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Rapunzel’s Beauty Secret - Fact or Fiction?: A deep dive into supplements for healthier hair

a woman of colour holds up a hair supplement bottle filled with bear-shaped supplements

Dear reader, this article is not meant to provide medical advice. Please speak with a health care provider prior to starting any kind of supplement, including natural health products like vitamins or minerals, or if you are concerned about a supplement you are already taking. 

Hair Supplements

Whether it be down the aisles at Costco, or in an instagram post from an A-list celebrity, you have probably seen them…the gummies promising healthier hair. With such exciting claims it is easy to see why these gummies have become so popular. The problem is that “natural” health products like these supplements are not as regulated as pharmaceuticals, meaning that supplement companies have more freedom with the claims they can make to consumers like us (1,2). So, how true are these promises of luxurious, strong, and healthy hair?

While there is quite a bit of variation in these gummies, their ingredient lists often overlap. In this article we will take a deep dive into some of the most common ingredients found in hair gummies to figure out whether they are really worth the cost.


What is biotin? Biotin, also referred to as B7, is a B vitamin (3,4). This vitamin helps our body breakdown fats, carbohydrates, and proteins from our food (3,5). Cells in our bodies often communicate with each other by using various signaling molecules; biotin is one of many chemicals that helps cells talk to one another (3,5). Biotin also helps to control how some of the genes in our DNA are expressed (3,5). Among its specific functions, biotin is involved in producing a structural protein found in the hair called Keratin (more on this protein below) (5). 

Do we need biotin supplements to get enough of it?  Biotin is an essential nutrient, meaning that it is a nutrient our bodies cannot make on their own, but also a nutrient that we can’t live without (3,4). Luckily most of us don’t have to! Biotin deficiency, which can worsen the health of your hair, is exceptionally rare in folks who are otherwise healthy (3). This is because biotin is found in many of the foods we commonly eat. For example, just half a cup of sweet potato contains 8% of the daily recommended value of biotin or a single egg contains 33% of the daily recommended value. (30mcg for people aged 19+ and 35mcg for those who are pregnant) (3). 

Will biotin supplements improve the health of our hair?  Looking at the current research, there are only a handful of case reports (a type of study that documents observations made from individual patients) that report positive results on hair health after biotin supplementation(3,6,7,8). It is difficult to make conclusions from these reports because of limitations in their study design*. For example, these reports followed a small number of patients and  did not use proper controls to compare against (3,6,7,8). The patients followed  were also children (11 months - 4 years old) who were diagnosed with other underlying health conditions, like alopecia or uncombable hair syndrome, that impacted the health of their hair (3,6,7,8). Based on the very limited evidence available, it seems that biotin supplements may be helpful for supporting hair health in folks with an underlying condition that impacts hair growth, or in people with biotin deficiency; but, more studies are still needed in a larger representative population (3). Unfortunately, there is currently no strong scientific evidence proving that biotin supplements will provide any added benefit to healthy individuals who already get enough biotin through their diet. 


Are there any health risks of taking biotin supplements?  ‘More’ is not ‘better’ when it comes to biotin. Biotin is a vitamin that can dissolve in water meaning that excess biotin in the bloodstream is just eliminated from the body through urine (3). While high biotin intake appears relatively safe, it can pose other problems (3). High-levels of biotin can interfere with some medical laboratory tests, such as thyroid function tests, leading to incorrect results (9).


What is keratin?  Keratin is a protein found in your body that makes up parts of your hair, skin, and nails, as well as the linings of various organs (10). It is a strong protein that provides support and protection for these parts of your body (10).

Do we need keratin supplements to get enough of it? Lucky for us, our bodies are capable of producing keratin proteins on their own (10). To produce keratin, our bodies need the right building blocks. These include protein, biotin (which we learned about above), vitamin A, and zinc (5,11,12). Foods containing these nutrients, like broccoli, eggs, or salmon, help to support the formation of keratin in the body (10). 

