Fact or Fiction? Does Supplemental Biotin Really Improve Hair and Nails?

Biotin, which is also known as vitamin H and vitamin B7, is an essential B-complex vitamin.1,2 It can be found in nuts and nut butters, whole grains, sweet potatoes, mushrooms, bananas, oatmeal, and cauliflower. Like other B vitamins, biotin serves a variety of purposes in the human body, such as converting food into energy, rebuilding tissue damage and muscle strength, controlling inflammation, supporting neurotransmitter activity and nerve signals, and protecting the brain from neurodegenerative diseases and cognitive dysfunction.1,2 Researchers also suggest biotin can moderate blood glucose levels and reduce nerve damage in patients with Type 1 or Type 2 diabetes, and might reduce nerve and muscle symptoms in patients with multiple sclerosis.1 During pregnancy, the intake of biotin is essential due to the role it plays in embryonic growth. Fifty percent of pregnant women are at risk for developing a biotin deficiency due to quicker biotin breakdown, which can lead to birth defects.1

Biotin is a water-soluble vitamin that is expelled from the body via urination when consumed in excess. Though excess levels of biotin are removed from the body on a daily basis, a biotin deficiency in people who are not pregnant is rare. Symptoms of a biotin deficiency include thinning hair, brittle nails, skin infections, rash around the eyes, mouth, and nose, seizures, lethargy, depression, and overly acidic urine.1

Biotin supplements are commonly marketed to promote growth, strength, and thickness of the hair and nails; however, the science is unclear when it comes to whether supplemental biotin provides any actual benefits to hair and nails among individuals who do not have a deficiency.1,2 In a case study3 involving three children with a hair condition characterized by slow-growing, straw-colored hair that could not be combed, the researchers indicated a positive change in the hair’s appearance after four months of daily supplementation with 3mg of biotin. One participant exhibited faster hair growth, strengthened hair, and better combability. Results of the other two participants were not reported. Over the course of five years after the study, hair was able to maintain its strength and improved combability without the assistance of biotin supplementation. Considering excess biotin is expelled from the body daily, these results call into question whether the five-year persistence of these hair improvements were due to the short period of biotin supplementation or another unknown cause.

The few prominent existing studies that assessed biotin for the treatment of brittle nails have shown positive results, suggesting supplementation can be an effective therapy for improving nail health in those with an underlying nail condition.


Given the limited case reports and studies circulating medical databases,7 it appears that biotin supplementation might be effective in those with an underlying hair or nail condition and/or a biotin deficiency, but what about its role in healthy individuals without compromised hair and/or nails and/or a deficiency in biotin? A review in Skin Appendage Disorders analyzed previously published studies to determine if supplemental biotin could cause hair and nail changes in participants without special conditions.6 After assessing 18 studies, researchers could not find sufficient evidence to suggest supplemental biotin’s effectiveness in people without hair and nail conditions and/or a biotin deficiency.6 Further research is still needed on the matter.

If you’re not pregnant and are following a varied and healthy diet, it’s unlikely you are deficient in biotin and probably would not benefit from taking supplemental biotin. However, if you have a specific hair or nail condition and/or have nutritional deficiencies, it is always best to first consult with your doctor to see biotin supplementation is right for you.


  1. National Institutes of Health site. Biotin. Updated 19 Feb 2020. https://ods.od.nih.gov/factsheets/Biotin- HealthProfessional/. Accessed Apr 13, 2020.
  2. Harvard T.H. Chan School of Public Health site. Biotin—vitamin B7. https://www.hsph.harvard.edu/ nutritionsource/biotin-vitamin-b7/.
    Accessed 13 Apr 2020.
  3. Shelley WB and Shelley ED. Uncombable hair syndrome: observations on response to biotin and occurrence in siblings with ectodermal dysplasia. J Am Acad Dermatol. 1985 Jul;13(1):97–102.
  4. Floersheim GL. [Treatment of brittle fingernails with biotin]. Z Hautkr. 1989 Jan 15;64(1):41–48.
  5. Colombo VE, Gerber F, Bronhofer M, and Floersheim GL. Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy. J Am Acad Dermatol. 1990 Dec;23(6 Pt 1):1127–1132.
  6. PatelDP,SwinkSM,Castelo-SoccioL.Areviewofthe use of biotin for hair loss. Skin Appendage Disord.


