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Does biotin help hair loss?
Short answer
Probably not, unless you have a deficiency or another underlying problem. A review of published cases found biotin helped hair or nails only in people with an underlying cause, and found a lack of evidence for healthy people. The NHS says most people get enough biotin from a varied diet. High-dose biotin can also distort some blood tests, including thyroid tests.
Key facts
- A 2017 review found biotin helped hair or nails only in people with an underlying problem.
- There is a lack of evidence that biotin helps healthy people grow hair.
- The NHS says 0.9 mg or less a day from supplements is unlikely to cause harm.
- Biotin can make thyroid blood test results falsely high or falsely low.
What the evidence shows
Biotin (vitamin B7) is widely sold for hair, skin and nails. A 2017 review by Patel and colleagues searched the medical literature and found 18 reported cases where biotin was used for hair or nail changes. In every case the person had an underlying problem, such as an inherited or acquired biotin deficiency or a specific hair or nail condition.
The authors concluded that research showing biotin works is limited, that the cases where it may help are uncommon, and that there is a "lack of sufficient evidence for supplementation in healthy individuals". There is no good evidence that biotin treats male pattern hair loss or female pattern hair loss.
How much biotin you need
The NHS says bacteria in the bowel make biotin, and it is also found in many foods, so "it's not clear if you need any additional biotin from the diet". It says you should be able to get all the biotin you need from a varied and balanced diet.
On supplements, the NHS says there is not enough evidence to know the effects of taking high daily doses, and that "Taking 0.9mg or less a day of biotin in supplements is unlikely to cause any harm." Many hair supplements contain more than that, so check the label.
Biotin can interfere with blood tests
This is the risk most people do not know about. Many laboratory tests use a biotin-based chemical reaction, and extra biotin in your blood can upset it. In 2023 the makers of levothyroxine, in agreement with the MHRA and the European Medicines Agency, warned healthcare professionals that biotin "may interfere with thyroid immunoassays" and that, depending on the test design, results "may be falsely increased or falsely decreased", which "may lead to inappropriate patient management or misdiagnosis".
The same letter says patients should tell their doctor if they are taking or have recently taken biotin, and that "multivitamins or supplements for hair, skin, and nails could also contain biotin". Our page on biotin and thyroid tests explains this further. If you are booking a thyroid blood test, tell the clinic about any biotin you take.
What to do instead
If you are losing hair, it is more useful to find the cause than to guess with supplements. The British Association of Dermatologists notes that blood tests may be used to rule out thyroid conditions and iron deficiency, both of which can cause shedding (see telogen effluvium). Our sister service offers a hair loss blood test panel for this.
If the cause is pattern hair loss, prescription and licensed treatments have a much larger evidence base than biotin, though none works for everyone. Choosing not to treat is also a valid option. If you would like a doctor's view, start the free online assessment.
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Start your free assessment →Related questions
Can biotin make hair loss worse?
There is no good evidence that it does. The bigger practical risk is that it can distort blood tests used to look for causes of hair loss, such as thyroid tests.
Should I stop biotin before a blood test?
Tell the doctor or laboratory that you take it, including any hair, skin and nail supplements. They can advise whether to pause it before the test or use a different test.
Is biotin deficiency common?
The review authors described the cases where biotin may help as uncommon, and the NHS says most people get enough from a varied diet.
Do hair gummies contain biotin?
Many do. The MHRA-agreed safety letter specifically warns that supplements for hair, skin and nails could contain biotin.
Can I take biotin alongside finasteride or minoxidil?
Tell your prescriber about every supplement you take. We ask about supplements in the assessment because they can matter for safety and for any blood tests.
Sources
- Patel DP et al. A review of the use of biotin for hair loss. Skin Appendage Disord 2017 (PubMed)
- NHS: vitamin B (biotin)
- Levothyroxine: biotin interference with laboratory tests, letter to healthcare professionals agreed with the MHRA (May 2023)
- British Association of Dermatologists: telogen effluvium patient leaflet
Facts checked against these sources on 4 October 2026. This page is general information, not personal medical advice. Read our editorial policy.