Will keratin supplements improve the health of our hair?  As we age, the amount of keratin our body produces decreases, meaning there is less natural keratin found in your hair (13). The loss of this keratin is thought to contribute to natural signs of aging, including hair loss (5). Given its large role in supporting the hair, keratin is often added to oral supplements claiming to improve hair health. But, what does the science say? Unfortunately, scientific research on the effects of keratin supplementation is very limited. One small study showed positive results on the hair (increased shininess and decreased hair loss) from a supplement that contained keratin (14). However, the supplement studied contained additional vitamins and minerals, making it difficult to make conclusions about keratin specifically (14). There is no other strong scientific evidence to support any added health benefits to the hair from keratin supplementation. Are there any health risks of taking keratin supplements? There is little scientific information available on the safety of oral keratin supplements. While this article focuses on oral supplements, there was also a warning issued by the FDA about hair smoothing and straightening treatments (not supplements) used on the hair that are sometimes branded as “keratin hair treatments”. Some of these treatments contain additional toxic chemicals that are harmful.

Vitamin A

What is vitamin A?  Vitamin A represents a group of compounds called retinoids (15). These compounds play a role in a number of important functions in the body, like supporting the immune system and vision (16). Vitamin A also supports the hair and oil-producing glands in our skin and scalp called sebaceous glands (17) (you can learn more about sebaceous glands and their impact on your skin here). It also helps to control the production of proteins like keratin (which we learned about above) that provide structure to the hair (12). 

Do we need vitamin A supplements to get enough of it? Vitamin A is also an essential vitamin. For most of us, getting our daily dose of vitamin A (700-900 mcg for people aged 19+ and 750 mcg for those who are pregnant) is effortless because it is readily available in many of the foods we eat (18). Vitamin A is found in foods as either pre-formed vitamin A (found in animal sources like eggs or fish), or as a pro-vitamin that is converted to vitamin A in our intestines (found in plant-based foods like sweet potatoes or carrots) (18). 

Will vitamin A supplements improve the health of our hair? Vitamin A is important to both the health of the scalp and the hair. Vitamin A deficiency can lead to fragile hair (19). However, there is little scientific research to support the use of additional vitamin A supplements in folks who get enough vitamin A through their diet (15).

Are there any health risks of taking vitamin A supplements? Unlike biotin, vitamin A does not easily dissolve in water–and therefore the bloodstream. Vitamin A is a fat-soluble vitamin, meaning that it dissolves in special fat droplets that flow through the bloodstream (18). This also means that it cannot leave the body through urine as quickly as water-soluble vitamins. Instead, Vitamin A is stored and builds up in your liver and fatty tissues (18). At high levels, vitamin A is toxic (18). A build-up of vitamin A can cause a number of negative side effects, like dry-skin or fatigue. In fact, over-supplementation of vitamin A may even cause hair loss (16,18)! Vitamin A supplements can also interfere with certain medications, for example retinoids like the psoriasis treatment acitretin (18).

Vitamin E 

What is vitamin E?  Vitamin E is an antioxidant, meaning that it helps get rid of free radicals (15,20). Free radicals are molecules that are formed naturally in the body through everyday body processes or by exposure to toxins in the environment (15). At high levels, free radicals can damage the cells in our body (15). The body can produce its own powerful antioxidants, but we can also get antioxidants through our diet by eating foods rich in certain vitamins like vitamin E (15).This makes vitamin E an important part of protecting the hair from damage (20). 

Do we need vitamin E supplements to get enough of it? Similar to the other vitamins discussed above, vitamin E is an essential vitamin that can be obtained through diet, particularly in plant-based oils, nuts, and seeds as well as green leafy vegetables (21). This means that we can get the daily recommended intake of vitamin E (15 mg for people aged 14+, including pregnant people) through our diet (21). 

Will vitamin E supplements improve the health of our hair? Once again, there is limited scientific evidence to support the use of vitamin E supplements in folks without vitamin E deficiency (16). While there have been skin benefits reported from studies looking at vitamin E that was applied to the skin, oral vitamin E supplements (vitamin E pills) alone do not seem to have the same benefits (20). One study did find that participants taking oral vitamin E supplements showed increased hair growth (22). However, this study had a small number of participants making it difficult to come to a conclusion about the effectiveness of oral vitamin E supplements on the hair (22). More studies are needed to say whether vitamin E supplements taken orally will provide added benefits to the health of the hair of folks who already get enough of the vitamin through their diet. 

Are there any health risks of taking vitamin E supplements? Too much vitamin E can have negative effects. Just like vitamin A, vitamin E is fat-soluble, so it can accumulate in body tissues (21). Taking in too much vitamin E, specifically from supplementation, can cause bleeding problems and it can interfere with some medications, including anticoagulant medications like Warfarin, and chemotherapy medications (16,21).