The Role of Nutrition in Brain Health

Our everyday brain functioning, such as thinking, learning,   feeling,  communicating,  even breathing and moving, are all influence by what we eat. The correlation between nutrition
and brain function begins in utero. Maternal eating habits start affecting fetal brain development as early as 6 to
8 weeks into gestation, when nervous system structures begin to form. Nutrition during pregnancy and the first two years of the baby’s life, as the brain rapidly develops, can affect sensory, movement, and response development, and, later, learning, memory, and emotion.1 Malnutrition in the mother can negatively impact fetal brain development, and malnutrition in the child can lead to learning disabilities and physical and emotional developmental delays, not
to mention other health issues.1 Brain development slows as the child ages, with the brain reaching its full size around 25 years of age. The brain and nervous system, however, never stop needing the proper nutrients for optimal functioning.1

Neurons Love High-quality Glucose

Neurons are nerve cells that form the basis of our entire nervous system. These cells are specialized to transmit information throughout the body using chemical and electrical impulses, allowing us to sense and respond to our external environment, as well as do things that don’t require conscious thought, like breathe, digest food, and pump blood through our circulatory system. Neurons need energy to transmit these complex instructions and signals, but where do they get energy and how do they use it?2 Through cellular respiration, a process that begins when stomach enzymes break down the food we eat, glucose (a type

of sugar) is released by the enzymes, absorbed through the cellular lining of the intestinal tract, and delivered into the bloodstream. There, glucose is stored, leveled, and then converted into cellular energy by insulin, a hormone that is released by the pancreas in response to the increased blood glucose levels.2,3

Glucose keeps neurons and every other type of cell in the body energized. And because neurons never rest, they’re always craving their sugary lifeforce, utilizing one half of all the glucose in the body. Eating nutrient-rich foods and complex carbohydrates, such as whole grains and fresh fruits and vegetables, allows a level, sustainable amount of glucose to be stored in the blood. Simple carbohydrates, on the other hand, are typically sourced from refined sugars and other highly processed foods that have been stripped of any naturally occurring fiber and nutrients through the refinement process. Without any fiber or nutrients, simple carbs from processed foods burn very quickly, resulting in a rapid spike followed by a drastic drop in blood sugar and insulin production, and over time, these chronic, drastic fluctuations in blood glucose and insulin production can lead to numerous health problems.3

Healthy Gut Microbiome = Happy Brain

The “good” bacteria that live in your gastrointestinal tract and comprise
the gut and intestinal microbiome also influence neuron functioning.2 95 percent of our serotonin, a neurotransmitter that moderates sleep, energy levels, and appetite, as well as conciliates mood and pain, is created in the gut microbiome.2 Eating highly processed foods can negatively alter the composition of the microbiome, and gut microbiome disruption has been associated with psychiatric and mood disorders, such as anxiety, depression, bipolar disorder, schizophrenia, and autism spectrum disorder.4

Oxidative Stress and Neurological Disorders

A diet high in refined sugars and saturated fats can lead to an imbalance of unstable molecules, such as free radicals containing oxygen and an uneven number of electrons, and antioxidants in the body, which can trigger an inflammatory response that can become chronic.4-7 The brain metabolizes 20 percent of the body’s oxygen supply to survive, making it especially susceptible to the pitfalls of excess free radicals.4-7
An overabundance of free radicals can damage or kill brain cells, impeding cognitive ability, accelerating brain aging, and increasing risk of neurodegenerative diseases, such
as Parkinson’s and Alzheimer’s.4-7 Researchers have discovered that damage to essential proteins, such as amyloid-beta peptides, by oxidative stress in the brain causes an increase in the mass of amyloid plaques associated with the progression of Alzheimer’s disease. Oxidative stress appears to have a negative association with mental health conditions, in particular depression8 and bipolar disorder.4-7

The neuroinflammation and oxidative stress associated with neurological disorders such as multiple sclerosis and epilepsy can often be linked to malnutrition.9 But the relationship between nutrition and neurological disorders goes beyond the dietary choices that cause or worsen the accompanying symptoms.9 Dietary intervention has been used to treat certain neurological disorders for decades. For example, several studies have demonstrated the effectiveness of using a ketogenic (keto) diet*—a diet high
in fat and low in carbohydrates—in the treatment of children and adolescents with drug-resistant epilepsy.10 Instead of converting glucose from carbohydrates, the body converts fat into energy using ketones (an acid released by the liver), which causes the body to enter a state of ketosis. Being in a state of ketosis significantly reduced seizures in the
study patients, though researchers are still trying to figure out the direct connection.10


