T3 + Vitamin A = LDL + Pregnenolone = All Sex Steroid Hormones

T3 + Vitamin A = LDL + Pregnenolone = All Sex Steroid Hormones

The Critical Biochemical Pathway Most People Never Learn About

In this episode of the Improvement Warrior Podcast (Substack, Apple), Jason Yun breaks down a critical biochemical pathway: how T3 (the active form of thyroid hormone) works with Vitamin A to help utilize LDL cholesterol, which then supports the production of pregnenolone — the precursor to all sex steroid hormones (testosterone, estrogen, progesterone, etc.).

Jason explains the interconnected roles of these molecules in energy production, hormone balance, fertility, mood, and overall vitality. He connects this pathway to his core teachings on circadian biology, mitochondrial health, and the importance of proper light exposure.

The discussion highlights why disruptions in this chain are common in modern life and offers practical insights into supporting it naturally through lifestyle, nutrition, and environment.

Whether you’re dealing with low energy, hormonal imbalances, or simply want to understand how your body produces and regulates sex steroids at the deepest level, this episode delivers clear, actionable knowledge rooted in real biology rather than conventional approaches.

Timestamp Log

• 0:00 – Intro & welcome to Episode 89

• 1:10 – Overview of the key pathway: T3 + Vitamin A

• 3:45 – Role of LDL Cholesterol in the process

• 6:20 – Pregnenolone as the mother hormone

• 9:00 – How this leads to all sex steroid hormones

• 11:30 – Practical implications for energy, hormones & vitality

• 13:45 – Ties to circadian biology, light exposure, and mitochondria

• 15:30 – Key takeaways and action steps

• 16:40 – Closing thoughts & outro

Resources Mentioned

• Improvement Warrior Newsletter

• Patreon

• Substack

• One Tap Zap

• Magnesium Breakthrough