- Most people only apply about 25% of the sunscreen they need — reapply every 2 hours regardless of SPF number.
- SPF only measures UVB protection; look for "broad-spectrum" on the label to also cover UVA rays.
- SPF 100 only blocks 1% more UVB than SPF 50 on paper, but real-world studies show people wearing SPF 50 got sunburned far more often.
- Sunscreen doesn't meaningfully block red light therapy, but to maximize benefits, use LUMEBOX first, then apply SPF after.
Even if you are applying SPF every day, your skin may not be as protected as you think. Studies have found that most people only apply ¼ of the SPF they should be! [1]
So in this blog, we break down everything you need to know: how to choose a protective sunscreen, how much to apply, and the 5 sunscreen mistakes most of us are making without realizing it.
Is Sunlight Beneficial?
Before we talk about blocking sunlight, it's worth acknowledging what it gives us.
The sun has been a health resource for humans throughout our entire evolution, supporting bone health, immune function, blood sugar regulation, and more. [2] So it's actually beneficial if we approach it sensibly.
Plus, the sun is known to emit red and near-infrared light wavelengths - emitted at their highest concentration during sunrise and sunset - famed for their cellular benefits (supporting energy inside our cells, managing stress, and supporting blood flow and relaxation)!
That said, more sun exposure also means more UV exposure and more risk for our skin:
- DNA damage
- Break down of collagen & elastin → signs of skin aging
- Suppression of immune responses in the skin
- Skin cancer
We’re not advocating for avoiding the sun completely, but it makes sense to be smart about how we get our light, and how we protect ourselves from it.
(Plus, this is one reason we love red light therapy - to avoid the harmful UV rays and still get that healthy dose of the wavelengths our cells thrive on).
Now, we'll break down the 5 most common sunscreen mistakes, so you can make sure your skin is protected… and that you get the most bang for your buck!
5 Sunscreen Mistakes We See People Making Every Summer
Mistake 1: Thinking SPF Protects Against Everything
SPF only measures protection against UVB rays, not UVA rays, so a broad-spectrum label is what actually covers both.
- SPF only measures protection against UVB rays (the wavelengths that cause sunburn).
- SPF says nothing about UVA rays, or red/near-infrared rays for that matter.
- UVA rays penetrate deeper into the skin and are responsible for fine lines, hyperpigmentation, and signs of skin aging.
-
Solution: Look for a broad-spectrum sunscreen.
Mistake 2: Applying Too Little & Not Reapplying Enough
Most people apply only a quarter of the recommended amount. [3]
- For the face, use 2 finger lengths of product.
- For full body, aim for a shot glass worth of sunscreen.
Reapply every 2 hours and immediately after swimming or sweating, regardless of SPF number!
Poll: How Much Better Is SPF 100 Than SPF 50?
You might assume a higher number means longer-lasting protection, or you may even have heard social media influencers say SPF100 is no better than SPF50 - what's the truth?
Here's the real math:
- SPF 50 blocks ~98% of UVB rays
- SPF 100 blocks ~99% [4]
- So on paper, SPF 100 only blocks 1% more UVB than SPF 50.
But the 1% math only holds up under perfect, lab-controlled application. Once real-world application enters the picture (most of us are only applying about 25% of what we should) the gap gets a lot bigger...
Study 1: 199 participants wore SPF 50+ on one side of their face and SPF 100+ on the other for a full day of skiing. 55% were more sunburned on the SPF 50+ side vs. just 5% on the SPF 100+ side. [5]
| SPF | Real-world sunburn rate (Study 1) |
| 50 | 55% more sunburned |
| 100 | 5% more sunburned |
Study 2: 55 participants wore SPF 50+ on one side of their face and SPF 100+ on the other for 5 consecutive days at the beach in Florida. 56% had more sunburn on the SPF 50+ side vs. just 7% on the SPF 100+ side. [6]
| SPF | Real-world sunburn rate (Study 2) |
| 50 | 56% more sunburned |
| 100 | 7% more sunburned |
So it would seem that in studies on humans, there is a real difference between SPF 50 and SPF 100; people wearing SPF 50 got sunburned far more often than those wearing SPF 100.
Bottom line: SPF 30 is your minimum, SPF 50 is a solid everyday default. If you're spending a full day outdoors, SPF 100 is worth it. The real-world gap is bigger than the "1%" you've heard.
But the biggest misconception? That a higher SPF number means longer-lasting protection. It doesn't. Reapplication is what determines that, not the number on the bottle.
P.S. Remember, SPF only tells you about UVB protection. It says nothing about UVA protection - check for broad-spectrum for that!
Mistake 3: Thinking "Water Resistant" Means Waterproof
"Water resistant" ≠ waterproof.
