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Gut Health8 April 2026

How to Balance Gut Flora: Which Probiotics Actually Work (and Which Don't)

Dr. Benedicte Lerche — About
Dr. Benedicte Lerche MSc PhD

MSc PhD · Biochemist & Metabolic Health Expert

Published 8 April 2026

· Updated 22 July 2026

· 5 min read

Your intestine is home to trillions of bacteria — both beneficial and harmful. In a healthy gut, the good bacteria outweigh the bad. But when this balance is disrupted, the consequences extend far beyond digestion.

What Is Gut Flora Imbalance?

Unwanted bacteria in the gut are constantly producing toxins called endotoxins. Under normal circumstances, the liver detoxifies these without any problems. However, an overgrowth of bad bacteria leads to excessive endotoxin production, which can irritate the intestinal lining, trigger inflammatory mediators, and cause symptoms such as irritable bowel syndrome, constipation, and diarrhoea.

A severe overgrowth of bad bacteria can also contribute to systemic inflammation if endotoxins and inflammatory mediators leak into the bloodstream — a key reason why reducing stress and supporting hormonal health, as I teach in my Hormone Rebalance Intensive™ course and my book Roadmap to Metabolic Health, matters so much — affecting hormones, thyroid function, skin health, and even blood pressure.

Symptoms of Gut Flora Imbalance

Because endotoxins can spread systemically, the symptoms of imbalanced gut flora are vast and varied:

  • Digestive discomfort
  • Constipation or diarrhoea
  • Impaired immune function
  • Chronic inflammation
  • Hormonal disturbances
  • Low thyroid function
  • Skin problems and rashes
  • High blood pressure

Why Gut Health Is Central to Metabolic Health

According to Dr. Ray Peat, a healthy gut is essential to overall health. His dietary approach focuses on choosing the right foods to support a healthy digestive system — foods that suppress the growth of bad bacteria while nourishing the gut lining.

This is a core principle in my course Gut Restoration™, where I teach exactly which foods and fibres help clean the intestine, reduce endotoxin load, and support a balanced gut environment. Gut health is also deeply connected to thyroid function and hormonal balance — which is why I also cover it in my Metabolic Nutrition Mastery™ course.

Do Probiotics Work?

Not all probiotics are created equal. According to Dr. Ray Peat, effective probiotics should balance the ratio of good to bad bacteria and promote the production of digestive enzymes. However, many probiotics on the market provide very little real benefit — and some can even make things worse.

The key is choosing the right type.

Why Most Probiotics Don't Work

The most common probiotics — yogurt-class acidophilus bacteria and lactic acid-forming bacteria — are found in the majority of probiotic supplements on the market. According to Dr. Ray Peat, these provide very little benefit in practice.

The theory is that by adding more good bacteria, you outcompete the bad. But in reality, this principle rarely works. The bad bacteria are well established and resilient — simply adding more good bacteria does not displace them effectively.

Which Probiotics Actually Work?

According to Dr. Ray Peat, the probiotics that produce real results are those with an antibiotic-like effect — meaning they actively kill bad bacteria rather than simply trying to outnumber them. When bad bacteria are eliminated, they release material that feeds the beneficial bacteria, further restoring the balance naturally.

This type of probiotic can produce significant, noticeable improvements in gut health — especially when combined with dietary changes that reduce the conditions bad bacteria need to thrive.

Diet First, Supplements Second

Before reaching for any probiotic supplement, it is important to address diet — you can learn which foods support a healthy gut and thyroid in my book How to Boost Metabolism with Food and my Metabolic Nutrition Mastery course. Many common foods — including those found in healthy diets — actively feed bad gut bacteria and promote endotoxin production.

In my course Gut Restoration™, I walk through the specific foods to eliminate, the foods to include, and how to structure your diet to create an environment where good bacteria can thrive. Once the dietary foundation is in place, adding an effective probiotic supplement can accelerate the healing process significantly.

For a broader understanding of how pro-metabolic nutrition supports gut, thyroid, and hormonal health together, my book

Topics

Dr. Benedicte Lerche MSc PhD — Biochemist and metabolic health expert

About the Author

Dr. Benedicte Lerche MSc PhD

Biochemist · Metabolic Health Expert · Author

Dr. Benedicte Lerche holds a Master's degree and PhD in biochemistry. After being diagnosed with hypothyroidism and finding that conventional treatment left her symptoms unresolved, she turned to Dr. Ray Peat's pro-metabolic research — and eventually restored her own thyroid function and health. She now dedicates her work to helping others do the same through evidence-based books, online courses, and one-on-one counseling.

Read Dr. Lerche's full story →
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