Anyone who has experienced thinning hair, excess shedding, or really any health or cosmetic issue, for that matter, has at least been curious about vitamins for healthy hair to try to solve the issue. 

And it will shock no one to learn the supplement and ‘beauty’ industries have reached values exceeding $163,986 million and $571 billion, respectively. 

As a licensed dietitian nutritionist, I understand better than most the critical roles that vitamins, minerals, amino acids, and botanicals can play in supporting our health. But, my training and experience also helps me to see the potential shortcomings and dangers of products marketed to a diverse group of people based solely on a single physical symptom. 

Let’s take a critical look at some of the most commonly included ingredients in hair vitamins and look at who (if anyone) they’re likely to benefit as well as some of the potential watch-outs. 

Do certain vitamins promote healthy hair? 

Nutrition has a huge impact on our health and the health of our hair. 

To name a few…

• Each strand of hair is built using proteins we get through our diet.
• Signs of under-eating can be reflected in our hair (e.g., brittle or thin hair).
• Diet can also have a big impact on our hormone balance.
• Nutrition influences gut health. In turn, our gut health determines how well we digest and absorb hair-critical nutrients, influences scalp health, and plays a pivotal role in maintaining immune balance to protect hair follicles. 

As a nutritionist, I am very tuned into how food and nutrients can fuel our hair health. But I think it’s important to remember that even though good nutrition (adequate food intake, balanced consumption of macronutrients and micronutrients) is essential for our health and healthy hair, that 1) not every health problem is “caused” by a nutritional issue and 2) not every health problem can be “fixed” by a supplement or change to our diet. 

Improving our nutrition will positively impact our general health and wellness and may even result in improved laboratory markers and a reduction in symptoms, including decreased hair shedding and/or regrowth. So, while we should keep an open mind about what’s possible for our health goals, we should also try to avoid thinking of our health as transactional because the reality is that not everything is under our control or fixable. 

What are hair vitamins? 

There are many different nutritional supplements and vitamins marketed to people experiencing hair loss and want to improve their hair health. The general hope motivating someone to purchase one of these products is that by including a specific vitamin, mineral, amino acid (a building block of protein), or botanical (i.e., medicinal plant), the issues with our hair will resolve. 

Although there are lots of options when it comes to hair vitamins, I wanted to look closely at the ones my clients ask me about most often. I decided to look at Prose, Nutrafol, and Olly. I’ll start by digging into some of the most commonly used vitamins & minerals. 

Are hair vitamins safe? 

In healthcare, good clinicians always consider the part of the Hippocratic oath that says, “First, do no harm.” That means the safety of an intervention (whether that is a nutritional supplement, pharmaceutical, or something else) should be considered first, and the overall effect should be more positive than negative.

Although many people feel that nutritional supplements are not dangerous, the truth is that they are not without risk. There is the potential for harm, especially when they are not purchased from reputable manufacturers or retailers and/or if they are not used correctly. 

Because nutritional supplements are not regulated by the Food and Drug Administration (FDA), there is little oversight for the safety or effectiveness of many supplements. Trustworthy supplement companies will be third-party tested for purity (which looks for contaminants) and potency (which looks at formulations and fillers); in essence, testing companies make sure that what the label says the supplement contains is in the product. 

It’s also important to purchase nutritional supplements through a reputable retailer. There are many counterfeit products sold through major online retailers every day. At best, this means you’re wasting your money on a low-quality product. At its worst, you could be unknowingly taking something that could cause lasting harm to your health. 

I always tell clients the only supplements I trust are professional-grade products from reputable manufacturers (e.g., Designs for Health, Pure Encapsulations, etc.) purchased through a trusted retailer like Fullscript or directly from the manufacturer. 

Beyond ensuring that the nutritional supplement you’re purchasing is legit, is making sure you use it appropriately. Even if you take a product as directed on the bottle, that bottle can’t tell you 1) if it is well-suited to your nutritional needs or 2) if it could cause adverse effects given your unique health status, history, etc. It’s always best to work with a licensed nutritionist to determine which nutritional supplements are right for you. 

How well studied are hair vitamins? 

