Lotions, Creams & Sun Exposure: What You’re Not Being Told

Most people focus on SPF when it comes to sun care - but what about your daily lotion?

(Here's my article on sunscreen if you have questions on that).

This question has been in my inbox multiple times this week (and in my private community) - so I thought it would be helpful to write a quick article on how lotions can interact with light - and not in the way many people think!

In this article I will help you understand how your skin interacts with different light frequencies, different lotions to use or avoid, how lotion on one part of the skin impacts the whole body, how your skin is responsible for hormone production, appetite regulation and more!

I'll try to leave the nerdier stuff down at the bottom - and the simple stuff at the top!

☀️Understanding Your Skin & The Light Spectrum

Sunlight delivers more than just UV rays ....It also includes:

 • Infrared (IR) and Red light: deeply healing, pro-mitochondrial, and anti-inflammatory.

 • UVA - nitric oxide release, mood, thyroid support, appetite regulation and skin pigmentation for protection.

 • UVB: triggers vitamin D synthesis - sulphates hormones & helps with fat burning

What you put on your skin can either support this system - or block it.

🧴The important question: Do Lotions and Creams Block Sunlight?

Your skin doesn’t just absorb sunlight, it also interprets it!

And what you put on your skin can dramatically change how well it reads those signals.

Let’s first break down how various moisturizers affect:

• 🔴 Red light (600–700nm)

• 🌈 Infrared (near and far) light (700–3,000+nm)

• 🌞 UVA (320–400nm)

• 🌞 UVB (290–320nm)

❌ Conventional Moisturizers 

(Drugstore lotions, creams, serums- even ones without SPF)

What they contain:

• Water emulsions, PEGs, silicones, dimethicone, synthetic fragrance, alcohols

Red & Infrared Light:

• Block or scatter red/IR via synthetic films or water-based matrices

• Disrupt skin’s melatonin and ATP production (Hamblin MR, 2017) 

UV Light (UVA & UVB): 

• Without labeled SPF, many still contain UV-filtering agents, titanium dioxide, or iron oxides for stability, color, or anti-aging

• May impair vitamin D production even if they don’t advertise SPF

• UVA is crucial for nitric oxide release and tanning- blockage disrupts these pathways 

Bottom Line:

• These products create a barrier to natural UV and red-light signaling

• They reduce your skin’s ability to adapt to and benefit from the sun

Citations:  Weller R. J Invest Dermatol. 2016 – UVA triggers nitric oxide synthesis

Marks R et al. Br J Dermatol. 1995 -  Sunscreen and cosmetic bases impair vitamin D synthesis

Krutmann J et al. J Dermatol Sci. 2017 - On light interaction and skin aging

✅ Beef Tallow-Based Creams

 (click here for my favorite brand and use code SARAHK)

(Grass-fed tallow + olive oil/beeswax blends)

Red & Infrared Light:

• Fully permeable

• Supports mitochondrial melatonin, ATP production, skin regeneration

UV Light (UVA & UVB):

• Does not block UV

• Allows for normal tanning response, melanin production, and vitamin D synthesis

Bottom Line:

• Ancestrally appropriate

• Nourishes skin without disrupting light absorption

Citation: D’Orazio et al. Int J Mol Sci. 2013 - UVA and UVB both critical for skin’s light response

🥥 Coconut Oil 

Red & Infrared Light: 

• Allows IR/red penetration

• Some antioxidant and anti-inflammatory effects

UV Light (UVA & UVB):

• Natural SPF of ~4–6

• Slightly reduces UVB- can modestly reduce vitamin D synthesis if used heavily

• Allows some tanning and UV signaling

Bottom Line:

• Fine in moderate amounts for sun-acclimated skin

• Not a true block, but avoid slathering pre-sun if aiming for full UV benefit 

Citation:  Mishra et al. Int J Res Pharm Sci. 2011 - Natural oils as mild sunscreens 

🌿 Plant-Based Oils (Jojoba, Squalane, Olive, etc.)

Red & Infrared Light: 

• Fully permeable

• Nourish mitochondria and skin barrier 

UV Light (UVA & UVB):

• Most do not block UV

• Exceptions: some unrefined oils (like citrus, bergamot) may cause photosensitivity 

Bottom Line:

• Excellent base for sun-friendly skincare

• Avoid photosensitizing essential oils pre-sun

 Citation: Rigo et al. Cosmetics. 2021 - Natural oils compatible with skin and sunlight 

⚠️ Tinted Moisturizers / Foundations (No SPF Label)

Red & Infrared Light:

• Can block or scatter due to pigments, mica, iron oxides

UV Light (UVA & UVB):

• May contain mineral reflectors or UV-blockers not labeled as SPF

• Often interfere with vitamin D synthesis and UVA-based nitric oxide signaling 

Bottom Line:

• These still alter light absorption - even if they’re “clean” or don’t say SPF

• Best applied after sun exposure if used 

Citations: Gulson et al. Toxicol Sci. 2010 - Skin absorption of zinc and titanium particles

Holick MF. N Engl J Med. 2007 - UVB and vitamin D pathway

🧪What About Retinol?

Retinol (Vitamin A derivatives) is photosensitizing. That means:

 • It makes your skin more vulnerable to UV damage.

 • It increases the risk of sunburn and pigmentation, even under moderate sunlight.

 • Most dermatologists recommend avoiding direct sun exposure after applying retinoids.

🔥 Bottom line: Retinol + sun = oxidative stress overload. Save retinol for evening use, or better yet - support your natural retinoid pathways with sunlight + dietary retinol from grass-fed liver, egg yolks, and raw dairy.

