Hair loss linked to gut and scalp bacteria in new study
NCT ID NCT07716748
First seen Jul 21, 2026 · Last updated Jul 22, 2026 · Updated 1 time
Summary
This study investigates whether the bacteria living in the gut and on the scalp differ between men with androgenetic alopecia (common hair loss) and those without. Researchers will also look at how these bacterial communities change after treatment with oral minoxidil, a standard hair-loss medication. By analyzing stool, scalp swabs, hair follicles, and blood samples, the study aims to uncover biological markers that could lead to better understanding and future treatments for hair loss.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- oral minoxidil
- What this could lead to
- If successful, this could reveal how gut and scalp bacteria influence hair loss and point toward new microbiome-based treatments.
- What could go wrong
- This is an early exploratory study with only 66 participants, so findings may not apply broadly. It focuses on biological markers, not on proving that minoxidil works.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Participants
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About 66 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Aug 2026
An estimate. Start dates often move.
- Expected to finish
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Jan 2028
An estimate. End dates often move.
- Lead sponsor
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A research network
The lead sponsor is a research network or cooperative group.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
Who is studied
AGA volunteers will be referred by clinicians from National Skin Centre Healthy volunteers will be recruited by recruitment posters at National Skin Centre
- Ages
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21 to 45 years
- Sex
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Male participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Male volunteer from 21 to 45 years old 2. Volunteer with BMI between 18.5 to 30 kg/m2 3. Volunteer willing and able to fulfill the study requirements and schedule 4. Volunteer willing to give their stool sample, as well as swabs, follicles, and blood. 5. Volunteer informed about the study objectives and procedures, and able to understand them 6. Volunteer who has given written informed consent Volunteers in the healthy control panel must satisfy the following criteria: 1. Volunteer in overall good health 2. Volunteer with no diagnosis of hair loss or other condition or treatment susceptible to impact hair count and microbiome. Volunteers in the AGA panel must satisfy the following criteria: 1. Volunteer diagnosed with Androgenetic Alopecia grade III Vertex to V on the Hamilton-Norwood scale 2. Volunteer willing to restrain from the use of any additional hair loss oral and topical pharmaceuticals (ex: topical minoxidil) over the course of the study 3. Volunteer eligible to undergo oral minoxidil treatment, with no contra-indication Exclusion Criteria: 1. Volunteer with severe gastro-intestinal symptoms (including gluten and lactose intolerance) 2. Volunteer with auto-immune disease, diabetes; hyper or hypo-thyroidism ; chronic kidney failure 3. Volunteer with diagnosis of scalp-related disease such as folliculitis, lichen planopilaris, folliculitis decalvans, tinea capitis, head lice, or seborrheic dermatitis 4. Volunteer undergoing hypertension treatment 5. Volunteer who undertook any oral anti-hair loss pharmaceutical treatment in the past 3 months (e.g. Finasteride) 6. Volunteer who undertakes any hormone-disrupting drug 7. Volunteer who used topical minoxidil or other pharmaceutical-grade topical hair restorers in the past 3 months 8. Volunteer with a total dandruff score above 1 on the L'Oreal Dandruff scale. 9. Volunteer who used perms or hair dyes in the past 2 months 10. Volunteer who underwent scalp reduction or hair transplant procedures 11. Volunteer who declares to be deprived of freedom by administrative or legal decision 12. Volunteer who cannot be contacted by phone in case of emergency 13. Volunteer having currently participating in another clinical study 14. Volunteer who used antibiotics or antifungal medication (topical to scalp and systemic) in the past 4 weeks 15. Volunteer who used probiotics supplements in the past 4 weeks. (dietary probiotics such as yogurt, kefir, and kimchi are acceptable) 16. Volunteer who follows a non-conventional diet (e.g. vegan, ketogenic, strict intermittent fasting diets) Non-inclusion Criteria: 1. Volunteer diagnosed with HIV, Hepatitis C, Hepatitis B 2. Volunteer with severe gastro-intestinal symptoms (including gluten and lactose intolerance) 3. Volunteer with auto-immune disease, diabetes; hyper or hypo-thyroidism ; chronic kidney failure 4. Volunteer with diagnosis of scalp-related disease such as folliculitis, lichen planopilaris, folliculitis decalvans, tinea capitis, head lice, or seborrheic dermatitis 5. Volunteer undergoing hypertension treatment 6. Volunteer who undertook any oral anti-hair loss pharmaceutical treatment in the past 3 months (e.g. Finasteride) 7. Volunteer who undertakes any hormone-disrupting drug 8. Volunteer who used topical minoxidil or other pharmaceutical-grade topical hair restorers in the past 3 months 9. Volunteer with a total dandruff score above 1 on the L'Oreal Dandruff scale. 10. Volunteer who used perms or hair dyes in the past 2 months 11. Volunteer who underwent scalp reduction or hair transplant procedures 12. Volunteer who declares to be deprived of freedom by administrative or legal decision 13. Volunteer who cannot be contacted by phone in case of emergency 14. Volunteer having currently participating in another clinical study 15. Volunteer who used antibiotics or antifungal medication (topical to scalp and systemic) in the past 4 weeks 16. Volunteer who used probiotics supplements in the past 4 weeks. (dietary probiotics such as yogurt, kefir, and kimchi are acceptable) 17. Volunteer who follows a non-conventional diet (e.g. vegan, ketogenic, strict intermittent fasting diets) 18. Volunteer who used anti-dandruff shampoo in the past 4 weeks (For example, commonly used brands for anti-dandruffs could be : Head \& Shoulders, Sebamed, Clear, Dove, Pantene, L'OREAL, Vichy Dercos)
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The official record
The full official record for this study. This one lists no contact details, but it is the first place any would appear.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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