The bottle should specify a durability window (e.g., 40 minutes). Apply 15–20 minutes before going in the water so it has time to form a protective film.
Mistake 4: Using the Wrong Formula for Your Skin
- Acne-prone skin? Look for "non-comedogenic" mineral sunscreens.
- Want a lightweight, invisible finish? That's why people reach for chemical formulas - although some contain ingredients that are worth researching first.
Choosing the Right Formula: Chemical vs. Mineral
Sunscreens are engineered to absorb or scatter UV radiation, but not every sunscreen on the market is formulated the same. Different ingredients may block (or at least decrease the absorption of) certain wavelengths.
There are two main types of sunscreen you will find in your local Walgreens or CVS that either TRAP or SCATTER UV rays into the atmosphere…
Chemical sunscreens:
- Use organic carbon compounds that absorb UV radiation
- Convert UV rays into heat, which is then released from the skin
- Tend to be lightweight and invisible
- Absorbs into the skin quickly
Mineral sunscreens:
- Physically scatter and reflect UV rays back into the atmosphere
- Contain physical blockers like titanium dioxide and zinc oxide
- Often leave a visible white layer as they sit on top of the skin
- Generally better tolerated by sensitive and acne-prone skin
Which one is best? The one you like and will use. It’s personal preference.
Did You Know? Skin Reflects Some Light, Too
Your skin itself selectively absorbs and reflects different wavelengths of light. In fact, about 4–7% of light is reflected straight off the surface before it even enters the skin. How?
- Natural oils on the skin surface create shine and increase reflection
- Light that travels into the upper layer of the skin or the deeper fat layer is largely re-emitted back upward through the skin layers / surface
- The skin is most transparent to red and near-infrared light (these wavelengths experience the least absorption and scattering) meaning they penetrate deepest (hence the benefits we see from red light therapy)
Our skin is also made up of several components that are capable of absorbing different wavelengths of light. According to Gajinov et al. (2010)[7], the key players are:
- Melanin: mostly absorbs UV light and shorter wavelengths. More melanin = more absorption (why darker skin types absorb significantly more UV)
- Hemoglobin: absorbs most light in the blue and green-yellow ranges
- Carotenoids: can absorb yellowish/olive tones
- Collagen and other proteins: absorb UV and visible/near infrared ranges
-
Water: can absorb infrared light (with a peak at 980nm)
Mistake 5: Missing the Spots People Forget
Smothering the face and body in sunscreen is all well and good, but don't forget the spots people miss. Here's where they are and the best type of coverage for each:
- Tops of ears (use a mineral stick for precise coverage)
- Lips (we love a dedicated SPF-50 lip balm like this. Mineral based and easy to reapply)
- Eyelids (a mineral sunscreen or SPF-infused eye cream is a gentler choice over chemical formulas)
- Back of the hands (broad-spectrum SPF that you don’t mind reapplying often - we choose chemical here)
- Hair part (a powder or spray mineral sunscreen is the easiest way to apply without weighing hair down)
Bonus content for our LUMEBOX users, you might be wondering…
Does Sunscreen Block Red Light Therapy?
TL;DR: No, not meaningfully. Sunscreen doesn't block red or near-infrared wavelengths in any significant way, but for the best results, apply your red light therapy first, then sunscreen after.
If red light therapy is already part of your skincare routine, sunscreen choice and timing can make a small difference in how much benefit you get. Here's what to weigh:
- Red light (~660nm) can be partially blocked by sunscreen, both chemical and mineral formulas
- Near-infrared light (~850nm) is barely affected by either type, it penetrates through sunscreen with minimal interference
- Mineral sunscreens (zinc oxide, titanium dioxide) tend to scatter slightly more red light than chemical formulas, especially thicker, whiter applications
- Chemical sunscreens absorb into skin quickly and don't sit as a surface barrier for long, which works in your favor if you're using red light shortly after applying
Should you worry about SPF affecting your RLT session?
No. SPF is a measurement system for UV protection. It has nothing to do with red or near-infrared wavelengths, which sit entirely outside the UV spectrum. A higher SPF number does not mean more RLT wavelengths are blocked.
The simple fix:
Use your red light device first, then apply sunscreen. This way you get the full benefit of your session before SPF goes on.
If that's not possible:
Don't skip your red light session just because sunscreen is already on. You're still getting the vast majority of the benefit (95%+ in most cases), sunscreen isn't designed to block these wavelengths, so any interference is minor.
Our Red Light + Sunscreen Routine:
- Use LUMEBOX in the morning on your face, before sunscreen and heading outside.
- Apply your sunscreen after your RLT session, once your skin has settled.
