Choosing Sunscreen Products

Choosing Sunscreen Products

One of the most important ways to protect the skin from premature aging is to use sunscreens. When it comes to choosing a sunscreen we suggest using the following guidelines:

 

  1. Select the sunscreen type you need (sensitive skin, sport block, oil-free, lotion, aerosol spray, etc.).
  2. Limit selection to products with an SPF of at least 30 that is also labeled 'broad-spectrum'.
  3. Choose a sunscreen product with either:
    1. both of the two mineral sunscreens (Zinc Oxide and Titanium Oxide),
    2. or three or more of the chemical sunscreens listed in the chart below where one of the sunscreens is Avobenzone in the maximum amount allowed, 3%.

1. Decide which formulation type you need.
Know your UV IndexNearly all the commonly sold sunscreens (see chart below) can be formulated in a wide variety of product forms, sensitive skin, sport block, oil-free, lotion, aerosol spray, and more. The amount of UV protection, however, is dependent on the type and amount of sunscreens present in the product and not on the product form. This simplifies selection, as you can focus first on choosing a product form which is best for your needs. For example if you are execising outside in the sun, choose a sportblock, or sweatproof, formula. If you are at the pool or the beach, choose a waterproof formula. The key is to use a product that you find easy to spread evenly over the skin and will stay in place depending on your activity, and that your skin can tolerate.

2. Select a product with an SPF of at least 30 and that is also marked 'broad spectrum'.
The skin needs shielding from all three types of UV radition: UVB, UVA2 and UVA1. UVB, which primarily reaches the top-most layer of skin, is responsible for acute photodamage, sunburn, and non-melanoma skin cancers. UVA rays, both 1 and 2, penetrate deeper into skin, and cause elastic tissue damage, photo-aging, and skin cancers, including deadly melanomas.

The SPF rating of a sunscreen product only measures UVB protection. It does not include UVA protection. New FDA regulations, however, regarding the term 'broad-spectrum' do provide the consumer with limited assurance about how much UVA protection a product has. If 'broad-spectrum is on the label that sunscreen product must protect against both UVB and UVA radiation and the UVA protection must be proportional to the UVB protection. The 'broad-spectrum' label does not require that the product protect against BOTH UVA1 or UVA2 radiation, however.

In addition, these new regulations also mandate that a sunscreen product cannot claim to protect against skin cancer and early skin aging if it has an SPF less than 15, and also disallow labeling a product greater than a SPF of 50. Research has shown that a product with an SPF of less than 15 does not provide adequate protection. On the other hand an SPF rating over 50 provides very little additional protection than an SPF of about 30 or 40. According to the American Academy of Dermatology an SPF 15 product blocks about 94% of UVB rays, an SPF 30 product blocks 97% of UVB rays, and an SPF 45 product blocks about 98% of rays. The difference in protection between SPF 45 and SPF 100 is less than 1%, which essentially means anything over an SPF of 50 is meaningless.

3. Picking the optimal combination of Sunscreens
The sunscreens found most often in sunscreen products are listed in the table below. This information in this table highlights the importance of the third guideline. For example, note that a sunscreen product with zinc oxide is the only sunscreen that provides protection against all three UV types. A zinc oxide sunscreen product, however, gains additional SPF protection in the UVB and UVA2 ranges if titanium oxide is added. For best protection therefore, avoid sunscreen products with only one of these minerals, and select only sunscreen products with both zinc and titanium oxide.

It is also best to avoid sunscreen products that contain zinc oxide or titanium oxide in combination with chemical sunscreens. The reason is that in general chemical sunscreens degrade, and lose potency in the presence of the mineral sunscreens zinc oxide and Titanium oxide. (There is research, however, which demonstrates that the rate which Avobenzone degrades in a sunscreen containing zinc or titamium oxide can be slowed down by approx. 50% if the zinc or titamium oxide are coated with silicates or manganese.)

