Question from Margaret Holloway, Decatur, Illinois: “I’m 58 years old and my hair has been thinning for about two years now. My doctor ran some basic bloodwork and said everything looked ‘normal,’ but I can see the difference in my ponytail and the part in my hair. I eat pretty well and I’m not under any unusual stress. Is there something I might be missing that’s causing this? I feel like I’m losing my mind along with my hair.”
Margaret, I hear this exact story at least once a week in my chair, and I want you to know you are absolutely not losing your mind. The “everything looks normal” conversation with a general practitioner is one of the most frustrating things my clients deal with, because standard panels miss a lot. A result can be technically within the reference range and still be low enough to affect your hair significantly. The reference range for something like ferritin, for example, is embarrassingly wide, and landing at the bottom of it is not the same as landing in the middle, even though both show up as “normal” on a printout.
Hair loss in women, especially after 50, has so many potential contributors that a single blood panel rarely tells the whole story. I’m not a doctor, and I’ll say that upfront, but after years of working with women through postpartum shedding, thyroid changes, menopause transitions, and general thinning, I’ve learned enough to ask better questions and point people in more useful directions. So let’s go through six deficiencies that are genuinely, quietly behind a lot of unexplained hair loss, so you can bring something more specific to your next appointment or work with a functional medicine doctor who will actually dig in.
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6. Zinc, the One Everyone Forgets About
Zinc doesn’t get nearly the attention it deserves in hair loss conversations, and I think it’s because it’s not as dramatic a deficiency as some of the others on this list. It sneaks up on you. The hair loss from low zinc tends to look diffuse, meaning it’s spread all over the scalp rather than concentrated at the part or the temples, and because it happens gradually, women often chalk it up to aging or stress before anyone thinks to check zinc levels.
What zinc actually does for your hair is support the oil glands around the follicle and play a role in protein synthesis, which matters because hair is essentially protein. When zinc drops, the follicle doesn’t get the structural support it needs to hold onto the hair shaft properly. You’ll also often see dry, flaky scalp alongside this kind of shedding, which is another clue.
The trickier thing about zinc is that testing it accurately is actually more complicated than most people realize. Serum zinc can look fine while intracellular zinc is low. If you’re working with a functional medicine doctor, ask about a red blood cell zinc test instead of just the standard serum test. Dietary sources like red meat, shellfish (oysters especially), and pumpkin seeds are your best friends here, and if you’re supplementing, zinc glycinate or zinc picolinate absorb better than zinc oxide. I’ve had clients do well with Nature’s Trove or Thorne zinc supplements, both of which are easy on the stomach compared to cheaper forms. Don’t mega-dose, though, because too much zinc actually blocks copper absorption and can create a whole different problem.
5. Vitamin D, Which Almost Everyone Is Low In but Rarely Thinks to Connect to Hair
I live in the Midwest, and I cannot tell you how many of my clients, when I ask if they’ve had their vitamin D checked, say “oh I take a D supplement” as though that settles it. Taking a supplement and having adequate levels are two different things, especially if you’re taking one of those low-dose 400 IU tablets that barely makes a dent. Vitamin D deficiency is genuinely epidemic in women over 50, and it has a pretty direct relationship with the hair growth cycle.
Vitamin D receptors are present in hair follicles, and research suggests that it plays a role in stimulating follicle cycling, meaning it helps follicles move through the growth phase properly. When D is low, follicles can get stuck in the resting phase longer than they should, and the result is hair that sheds and doesn’t replace itself at the same rate. It’s not like you go bald overnight. It’s more like the density slowly, slowly thins over months and you look back at photos from three years ago and wonder what happened.
The generally accepted threshold for “sufficient” vitamin D is around 30 ng/mL, but many functional medicine practitioners and integrative dermatologists aim for 50 to 70 ng/mL for optimal function, including hair health. If your doctor tested you and said you were fine at 32, it might be worth a second opinion on what “fine” means for your specific situation. Supplementing with D3 alongside K2 helps with absorption and directs the calcium properly, so look for a combined formula. Designs for Health and Nordic Naturals both make solid D3/K2 combinations that I’ve recommended to clients and heard good things back about.
