Sunscreens and UV rays

UV light / Sun / Photodamage is one of the biggest external factors contributing to the ageing of the skin. I am in total agreement with the beauty industry when it comes to the importance of wearing sunscreen on daily basis.

The best way to approach the sunscreen opportunity is by doing the following:

1)      Consider your skin type. Remember that sunscreens are part of “skin type” skin care

2)      Access your skin sensitivity to UV light by consulting with cosmetic dermatologist or use Fitzpatrick scale for self-assessment

Having this information, you will be able to create healthy habits when it comes to sun exposure. You will also be better equipped to choose a product that fits your personal needs.

Before we proceed to sunscreens, I wanted to cover the much talked about UV rays and how they affect the formulation of the sunscreen:

Activity level

Affected layer of the skin Effects

SPF / Broad Spectrum




UVC is absorbed by the ozone layer and does not reach the earth




Less active during morning hours (before 10 am) and evening hours (after 4 pm) and in winter

That said, consider your location as well



–         Epidermis


–          Sunburns

–          Contribute to aging and skin cancer



SPF measures sunscreens’ ability to filter only! UVB rays





95% of the UV radiation reaching the earth!!!

Active throughout the year and at all times of the day


–         Epidermis

–         Dermis



–          Leading cause of aging: Affects collagen since it penetrates deep into the skin

–          Significant cause of skin cancer


Broad Spectrum

The only sunscreen that will protect your skin against UVA  rays is the one that is labeled as “Broad Spectrum”.

SPF only measures protection from UVB rays and it does not tell you anything about protection from UVA rays.



Be aware that most ingredients in the sunscreen shield against UVB rays, far fewer have UVA coverage and only a handful offer both. Before I move on to the sunscreen products themselves, I also wanted to cover the terms mentioned above: SPF and Broad spectrum.


SPF (Sun Protection Factor)

SPF says nothing about protection from UVA rays. All it measures is sunscreens’ ability to filter only! UVB rays. Looking at the sunscreen products, you will notice a number listed next to the SPF:

SPF 15

SPF 30

SPF 50


% of UVB rays the sunscreen shields from






What does the number mean?



You can be in the sun 15 times longer that you can without the sunscreen before burning


You can be in the sun 30 times longer that you can without the sunscreen before burning


You can be in the sun 50 times longer that you can without the sunscreen before burning



The difference in efficiency between SPF 30 and SPF 50 is only 1%, yet the price difference is substantial. Dermatologists suggest that sunscreen producers capitalize on the general public’s misconception of what SPF represents as most of the people think that the number is the indication of strength of protection. Some countries consider banning SPF 50 sunscreens due to “misleading” and inefficient protection. As for the dermatologists, they suggest using sunscreens with SPF 30 since those are very effective and is readily available at many price points.


Broad Spectrum / Full Spectrum

In the above table, I mentioned Full Spectrum sunscreens in relevance to UVA rays since I wanted to make the distinction between SPF and Broad Spectrum sunscreens really obvious and simple. That said, Broad Spectrum sunscreens actually protect from both UVA and UVB rays!


Water Resistant

Sunscreens marked as “water resistant” should indicate the measure of time as well. It is usually 40 minutes or 80 minutes.


Generally guideline:

No matter the spectrum and SPF factor you choose, sunscreens need to be applied throughout the whole body unless you are wearing SPF clothing. You should also re-apply sunscreen every 2 hours over the skin exposed to the direct sun light.


Knowing what to look for and what to protect from, you can easily choose the type of sunscreen that would do the job and be compatible with your skin type.

There are two major types to choose from:

Physical (Sunblock)

Chemical (Sunscreen)


How does it work?


Physical blockers:

Physical sunscreens contain active mineral ingredients which sit on top of the skin to reflect, deflect and scatter damaging UV rays from the skin


Chemical absorbers:

Chemical sunscreens contain carbon – based compounds which create chemical reaction and work by changing UV rays into heat, then releasing that heat from skin





–         Zinc oxide

–         Titanium dioxide


–         Avobenzone (most commonly used and the most unstable one since it degrades in sunlight)

–         Octinoxate

–         Ocisalate

–         Octocrylene

–         Oxybenzone





–         Protect from UVA and UVB rays

–         Immediate action, no need to wait

–         Lasts longer in direct UV light (but not if you are exercising)

–         Less likely to cause stinging reaction on the skin

–         Less likely to be pore clogging (which makes it ideal for blemish prone skin)

–         Better for those with heat- activated skin (rosacea, redness, inflammation) since it deflects the heat and energy given off by the sun away from the skin


–         Thin is texture making it easy to apply and spread

–         Only small amount is needed




–         Need to reapply frequently since it can be easily rubbed off, rinsed off or sweated away from the skin

–         Can be less protective if not applied generously

–         Zink oxide and titanium dioxide give off that whitish film effect on the skin


–         Can potentially cause an increase in existing brown spots and discoloration due to higher internal skin temperature (Over-heated skin can make brown spots worse)

–         Increased chance of redness for heat activated skin (rosacea – prone skin, etc)

–         Needs frequent re-application: in direct UV light, it gets used up quicker

–         May clog pores in oily skin type

–         The higher the SPF, the higher the chance of irritation for sensitive skin



Be aware



Size of particles matters!

Zinc oxide and titanium dioxide are said to be safe, stable and non – absorbent. The drawback: they produce a white cast.

Nano technology helped to minimize the size of the particles making physical sunscreens less thick and less white cast producing. The drawback: the smaller the particle size, the less effective the sunscreen is. Also, there is a debate which strongly suggests that nano-particles of zinc and titanium are absorbed into the blood stream which can cause / contribute to development of health issues. Nano – particles can also be pore clogging.



Thank for reading,


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