The alternative to mineral sunscreens are sunscreen products containing combinations of chemical sunscreens. Note that there is only one chemical sunscreen, Avobenzone that will protect against UVA1 radiation, and therefore any chemical sunscreen product should always contain, at least, Avobenzone and contain it in the maximum amount allowed, 3%. Sunscreen products containing Avobenzone should always contain combinations of at least two other chemical sunscreens. This is because 1) Avobenzone only provides UVA1 protection and 2) it is photo-unstable. Adding addition chemical sunscreens to provide UVB and UVA2 are necessary for broad spectrum protection. Avobenzone will also lose almost half it's strength in daylight within an hour after application, unless the chemical sunscreens Octocrylene and Meroxyl SX, are added to photo-stabililze Avobenzone.

The using the chart below it can be seen the only way to combine chemical sunscreen to arrive at a photo-stable broad spectrum sunscreen product is to use Avobenzone and at least two other chemical sunscreens. A chemical sunscreen product should contain Avobenzone, the photo-stabilizing sunscreens Octocrylene or Meroxyl SX and at least one additional UVA2 blocking chemical sunscreen.

In summary, picking a sunscreen that provides good protection it isn't really as difficult as it may initially appear. The limited number of sunscreens in common use, and the new FDA regulations on SPF and 'broad-spectrum' labeling simplify the issue. Just follow a these three guidelines and remember sunscreens do not provide complete protection from the sun. Limit exposure and avoid the mid-day sun when the solar index is higher.

Commonly used Sunscreens, FDA approved:

sunscreen (alternate & trade names) range % allowed comments
Avobenzone
(Butyl methoxy-dibenzoyl-methane, Parsol 1789, Eusolex 9020, Escalol 517 )
UVA1
chemical
3% Degrades in sunlight; but be photo-stabilized with octocrylene, 4-MBC, Tinosorb, Meroxyl SX. Degrades when used with octinoxate, zinc oxide and titanium oxide; more info
Dioxybenzone
(Benzophenone-8)
UVB, UVA2
chemical
3% Derivative of benzophenone
Ensulizole
(Eusolex 232, Parsol HS)
UVB
chemical
4% Feels lighter on skin; Used in sunscreens with less greasy finish; more info
Helioplex
(avobenzone + oxybenzone)
UVB, UVA1, UVA2
chemical
9% Neutragena's tradename for a combination of avobenzone + oxybenzone;
Homosalate
(Homomethyl salicylate, HMS)
UVB
chemical
15% Currently one of the most widely used chemical sunscreens more info,
Meradimate
(Menthyl anthranilate)
UVA2
chemical
5%  
Mexoryl SX
(Terephthalylidene dicamphor sulfonic acid, TDSA, Ecamsule)
UVA2
chemical
3% Photostable; Water-soluble more info
Octinoxate
(Octyl methoxy-cinnamate, OMC, Ethylhexyl methoxycinnamate, EHMC, Escalol 557, Parsol MCX, Eusolex 2292, Tinosorb OMC, Uvinul MC80)
UVB
chemical
7.5% Currently one of the most widely used chemical sunscreens, known for its low potential to sensitize skin. Estrogenic effects are noted in laboratory animals. more info
Octisalate
(Octyl salicylate, Ethylhexyl salicylate, EHS, Escalol 587)
UVB
chemical
5% Has emollient and water-resistant properties; It is a weak UVB absorber with low toxicity concerns. A little greasy more info
Octocrylene
(Uvinul N539T, OCR, Eusolex OCR)
UVB
chemical
10% In 2006, a study found that octocrylene may increase skin's photosensitivity to the sun, increasing free radicals, will stablilized avobenzone.
Oxybenzone
(Benzophenone-3, BP3, Uvinul M40, Eusolex 4360, Escalol 567)
UVB, UVA2
chemical
6% In 2006, a study showed that oxybenzone can be photo-carcinogenic more info
Sulisobenzone
(Benzophenone-4, BP4, Uvinul MS40, Escalol 577)
UVB, UVA2
chemical
10% more info
Trolamine salicylate
(Triethanolamine salicylate)
UVB
chemical
12% Odorless, also used in analgesic creams; FDA approved more info
Titanium Dioxide (TiO2) UVB, UVA2
mineral
25% Physical barrier, Photostable; Less likely to cause irritation but may cause breakouts for some people; Responsible for a sunscreen's 'white cast'
Zinc Oxide (ZnO) UVB, UVA2, UVA1
mineral
25% Physical Barrier, Photostable; Less likely to cause irritation; Responsible for a sunscreen's white cast

 

Posted by Niora Niora