SPF Demystified: What That Number on Your Sunscreen Really Means (and Why It Matters)

Terryanne Daniel • July 24, 2025

SPF Demystified: What That Number on Your Sunscreen Really Means (and Why It Matters)

We all know we should be wearing sunscreen every day. In fact, every dermatologist, doctor, and aesthetician agrees: SPF 30 should be a non-negotiable part of your daily routine. At Beam & Bare, we’re all about education and skin health—so we hear your questions all the time:

  • “If my moisturizer is SPF 20, isn’t that enough?”
  • “Is SPF 75 better than SPF 30?”
  • “If I layer SPF 20 and SPF 30, do I get SPF 50?”
  • “What even is SPF?”

We get it—it’s confusing! So let’s clear it all up with this practical, expert-backed guide from Beam & Bare.


 First Things First: What Is SPF?

SPF stands for Sun Protection Factor. It measures protection against UVB rays—the ones that cause sunburn and contribute to skin cancer.

However, SPF doesn’t tell you anything about UVA protection—which is just as important. UVA rays penetrate deeper into the skin and are responsible for aging, sun spots, and long-term DNA damage.

 Beam & Bare Pro Tip:

Look for "Broad Spectrum" on your sunscreen label. This means the product protects against both UVA and UVB rays. 


 What Does SPF 30 Actually Mean?

SPF isn’t about “how long” you can stay in the sun—it’s about how much of the sun’s UVB rays are blocked.

Here’s how it breaks down:

  • SPF 15 blocks about 93% of UVB rays
  • SPF 30 blocks about 97%
  • SPF 50 blocks about 98%
  • SPF 100 blocks about 99%

That means SPF 30 blocks about half as many rays as SPF 15 lets through, while SPF 50 gives you just 1% more protection than SPF 30. So more isn’t always dramatically better—and no sunscreen blocks 100% of rays.


 Does Higher SPF Last Longer?

No.
All sunscreens—regardless of SPF—must be reapplied every 2 hours.
 Period.

Even the best sunscreen degrades with time, sweat, water, rubbing, or towel-drying. Whether you’re using SPF 30 or SPF 100, reapplication is key.


 Water & Sweat: What You Need to Know

Going for a swim? Headed out for a long hike? Here’s what to look for on the label:

  • Not water-resistant: Reapply immediately after water or sweat
  • Water-resistant (40 min): Reapply after 40 minutes in water
  • Water-resistant (80 min): Offers up to 80 minutes of protection before needing a touch-up

 Beam & Bare Favourite:
Our 
Colorescience Flex or Brush-On Mineral Powder SPF 30 is water-resistant for 80 minutes—and still lightweight, dry, and invisible. Perfect for touch-ups on the go!


 Chemical vs. Mineral: What’s the Difference?

At Beam & Bare, we often recommend mineral sunscreens for their immediate, broad-spectrum protection and suitability for sensitive or post-treatment skin.

Chemical SunscreenMineral SunscreenHow it worksAbsorbs UV and converts to heatReflects + scatters UV raysKey ingredientsOxybenzone, Avobenzone.     Zinc Oxide, Titanium DioxideProsLightweight textureGentle, safe, instant protectionBest forEveryday wear under makeupSensitive skin & outdoor protection


 Available at Beam & Bare:

  • Vivier Sheer SPF 30 Mineral Sunscreen
  • Colorescience Sunforgettable Flex SPF 50
  • Colorescience Brush-On Mineral Powder SPF 30

Drop by our clinic or shop these in-person—we’re happy to help you find the perfect fit for your skin type and lifestyle!


 Should You Layer SPF Products?

Unfortunately, layering SPF products doesn’t add them together.
SPF 20 moisturizer + SPF 30 powder ≠ SPF 50. You’ll only be protected at the 
higher number, not the sum.

So, stick with your highest SPF product, and always apply generously.


 How to Maximize Your Protection

Here’s the Beam & Bare Protection Routine for serious sun-smart skincare:

  1. Apply a generous layer of SPF 30+ mineral sunscreen to clean skin before dressing.
  2. Layer with UPF-rated clothing and wide-brimmed hats.
  3. Use Brush-On SPF 30 Mineral Powder for easy, invisible reapplication on face, neck, and hands—every 2 hours.
  4. Don’t forget sunglasses and lip balm with SPF!


 Beam & Bare’s Quick SPF FAQs

What’s the difference between SPF 30 and SPF 50?
About 1.3%. SPF 30 blocks 97% of UVB rays, SPF 50 blocks 98%.

Does higher SPF last longer?
No—all sunscreens need to be reapplied 
every 2 hours.

Best SPF for sensitive skin?
Mineral SPF 30+ like 
Vivier Sheer SPF 30 or Colorescience Flex SPF 50.

Is there a safe way to tan?
Any tan from UV rays = skin damage. The only safe tan is a 
self-tanner.

