There are over 100 trillion micro organisms living in our guts, on our skin, even it turns out in our nose, mouth, eyes and brain.
The body depends on these to help regulate things like immune function, digestion, and intestinal mechanisms, and to help defend against infection and inflammation. These beneficial microorganisms even produce nutrients, in the form of short chain fatty acids, and vitamins.
Gut bacteria moved in as commensal organisms during our evolutionary development as Homo sapiens. Our ancestors ingested dirt and soil with almost everything they ate, and the billions of beneficial microorganisms came too.
Gut health has become a hot topic lately, with mounting research indicating that the state of the bacteria in the intestinal tract influences many elements of health. The immune system in particular depends upon a healthy balance of bacteria in the gut. Good gut health is a state where there is a predominance of “friendly” bacteria over the “bad” bacteria. However, where the status is the other way around it can cause illness.
It is unfortunately a common occurrence for harmful or missing bacteria to compromise gut health and promote a variety of health irregularities. This state of ‘dysbiosis’ occurs when poor dietary habits, environmental stressors, and adverse lifestyle practices (eating carbs, seed oils, too much stress, not enough sleep, etc.) can cause harmful bacteria to override the delicate balance of microorganisms in the gut.
Can gut health be linked to hair growth or loss?
New research is coming out all the time showing that our microbiome affects many aspects of our health, from our immunity to our nutrient metabolism as mentioned above, to maybe even alter a genetic predisposition to hair health issues.
Might a single microorganism inside our microbiome influence hair loss? Are there any bacteria that might help us prevent or even reverse pattern hair loss?
While the evidence is still inconclusive, there are some signs that one strain of a specific bacteria might help. The species of bacteria is called Lactobacillus Reuteri (L. reuteri). We recently discovered some research that shows a specific strain of L. reuteri may help encourage hair follicle development, promote faster hair growth, prevent hair thinning, and even increase the number of our hairs in the anagen (growth) stage of the hair cycle.
What Is L. Reuteri?
Lactobacillus Reuteri (L. Reuteri) is a bacterium found primarily in the gut. L. reuteri can also colonise certain fermented foods — like yoghurt. In normal circumstances, L. reuteri is passed from mothers to babies during breastfeeding where it colonises our intestines and then remains in our guts throughout adulthood… so long as a disease or antibiotics don’t wipe them out.
The results of the research on L. reuteri are very positive.
But what about hair health? Can recolonising the gut with L. reuteri improve our predisposition to pattern hair loss — or improve our speed of hair growth or even hair quality?
L. Reuteri‘s Effects On Hair Growth And Hair Quality
The research team we discovered wanted to test whether supplementing with bacteria — like L. reuteri — might improve physical appearance — i.e.: the quality of the skin and hair. So, they conducted a series of tests.
The test compared young rats (20-24 weeks old) fed a standard diet to young rats fed a probiotic-rich diet through yogurt supplementation.
The results were impressive.
After 20-24 weeks, the rats fed a probiotic-rich diet saw a 50% increase in skin thickness. And the probiotic-fed male rats expressed an average of 12 hair follicles to every control group rat’s hair follicle (a 1,200% increase).
Interestingly, 74% of the hairs in probiotic-fed rats were found to be in an anagen (growth) phase. And the control group? Quite the opposite. In fact, 64% of rats in the control group were found to have telogen dominance — a condition where at least 50% of the hair follicles on the rats were in a “resting” (no growth) stage of the hair cycle.
Unsurprisingly, these results carried over into hair quality. Rats fed the probiotics had significantly shinier hair.
The results all sounded promising, but there was a confounding factor inside the test. The yogurt that was used to feed the probiotic group also contained other vitamins and nutrients — like vitamin D.
So, the researchers chose to redo the experiment, but this time, instead of using yogurt (which contained other adjunct nutrients and vitamins and a number of lactobacillus species), they decided to feed both rat groups the exact same food, but for the test group, they would also add a bacterial species into their drinking water. And the selected bacterial species to represent all lactobacillus? L. reuteri.
Despite this test version now controlling for the same vitamins and minerals, the test results for the L. reuteri-fed group were nearly identical to the original tests’ yogurt-fed group.
Just by introducing this single bacterial species, male L. reuteri-fed rats experienced a 100% increase in dermal (skin) thickness, a 106% increase in anagen hair follicle counts, increased rates of hair regrowth after shaving, and the same increases to hair shine as the probiotic-fed mice from the previous experiment.
