Sunscreen is a term used to refer to both a product and an ingredient. It can be both a cream or lotion rubbed onto the skin to protect it from the sun and as well as active ingredient. Sunscreen, also referred to as sunblock and suntan lotion, is a topical product that absorbs or reflects some of the sun's ultraviolet radiation, thus protecting against sunburn.
Some minerals such as zinc oxide or titanium dioxide, act as a physical sunblock. Physical sunblocks function to reflect UV rays, similar to how white paint reflects light. If you remember the thick, white sunscreen worn in the 1980s and 1990s, the color was due to these compounds; because manufacturers make inorganic particles much smaller now (such as nanoparticles), we don't see the visible white.
Along with inorganic chemicals (minerals), sunscreens often contain organic chemicals, such as avobenzone or oxybenzone. These molecules absorb UV radiation, rather than deflecting light, through their chemical bonds. As the bonds absorb UV radiation, the components of the sunscreen slowly break down and release heat.
The term “SPF” on sunscreen bottles stands for Sun Protection Factor. It refers to how well the sunscreen protects against one type of UV radiation, called UVB. UVB rays cause sunburn and several varieties of skin cancer.
Another type of radiation, called UVA, penetrates deeper into the skin. UVA radiation can cause premature wrinkling, age spots and can heighten the risk for some skin cancers. Sunscreens labeled "broad-spectrum" block against both UVA and UVB radiation. There is no standard at this time for listing UVA blocking power.
Most organizations recommend using sunscreen with an SPF between 15 and 50 (SPF higher than 50 has not been proven to be any more effective than SPF 50). A sunscreen with an SPF of 15 protects against about 93 percent of UVB rays, and one with an SPF of 30 protects against 97 percent of rays, according to the Mayo Clinic. No SPF can block 100 percent of UV rays.
There is a common misconception that SPF relates to the amount of time of solar exposure. Many people believe that, if they usually get sunburned in twenty minutes, then an SPF 15 sunscreen will allow them to stay in the sun for 300 minutes or 5 hours (e.g., 15 times longer) without getting sunburn. This is not true because SPF is not directly related to time of solar exposure but to the amount (intensity) of solar exposure. The sun is stronger mid-day compared to early morning and early evening hours. That means your risk of sunburn is higher at mid-day. Solar intensity is also related to geographic location, with lower latitudes having greater solar intensity.
Sunscreen products are regulated as over-the-counter drugs by the U.S. Food and Drug Administration (FDA). The FDA has safety and effectiveness regulations in place that govern the manufacture and marketing of all sunscreen products, including safety data on sunscreen ingredients.
Every drug contains active ingredients and inactive ingredients. In the case of sunscreen, active ingredients are the ones that are protecting your skin from the sun’s harmful UV rays. Inactive ingredients are all other ingredients that are not active ingredients, such as water, oil, scent and preservatives, that may be used in formulating sunscreens. Below is a list of acceptable active ingredients in products that are labeled as a sunscreen:
- Aminobenzoic acid
- Avobenzone
- Cinoxate
- Dioxybenzone
- Homosalate
- Menthyl anthranilate
- Octocrylene
- Octyl methoxycinnamate
- Octyl salicylate
- Oxybenzone
- Padimate O
- Phenylbenzimidazole sulfonic acid
- Sulisobenzone
- Titanium dioxide
- Trolamine salicylate
- Zinc oxide
FDA regulations require all sunscreens and other nonprescription drugs to have an expiration date unless stability testing conducted by the manufacturer shows (proves) that the product will remain stable for at least three years. That means a sunscreen product that doesn’t have an expiration date is considered expired three years after purchase.
Sunscreen manufacturers now are banned from claiming that sunscreen is "waterproof" or "sweat-proof," since the FDA has determined that those terms are misleading. And, water-resistant sunscreen should be reapplied after getting out of the water or after sweating since sunscreen is not formulated to withstand prolonged exposure to water or sweat.
