Do you know your filters?

The featured image is ultrasun’s ingredients label of (Anti-ageing and anti-pigmentation face cream SPF 50+) and the highlighted ingredients are UVA and UVB filters that are doing all the hard work. In the USA, such ingredients are referred to as “Active Ingredients.” Every other ingredient is (e.g.) stabilising the product or making it smoother.

“UV filters” are substances which are exclusively or mainly intended to protect the skin against certain UV radiation by absorbing, reflecting or scattering UV radiation.

What should you want from these filters?

Over-exposure to UVA and UVB causes: reddening of the skin (erythema), skin cancer and photo-aging (loss of skin elasticity, elasticity). We want protection against these (photo protection).

We want the LEAST amount of UV filters that achieve the best photo protection. The critical wavelength that EU regulations lean on is 370nm. Typically, the more UV filters included in a sunscreen composition the higher the SPF, but there are some patents where ingredients do act in synergy with each other to achieve 370nm – this number is important BECAUSE without it, you won’t see the UVA logo

Source: http://europa.eu/rapid/press-release_IP-09-1057_en.htm

However, as a consumer, one has to assume the linearity of photoprotection – this is best illustrated by Zinc Oxide and Titanium Dioxide.

Zinc Oxide and Titanium Dioxide

The graph shows absorbance of both Titanium Dioxide and Zinc Oxide. As you can see both compliment each other covering the entire UV spectrum from 320 to about 370nm.

Source: Threes G Smijs, Stanislav Pavel “Titanium dioxide and zinc oxide nanoparticles in sunscreens: focus on their safety and effectiveness” Nanotechnology, Science and Applications 2011:4 95–112
https://doi.org/10.2147/NSA.S19419
  • Zinc Oxide absorbance > Titanium Dioxide between 350nm – 370nm
  • Titanium Dioxide Absorbance > Zinc Oxide absorbance below 350nm.

What are the most common UVA and UVB filters?

Under product listing (follow this link), there are 25 sunscreen products, which are MADE in a MIXTURE of COUNTRIES. After surveying the ingredient lists, the most common ingredients are:

  1. Octinoxate
  2. Avobenzone
  3. Titanium Dioxide
  4. Octocrylene
  5. Oxybenzone
  6. Octisalate
  7. Bemotrizinol
  8. Zinc oxide
  9. Biscotrizole

This is their absorbance levels

Given that the number of permitted filters in the USA is 16 and 23 in Europe, this does appear to be a short list. But I am reassured by two facts: no of UVA filters > UVB filters.

(For ease of reference, I have put the common name above – BUT please note that the proper INCI name of the ingredient is what appears on labels).

What else should we be looking for?

You also want ALL the sunscreen ingredients to be in the top 7 of all ingredients. In most countries, ingredients are listed in descending order of quantity.

Taking Ultrasun (again) the filters listed are:

  • Octocrylene (2nd out of 35 ingredients)
  • Butyl-Methoxydibenzoylmethane (Avobenzone) (5th out of 35 ingredients)
  • Titanium Dioxide (Nano) (6th out of 35 ingredients)
  • Diethylhexyl Butamido Triazone (11th out of 35 ingredients)
  • Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (15th out of 35 ingredients)

Ingredients are listed in descending order of quantity. Generally, water will be the number 1 ingredient at about 50% of the entire composition. The quantities of Octocrylene, Avobenzone and Titanium Dioxide would indicate that quantities of all 3 are quite high, making the product effective.

If you are asking yourself why add ingredients at 11 and 15 position? The answer is simple – Avobenzone is notoriously photounstable. The ingredient label contains octocrylene which stabilises Avobenzone but just to be sure, it appears that the manufacturers have thrown everything including the kitchen sink at photoprotection – hence ingredients at positions 11 and 15.

Are there other filters that exist?

Yes, the EU lists out 23 filters, the US has 16 permitted filters (but this is about to change).

Summary

We are looking for (i) multiple filters and (ii) we want the filters to cover UVA and UVB rays). Additionally, we want a sufficient quantity of the filters, so they should appear in the top 7 of all ingredients.

Please let me know how you get a long!

See also Top 5 Sunscreen Recommendations, Guide to Buying Sun Protection, Do You Understand The Gibberish on Sunscreen Labels?

Sources and uses: Sunscreen compositions having synergestic combination of UV filters available at https://patents.google.com/patent/US9107843B2/en

REGULATION (EC) No 1223/2009 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 30 November 2009 on cosmetic products (recast) available at https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32009R1223

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Happy Skin Days ©  2021.  © Angeli Sinha 2021. All rights reserved. The contents of this blog, including images are protected by copyright law.  My content cannot be replicated without my consent. You can write to me at email@happyskindays.com

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