quite effective in not only filtering out UV rays but also preventing other ingredients from being degraded by the sun. It does not penetrate the skin to a large degree but allows for other ingredients to do so.
Cons of Benzophenone-4
This chemical ultraviolet UV filter was tested over a 3-year period for allergens in patch tests. It showed to produce not only more positive patch test results than other UV filters but it also was the third most frequently positive result overall. Those experiencing an allergic reaction saw redness, swelling, itching, and fluid-filled blisters. They could develop immediately or over several days.
This ingredient may or may not work well for you in the Curly Girl Method, but unfortunately you will have to make that determination by using it to see how it fares with your CG routine. Of course if you notice swelling, itching, or redness, discontinue use.
Read more: Top 15 Products with UV Protection