It is also important to remember that high-number SPF lasts the same amount of time as low-number SPF. High-value SPF does not allow you to spend additional time outdoors without reapplication. All sunscreens need to be applied roughly every two hours or according to the time on the label, even on cloudy days and after swimming or sweating.
It is essential to understand how the FDA requires that SPF testing be performed. The FDA requires that 2 mg/cm2 of SPF be applied to a subject’s back, and the size of the test site must be at least 30 cm2. It is required that ten different test subjects be used. After application of the SPF, there is a 15-minute waiting period. Skin is then exposed to six sessions of UVB exposure (the dose depends on the patient’s Fitzpatrick Skin Type). The minimal erythema dose (MED) is the smallest UV dose that produces perceptible redness of the skin (erythema) with clearly defined borders. In the FDA studies, the MED is measured at 16 to 24 hours after UV exposure. The person who evaluates the test subsites should not be the same person who applied the sunscreen to the test site or administered the UV doses. This practice prevents researcher bias. The MED is used to determine the product SPF.
If your company wants to make water-resistant claims (following 40 minutes exposure) in addition to SPF claims, the following procedure is used:
- Apply the SPF 2mg/cm2 as described above
- Perform moderate activity in water for 20 minutes.
- Rest out of water for 15 minutes. Do not towel test site.
- Perform moderate activity in water for 20 minutes.
- Allow test sites to dry thoroughly without toweling.
- Perform the UV testing as described above.
Testing your sunscreen formulation to ensure compliance can be costly and time consuming. One SPF testing lab, AMA Laboratories, will perform SPF 30, 80 min waterproof and broad-spectrum testing for a little less than $5000. If you only require SPF testing and are not making any waterproof or broad-spectrum claims that number goes down to less than $2500.
However, the FDA Sunscreen monograph is only one of the regulations that sunscreen products must follow. Sunscreens must also adhere to all the other regulations that apply to OTC drug products. Two major requirements that you must be able to prove are that you have the amount of active ingredient in your product that you claim is in the formula, and you have to test each batch before you can sell it.
Other regulations include (but are not limited to) the following:
- Follow pharmaceutical cGMP instead of cosmetic cGMP
- Facility must be registered as a pharmaceutical manufacturing facility with the FDA.
- Perform testing on each raw material to determine its chemical makeup and quality (these fees run in the tens of thousands).
- Qualify all suppliers of all drug raw materials (active ingredients).
- Document and train annually all employees that work on or affect the OTC drug on cGMP.
- Use the correct type of batch records and file all related information correctly with the FDA.
- After initial listing of a drug and submission of its labeling, any labeling changes or updates must be submitted every June and December or more frequently, as changes occur.
Many small companies hire a consultant or private label sunscreen from other manufacturers to avoid the paperwork and prevent costly mistakes.
While it may seem novel to want to offer handcrafted, homemade sunscreen, the reality is that this product class is highly regulated for a reason. Cancer prevention, in particular, is nothing to scoff at and the tools are in place to ethically and legally offer unique formulations if they fall within the guidelines set forth by the FDA. Over The Counter drug classifications were put in place to reduce the incidence of “snake oil salesman” and unscrupulous businesses hawking products that could not live up to their claims. While it’s an “in demand” product, the reality is it is also an expensive product to manufacture, and that is directly related to the requirement to prove your claims.
References:- Guidance For Industry. Labelling and Effectiveness Testing: Sunscreen Drug Products for Over-The-Counter Human Use - Small Entity Compliance Guide https://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm330696.pdf
- American Academy of Dermatology: Sunscreen FAQs https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs
- Sunscreen: How To Help Protect Your Skin From The Sun https://www.fda.gov/Drugs/ResourcesForYou/Consumers/BuyingUsingMedicineSafely/UnderstandingOver-the-CounterMedicines/ucm239463.htm
- AMA Laboratories: SPF Testing https://www.amalabs.com/services/testing/spf-testing/
