The Hidden Nutrient Behind Hair Growth: Why Experts Say Products Alone Aren’t Enough

In a market flooded with hair serums, growth oils, and topical treatments, millions still face hair thinning, breakage, and even early-stage baldness.

But according to Dr. Eric Berg, a prominent nutritionist and health educator, the missing solution might not be in your bathroom cabinet, but on your plate.

Dr. Berg points to leucine, an essential amino acid, as one of the most overlooked yet critical nutrients for hair growth.

“Leucine plays a fundamental role in hair structure,” he explains.

“It’s necessary for keratin production, which is the primary protein that makes up your hair.”

Without sufficient leucine, hair becomes weak, brittle, and prone to thinning.

Beyond supporting keratin, leucine also aids the production of collagen, which adds strength and elasticity to hair strands, making them more resilient to damage.

“What people don’t realize is that hair health is not just about what you put on it, it's deeply tied to internal health,” says Dr. Berg.

“If your body is deficient in key amino acids, no amount of external treatment will permanently fix the problem.”

Interestingly, leucine also plays a supportive role in iron absorption, and iron deficiency is a well-documented cause of hair loss, particularly in women.

“Iron and leucine work together,” Dr. Berg adds. “If you’re lacking in either, your hair will reflect that imbalance.”

So where can you get leucine?

According to Dr. Berg, red meat is one of the richest natural sources.

Other foods such as fish, chicken, eggs, and dairy also offer good amounts.

While some supplements and protein shakes contain leucine, he strongly recommends getting it from whole food sources for optimal absorption and long-term benefits.

However, Dr. Berg cautions against seeing leucine as a magic fix.

“Leucine is powerful, yes, but hair health is multifaceted,” he says.

Factors like stress, hormonal imbalances, chronic inflammation, and poor gut health can also impair hair growth, even with good nutrition.

He also emphasizes that relying solely on hair products or supplements without addressing dietary habits is one of the most common mistakes people make.

“The marketing behind hair care products is strong, but the biology of hair is stronger. You must nourish the root cause, literally,” he says.

For anyone experiencing persistent hair issues, Dr. Berg recommends a full nutritional assessment before resorting to expensive treatments.

“Check your diet first. Increase high-quality proteins, manage stress, and support gut health. Your hair will respond.”

In a culture obsessed with surface-level solutions, this inside-out approach might just be the reset button the hair care industry needs.

As science continues to link amino acids like leucine to hair growth and strength, the message is clear: healthy hair starts from within.