How much sunscreen should you apply? How often should I reapply sunscreen?

If I had a dollar for every time I was asked these two questions, I’d be super-rich.

However, I’m unsurprised these questions keep cropping up:  there is so much conflicting information.

I’ll tell you what I do (and why) and then, what the “official” guidelines for sunscreen use are.

If there is only ONE thing you takeaway from this blog: always OVERAPPLY an SPF 30+ sunscreen.

1. My every day sunscreen routine

I use European sunscreens and they (generally) have labelling that gives guidance on their packaging or website. For example, the Swiss brand, Ultrasun specify 1 finger of sun protection for just your face and an additional finger for neck and ears.

Irrespective of the sunscreen, I use about 3ml – 5ml for my face (and yes, I have measured it).

This amount is about a Euro 2 coin in diameter. If you are thinking that is too much sunscreen – you are not wrong.

But I have a big face and I would rather OVERAPPLY sunscreen then underapply, as studies persistently show:  People typically apply 0.5 to 1.5 mg/cm² of sunscreen in real life instead of the 2 mg/cm² dosage prescribed in SPF test.

BUT here is the thing: when the dose (i.e., 2 mg/cm²) is halved, the SPF can reduce by as much as 60%+

Applying 50% of the recommended amount of SPF results in SPF 50 becoming SPF 17-SPF 37, which at its worst is a 65%+ reduction in SPF.

See also Difference between SPF 15 and SPF 50 for more information

How often do I/should I reapply?

The consensus between different regulatory bodies is sunscreen should be reapplied at least every two hours, and more often if you’re sweating or jumping in and out of the water.

I don’t apply every 2 hours.

I wear sunscreen first thing in the morning and once in the afternoon at about 3pm.

But I live in a country where the average temperature for 6 months is 40C-50C. During those months, I will reapply sunscreen every time I step out during daylight. This is because I “sweat-off” my sunscreen.

2. Sunscreen best practices

I adopt these in my daily skincare routine and you should too.

3. Official guidance on sunscreen….

The verbatim guidance given in different countries is:

Australia Cancer Org

For an adult, the recommended application is 5ml (approximately one teaspoon) for each arm, leg, body front, body back and face (including neck and ears). That equates to a total of 35mL (approximately seven teaspoons) for a full body application.

European Union

Sunscreen products have to be applied in quantities similar to the ones used for testing, i.e. 2 mg/cm², which equals 6 teaspoons of lotion (approx. 36 grams) for the body of one average adult person.

(source: Commission Recommendation 2006/647/EC)

USA Food & Drug Administration

An average-sized adult or child needs at least one ounce of sunscreen (about the amount it takes to fill a shot glass) to evenly cover the body from head to toe.”  In practice, this means applying the equivalent of a shot glass (two tablespoons) of sunscreen to the exposed areas of the face and body – a nickel-sized dollop to the face alone. If you’re using a spray, apply until an even sheen appears on the skin.

4. Why you often see conflicting advice on how much sunscreen to wear….

is simply because there is no global sunscreen treaty or regulation. Our lives would be simpler if the sunscreen I could buy in the USA had the same efficacy as that in Australia, the EU or India.
But that is not reality here and quite honestly, unless the US does not improve the state of its sunscreen regulation, we are going to keep seeing conflicting advice.

Closing

I hope this provides some clarity to all of you, Please let me know if you have any queries by leaving a comment or drop me a line at email@happyskindays.com

***