Vitamin C 

What is vitamin C?  Vitamin C, also referred to as L-ascorbic acid, is an essential vitamin (23). Vitamin C has a number of important functions in the body. It is an antioxidant like vitamin E and it is involved in the formation of a structural protein called collagen, which makes up our connective tissues (23). Vitamin C also supports the absorption of iron by the intestines (16). This makes vitamin C particularly important in folks who have an iron deficiency, which is itself related to hair loss (15,16,24)

Do we need vitamin C supplements to get enough of it? Much like biotin, vitamin C is a vitamin that our bodies cannot produce on their own so we have to get it through our food. Luckily, vitamin C can be easily found in fruits and vegetables, making it relatively easy to meet the daily recommended intake (75-90 mg for people aged 19+ and 85 mg for those who are pregnant) (23). 

Will vitamin C supplements improve the health of our hair? Vitamin C deficiency can lead to brittle hair and body hair that grows in a corkscrew pattern (23). Studies conducted in cells and animals have suggested that vitamin C promotes hair growth (19). However, there are no strong scientific studies conducted in humans that confirm these findings. While vitamin C is important in the health of our hair, it is still unclear whether it is beneficial to take it as a supplement when you don’t have a vitamin C deficiency.  

Are there any health risks of taking biotin supplements? Vitamin C is a water-soluble vitamin, meaning excess vitamin C in our bodies is eliminated in our urine (23). While high vitamin C intake is relatively safe, it can interact with certain medications and may cause abdominal pains and nausea (23).


What is zinc?  Zinc is an essential mineral that our bodies cannot make on their own (16). Much like some of the vitamins and proteins we discussed above, zinc must be consumed through our diet (16). This mineral is essential to the function of the proteins in our cells and for gene expression (15). It is thought that zinc supports the growth and replication of the special cells in our body that produce keratin (11). 

Do we need zinc supplements to get enough of it?  It is relatively easy to obtain zinc through our diet. The daily recommended intake of zinc is 8-11 mg (11-12 mg for pregnant folks) (25). Zinc is readily found in meats and seafood, as well as legumes, whole grains, and fortified cereals (25). However, many of the plant-based sources of zinc also contain a compound called phytates that can bind to minerals like zinc and limit their absorption (25). As a result, people who have a plant-based diet or have digestive disorders that limit absorption are more likely to experience zinc deficiency (25). 

Will zinc supplements improve the health of our hair?  Zinc deficiency can negatively impact the hair, skin, and nails, among other organ systems (16,17). The exact mechanism of how zinc supports the hair is unclear, but it does seem to be important for hair health (15). However, there is no strong scientific evidence to suggest that taking additional zinc supplements will further support the health of hair in folks who get enough zinc through their diet(15,16,26). 

Are there any health risks of taking zinc supplements?  It is important to speak to your primary health care provider before taking supplements that contain zinc. This is because consuming too much zinc through supplements can be toxic, leading to unpleasant side effects like nausea and vomiting (15,25). Zinc supplements may also interact with certain medications, including antibiotics which are used to treat infections (27).


So, are these gummies too good to be true? The answer is…maybe. There is very little  research supporting hair growth from hair supplements and their individual ingredients. This makes it difficult to say for certain whether these gummies will fulfill promises of healthier hair. While it is true that the vitamins, minerals, and proteins reviewed above are all vital to the health of our hair, there is a large knowledge gap around whether supplementation will offer any additional hair benefits in otherwise healthy folks. The limited evidence available suggests that these supplements may be helpful in folks who have an existing nutrient deficiency. For most of us, these kinds of nutrient deficiencies are not a concern. However, if you are worried about any deficiencies, particularly if you are on a diet which omits certain foods or food groups, please speak with your primary health care provider before starting any supplements. If you are experiencing hair loss, it is important to speak with your primary health care provider as other health conditions can also be linked to hair loss.  


