Everything You Need to Know About Sunscreen

In my day-to-day skin care consulting, I constantly and consistently mention wearing sunscreen.

Sunscreen should always be above an SPF of 30. SPF (sun protection factor) correlates to the amount to time the skin can withstand UV radiation before it turns red. This, however, is not a measurement of DNA damage. It is not a perfect or accurate way of measuring sun damage/carcinogenesis of the sun in an individual’s skin.

A product with an SPF greater than 30 is minimally more effective. For any increase in SPF, you may only get a few extra minutes before your skin begins to redden. An SPF of 30 is the lowest effective number to be used. Because it is a measure of redness, an SPF of 30 or above should always be reapplied every two hours.

Sunscreen FAQs:


Absolutely! The sun can damage any area of the skin, including your scalp. Plus, the sun can bleach and dry out your hair. Make sure to use at least an SPF 30 on any exposed part of your scalp. Also consider a moisturizing and protecting product for your tresses. Of course, you can always be ultra-fashionable and use a large hat to protect your hair and face.


Sunscreen should be applied about 30 minutes prior to sun exposure, and 1 ounce should be applied to each extremity. That’s 1 ounce for each arm, 1 ounce for each leg, 1 ounce for the front of your torso, 1 ounce for the back of your torso, and 1 ounce for your face and neck area. Yes, that’s 7-8 ounces total, but you want to block the sun, not simply screen it.


The best solution is to use a physical barrier like a hat, visor, or sweatband. You can use a sunscreen stick, but studies have shown that they aren’t as effective as traditional sunscreen products.


I’ll answer this as a two-part question. First, sunscreen should be applied at least every two hours and more if you’re sweating a lot, swimming or doing any other activity that is rubbing off or wearing away at your sunscreen. They are designed to remain at original strength for up to three years. This means that you can use leftover sunscreen from one year to the next. Some sunscreens include an expiration date — a date indicating when they’re no longer effective. Discard sunscreen that is past its expiration date.

A lot of patients also ask what type of sunscreen I use personally. Some of my favorite sunscreen products are:

• Tizo Tinted Sunscreens (and clear varieties)

• Neutrogena Sheer Mineral line

• Vanicream Sunscreen

• Blue Lizard Sunscreen (local company)

• California Baby Sunscreen

Remember sunscreen is not perfect and cannot replace sun avoidance and protective clothing!

Dr. Purvisha Patel is a Board-certified Dermatologist, Mohs Surgeon, Creator of Visha Skin Care, and Owner of Advanced Dermatology & Skin Cancer Associates. For more information, visit advanceddermatologymemphis.com or call 901.759.2322.

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