Where can I buy trusted SPF products?
Right here at 
Beam & Bare! We carry VivierColorescience, and other dermatologist-approved brands in-clinic.



 Final Word: Why SPF Matters

Daily SPF is the most effective anti-aging product you can use. It helps prevent:

  • Sunburn
  • Wrinkles and pigmentation
  • Skin cancer, including melanoma

Our skin is constantly exposed—even on cloudy days or through windows. That’s why Beam & Bare recommends applying SPF 30 or higher every single day, and reapplying consistently.

Your future skin will thank you.

Have questions or need help choosing a sunscreen?
Book a complimentary consultation at 
Beam & Bare, or visit us in-clinic to browse our curated SPF essentials.


By Terryanne Daniel October 31, 2021
One of the more prominent catch phrases of late is “Self-Care”. But what does that really look like? The truth of it is, only you can answer that! Self-Care is a gentle way of reminding us we need to take care of ourselves, possibly first. For example, if you have flown in an airplane they teach us even before takeoff - dawn your mask first before assisting others. You cannot pour from an empty cup, so whatever your version of Self-Care looks like, it should be something we all do every day. It teaches us the importance of Self-Love. Here are some genuine ideas. Health is first. Most doctors are not seeing patients in person right now. But this does not mean you do not address issues of concern. Update your blood work, discuss mental health strategies, ask their team about resources to assist you through COVID decisions. Yes, book your dental checkup and cleaning. Body hurts? Book that massage. Revisit the Chiropractor. Exercise and stretching are also important. You will thank yourself later. Health is first and foremost! Get out there! Shut off the phones, the tv, and crank the tunes and wiggle a wee bit, or dance like your life depends on it. “Music is to the soul what words are to the mind.” Exercise is important, but now your mental health is at the forefront. Do you have a hobby or is there something you have always wanted to try? Recently, I took up Archery. Called a few friends, and once a week we get together, kill a few balloons, giggle, belly laugh and have a lot of fun. A massive thank you to James and his crew at Antler River Archery in Delaware. It does not matter what you do, as long as you get out and do something, even if it’s just going for a nice walk, getting fresh air is also important. We all need to protect our skin as well. The hard truth is an appropriate SPF is required for all seasons, for all skin types, for all ages, no matter what your vocation. In addition, healthy skin can assist in our mental health by boosting our confidence. Do not misunderstand this, it is not meant to be body or age shaming. Every day we rise and the first person we usually see is ourselves staring back in the bathroom mirror. You are beautiful. I know from firsthand experience, sometimes it is just harder for us to see it. Dehydrated, malnourished, mask irritated skin can flood our brains with less than accurate thoughts. Cleansing adequately, replenishing hydration, repairing environmental damage and adding nourishment when our skin needs it, is a very clear choice in boosting our health as well as our confidence. But of course, my favourite suggestion, pamper yourself in life's simple pleasures. Get that facial, update your skincare, reserve a table at your favourite restaurant, take a ride in the country, play golf, whatever is your key to mindfulness. You absolutely deserve it. Take in the “Easy”. One of our therapists said that to me and I felt stupefied. Almost as if I did not even realize this was an option. So again, take in the “Easy”, look at your to do list and see what can be eliminated, and what can you delegate in order to make time for yourself and your wellbeing. I guess what I am trying to say is, YOU are absolutely amazing! Don’t doubt it for a moment, I am talking to you. For most of us, we never find enough time in our day to realize just how amazing we actually are. We are so busy trying to be strong for those around us, the time just slips on past us. And at the end of the day, exhaustion rocks us to sleep, bedded in the blanket of worry. Bottom line… Did you do enough? You did. Now go take in the “Easy”. Who is Terryanne Daniel? Terryanne is the Centre Director for Synergy Centre, a multidisciplinary health care facility located in Northwest London. Owner of Synergy Aesthetic & Laser. Dental Professor for Fanshawe College. Certified Human Behaviour Specialist. Advanced Skincare Specialist, Certified Laser Technician. Humanitarian and Sponsor Mum to three children in Nicaragua. More importantly Mother of four, Grandma of two and let’s not forget wife to the most incredible person that is able to keep up with her shenanigans. Terryanne remains passionate about healthcare work, and the caring for others.
By kevin Wu February 11, 2021
When the skin is hydrated it is healthy, glowing and feels great! So how do we keep the skin hydrated and nourished? Contrary to popular belief, moisturizers do not give the skin hydration, they lock it in. A serum is what gives the skin hydration! Moisturizers and serums work together to replenish hydration and keep it in the skin.
By kevin Wu February 10, 2021
Skin - Everyone deserves healthy skin and it is possible for everyone to achieve! When we consider all the different types of treatments offered by skincare therapists and dermatologists - facials, injectables, light therapy, laser services, skin tightening, collagen remodelling, skin resurfacing, and micro-needling. The common factor of all of these services is to promote collagen production for healthier, youthful-looking skin.