  1. Government of Canada. How Drugs are Reviewed in Canada. 2015 Feb 12. Available from: [Accessed 2022 Jul 15]

  2. Mine Y, Young D. Regulation of natural health products in Canada. Food science and technology research. 2009;15(5):459-68. Available from:

  3. NIH. Biotin: fact sheet for healthcare professionals. 2022 Jan 10. Available from: [Accessed 2022 Jul 15]

  4. Cleveland Clinic. Biotin Benefits: What the Experts Have to Say. 2022 Jan 13. Available from: [Accessed 2022 Jul 15]

  5. Yousif J, Farshchian M, Potts GA. Oral nail growth supplements: a comprehensive review. International Journal of Dermatology. 2021 Aug 5. Available from:

  6. Boccaletti V, Zendri E, Giordano G, Gnetti L, De Panfilis G. Familial uncombable hair syndrome: ultrastructural hair study and response to biotin. Pediatric dermatology. 2007 May;24(3):E14-6. Available from:

  7. Shelley WB, Shelley ED. Uncombable hair syndrome: observations on response to biotin and occurrence in siblings with ectodermal dysplasia. Journal of the American Academy of Dermatology. 1985 Jul 1;13(1):97-102. Available from:

  8. Mock DM, Baswell DL, Baker H, Holman RT, Sweetman L. Biotin deficiency complicating parenteral alimentation: Diagnosis, metabolic repercussions, and treatment. The Journal of pediatrics. 1985 May 1;106(5):762-9. Available from:

  9. FDA. UPDATE: The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication. 2019 Nov 5. Available from: [Accessed 2022 Jul 15]

  10. Cleveland Clinic. Keratin. 2022 Jun 9. Available from: [Accessed 2022 Jul 15]

  11. Ogawa Y, Kinoshita M, Shimada S, Kawamura T. Zinc in keratinocytes and langerhans cells: Relevance to the epidermal homeostasis. Journal of Immunology Research. 2018 Dec 9;2018. Available from:

  12. Törmä H. Regulation of keratin expression by retinoids. Dermato-endocrinology. 2011 Jul 1;3(3):136-40. Available from:

  13. Giesen M, Gruedl S, Holtkoetter O, Fuhrmann G, Koerner A, Petersohn D. Ageing processes influence keratin and KAP expression in human hair follicles. Experimental dermatology. 2011 Sep;20(9):759-61. Available from:

  14. Beer C, Wood S, Veghte RH. A clinical trial to investigate the effect of Cynatine HNS on hair and nail parameters. The Scientific World Journal. 2014 Jan 1;2014. Available from:

  15. Guo EL, Katta R. Diet and hair loss: effects of nutrient deficiency and supplement use. Dermatology practical & conceptual. 2017 Jan;7(1):1. Available from:

  16. Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The role of vitamins and minerals in hair loss: a review. Dermatology and therapy. 2019 Mar;9(1):51-70. Available from:

  17. Everts HB. Endogenous retinoids in the hair follicle and sebaceous gland. Biochimica et Biophysica Acta (BBA)-Molecular and Cell Biology of Lipids. 2012 Jan 1;1821(1):222-9. Available from:

  18. NIH. Vitamin A and carotenoids: fact sheet for health professionals. 2022 Jun 15. Available from: [Accessed 2022 Jul 15]

  19. Ruiz-Tagle SA, Figueira MM, Vial V, Espinoza-Benavides L, Miteva M. Micronutrients in hair loss. Our Dermatology Online/Nasza Dermatologia Online. 2018 Jul 1;9(3). Available from:

  20. Oregon State University. Vitamin E and Skin Health. Available from: [Accessed 2022 Jul 15]

  21. NIH. Vitamin E: fact sheet for health professionals. 2021 Mar 26. Available from: [Accessed 2022 Jul 15]

  22. Beoy LA, Woei WJ, Hay YK. Effects of tocotrienol supplementation on hair growth in human volunteers. Tropical life sciences research. 2010 Dec;21(2):91. Available from:

  23. NIH. Vitamin C: fact sheet for health professionals. 2021 Mar 26. Available from: [Accessed 2022 Jul 15]

  24. Mayo Clinic. Iron deficiency anemia. 2022 Jan 24. Available from: [Accessed 2022 Jul 15]

  25. Harvard. The nutrition source: zinc. 2019 Sep 17. Available from: [Accessed 2022 Jul 15]

  26. Thompson KG, Kim N. Dietary supplements in dermatology: A review of the evidence for zinc, biotin, vitamin D, nicotinamide, and Polypodium. Journal of the American Academy of Dermatology. 2021 Apr 1;84(4):1042-50. Available from:

  27. NIH. Zinc: fact sheet for health professionals. 2021 Dec 7. Available from: [Accessed 2022 Jul 15]

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