How SPF testing of a product is done?

Sunlight is probably the most essential element for the survival of life on earth. However, it is this sunlight that can also cause potential damage to the skin, leading to skin cancer and other skin diseases, thanks to the human race that has damaged the natural sunscreen – the ozone layer. However, with so many products that are there in the market, carefully formulated to protect the skin from this severe damage of the sun, it can well be prevented. But, which product is useful and whether it is capable enough to prevent the sun is subject to SPF testing. It is this test that can tell if a product has all that it takes to prevent the sun.

Why SPF testing is needed?

Although different products include different ingredients to protect and prevent the sun, the effectiveness of these ingredients cannot be determined that easily. There are various factors that control whether a product will effectively absorb the UV rays of the sun or not. These factors are:

Type of ingredients and formula used in a product

Mode of application

Type of skin

Grade of UV exposure.

It is only by a SPF testing that the potential of a sunscreen formula to prevent the sun can be determined.

Types of SPF testing:

There are two types of this test that can determine the SPF of a product. These are:

In-Vivo Method:

In this method, a measured amount of a sunscreen product is applied on human volunteers. Usually this application is 2 mg of the formula/cm2. After this application, five increasing doses of UV rays or stimulating sunlight is applied on the skin of a subject volunteer, both on the area where the sunscreen product is applied as well as on an area where there was no sunscreen applied. After 16 to 24 hours of this application, both these areas are examined to check for the difference of damage and thereby the SPF amount is determined.

In-Vitro Method:

This method on the other hand is non-invasive and the SPF test or sun protective factor test is done on artificial substrates. It this process computerized mathematical models are used to determine the amount of SPF in the product.

Choose a good chemical testing lab:

All these tests are done at best and certified chemical laboratories. It is very important that you choose a good chemical lab for this SPF testing, so that your test results are accurate. You need to make sure that the lab that you have chosen is registered and certified as well as affiliated to a trustworthy organisation of international repute.

Without this certification or registration of a chemical lab that you have chosen, results of a chemical test will not be considered trustworthy. So, if you want to determine the exact SPF of a product, just formulating your product will not be enough. You must go for a thorough and intensive SPF testing through the possible methods for determining the result.

Consumer testing of SPF formulations

SPF formulations by virtue of ingredients present therein can be sticky and heavy on the skin. This can be a major deterrent for consumer acceptability. Finally, the success of the product in the market place would depend on consumer liking and preference for various sensory attributes; the ‘feel good’ factor….

However, methodical evaluation of sensory attributes of SPF formulations can be done using acceptable techniques like those stipulated by ASTM. Finally, consumer study of the short listed formulation will conclude comprehensive evaluation of any SPF product before it is launched in the market place.

Former teacher and freelance writer. He writes for a wide variety of websites, covering diverse topics in technology, entertainment, international news and gaming.