When we think about improving sleep, most people picture relaxing teas, darker bedrooms, or switching off screens.

But new research suggests another key player might be your gut — specifically, the bacteria that thrive on certain dietary fibres.

A 2023 Journal of Clinical Biochemistry and Nutrition study found that partially hydrolyzed guar gum (PHGG) — a gentle, soluble dietary fibre — may do more than just support digestion. It could also play a role in better sleep and improved motivation.

What the Study Found

Researchers in Japan conducted a randomised, double-blind, placebo-controlled trial with healthy men and women who consumed either 3 g or 5 g of PHGG daily for eight weeks.

Compared to placebo, those taking PHGG experienced:

✅ Improved gut balance – fewer “harmful mucolytic bacteria” in the intestine.

✅ Better bowel regularity – more consistent and satisfying bowel movements.

✅ Enhanced mental wellbeing – participants in the higher-dose group reported better sleep quality and motivation scores.

The authors concluded that PHGG may relieve constipation while positively influencing gut-brain communication, which could explain the uplift in mood and rest.

How Gut Health Affects Sleep

Your gut and brain are connected through the gut-brain axis, a two-way communication system involving nerves, hormones, and metabolites from your gut microbes.

When your gut flora is balanced, it produces more short-chain fatty acids (SCFAs) and neurotransmitter precursors that help regulate circadian rhythm, stress, and inflammation — all of which affect how well you sleep.

By feeding beneficial bacteria, PHGG helps restore microbial balance, supporting both digestive comfort and mental clarity.

How to Take PHGG

You don’t need a huge dose to notice benefits. Most studies use between 3–5 g daily, stirred into water, juice, smoothies, or coffee. It dissolves completely and is gentle on the stomach — ideal even for those sensitive to other fibres.

If you’re wondering where to buy partially hydrolyzed guar gum, choose a pure, unflavoured powder with no fillers or artificial additives for the best gut and sleep results.

This article is for educational purposes only. Please consult your healthcare practitioner before making dietary changes or starting new supplements.