My End-of-Summer Vitamin D Numbers (and Why Many Experts Would Call Them “Too Low”)

Most doctors and health experts still look at one number - 25-hydroxyvitamin D (25-OH D) - and say it needs to be at least 70–100 ng/mL, and if it isn't - you’re deficient and need supplements.

But here’s the missing nuance: vitamin D is not necessarily a “more is better” nutrient. It’s a light-driven hormone system with multiple forms, seasonal rhythms, and genetic regulation. Looking only at storage levels misses the bigger picture.

Today I am going to share my spring numbers & fall numbers from this year, talk about why I am happy with these - why many people might be chronically low - and what I plan on doing this fall & winter.

A few announcements:

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Before I start - I want to give full disclosure that I am not a doctor & I am definitely not your doctor (even though you already know that 🤓)......so I ask you to listen with an open mind, and ultimately make decisions for yourself based on your intuition, talking with your doctor (or healthcare consultant) and your own personal experience.

My goal is never to fear-monger - but only to provide evidence to open more conversations and deeper research.

I recently did a whole bunch of labs to "check in" on myself - as I like to do every few months.

Not only do I read them - but I have a functional blood chemistry expert who takes a second look (​click here for his information​) - and I have had many conversations with ​Jim Stephenson Jr ​- who I consider one of the world's experts on this topic.

OK - so here are my numbers: ⬇️

 

 

What the Seasonal Shifts in Both Numbers Mean:

Spring: Coming out of winter, my storage pool was moderate at 45 ng/mL (this was with no winter supplementation...and while I do own a ​UVB lamp ​- I did not really use it over the winter), and my active hormone was high-normal at 60 pg/mL. This is compensation - the body converting more when storage is lower.

Fall: After a summer of safe sun exposure (and no supplementation), my storage pool rose by 15 points to 60 ng/mL, while active hormone dropped to a steady mid-range 39 pg/mL. My body no longer needed to over-convert.

This is exactly how the system is designed to work: seasonal rise in storage, balanced activation, and efficient regulation.

(Explained Simply)

Spring (after winter):

• My vitamin D “savings account” (storage form, 25-OH) was moderate at 45 ng/mL.
• Translation: Because reserves were lower after the dark winter months, my body was smart - it pulled more out of savings and put it into circulation so I could keep functioning well.

Fall (after summer):

• After months of sunlight, my savings account (25-OH) grew to 60 ng/mL - a healthy increase of 15 points.
• At the same time, my active form (1,25-D) settled into the middle of the range at 39 pg/mL.
• Translation: With more in savings, my body didn’t have to spend as aggressively. It could relax and keep things steady.

The Bigger Picture (that most people. misunderstand):

Your vitamin D system works like a "bank account": in winter, you spend more and save less. In summer, you stockpile more and don’t have to spend as hard. That’s not deficiency - that’s how the system is supposed to work in seasonal rhythm.

The problem with modern society is that most people burn through their vitamin D stores due to living out of sync with natural rhythms - surrounding by things that drain exclusion zone water & increase stress hormones (more on that later & how you can support yourself this fall & winter)....

More to the story with "low" vitamin D numbers:

This is where I want to bring in a clip from Tim Ferriss’ podcast that I came across yesterday, because it illustrates the confusion perfectly.

 ​Click here to watch the clip ​ 

 ​ ​Tim explains that despite taking 5,000 IU/day (I assume he was also taking K2 and magnesium - as he is a smart guy) and getting daily sun exposure (he said one hour a day), his labs still show him “barely squeaking by” at ~30 ng/mL. He notes the same is true for most of his friends, across ethnicities. He asks the obvious question: How is it possible that everyone looks deficient if they’re taking pills and getting sun?

Rhonda Patrick's answer is:

• We measure vitamin D with 25-OH D, a proxy - not the active hormone (125)
• Conversion from D₃ → 25-OH requires magnesium (half of Americans are deficient).
• Genetic SNPs reduce cutaneous production and conversion efficiency.
• Supplement variability: actual IU content often doesn’t match the label.
• Skin pigmentation: more melanin requires longer UVB exposure for equivalent synthesis.

Here’s my theory:

• The skin makes vitamin D differently than pills. When UVB hits the skin, it doesn’t just make D3 - it also makes tachysterol, lumisterol, and other protective metabolites. These act like natural “dimmers” to prevent overshooting.
• Supplements skip this process. Oral D3 bypasses the skin and doesn’t produce these balancing photoproducts. Some researchers suggest this may confuse the system - the body may dial back natural production, or the metabolite balance may shift.
• Sunlight-driven vitamin D metabolism creates a broader spectrum of compounds.
• Supplemented vitamin D produces a narrower set of metabolites.
• That difference likely matters for regulation, immunity, and feedback.
• We also have to take a look at blue light exposure, NNEMF exposure, deuterium, and stress - as these deplete exclusion zone water (while these ideas are "fringe" - and not widely accepted).

So while experts scratch their heads about “deficiency” despite supplements + sun, the deeper story may be that supplementation changes the body’s natural feedback system, and modern life - without proper circadian signaling and NNEMF mitigation - could potentially keep D levels lower.

Again - I am speculative here - but raising these important questions for deeper discussion.

PS - these were my magnesium levels ⬇️

 

PPS - I also carry a few common SNPs (genetic variants) that make converting vitamin D from its storage form (25-OH) into its active form (1,25-OH) less efficient.

Because of this, I was advised to supplement with high doses, but instead of blindly following that advice, I’ve chosen to monitor both my numbers and how I feel - while focusing on the fundamentals that actually drive vitamin D regulation: circadian rhythm, light exposure, seasonal cold exposure,​ red light therapy,​ hydration, seasonal eating, and mitochondrial health. So far, my labs show that these basics are working for me at this time.