4. Magnesium, the Deficiency That Hides Behind Other Symptoms
Here’s the thing about magnesium that makes it so hard to pin down. It presents as about seventeen different problems simultaneously, so you’re sitting there dealing with poor sleep, muscle cramps, anxiety, and hair thinning, and nobody connects the dots because those all look like separate issues. Magnesium is involved in over 300 enzymatic reactions in the body, and hair follicle health is somewhere in that long list, because follicle cells divide rapidly and that process requires magnesium.
Low magnesium also affects cortisol regulation, and when cortisol stays elevated, hair follicles get signals to exit the growth phase early. So there’s a kind of double effect, where the deficiency directly impairs follicle function and also creates a stress response that compounds the problem. I had a client a few years ago, a retired teacher in her early sixties, who had been managing insomnia with everything under the sun and happened to mention at one of her appointments that her hair had been falling out in the shower in handfuls. She’d been to a dermatologist and an endocrinologist. Nobody had checked magnesium. Her integrative doctor eventually did, found her levels were low, started her on magnesium glycinate, and within about six months she told me her hair felt thicker and she was sleeping through the night for the first time in years. I’m not saying magnesium is magic, but it was clearly what she was missing.
Serum magnesium is notoriously unreliable as a test because your body keeps blood magnesium stable even when tissue stores are depleted. A red blood cell magnesium test gives a much better picture. Food-wise, dark leafy greens, nuts, seeds, and dark chocolate are your best sources. For supplementing, magnesium glycinate is the form I hear the most positive feedback about because it doesn’t cause digestive issues the way magnesium oxide can. Pure Encapsulations and Klaire Labs are two brands worth looking at if you want pharmaceutical-grade quality.
3. B12, Especially If You’re Eating Less Meat or Taking Metformin
B12 deficiency and hair loss is a connection that does come up in conventional medicine occasionally, but it gets missed constantly in women over 50 for a couple of specific reasons. First, absorption of B12 from food declines with age because stomach acid production decreases and you need that acid to free B12 from protein so it can be absorbed. Second, some very common medications, particularly Metformin for blood sugar management and proton pump inhibitors for acid reflux, actively deplete B12 over time. If you’re on either of those and nobody has talked to you about monitoring your B12, that’s worth bringing up.
B12 is essential for red blood cell production, and red blood cells carry oxygen to the scalp and follicles. When B12 is insufficient, the oxygen supply to the follicle gets compromised, and hair growth slows or stops. The shedding associated with B12 deficiency can be substantial, and it often comes alongside fatigue, brain fog, and sometimes a sore tongue or tingling in the hands, though not always. You can have a significant deficiency and feel fine in most areas while your hair takes the hit.
The standard B12 serum test is a starting point, but ask your doctor to also check methylmalonic acid and homocysteine, which are better functional markers of whether your body is actually using the B12 it has. And if you’re supplementing, sublingual methylcobalamin absorbs far better than cyanocobalamin tablets, especially if absorption is already an issue in your gut. Jarrow Formulas makes a widely trusted sublingual B12 that’s been around forever and works well for most people. If your levels are severely low, your doctor may recommend injections, which bypass absorption issues entirely and are worth asking about.
2. Iron and Ferritin, Which Are Not the Same Thing and Both Matter
This is the one that probably makes me the most passionate because it gets dismissed so often and it is behind so much hair loss in women, particularly in the perimenopause and early menopause window when cycles are still happening but often heavier and more irregular than they used to be. Iron deficiency is one of the most well-documented causes of diffuse hair loss in women, and ferritin, which is the stored form of iron, is specifically implicated in hair follicle health even when full iron-deficiency anemia hasn’t developed yet.
Your body treats ferritin as a reserve, and when stores get low, it pulls from wherever it can to keep essential functions running. Hair is not considered essential. So the follicle gets robbed. Dermatologists and trichologists who specialize in hair loss often say ferritin should be above 70 ng/mL for optimal hair growth, and some aim for 100 or higher, but the conventional “normal” range bottoms out around 12 or even lower depending on the lab. A woman walking around with ferritin at 15 will absolutely be told her iron is normal. And she will absolutely be losing hair.
