Sunscreen V's Sunblock - What is the difference?
The short answer? YES! If you only ever thought sunscreen was simply sunscreen and the only real difference was the range of SPF (sun protection factor) on the bottle, you're in for a surprise! Sunblock, also known as a physical sun block is very different in how it performs on the skin and most importantly, how it protects from Sunscreen - also known as a chemical sunscreen. Both have their advantages and disadvantages, which one should you pick? Well that depends on your lifestyle. We break both down below to explain the difference.
Physical Sun Blocks
They form an opaque film over the area where they are applied so that ultraviolet radiation is reflected away from the skin. These preparations are called 'total blocks' because they prevent both UVA and UVB from hitting the skin.
Note: If these sunblocks are exposed to any moisture such as sweat or water the protection they provide will be removed. If you move it you lose it!
Examples: Sun block UV protection
- Zinc Oxide 250-380nm
- Titanium Dioxide 250-400nm
In clinic we have Hydrashield SPF 15+ that is a blend of physical sunblock combined with a moisturiser.
Chemical sunscreens absorb the harmful UVA and UVB rays in the upper layers of the epidermis (skin) to protect against sunburn and will not wash off.
Due to a combination of chemical sunscreen agents and artificial fragrance and fillers, a high proportion of these products have a reputation for being highly irritant to sensitive skins.
In recent times there have been improvements in chemical sunscreen formulations with many of these potentially irritating ingredients omitted, making them better tolerated by typically reactive skin conditions. (Become an ingredient list reader).
Chemical sunscreens with a Liposomal delivery system are free of irritating ingredients and allow the sunscreen particles to remain suspended in the Stratum Corneum (the skin) thereby reducing the potential for irritation.
Examples: Chemical sunscreen UV protection
- Aminobenzoic acid(PABA) 260-313nm
- Octylmethoxycinnamate 270-328nm
- Octyl Salicylate 300-310nm
- Methyl anthralinate 290-320nm
- Oxybenzone 270-350nm
- Dioxybenzone 260-380nm
- Avobenzone 310-400nm
In clinic we offer Handsfree SPF 30+ as well as Mineral Suncare SPF 50+ Sunscreens to offer you complete sun protection.
Does 30+ SPF offer twice the protection of 15+?
NO! While it is logical to assume it would, something that many people find surprising is the difference in protection that SPF provides. Firstly we need to understand what SPF actually is.
SPF refers to the time taken for your skin to burn without any protection versus the time taken with a sunscreen/sunblock on. Confused? So are we! So lets break it down a little further...
SPF is related to the total amount of sun exposure rather than simply the length of sun exposure. It is a common mistake to assume that the duration of effectiveness of a sunscreen can be calculated simply by multiplying the SPF by the length of time it takes for him or her to suffer a burn without sunscreen, because the amount of sun exposure a person receives is dependent upon more than just the length of time spent in the sun. The amount of sun exposure depends upon a number of factors including the length of exposure, time of day, geographic location, and weather conditions. So if you are in Melbourne you will require more sun exposure to get burnt, than if you were in Cairns, as a consequence, just going by time alone is not an effective measure of ensuring you don't get burnt.
Ever wondered why on extremely hot, sunny days, even if you have been wearing sunscreen, you STILL managed to get burnt? Well this is why.
A common mistake is applying too little sunscreen, which can drastically reduce the effective SPF of the product. About 5-6 teaspoons of sunscreen is recommended to cover the entire body. Sunscreen must be reapplied every two hours when staying outdoors for a prolonged period of time. Sunscreen should also be applied at least 30 minutes before going outdoors.
Also, did you know that SPF ratings are based on an application of 2mm thick per cm2? That's A LOT OF SUNSCREEN! For most of us, we simply would never put this much on.
SPF also is related to the amount of UV rays it is capable of blocking, along with the time taken, however the difference between SPF 15 and SPF 30 is not a case of simply doubling the blockage, it is actually much more confusing....
SPF 15 – Blocks 94% of UV rays
SPF 30 – Blocks 96.7% of UV rays
SPF 50 - Blocks 98% of UV rays
You should be aware that: NO SUNSCREEN/SUNBLOCK is capable of 100% blockage of UV rays
Regardless of the type of sunblock or sunscreen that is used the Australian Cancer Council recommends reapplication every 2 hours - even if the product is advertised as being effective for longer.
What about SPF 50+?
In November 2012, the Therapeutic Goods Administration announced a new standard for sunscreens sold in Australia, increasing the maximum sun protection factor from SPF30+ to SPF50+.
The standard requires the same level of Ultra Violet B (UVB) protection, with improved Ultra Violet A (UVA) protection for new formulas.
UVB is the major cause of sunburn and increased skin cancer risk, while UVA contributes to ageing of the skin, as well as skin cancer risk.
The change brings Australia and New Zealand into line with the United States and Europe, where SPF50+ labelling is already allowed.
SPF50+ sunscreen still needs to be applied just as liberally, re-applied every two hours (or after swimming, exercising and towel drying) and used in combination with other sun protection measures including sun protective hats, protective clothing, sunglasses and shade.
So should I just throw out my SPF 30+ sunscreen?
Whilst having a higher level of protection in our harsh environment, here in Australia, is fantastic. We need to be mindful however, that the new level of protection should not be overestimated. SPF50+ offers only marginally better protection from Ultra Violet B (UVB) radiation than SPF30+. SPF50+ filters out 98% of UVB radiation compared to 96.7% blocked by SPF30+. So when going to purchase your next sunscreen, you may choose a higher level of protection, but for your current 30+? That's also highly effective.
I was overseas and saw SPF 90 and 100, considering Australia has such strong sun exposure, why don't we have higher levels of sunscreen here?
As shown previously, our current level of protection is incredibly high and NO SUNSCREEN PROVIDES 100% PROTECTION - although some sunscreens are touted as being SPF 80 or higher this is simply a marketing strategy and they are in fact, no more effective than what we currently have here in Australia. Given this, and our highly stringent labelling laws in Australia, companies are prohibited to label their product in this manner due to the misleading basis. Other countries however, do not have these measures in place, which is why when travelling you may see this elsewhere. Be assured however, that we have the highest protection offered.