The Gut–Hormone–Hair Connection: What’s Really Behind Healthy Hair

Ashley Osborne
Aug 14, 2025
2 min read

Ashley Osborne, functional medicine nurse practitioner and founder of Biome Elite, speaks on a women’s health panel about the connection between gut health, hormones, and hair loss prevention. She shares expert insights on nutrient deficiencies, hormone imbalance, and the gut–brain axis.

Last week, I had the privilege of speaking on a panel about the intersection of gut health, hormones, and hair—three systems that are more connected than most people realize.

Whether you’re dealing with thinning, breakage, dullness, or excessive shedding, it’s important to look beyond surface treatments. Here’s what every woman should know:

💊 Key Nutrients for Healthy Hair

Hair is one of the fastest-growing tissues in the body, and it requires consistent nourishment to thrive. The most important nutrients for strong, vibrant hair include:

Biotin (B7): Supports keratin production and follicle strength.
Iron: Vital for oxygen delivery to the scalp. Deficiency is a common cause of shedding, especially in women.
Zinc: Helps with follicle repair and reduces inflammation.
Vitamin D: Plays a regulatory role in hair cycling and immune balance.
Protein: Hair is made of keratin, a structural protein—without enough dietary protein, growth slows.
Omega-3s: Support scalp hydration and reduce inflammation that can damage follicles.

Even mild deficiencies in these nutrients can lead to thinning, brittleness, or hair that just won’t grow.

🔁 How Hormones Impact Hair

Hormones are one of the most influential drivers of hair quality and quantity. Here’s how:

Estrogen supports hair growth and thickness. When levels decline (like in perimenopause or postpartum), many women notice thinning.
Progesterone balances the effects of androgens and helps keep the scalp calm.
Testosterone/DHT (dihydrotestosterone) can shrink hair follicles when elevated or unbalanced—contributing to pattern thinning.
Cortisol (stress hormone) can disrupt the hair cycle, pushing follicles into a shedding phase.

When hormones are off—especially during life transitions—your hair often reflects it.

🌱 The Gut–Hair Connection

Gut health is often the missing piece in the hair loss puzzle.

The gut microbiome plays a direct role in absorbing and synthesizing hair-critical nutrients like biotin, B12, and iron. If you have bloating, food sensitivities, or leaky gut, you may not be absorbing what you’re eating.
Your gut also helps detox excess hormones, regulate inflammation, and produce neurotransmitters that impact stress—another major hair disruptor.
Dysbiosis or gut inflammation can silently sabotage hair growth even if you’re taking all the right supplements.

Your gut sets the foundation. When it’s inflamed or imbalanced, your hair can’t get what it needs to grow and thrive.