Compound Deep-Dive

Tier 1: MainstreamA foundational supplement for most people, especially during winter or for those with limited sun exposure.

Vitamin D3

CholecalciferolVitamin D

Foundational for health and immunity

Hype Risk

2/10

Noticeability

4/10

Evidence Tier

Strong

Cost / Month

~$3

Mainstream compound

What it's actually good for

Immunity

Research Supported

Reduces risk of acute respiratory tract infections.

Longevity

Mixed Evidence

Associated with lower all-cause mortality in deficient populations.

Mood

Mixed Evidence

May improve symptoms of seasonal affective disorder.

Energy: neutralFocus: neutralSleep: neutralMuscle: neutralRecovery: neutral

How it works

Essential for calcium absorption and bone mineralization. Strong evidence supports its role in immune function and respiratory health, though effects on non-skeletal outcomes in non-deficient individuals are mixed.

Vitamin D3 is converted into calcitriol, which acts as a steroid hormone to regulate calcium absorption and modulate immune cell activity.

Safety

Excessive intake can lead to hypercalcemia
May interfere with sleep if taken late in the day

The full StackRoast report adds

The exact dose, timing, and effective range to actually run it at
Where people go wrong with it — the dose-creep and timing traps
What Vitamin D3 clashes with or duplicates in your stack
Which brands are actually worth buying

Roast My Stack →

Community Reality Check

Distilled from 5000 threads

Confidence: high

What users report

Mood stability
Immune support
Correcting deficiency

The catch

Insomnia
Anxiety at high doses

Side effects reported

Insomnia
Hypercalcemia (rare)

https://www.reddit.com/r/Supplementshttps://www.reddit.com/r/VitaminD

The Receipts

9 sources— studies, videos & links

Videos

Vitamin D and Immune Function

Huberman Lab

Dr. Huberman discusses the role of Vitamin D in immune health and hormone regulation.

Vitamin D: The Sunshine Vitamin

FoundMyFitness

Dr. Rhonda Patrick provides a deep dive into Vitamin D's impact on longevity and DNA repair.

Papers

Manson et al. (2019)rct2019

The VITAL trial found that Vitamin D3 did not lower the incidence of cancer or cardiovascular events but is essential for bone health.

Martineau et al. (2017)meta-analysis2017

A large meta-analysis showing Vitamin D supplementation reduces the risk of acute respiratory tract infections.

Creators

Rhonda Patrick

YouTube

Ph.D. in biomedical science with extensive research on Vitamin D.

Andrew Huberman

YouTube

Professor of Neurobiology at Stanford who covers Vitamin D in the context of hormones and immunity.

Clinical Sources

NIH Office of Dietary Supplementsofficial Examine.com Vitamin Dclinical VITAL Study (PubMed)clinical

Taking Vitamin D3 in a stack? Find out if the combination actually makes sense.

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