Dry, flaky skin (unfortunately) seems to come around every winter. As temperatures drop and indoor heating turns on, the skin barrier takes a hit. You lose moisture faster and become more prone to irritation.
Topical products like serums and moisturizers are helpful, of course. But emerging research suggests your gut, particularly your fiber intake, may also play a role in supporting skin hydration from the inside out.*
A randomized controlled trial looked at whether a specific prebiotic fiber could help maintain skin moisture1 during the dry winter months. Here’s what they found.
About the study
This 12-week randomized, double-blind, placebo-controlled study was conducted in Tokyo during winter (January through April). Seventy healthy adults (mostly women in their mid-40s) were assigned to take either 5 grams of partially hydrolyzed guar bean fiber daily or a placebo.
Guar fiber is derived from guar beans (also known as cluster beans), which are commonly grown in India and Pakistan but not widely consumed in the U.S. The seeds are rich in soluble fiber. When the fiber is partially hydrolyzed (broken down), it becomes easier to digest and less likely to cause bloating, making it well-suited for supplementation.
Researchers measured:
- Skin hydration (stratum corneum hydration)
- Trans-epidermal water loss (TEWL), a marker of skin barrier strength
- Skin elasticity parameters
- Self-reported skin satisfaction
Importantly, weather conditions were similar at baseline and at six weeks, meaning early changes were less likely to be explained by seasonal shifts alone.
Guar fiber helps keep skin hydrated*
In this study, those taking the guar fiber started to notice meaningful improvements in their skin within 6 weeks,
- Skin hydration increased by about 4–8% across the cheek, upper arm, and upper back
- TEWL decreased by roughly 12–17%, indicating stronger barrier function
These improvements were significantly greater than for those taking the placebo.
By 12 weeks, additional benefits emerged. The guar fiber group showed significant improvements in multiple skin elasticity, firmness, and flexibility.*
Why is guar fiber so beneficial?
Researchers propose two main mechanisms.
First, guar fiber is a water-binding soluble fiber that may help regulate overall water balance by supporting systemic hydration. Overall, this may reduce excessive water loss through the skin and help maintain barrier function.*
Second, as a prebiotic, guar fiber supports gut health and nutrient absorption. A healthier gut environment may improve the uptake and utilization of nutrients involved in collagen formation and overall skin integrity.*
How to get more guar fiber
One of the simplest ways to add more guar fiber to your routine is with a high-quality supplement like organic fiber+ with prebiotic support. Each serving delivers 6 grams of fiber, primarily from guar beans (along with green kiwi and mushrooms), sourced from the same partially hydrolyzed guar fiber used in the study.
Beyond supporting digestion and overall gut health, guar fiber has also been shown to:
- Help reduce occasional gas and bloating2*
- Support healthy cholesterol levels3*
- Promote appetite regulation4*
Unlike many fiber powders, this formula won’t clump or gel in water. It mixes smoothly into both hot and cold liquids. You can also stir a scoop into oatmeal or blend it into yogurt for an easy fiber boost.
The takeaway
Fiber plays so many critical roles in our health (from balancing blood sugar to improving gut health and digestion). Now, there’s mounting evidence, thanks to studies like this one, that certain prebiotic fibers are also beneficial for skin health.*
So if your skin is feeling extra dry or flaky, try adding more guar fiber to your diet before adding more steps to your skincare routine.