When do I need to use sunscreen?
The general advice is to use a primary sunscreen when the UV index is 3 or more during your outdoor exposure.
You may need to use a sunscreen even for lower UV index if your skin burns easily or for prolonged outdoor exposure
How do I use sunscreen?
Apply liberally onto clean, dry skin and rub evenly at least 20 minutes before sun exposure. Re-apply every 2 hours and after swimming, exercise or towel drying.
Use at least 35ml per adult application: 5ml (a teaspoon) to the face (including ears and neck), each limb, the back, and the front of the body.
Avoid intensive midday sun or prolonged sun exposure. Keep young children out of direct sunlight. Wear protective clothing, a hat, sunglasses and sufficient Maxiblock sunscreen for all unprotected areas.
Sunscreens are for external use only. Avoid contact with eyes or fabrics.
Discontinue use if signs of irritation or rash appear.
For sensitive skins, test product for any irritation on a small area of skin.
How often should I reapply sunscreen?
Sunscreen should be applied at least 20 minutes before sun exposure to allow the ingredients to fully bind to the skin.
Reapplication of sunscreen is just as important as putting it on in the first place, so reapply the same amount at regular intervals.
Dermatologists normally advise reapplying after approximately two hours.
Why should I reapply sunscreen regularly?
Even with a sunscreen that has 4 hours water resistance, you should re-apply every 2 hours.
The Australian standard for water resistance is the most stringent standard worldwide but does not mean that you can continuously spend 4 hours having fun in the water and still be protected.
It measures the SPF protection remaining after 4 hours spent in a jacuzzi and does not account for the sunscreen lost by sweating, towel drying, friction with water or contact with clothing or other surfaces such as chairs for example.
Sunscreen should be re-applied frequently to ‘touch-up’ the applied sunscreen and ensure it is functioning effectively at all times.
Why should I use sunscreen with insect-repellant?
A quality SPF50+ sunscreen is made of up to 30% UV actives, and most insect repellent uses between 10% and 30% of repellent actives. That is lots of chemicals that need to work together.
There is no guarantee that applying an insect repellent and a sunscreen separately will work or be harmless.
A sunscreen & insect repellent combination has been specifically developed to ensure the product does perform as a primary sunscreen as well as an effective insect repellent. It is subject to TGA and APVMA regulations and needs to be listed on both government registries.
What is the UV index?
The ultraviolet index or UV Index is an international standard measuring the strength of UVB, the sunburnt-producing UV rays.
It is a linear index: if it takes 30mn to get sunburnt at UV index 3, it will take only 1/5 of that time, or 6 minutes to get a similar sunburnt at UV index 15.
What is UVA and UVB?
UV radiations hitting Earth surface may be split into 2 categories: UVA (320~400nm) and UVB (290~320nm).
UVB rays are directly responsible for burning, tanning, and skin ageing, and also plays a determinant role in the development of skin cancer. Protection against UVB is measured by the SPF factor method.
UVA rays account for up to 95 percent of the solar UV radiation reaching the Earth’s surface. They penetrate into the deeper layers of the skin, playing a major part in tanning and skin aging, and also initiate and exacerbate the development of skin cancers.
We are exposed to large doses of UVA throughout our lifetime and proper protection is essential. The SPF factor does not measure protection against UVA, however the term “broad spectrum” is used to indicate a sunscreen’s ability to protect against UVA radiations.
UVA rays account for up to 95 percent of the solar UV radiation reaching the Earth’s surface. They penetrate the deeper layers of the skin, playing a major part in skin aging, and also initiate and exacerbate the development of skin cancers.
UVA rays can be up to 50 times more prevalent than UVB rays, and can penetrate glass and clouds. We are exposed to large doses of UVA throughout our lifetime and proper protection is essential. The SPF factor does not measure protection against UVA.
What is MED?
MED stands for the minimal erythemal dose, or the smallest time required to get sunburnt.
In Australia, MED can be as low as a few minutes for unprotected skin and varies with several factors (skin type, sun inclination, time of the day, geographic location, season…).
How is sun protection factor (SPF) determined?
By burning people’s back. The only SPF test currently approved is “in-vivo”, which means tested on adults (tests on children are forbidden).
A specialised testing laboratory uses a simulated beam of sunlight directed onto the back of volunteers for predetermined periods of time, first establishing the individuals MED, before then repeating with sunscreen applied to determine the protection factor.
The SPF is determined for at least 10 individuals and averaged to establish the maximum claimable SPF.
SPF is the ratio of MED for protected and unprotected skin and is a reliable measurement of protection against UVB.
As an example, if a person’s skin takes 5 minutes to burn when unprotected, an SPF50+ sunscreen applied correctly would take 60 times longer to burn, allowing 300min of protection. Sunscreens however need to be re-applied frequently.
The SPF rating is a reliable measurement of protection against UVB (short-spectrum) wavelengths. SPF is the comparative ratio between the minimal erythemal dose (MED) – the time it takes for reddening or sunburn to start – in skin protected with sunscreen and the MED in unprotected skin.