Also - avoid excessive blue light exposure from screens & LEDs as this has been shown to lower vitamin A levels. 

🧴Zinc Oxide & Mineral Sunscreens

Zinc oxide is a physical sunblock, meaning it reflects UV rays, particularly UVB. While it’s safer than chemical SPF filters (like oxybenzone), it:

 • Blocks vitamin D production

 • Reflects both beneficial and harmful UV

 • May partially scatter infrared if it’s non-nano (larger particle size)

If you need to use it, opt for non-nano zinc oxide on the nose, under eyes, or shoulders during peak UV when needed - but don’t use it daily as a moisturizer.

A few more common questions....

👃Face vs Body: Uneven Application?

Yes - this does matter!

If you apply a lotion, cream, or sunscreen only on your face:

 • You may block UVA/UVB/red/IR from reaching facial skin, which means:

 • Less melanin production (aka less protection)

 • Reduced vitamin D synthesis in that area

 • Greater asymmetry in skin tone, aging, and photoadaptation

Your face is also more photoreactive - so blocking light here while your arms or legs adapt naturally can create a mismatch in skin signaling.

💡Pro tip: If you’re going outside in strong UV light - wear a wide brimmed hat (this is what I do) or choose light-friendly skincare across all exposed areas - or better yet, nothing until after your sun session.

Q: Is it bad to wear makeup or tinted moisturizer in the sun?

If it contains SPF or occlusive agents, so it can block light signals.

Q: Can my lotion interfere with melanin production?

Yes - blocking UVA and IR can impair melanogenesis (your body’s natural tanning and UV defense system).

Look for oil-based options with ingredients like:

 • Astaxanthin

 • Tallow 

 • Beeswax

 • Non-comedogenic oils like jojoba or squalane

These can nourish the skin without interfering with light absorption.

☀️The Bigger Picture about skin exposure (and more science for my nerds 🤓) -  Melanocytes as Hormone Regulators

Melanocytes: 

• Express receptors for estrogen, cortisol, ACTH, prolactin, and even leptin

• • α-MSH (alpha melanocyte-stimulating hormone)

  • ACTH (adrenocorticotropic hormone)

  • Corticotropin-releasing hormone (CRH)

    Can produce hormones locally, like: 

These hormones are usually made by the brain - but melanocytes produce them in the skin, responding directly to light, stress, and immune signals.

 This means your skin can independently regulate stress and pigment, depending on your sunlight exposure and hormonal state.

Citation: Slominski A et al. “The cutaneous CRH system.” Endocr Rev. 2013.

☀️ Light, Melanocytes & Hormonal Feedback

Melanocytes are photoresponsive - meaning they react directly to different wavelengths of light:

• UVA: stimulates NO (nitric oxide) release and melanin dispersion (fast tanning)

• UVB: triggers vitamin D synthesis and longer-term melanin production

• Red and infrared light: support mitochondrial health in melanocytes, lowering inflammation and prepping them to respond to UV without damage

These cells are literally wired to read light, and when they do, they signal to the rest of your body - including your thyroid, pituitary, and adrenal systems - to regulate homeostasis.

Citation: Skobowiat C et al. “UVB and UVA activate neural pathways from skin to brain.” Photochem Photobiol Sci. 2011.

🧠 Melanocytes = Part of Your Skin-Brain Axis

 Because melanocytes produce α-MSH, they influence:

• Appetite regulation

• Sex hormones

• Cortisol rhythms

• Anti-inflammatory activity (via MC1R and MC4R receptors)

This is the same hormone system used in the brain’s hypothalamus to regulate leptin, ghrelin, and cortisol - proving that the skin is an endocrine organ that talks directly to your central hormone systems.

 Citation: Brzoska T et al. “α-MSH and MC1R in immune regulation.” Peptides. 2008.

🦠 Melanocytes & The Skin Microbiome 

• Melanocytes influence the pH and lipid environment of the skin through melanin and local hormone production

• This affects which microbes can thrive or die off (like Staph epidermidis, Cutibacterium acnes)

• Melanin itself has antimicrobial properties and helps buffer UV-induced microbial imbalances  

Light, hormones, and microbiome are not separate - they’re a co-regulated triad starting with melanocytes.

Citation: Luger TA. “α-MSH and the skin immune system.” J Invest Dermatol. 2003. 

⚠️ What Disrupts Melanocyte Function?

• Chronic indoor living → no light = low melanin signaling

• Artificial blue light → overstimulates melanocyte oxidative stress

• Sunscreen, tinted moisturizers, conventional lotions → block red/IR and UV = no hormonal feedback

• Low-fat diets or vitamin A/D deficiency → no support for melanin production

✅ How to Support Melanocytes Naturally 

• 🌅 Morning Sunrise + UVA + visible light = boosts α-MSH and primes skin defenses

• 🥚 Nutrient-dense fats = vitamin A, zinc, copper for melanin production

• 🧴 Avoid conventional creams before sun - use light-friendly skincare (tallow, jojoba)

• 💤 Fix circadian rhythm - melanocytes have their own peripheral clocks that sync with the sun (and make sure to block artificial light at night)

Download MyCircadianApp & Use code SARAHK to understand when Sunrise - UVA - UVB - Sunset & Nightfall happen for you!

Instead of defaulting to lotions that might block healing light or trigger damage when exposed to UV, consider going barefaced during your sun sessions - wearing a wide brimmed hat - or switching to light-compatible products that let your biology sync with nature.

Hope this article was helpful and informative!

Want to dive deeper? Get SUNWISE - my safe sun exposure + summer nutrition course at 40% off - or Get Quantum Nutrition (which includes Sunwise & mini courses on light exposure for each season)!