  • Increasing consumption of whole, plant-based foods provides brain neurons and other cells in the nervous system and throughout the body a level, sustainable supply of blood glucose, which is needed for optimal functioning.
  • Consumption of highly processed foods provides the body with very little nutritional benefit, while causing rapid, disruptive spikes and drops in blood glucose. Irregularity in blood glucose levels can result in impaired insulin production and/or sensitivity, which in turn increases the risk of developing several chronic, serious health disorders.
  • Positive dietary changes can enhance the good bacteria in our gut microbiome, which plays a significant role in our emotional regulation.
  • Nutrient-rich foods help to maintain the balance between unstable molecules and antioxidants, reducing the risk of oxidative stress in the brain. Oxidative stress can impede cognition, accelerate brain aging, and increase the risk of developing certain neurological disorders, such as Parkinson’s and Alzheimer’s.11


1. Bayol SA, Simbi BH, Bertrand JA, and Stickland NC. Offspring from mothers fed a ‘junk food’ diet in pregnancy and lactation exhibit exacerbated adiposity that is more pronounced in females. The Journal of Physiology. 2008;586:3219–3230.

2. Selhub E, MD. Nutritional psychiatry: your brain on food. 16 Nov 2015. Harvard Health Publishing. https://www.health.harvard.edu/ blog/nutritional-psychiatry-your-brain-on- food-201511168626. Accessed 11 Apr 2020.

3. Edwards, S. Sugar and the brain. Harvard Mahoney Neuroscience Institute. https:// neuro.hms.harvard.edu/harvard-mahoney- neuroscience-institute/brain-newsletter/and- brain/sugar-and-brain. Accessed 11 Apr 2020.

4. Salim S. Oxidative stress and the central nervous system. J Pharmacol Exp Ther. 2017;360(1):201–205.

5. Johnson EJ, Vishwanathan R, Johnson MA,
et al. Relationship between Serum and
Brain Carotenoids, α-Tocopherol, and Retinol Concentrations and Cognitive Performance in the Oldest Old from the Georgia Centenarian Study. J Aging Res. 2013:951786.

6. Popa-Wagner A, Mitran S, Sivanesan S, et al. ROS and Brain Diseases: The Good, the Bad, and the Ugly. Oxidative Medicine and Cellular

Longevity. 2013;2013: 963520.
7. Taylor VH. The microbiome and mental

health: Hope or hype? J Psychiatry Neurosci.

8. Black CN, Bot M, Scheffer PG, et al. Is

depression associated with increased oxidative stress? A systematic review and meta-analysis. Psychoneuroendocrinology.
2015 ;51): 164-175

9. Francis HM, Stevenson RJ. Potential for diet to prevent and remediate cognitive deficits in neurological disorders. Nutrition Reviews. 2018;(76):204–217.

10. D’Andrea Meira I, Romão TT, Pires do Prado HJ, et al. Ketogenic diet and epilepsy: what we know So Far. Front Neurosci. 2019;13:5.

11. Harvard Health Publishing Site. Healthbeat. Foods linked to better brainpower. https:// www.health.harvard.edu/mind-and-mood/ foods-linked-to-better-brainpower. Accessed 11 Apr 2020.

12. Alisi L, Cao R, De Angelis C, et al. The relationships between vitamin K and cognition: a review of current evidence. Front Neurol. 2019;10:239.

13. Reynolds EH. Folic acid, ageing, depression, and dementia. BMJ. 2002;324(7352):1512–1515.

14. Devore EE, Kang JH, Breteler MM, and Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol. 2012;72(1):135–43.

15. Pribis P and Shukitt-Hale B. Cognition: the new frontier for nuts and berries. Am J Clin Nutr. 2014;100(1):347S-52S.

16. Dawson SL, Dash SR, and Jacka FN. The importance of diet and gut health to the treatment and prevention of mental disorders. Int Rev Neurobiol. 2016;131:325–346.

* Editor’s note: The keto diet should not be followed unless under the direct supervision
of a qualified healthcare clinician who closely monitors the patient. This diet can cause vitamin deficiencies and has been associated with chronic health conditions including heart disease, Type 2 diabetes, and certain cancers).

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