Nutrition can be a tricky subject to research. One main reason is that nutrition (especially when it involves your diet) doesn’t fit neatly into the study designs built for pharmaceuticals. For example, a well-designed pharmaceutical study will control for the placebo effect and the observer-expectancy effect by making sure that no one – not the participants, not the healthcare providers – will know who is getting the ‘real’ treatment and who is getting the placebo. It’s hard to accomplish this when you’re studying nutrition (I think you would know if you were offered real broccoli, vs placebo broccoli, for example). 

Another thing (among many things) that can make nutrition difficult to research is funding: who is going to pay for a big study with many participants and researchers, conducted over a substantial period of time? Studies (especially well-conducted ones) cost a lot of money to run, and the potential for upside (impact or profit) is usually fairly limited in nutritional research. Think of how many times you’ve read an article telling you that coffee is bad for you, then that it’s good for you, then that it’s bad for you again. Did reading any of those studies really change your behavior (i.e., have an impact)? Did anyone directly profit in a big way when those studies were published? Unlikely. 

I’m not trying to say that we know nothing in terms of nutrition research, but I think it’s important to keep this info in mind and remember that it’s an evolving field of study. 

I need to make you aware of something I have noticed with hair vitamin studies: they are almost always paid for by the manufacturers themselves. Remember that studies are expensive. When a company pays for a study of its own product, they’re putting a lot of money on the line and would be very keen to make sure that this study they are paying for has a conclusion that is favorable to them.

It’s not hard to see where the conflict of interest is when you consider how devastating it would be for a company to pay for a study that shows that their product doesn’t work, or worse, leads to horrible side effects. In fact, I’d venture to guess that any study like this showing poor results probably never sees the light of day or gets published. 

So, when a hair vitamin says it’s “science-backed”, “backed by clinical studies”, etc. it’s a safe assumption that this was their own research (sometimes even conducted in-house using the people that work for them) and isn’t as impressive as it sounds. 

Does experiencing hair loss mean that you need a supplement? 

Just because someone is experiencing hair loss does not necessarily mean that they are nutritionally deficient or would benefit from a supplement. It’s best to work with a licensed nutritionist who can assess what dietary changes or supplements you would benefit from – and – be able to identify the source (aka root cause) of the nutritional deficiency. For example, someone with several nutritional deficiencies may need help optimizing their digestion and improving gut health. Supplementing with the missing nutrients can be helpful for a while, but it’s often done alongside other important improvements to your health. 

Vitamins for Healthy Hair

Vitamin A for Hair Loss

Vitamin A is a fat-soluble nutrient that plays many important roles in the body, including cell growth and immune function. Most nutritional supplements contain beta carotene, also called “pro-vitamin A” because they need to be converted into the active form of vitamin A (retinol) in the body. 

Vitamin A may help support collagen production in the skin, so the companies developing vitamins may be hoping that it is also beneficial for healthy hair and hair loss through the same mechanism, although there is no research I could find to support this. 

Because it is a fat-soluble vitamin, there is a risk of toxicity, meaning it’s important not to take too much of it. Some data also shows that vitamin A excess can cause hair loss, so this is not a ‘more is better situation’. 

It depends on the individual I am working with, but, in general, if I am working with a client that I believe would benefit from supplemental vitamin A, I will limit it to <2500 IU preformed vitamin A and/or <2500 IU pro-vitamin A (beta carotene) (supported here) and not exceed 5000 IU per day of retinal activity equivalents (RAE).  

Watch Out: 

Make sure you are considering any other supplements you are taking (e.g., multivitamins) that may contain the same nutrients as hair vitamins. This can lead to accidental toxicity. 

Testing vitamin A levels: 

You can have vitamin A serum levels tested by your doctor or through outpatient clinical laboratories. 

Vitamin D for Hair Loss

Vitamin D is another important fat-soluble nutrient that can help support immune balance. There are few food sources of vitamin D, but our bodies can produce their own when our skin is exposed to the sun. 

In addition to helping support a balanced immune system (which is important to protect our hair follicles against autoimmune attacks), vitamin D also supports the cells that produce keratin. Keratin is the protein that makes up each strand of our hair, and keratinocytes are the cells that produce keratin. 

