Everything you need to know about sunscreens (well, almost everything)

Living in the UK I’m used to the sun being pretty darn temperamental (“She’s out! Nope, she’s gone back in again!” *sigh*) but sunscreens are a year-round topic I have long wanted to address on this blog.

Questions such as “should I be wearing sunscreen everyday, even in winter?” and “how do I know my sunscreen is working?” have prompted me to investigate.

For your reading pleasure I’ve written up a summary of my findings (time to grab a cuppa). Alternatively, if you’d like to cut straight to my favourite SPF products click here.

Before you read on

It’s important you know there is a heck of a lot of conflicting information and opinion out there (researching this post has definitely lead to me wanting to tear my hair out!!). Whilst I don’t pretend to have all the answers (far from it) it is my hope this post will at least prompt you to think about the ways in which you are currently protecting your skin and what changes you could make (today?tomorrow?!)…to be more sun safe.

The questions I aim to answer
  • What exactly is SPF?
  • How does it work?
  • What is the difference between a mineral and non-mineral (chemical) SPF and which is better for me?
  • How can I be more sun safe?
Your SPF cheat sheet

What is SPF?

SPF is a rating which stands for ‘Sun Protection Factor’. It was commercially introduced sometime during the mid-60s/70s by the founder of Piz Buin, Swiss chemist Franz Greiter.

How does SPF work?

SPF is a topical product which comes in the form of a cream, oil or mist. It is applied directly to the skin as a way of absorbing (and converting into heat) or reflecting the sun’s rays.

Why do we need SPF?

The sun (as much as we love it ) produces types of harmful radiation known as gamma rays.

A quick way to remember them is:


1. UVB rays
UVB penetrates the epidermis, or top layer of the skin, leading to a reddening of the skin (if unprotected) and eventually sunburn.

2. UVA rays
The longer and more prevalent of the two rays, UVA will penetrate the skin at a deeper level, right down to the dermis and beneath it. UVA rays cause DNA damage (at cell level). This causes the collagen within the dermis to break down and lines to form (wrinkling). Long-term exposure to UVA is one of the leading causes of ageing.

Both types of UV radiation play key roles in the development of skin cancers.


Darling, you missed a bit


Higher? Lower? (Brucey voice optional)

Wearing SPF will protect your skin from absorbing radiation (which we know can be harmful when skin is exposed over a period of time), however, the rating system currently offers a number of different ‘strengths’ which can be confusing.

Did you know that there is minimal difference between the percentage of UVB rays blocked by a product labeled SPF 15 versus one labeled SPF 50? (I did not know this!)

SPF 15 blocks 93% of UVB rays
SPF 30 blocks 97% of UVB rays
SPF 50+ blocks 98% of UVB rays

Source: badgerbalm.com

NB: The SPF rating can also refer to the number of minutes a person can be in the sun before they will burn. 

Broad spectrum

The majority of SPF products now state they protect against both UVB and UVA (e.g. ‘Broad spectrum’)  but if in doubt, check for this on the label.

You may also come across a PA rating which is indicated by a number of ‘+’s (e.g. PA +++). Developed in Asia, the PA rating measures the level of protection against UVA and the more ‘+’s are indicated on the label the better (currently goes up to a maximum of four depending on the country. Don’t ask me to explain anything else about the PA rating. The articles I’ve read have made my eyes go funny).

Mineral versus chemical

This is where my brain raises a very weary hand and begs to go home early. I’ve read oodles on this but am still unable to give you a clear ‘which is better for you’ answer. I’m not sure anyone can at this stage given the amount of research that is still underway (more so outside the US).

What I can do is save you the headache of researching this topic by summarising some of the key facts and findings about each below:

  • A mineral sunscreen will contain either zinc oxide or titanium dioxide, or a combination of the two. Both minerals block* UV rays and are not absorbed by the skin**.