So how can something as simple as a bacterium like L. reuteri increase hair shine and hair follicle count so significantly?
There’s no straightforward answer. But these researchers attributed L. reuteri‘s hair-promoting effects to the bacteria’s impacts on certain signalling proteins. Specifically, an anti-inflammatory cytokine called Interleukin-10 (IL-10).
L. Reuteri Improves Hair Quality By Increasing Anti-Inflammatory Cytokines
Interleukin-10 (IL-10) is one of the anti-inflammatory cytokines that need to be active to help regulate healing processes, improve hair growth, and even prevent chronic systemic inflammation. And unsurprisingly, chronic inflammation of our scalps is a precursor to pattern hair loss.
So, if you are genetically predisposed and want to prevent (or even reverse) pattern hair loss, it’s in your best interest to balance your anti-inflammatory and pro-inflammatory cytokines in your skin and reduce chronic inflammation to slow (or stop) hair thinning.
But What About Humans? Does L. Reuteri Increase Hair Growth In Humans?
There aren’t yet any studies on humans to determine whether L. reuteri will help humans slow, stop, or reverse pattern hair loss. And unfortunately — when it comes to reversing pattern hair loss — rat studies rarely (if ever) translate to humans.
But there’s good news! Of all the L. reuteri studies we reviewed, the results for rats and humans shows the same directional results.
So, at the very least, introducing L. reuteri should have significant positive effect on human health — and potentially our hair health.
And even better — there’s evidence that l. reuteri might improve the conditions that often precede pattern hair loss. In fact, taking all the research into context, L. reuteri supplementation in humans might be critical to promoting longevity, decreasing inflammation, increasing vitamin absorption, balancing our hormones, maintaining our hair health, and even living with less stress and anxiety.
Should You Supplement With Lactobacillus Reuteri To Improve Hair Loss?
The evidence on whether L. reuteri’s effects on hair will translate to humans is currently unavailable. But the studies show that this bacterium is recognised as helpful in a number of ways, such as improving hormonal function, vitamin D levels, and anti-inflammatory T cells (among several other benefits).
Considering no toxic events in humans has been reported — even in studies at 10 billion IU’s per day — we think the supplementing could be beneficial.
But that doesn’t mean you should grab the first L. reuteri supplement you find.
Most studies on L. reuteri are on specific proprietary strains of the bacteria. Cross-comparing results of one study to another is pointless until you have species-to-species comparisons.
Lactobacillus reuteri comes in many different strains. And unfortunately, most studies testing L. reuteri’s effects on health are actually testing proprietary strains of L. reuteri — and not the same strain over and over again.
The Good News
The studies showing the benefits of L. reuteri on hair health and skin health were all done on the same bacterial strain. And that bacterial strain is L. reuteri ATCC PTA 6475.
This strain of L. reuteri is available as a supplement to humans.
The Bad News
The L. reuteri studies demonstrating significant improvements to skin health, and hair health all fed the mice a dosage of 350,000 IU’s of L. reuteri daily.
In humans, if we control for weight, we’d need a dose of several billion IU’s per day to match the same amount that the mice were fed. And unfortunately, most L. reuteri supplements only come in 100 million IU increments. And they’re not cheap or easy to come by (we get ours sent from Sweden!).
Unfortunately, if you’re not exposed to this bacterium at a young age it’s very hard to successfully recolonise our guts without continued supplementation into adulthood. Even though, with sufficient supplementation L. Reuteri can recolonise our guts within weeks, if we stop supplementing, the bacteria can get outcompeted by bad bacteria and die off just as quickly.
Even still, there are people experimenting with 100 million IU’s of L. reuteri daily that have reported improvements in their depression, or anxiety, a more youthful ‘glow’, and better overall energy levels.
Which L. Reuteri Supplement Should You Use For Hair Growth Optimisation?
We’ve done enough research to feel confident in recommending an L. reuteri supplement that checks all of the boxes (the right strain for skin and hair benefits, and the highest number of IU’s that are available to humans).
The company is called BioGaia — and they sell a 100 million IU chewable probiotic of L. reuteri in the correct strains — L. reuteri ATC PTA 6475. You can check out their site (and their products) here.
We make yogurt using a special process to amplify the bacterial counts into the billions.