Vitamin D is something that I routinely test in new clients (especially ones with autoimmune issues or those that live in northern climates or who wear sunscreen every second they’re outside). Testing vitamin D levels before and after supplementing is important to ensure that the dose someone is taking is correct and to avoid toxicity (remember that there are specific toxicity concerns with fat-soluble nutrients). I like my clients to have vitamin D (25-OH vitamin D) between 50-80 ng/mL. I use their current blood levels to help inform how much to supplement. 

From what I could see, most vitamin D-containing hair vitamins have around 2500 IU of vitamin D, which is likely too low to make a difference in most people with a vitamin D need. So, if testing shows that someone needs vitamin D, they should work with a licensed nutritionist to get the dosing right while avoiding supplementing to excess. 

Testing vitamin D levels: 

You can have vitamin D blood levels (25-OH vitamin D) tested through your doctor or outpatient clinical laboratories. 

Biotin for Hair Loss

Biotin is a B vitamin (technically, it’s vitamin B7 or vitamin H), and it’s one of the more commonly included ingredients in hair vitamins. We can obtain biotin in our diet through foods like eggs, beans, nuts, seeds, and other protein-rich foods. On top of the biotin we get through our diet, a healthy gut microbiome can also produce biotin. 

Just a note about gut health: commonly, clients I work with will be low in one or multiple different nutrients and also be experiencing gut health issues. Since our gut is where we can digest foods and absorb nutrients, it only makes sense that there could be underlying issues that need to be addressed there. In my clinic, we work on addressing gut health in addition to any nutrient deficiencies versus just blindly supplementing.  

The recommended daily intake of biotin is 30 mcg. A deficiency of biotin in the US is very rare. While it is true that biotin deficiency can cause hair loss, that does not mean that hair loss is always the result of biotin. Despite some hair vitamins containing 100 or more times the recommended daily intake, there isn’t any evidence that high-dose supplementation with biotin will improve hair health in people without a deficiency. 

Watch out: 

Supplementing with biotin can interfere with lab test results – including thyroid tests. It’s important to avoid taking biotin-containing supplements for a few days before testing to get accurate results. Please also let your doctor know about any nutritional supplements you are taking. 

Testing biotin levels: 

The best way to assess functional levels of biotin is with an organic acid test (OAT) that looks at beta-hydroxyisovalerate levels in a urine sample. Although many different labs are offering this test, my preferred one is the DUTCH Complete which looks at adrenal function, steroid hormone levels, as well as OATs. 

Iodine for Hair Loss

Iodine is a mineral that supports thyroid hormone production and activation. Active thyroid hormone is critical to our wellbeing and iodine is a necessary nutrient. Thyroid health can have a huge impact on our hair health, so hair vitamin manufacturers are likely hoping that supplemental iodine will help support normal thyroid function and improve hair. 

If we have too little iodine in our diet, we can experience under-active thyroid (called hypothyroid). However, under-active thyroid can be caused by many factors, and sometimes supplementing with iodine isn’t helpful. Excess iodine supplementation can lead to hyperthyroid as well as hypothyroid and worsen autoimmune thyroid issues in some.

When supplemental iodine would be helpful to a client, I typically have them stick to a dose of around 150 mcg per day or less (this is 100% of the daily value of iodine for non-pregnant/nursing adults). This is much less than some of the hair vitamins contain, but it’s safer with less risk of excess, which could also harm hair health by provoking thyroid issues. Iodine is not a “more is better” nutrient. 

Testing iodine levels: 

There aren’t reliable or easy ways to test iodine levels. I typically use my client’s food journals to calculate how much iodine they get in their regular diet. Iodine-containing foods include seaweed (like dulse and nori), seafood, dairy, eggs, and iodized salt. 

When determining if supplemental iodine would be helpful to their thyroid health, I like to have their doctors run a full thyroid panel including TSH, Free T4, Free T3, Reverse T3, Anti-TPO, and Anti-TG autoantibodies.

If you are ready to take a whole-body approach to hair health and work with a functional nutritionist to uncover and resolve root cause issues, apply to work with me today.