In Australia, MED for unprotected skin can be as low as a few minutes, and it is therefore essential to be protected against sun damages.
An SPF 50+ sunscreen correctly applied at the recommended dose will extend MED by approximately 60 times. That figure may not be realistic as the recommended dose may not be applied consistently across the exposed surface, and sun damage can occur even without reddening. Swimming and sweating can also affect the length of time that sunscreen is effective, and it is recommended to reapply sunscreen at least every 2 hours.
What does broad spectrum mean?
For sunscreen, broad spectrum means protection from both UVB and UVA rays.
The modern 2012 standard imposes additional protection against UVA rays and has thus improved the quality of the sun protection products available in Australia.
Is SPF50+ significantly better than SPF30?
Significantly better. SPF30+ complies with the older 1998 standard, while SPF50+ complies with the latest standard dated 2012.
SPF50+ means an SPF of at least 60, or approximately double the protection provided by SPF30. As most consumers don’t use enough sunscreen to achieve the claimed SPF, that difference does matter.
The most important improvement is in the UVA protection arena: UVA has been found to be primarily responsible for skin ageing and skin cancer. And 1998 standard did not impose any substantial protection against these UVA. This has been fixed by the 2012 standard.
What is the difference between a chemical and mineral filter?
Fundamentally none. A mineral filter is another name for inorganic UV absorbers, a class of man-made chemical filters.
Organic “chemical” UV filters absorb UV energy.
Modern inorganic “physical” UV filters absorb UV energy too. A white coating on the skin will mostly be reflecting or scattering UV rays. However, sunscreens that use nanotechnology to achieve the required transparency on the skin will predominantly absorb UV radiation like their organic "chemical" cousins.
Both are safe and effective at filtering harmful UV energy when formulated and used properly.
Are sunscreens photo-stable?
Photo-stability can vary product to product as a consequence of a range of factors, however, the regulatory requirements are such that the products must be very photo-stable to be able to meet these requirements.
What is unique about zinc?
Zinc oxide is a naturally occurring inorganic chemical that exhibits excellent broad-spectrum protection against UVB and UVA rays.
The Zinc oxide used in sunscreens is engineered to be invisible on the skin, delivering that exceptional broad-spectrum sun protection in a cosmetically acceptable transparency.
Manufactured in chemical plants using inorganic chemicals as raw materials, it is no more and no less natural than the other UV filters.
Are sunscreens dangerous?
Sunscreens sold in Australia are regulated products with the ingredients and manufacturing methods being highly controlled by the Australia TGA.
All the ingredients used to formulate sunscreens are regulated and continuously assessed by sophisticated regulatory authorities in Europe, USA, Japan and Australia.
Avoiding the use of sunscreens is not advised. UV radiation from the sun is extremely dangerous and therefore not using sunscreens when needed is very dangerous and will significantly increase chances of developing skin cancer.
Are nano-particles dangerous?
And in sunscreen, nano can be relatively big.
Nano is defined as less than 100 nanometers, or at least 200 times smaller than human hair diameter.
Most UV filters are a few nanometers big but are not classified as nanoparticles as they are liquid.
The latest innovations in UV filters include larger organic molecules called nano-particulates because they are bigger and solid.
Some sunscreens use nano-sized or nano-structured inorganic chemicals (zinc oxide or titanium dioxide) as UV filters. These are classified as nanoparticles, and they are much larger than most UV filters used in sunscreens. Their safety has been confirmed by TGA and many regulatory authorities across the world.
Is paraben-free sunscreen safer?
All primary sunscreens need to comply with TGA regulations, which includes a rigorous test of their microbial control efficacy.
Any formulation with water needs preservation, and almost all sunscreens contain water.
Parabens are naturally occurring chemicals very effective at controlling microbes at a very low dose. They have been used for decades and are proven to be a safe solution overall.
Some preservatives used to replace parabens have been shown to be responsible for contact allergy epidemics.
What are the dangers with sunscreen sprays?
Any spray must be used away from the face to avoid micro-droplets penetrating the lung system with potentially devastating consequences over time.
The convenient pressurised sunscreen sprays mix a sunscreen formulation (lotion or alcoholic based) with flammable gases in a metal can. A 170g can will contain approximately 100g of sunscreen formulation, of about 3 full-body adult applications.
Over-spray can cause a loss in the applied sunscreen, to the point that a 170g can delivers only as little as 70g of sunscreen, or 2 adult applications per can only.
Will sunscreen use create vitamin-D deficiency?
The biochemistry of Vitamin-D synthesis is complex, and affected by many factor, UVB exposure being among them.
Vitamin-D photo-synthesis is promoted by UVB rays between 260nm and 315nm, which includes the UVB rays responsible for sunburnt. Insufficient exposure to UVB rays can therefore contribute to Vitamin-D deficiency.
Sun protection and Vitamin-D photo-synthesis are trade-offs; it is recommended to regularly enjoy a 20-minute unprotected sun exposure when UV index is less than 3 to promote Vitamin-D synthesis naturally and safely.
Other good sources of Vitamin-D are: fatty fishes; and Vitamin-D supplements if need be.