- If you're using LUMEBOX in the evening, remove makeup and cleanse your face first, then use LUMEBOX on clean skin.
If you've already applied sunscreen and want to use LUMEBOX, you don't need to wash it off, the impact is expected to be minimal. Clean skin is ideal, but don't let it stop you from getting your session in!
More Ways to Help Skin Repair Damage
1. Add antioxidants (like vitamin C)
UV exposure creates stress in the skin. Vitamin C may help neutralize free radicals before they contribute to inflammation, skin damage, and collagen breakdown.
Our summer favorites:
- 1 cup strawberries (~85mg vitamin C)
- 1 kiwi (~50mg vitamin C)
- ½ red bell pepper (~100mg vitamin C)
Pro tip: Pair vitamin C-rich foods with healthy fats + vitamin E-rich foods for antioxidant support.
2. Red light therapy
Red and near-infrared light may support healthy looking skin and circulation.
Plus, one fascinating study tested whether 660 nm red light (the wavelength you’d get from LUMEBOX in RED Mode) before UV exposure could help the skin build resistance to sunburn. [8]
While the study wasn’t done using LUMEBOX, it used a research-grade LED device with a similar wavelength and irradiance.
24 hours later, the side treated with red light showed:
- 85% had less sunburn
- Reduced post-inflammatory hyperpigmentation
Of course, this does NOT mean that LUMEBOX (or any red light device) should replace your sunscreen. But it's a fascinating finding, and why I like adding a LUMEBOX session to my skincare routine before I apply that SPF.
New to red light therapy? Download our free eBook to help you choose the best device.
Already have a LUMEBOX? Download our 6 time-saving tricks guide!
Medical Disclaimer: The information contained in this blog post is intended for educational purposes only and should not be used as medical advice. Everyone responds to light differently. Testimonials are not a guarantee of the results you or anyone who uses LUMEBOX will get because your success depends entirely on your circumstances, and the studies on red light therapy shared were not specifically performed using LUMEBOX. Please check with your doctor before using red light therapy and do not change your medical treatments or lifestyle without consulting your physician first.
References:
[1] Moradi Tuchayi, S., Wang, Z., Yan, J., Garibyan, L., Bai, X., & Gilchrest, B. A. (2023). Sunscreens: Misconceptions and misinformation. Journal of Investigative Dermatology, 143(8), 1406–1411. https://doi.org/10.1016/j.jid.2023.03.1677
[2] Raymond-Lezman JR, Riskin SI. Benefits and Risks of Sun Exposure to Maintain Adequate Vitamin D Levels. Cureus. 2023 May 5;15(5):e38578. doi: 10.7759/cureus.38578. PMID: 37284402; PMCID: PMC10239563.
[3] Moradi Tuchayi, S., Wang, Z., Yan, J., Garibyan, L., Bai, X., & Gilchrest, B. A. (2023). Sunscreens: Misconceptions and misinformation. Journal of Investigative Dermatology, 143(8), 1406–1411. https://doi.org/10.1016/j.jid.2023.03.1677
[4] Moradi Tuchayi, S., Wang, Z., Yan, J., Garibyan, L., Bai, X., & Gilchrest, B. A. (2023). Sunscreens: Misconceptions and misinformation. Journal of Investigative Dermatology, 143(8), 1406–1411. https://doi.org/10.1016/j.jid.2023.03.1677
[5] Kohli, I., Nicholson, C. L., Williams, J. D., Lyons, A. B., Seo, I., Maitra, P., Tian, X., Atillasoy, E., Lim, H. W., & Hamzavi, I. H. (2020). Greater efficacy of SPF 100+ sunscreen compared with SPF 50+ in sunburn prevention during 5 consecutive days of sunlight exposure: A randomized, double-blind clinical trial. Journal of the American Academy of Dermatology, 82(4), 869–877. https://doi.org/10.1016/j.jaad.2019.09.018
[6] Williams, J., Maitra, P., Atillasoy, E., Wu, M.-M., Farberg, A., & Rigel, D. (2017). High SPF sunscreen provides significant clinical benefit in actual use conditions: SPF 100+ is more effective than SPF 50+. Journal of the American Academy of Dermatology, 76(6, Suppl. 1), AB154. https://doi.org/10.1016/j.jaad.2017.04.599
[7] Gajinov, Z., Matić, M., Prćić, S., & Đuran, V. (2010). Optical properties of the human skin. Serbian Journal of Dermatology and Venereology, 2(4), 131–136. https://doi.org/10.2478/v10249-011-0029-5
[8] Barolet D, Boucher A. LED photoprevention: reduced MED response following multiple LED exposures. Lasers Surg Med. 2008 Feb;40(2):106-12. doi: 10.1002/lsm.20615. PMID: 18306161.
