Stop Taking Vitamin D if You Can’t Get Sunlight… Do This Instead

DeLauer emphasizes that the gut becomes the primary site of vitamin D entry when sun exposure is absent. He points out that we often pass dietary vitamin D through undigested, so optimizing the microbiome with fermented kefir, along with gelatinous foods like bone broth and collagen, can maximize what you get from your meals. He also mentions new, early-stage research into a bacterial connection between gut, skin, and UVB conversion, framing gut health as a hidden lever for vitamin D status.

DeLauer stresses that people often overlook magnesium when trying to raise vitamin D levels. He'd tolerate a high dose of up to 700–800 mg because if it causes digestive urgency, being stuck indoors means the bathroom is conveniently close. He specifically recommends a sustained-release magnesium like di-magnesium malate to provide a steady supply and avoid the abrupt laxative effect of some magnesium salts. The goal is to ensure that whatever vitamin D you do manage to get from food, cod liver oil, or a UVB lamp is efficiently converted into its usable form.

DeLauer builds a comprehensive artificial light protocol. First thing in the morning, he'd sit by a window for 15 minutes, leveraging the eye's contrast adaptation to make even filtered daylight a strong zeitgeber. Then he'd use the multi-wavelength lamp, which has 10 UVB intensity programs so you can gradually build exposure, and separate red/NIR modes to simulate sunrise and sunset. He notes data suggesting UVB lamps can deliver higher vitamin D synthesis than natural sunlight in some cases, but insists they aren't a replacement for the full sensory immune experience of being outdoors. The lamp's near-infrared mode also boosts cellular energy, and the red light mode increases GABA, providing cognitive benefits that partially mimic the relaxation from sun exposure.

DeLauer openly dislikes synthetic vitamin D supplements, questioning their source and calling them 'unopposed' — a high dose of D without the co-factors found in sun-made or food-derived vitamin D. He prefers cod liver oil as a food-based source that provides not just vitamin D, but also retinol (vitamin A) and the long-chain omega-3s EPA and DHA. He mentions that omega-3s influence cell fluidity, a property also modulated by sunlight, making cod liver oil a more holistic choice. He warns against excessive intake due to the risk of vitamin A toxicity, but believes 1–2 teaspoons is a safe, effective daily dose.

DeLauer highlights a dual benefit of exercise. Resistance training directly boosts the body's utilization of vitamin D, making the nutrient more bioactive. He notes newer research suggesting resistance training may outperform cardio in this metabolic role. Meanwhile, cardio and any fat-loss activity help because vitamin D gets trapped in fat cells; shedding that fat releases the stored D, raising blood levels. So a mix of resistance work and some aerobic exercise provides the best strategy for keeping vitamin D available when you have no sun exposure.

DeLauer notes that being indoors strips away not just vitamin D but also the immune system stimulation provided by sunlight on the skin. He suggests a simple at-home contrast routine — a hot bath to mimic the warmth of sun or a sauna, followed by a quick cold shower — to recreate a similar immunologic stressor. This hormetic 'temperature shock' can help maintain a responsive immune system even during long periods without direct sunlight.

DeLauer points out that a substantial portion of our daily dopamine bursts comes from sunlight hitting the retina and skin. When you're stuck inside, that pathway goes dark. He recommends an overt strategy: supplement with pure tyrosine in the morning to provide raw material for dopamine synthesis, and deliberately pair it with energetic, uplifting music around the same time you'd normally get outdoor light. This combination creates a reliable proxy for the sun-driven dopamine lift, helping to sustain drive and positive mood through an extended indoor stint.

DeLauer explains that serotonin is the 'everything is copacetic' neurotransmitter, heavily influenced by sunlight. Without it, people often feel on edge. He proposes a disciplined 30-day protocol with 5-HTP, starting low at 50 mg to let the system adapt, ramping to 100 mg, then 150 mg, mirroring the gradual increase of serotonin demand in prolonged sun absence. After the 30 days, he insists on a washout period to avoid receptor downregulation, reflecting his cautious stance on neurotransmitter precursors.

DeLauer is generally opposed to habitual melatonin use, but in the specific scenario of 30 days indoors with only artificial light, he concedes that a sub-physiological dose of a quarter milligram can be a useful circadian 'insurance policy.' He emphasizes that it should not be used as a sleep aid, but as a timing cue. If the red light regimen around sunset is working, he says you may not need it at all.

He states that synthetic vitamin D (from supplements) is 'unopposed,' meaning it delivers a bolus of vitamin D without the synergistic nutrients that accompany it in nature, such as vitamin A, omega-3s, and other photoprotective compounds produced in skin during sun exposure. He prefers cod liver oil because it provides modest D along with A and omega-3s in a natural matrix. He acknowledges that in dire circumstances supplements could be used, but he wants people to prioritize food and light-based sources.

DeLauer explains that weight-bearing exercise triggers a catalytic effect on vitamin D metabolism, possibly through increased expression of enzymes or receptors. He notes emerging data showing resistance training may be superior to cardio in this regard. Additionally, he states that losing body fat through cardio releases vitamin D that has been sequestered in adipose tissue, giving a complementary benefit. The combination of resistance and fat loss creates a dual-action approach to boosting vitamin D availability when sun exposure is absent.

He explains that astaxanthin is produced by algae that is directly hit by the sun, causing the compound to photoreact. Consuming it then imparts some of that photoreactivity to the human body, providing an antioxidant effect that guards the skin similarly to how sunlight exposure can build UV resilience (hormesis). He also says it might help prevent sunburn when you eventually return outside, making it both a protective and a mimicking agent.

He uses the analogy of someone emerging from a cave: even a tiny port hole of light appears blinding because the visual system has downregulated. After 30 days indoors, sitting by a window for 15 minutes feels like a major brightness shift, which can drive cortisol/melatonin timing and mood pathways. He stresses that this is not about vitamin D production, but about maintaining a functional circadian rhythm and giving the brain the 'daytime' signal it's otherwise missing.

He explains that much of the vitamin D we consume passes through unabsorbed. Improving the gut microbiome with fermented foods like kefir, along with bone broth and collagen to support the gut lining, can increase the amount of vitamin D that is metabolized from food. He even hints at early evidence that the microbiome might affect how well we convert UVB light hitting the skin into active vitamin D, making gut health a priority when sun exposure is absent.