Why Modern Life Might Be Eroding Vitamin D (Beyond Just Sun)

• We know melatonin, the hormone your body produces at night, can bind to the Vitamin D Receptor (VDR) and support aspects of vitamin D signaling. So when melatonin production is disrupted (by light at night, screens, etc.), you may lose out on a backup system.
• Light therapies like red or near-infrared light help reduce inflammation, support skin health, and improve cellular repair - all of which can make your skin more efficient at converting UVB to vitamin D when you do get sun. But they don’t directly produce vitamin D.
• Magnesium is a required cofactor for several of the enzymes that convert active vitamin D forms. Low magnesium intake is common and may slow conversion. (This is well documented.)

Mechanistic studies support these ideas (so they may be speculative now - but there is some interesting evidence & I strongly believe in these):

• Cold exposure, “internal biophotons,” seasonal eating, and stress/repair cycles may help “preserve” vitamin D reserves in the winter

Why Chasing High Vitamin D Isn’t Necessarily the Answer

It’s tempting to think that if some vitamin D is good, more must be better. But large-scale evidence doesn’t support that idea. When researchers look at outcomes like fractures, cardiovascular disease, or all-cause mortality, pushing 25-OH vitamin D levels above 60–70 ng/mL doesn’t consistently help - and sometimes increases risk.

• VITAL Trial: Daily 2000 IU vitamin D₃ for 5 years did not reduce fractures or major health outcomes despite raising blood levels. (Manson et al., N Engl J Med, 2019. PMID: 30415629)
• High-dose bolus harm: Annual 500,000 IU increased falls and fractures in older women. (Sanders et al., JAMA, 2010. PMID: 20157135)
• Monthly high-dose harm: Monthly 60,000 IU vitamin D increased falls in older adults. (Bischoff-Ferrari et al., JAMA Intern Med, 2016. PMID: 26747333)
• Kidney stone risk: Calcium + vitamin D supplementation raised kidney stone incidence in the Women’s Health Initiative. (Jackson et al., N Engl J Med, 2006. PMID: 16481635)

When you look across large cohort studies and pooled mortality data, the lowest risk consistently appears in the mid-range - roughly 40–60 ng/mL. That’s exactly what Rhonda Patrick highlighted in her conversation with Tim Ferriss, and it’s exactly where my own labs have landed.

(Zittermann et al., 2012; Chowdhury et al., 2014)

But what about Cancer Prevention?

Some people argue that vitamin D levels need to be above 60 or even 80 ng/mL for cancer prevention. That idea comes mostly from observational studies showing that people with higher vitamin D levels have lower cancer risk.

But here’s the catch: correlation is not causation. People with higher vitamin D often have healthier lifestyles overall - more sunlight, more outdoor activity, better diets, and those factors can drive both higher vitamin D and lower cancer risk.

When researchers actually put this to the test in large randomized controlled trials, raising vitamin D with supplements didn’t lower cancer incidence in a consistent way. The VITAL trial (Manson et al., NEJM 2019), which gave 2,000 IU/day for 5 years to over 25,000 adults, found no reduction in invasive cancer incidence compared to placebo - even though blood levels rose.

And again - this is why many experts now point to the mid-range - around 40- 60 ng/mL - as the sweet spot. It’s where we see the lowest risk of all-cause mortality in pooled analyses, without the potential harms of overshooting (like higher falls, fractures, or kidney stones in some high-dose trials).

The big picture, and how I plan on spending my fall & winter:

My labs show that vitamin D health isn’t just about chasing a number on a blood test, and even with genetic variants that make conversion harder, my body has shown it can regulate vitamin D naturally when I honor the basics - sunlight, circadian rhythm, hydration, seasonal eating, and mitochondrial support.

As we head into fall and winter, this is where most people go wrong: they double down on pills (again - that is always your individual choice) while ignoring the circadian and quantum signals that actually determine how vitamin D (and every other hormone) works.

My approach is to lean into seasonality - earlier nights, more rest and repair, nourishing seasonal foods, safe light practices, and stress management. That’s how I plan to move into the darker months with strong immunity, steady energy, and hormone balance.

I have more thoughts on winter tanning beds - UVB lights, and supplements - so stay tuned for future articles!

✨ If you want to follow the same seasonal strategies, my ​Quantum Winter Blueprint is $50 off ​- but only for one more day. Inside, you’ll learn how to align your biology with the season using light, cold, food, red light therapy and circadian strategies that preserve energy instead of depleting it.

🌞 And if you’re a practitioner or a deeper learner who wants to go beyond the basics - understanding the sources and mechanisms behind these shifts - I break it all down in my ​Leptin Master Plan​, which is designed to help you apply these principles at the clinical level or dive deeper if you are an advanced learner.

 ​More on this topic: You've been warned about sunlight - but not supplements​ 

References

1. Slominski AT, Kim T-K, Qayyum S, Song Y, Janjetovic Z, Oak ASW, Slominski RM, Raman C, Qureshi SM, Stefan J, Tang EKY, Tuckey RC. Melatonin, mitochondria, and the skin. Cell Mol Life Sci. 2020 Feb;77(9):1659-1671.
2. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361.
3. Deng X, Song Y, Manson JE, Signorello LB, Zhang SM, Shrubsole MJ, Ness RM, Seidner DL, Dai Q. Magnesium, vitamin D status and mortality: results from US National Health and Nutrition Examination Survey (NHANES) 2001 to 2006 and NHANES III. BMC Med. 2013 Aug 27;11:187.
4. Tian XQ, Chen TC, Lu Z, Shao Q, Holick MF. Characterization of the translocation process of vitamin D3 from the skin into the circulation. Endocrinology. 1994;135(2):655-661.