* To give you an example of how mixed the information is online I’ve read articles which state that zinc oxide and titanium dioxide physically block or reflect the sun’s rays (1, 2, 3), whilst other articles say ‘zinc oxide absorbs UV and turns it into comparably harmless infrared, which it disposes of as heat.’ (Source). I guess the point is it doesn’t matter how the ingredients deal with the sun’s rays, as long as we’re protected!)
**  toxicity levels of less than 0.01% have been recorded in people using sunscreens containing zinc oxide. Small fry (pardon the pun) when compared to chemical sunscreen ingredient Oxybenzone (bad boy of the bunch) which has been found in mother’s milk(!) and produced toxicity levels of a whopping 1-9%.

  • A chemical sunscreen will contain include ingredients such as:


Avobenzone (offers high UVA protection)
Octinoxate (I would avoid using this based on this article alone!)
Oxybenzone (this one regularly gets a bad rap)
Helioplex (contains avobenzone and oxybenzone and was developed by Neutrogena)
Mexoryl SX and XL (developed by L’Oreal and FDA approved in 2006)
Homosalate (used in a whopping 45% of US sunscreens, multiple concerns with this one)


– Unlike mineral sunscreens, chemical sunscreens do not reflect white (are generally colourless, unless part of a hybrid sunscreen) and are therefore more appealing cosmetically/aesthetically, particularly when it comes to being worn in conjunction with makeup.


– Application is required 20 minutes before sun exposure so the product has time for the chemicals to be absorbed by the skin.
– Can cause allergic reactions, increase the production of free radicals (bad for the skin) and disrupt hormones (I found this article really interesting. Scroll down to ‘Chemical Sunscreens’).

  • A hybrid sunscreen will contain a combination of mineral and chemical ingredients.
What do I think?
  • I’ve read enough to question whether not wearing sunscreen is the only or primary cause of skin cancer (‘there is no evidence that excess sun exposure causes melanoma, while there is data showing that chronic sun exposure and vitamin D seem to prevent it’; Source). Confused? LOL.
  • There are other ways to protect oneself from UV rays (diet, covering up, seeking shade etc)
  • In terms of the key ingredients currently available zinc oxide seems to be coming out on top. Reasons include: it’s mineral and therefore not absorbed by the skin (although see my note above re. 0.01%); it protects against UVB and UVA (you’ll need to do your own research to discover just how much UVA protection is offered by zinc oxide but I have read that zinc oxide is more effective than titanium dioxide at protecting against UVA); is recommended for babies/toddlers and for those with sensitive skin (is non-allergenic)
Oversized sun hat, ASOS, £16
Ways to be more sun safe
  • Wear a hat (anything goes! But beware of baseball caps that don’t protect the sides of your face or your neck)
  • Wear comfortable, loose fitting clothing (pref long sleeved and covering your legs somehow)
  • Where possible, sit/stand/sleep in the shade
  • Wear a high factor (SPF 30+) cream when doing outside sports
  • Give coconut oil a whirl (it has a natural SPF of 10). Just don’t sit out there for hours in it!
  • Opt for fake tan!

melanin: a brown pigment in the skin. Increases after sun exposure. Melanin protects the skin by absorbing UVB and UVA radiation, dissipating the energy as harmless heat. It can only do this up until a point (hence why we need SPF).

melanoma: a type of skin cancer

Further reading and watching

Sun, Sunscreen, Skin Cancer and Safety: How Much do You Need? (article is from 2010 but is very thorough) http://www.kitchenstewardship.com/2010/07/20/sun-sunscreen-skin-cancer-and-safety-how-much-do-you-need/Is my sunscreen toxic?

http://draxe.com/75-of-sunscreens-are-toxic-what-to-do-instead/The Trouble With Sunscreens

http://www.ewg.org/2015sunscreen/report/the-trouble-with-sunscreen-chemicals/Coconut Oil – A Natural SPF

http://naturalsociety.com/ditch-toxic-sunscreen-use-coconut-oil-instead/Lisa Eldridge’s Stay Younger, Longer – the Lowdown on Sunscreens (20 min vid)

http://www.lisaeldridge.com/video/27000/youth-in-a-tube-the-lowdown-on-sunscreen/#.VcIJLOtH22wUnderstanding UVA and UVB


Image credits: Pinterest and Shutterstock

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