I’ve had this conversation so many times. A client comes in, she’s been shedding for a year, she had bloodwork done, everything was normal. I ask specifically if they checked ferritin. Sometimes yes, sometimes no. When it was checked, she shows me the result and it’s low-normal, maybe 18 or 22, and she was told not to worry about it. Getting ferritin up takes time, often six months to a year of consistent supplementation paired with vitamin C to aid absorption and taken away from coffee and calcium. Thorne Iron Bisglycinate or Gentle Iron by Solgar are both forms that are much gentler on the stomach than ferrous sulfate and absorb well. This is genuinely one of the most impactful things you can address if it turns out to be your issue, and when ferritin comes up, the hair response is often noticeable and meaningful.
1. Biotin Is Not the Answer, But the B-Vitamin Complex It Belongs To Might Be
I knew this would be the one that surprises people, and I want to be clear because I feel strongly about this. Biotin has been marketed so aggressively as the hair growth vitamin that the supplement aisle is absolutely drowning in high-dose biotin products, and most women with hair loss have already tried it. Here’s my take after years of watching clients try it: isolated high-dose biotin supplementation helps a very small subset of people, specifically those who are actually biotin deficient, which is genuinely uncommon. For everyone else, those 5,000 and 10,000 mcg tablets are largely unnecessary, and they can actually interfere with thyroid lab results and certain cardiac tests, which is something your doctor needs to know about if you’re taking them.
What is worth paying attention to is the broader B-vitamin complex that biotin belongs to, specifically the interplay between B2 (riboflavin), B3 (niacin), B6, B7 (biotin), and B9 (folate). These vitamins work together in metabolic pathways that affect cellular energy, protein synthesis, and the health of rapidly dividing cells like, yes, hair follicles. A low-grade deficiency in B2 or B6 specifically has been linked to hair shedding, and these are the ones that almost never get tested and almost never get supplemented because nobody’s marketing them on a giant shampoo bottle.
B6 is particularly interesting because it’s involved in the conversion of amino acids and also plays a role in hormone metabolism, including estrogen and progesterone, which become a whole conversation of their own during perimenopause and menopause. If your hormones are shifting, your B6 needs may actually increase. And folate, the natural food form of folic acid, supports cell division in the follicle matrix. Eating a diet rich in leafy greens, legumes, eggs, and whole grains gives you a solid foundation, but if you want to supplement strategically, a good whole-food-based B-complex beats isolated high-dose biotin almost every time for most women. Garden of Life and MegaFood both make whole-food B complexes that are well-formulated and include the full spectrum rather than just the one vitamin with the good marketing. This is what I’d actually point you toward, Margaret, instead of the biotin gummies that are everywhere right now.
What to Actually Do Next
If you’ve read through all of this and you’re thinking, “okay, but how do I get my doctor to test for all of this,” I understand the frustration because general practitioners work within a system that doesn’t always make this easy. The best move, if it’s accessible to you, is to find a functional medicine doctor or an integrative dermatologist who specializes in hair loss, sometimes called a trichologist. They will order a comprehensive panel that includes ferritin specifically, not just hemoglobin, red blood cell zinc and magnesium rather than just serum levels, 25-OH vitamin D, full B12 with methylmalonic acid, and a full thyroid panel including free T3 and reverse T3, because thyroid issues are their own enormous category of hair loss contributor that I didn’t even get to in this piece.
You can also go through services like Ulta Lab Tests or Walk-In Lab to order your own panels without a doctor’s order, which gives you data to bring to any appointment rather than showing up and hoping they’ll run the right tests. Knowledge is leverage in those conversations.
While you’re doing the investigative work, support your hair from the outside too. A gentle, sulfate-free shampoo like Pura D’or or Briogeo Scalp Revival can help reduce unnecessary mechanical stress on fragile strands, and a weekly scalp massage with something like rosemary oil has actual research behind it for supporting follicle circulation. It’s not a substitute for addressing the root cause, but it feels good and it’s doing something real while you wait for your levels to come up.
Margaret, your hair has a story, and right now it’s telling you something your bloodwork panel didn’t catch. You’re not imagining the change, you’re not overreacting, and you deserve a more thorough investigation than “everything looks normal.” I hope this gives you something specific and actionable to bring to your next conversation with a provider who will actually listen. You’ve got this.