From Sandra Kowalczyk, Bozeman, Montana: “I’ve been noticing my hair has been shedding a lot more than usual and it feels thinner at the crown. My stylist mentioned it could be nutritional, but I don’t really know what to look for or where to start. Can you break down what’s actually going on and what I should be doing about it?”
Sandra, I’m so glad you asked this because honestly this comes up in my chair more than almost anything else lately, and most women have no idea the story their hair is already telling. The frustrating part is that by the time you notice the shedding or the dullness or that weird texture shift that makes your hair feel like it belongs to someone else, the deficiency has usually been building for months. Hair is slow. The changes you’re seeing now reflect what was happening inside your body back in the spring, maybe earlier.
I’ve had women come in convinced they needed a completely new cut or a keratin treatment to fix what was going on, and I have to gently tell them, the cut isn’t going to fix this. I had one client, a retired teacher, who kept blaming her shampoo. We went through three different professional lines together over two years before her doctor finally ran a full blood panel and found her ferritin was practically nonexistent. Once she got that sorted, her hair changed in ways no product could have touched.
So let’s actually talk about what’s going on, what to look for, and what to do about it, because you deserve a real answer.
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8. Dry, Brittle Strands That Break Before They Can Grow
Breakage is one of those things that gets blamed on everything from heat tools to hard water, and sure, those things matter, but when a client sits down in my chair and I start running my fingers through her hair and feel that dry, snapping texture all the way from mid-shaft to ends, I start asking different questions. Specifically, I want to know how much fat she’s eating.
Vitamin A deficiency can absolutely contribute to dryness, but the more common culprit I see in women over 40 is not getting enough healthy dietary fat, which affects how the body absorbs fat-soluble vitamins like A, D, E, and K. Your scalp needs sebum to keep the hair shaft coated and protected, and if that natural oil production drops, the strand becomes porous and fragile before it’s even gotten past your ears. Essential fatty acids from things like salmon, walnuts, flaxseed, and avocado play a direct role here.
From a product standpoint, a good deep conditioning treatment can buy you some time and make the hair more manageable while you work on what’s happening internally. I reach for Olaplex No. 8 Bond Intense Moisture Mask pretty regularly on clients dealing with this texture. It won’t fix a deficiency, but it does reduce the mechanical damage that comes with brittle hair, which matters because every single break is length you’re losing. If you want to go deeper on the nutrition side, look into omega-3 fish oil supplements, which have solid research behind them for skin and scalp health. Give it three months minimum before you expect to see anything.
7. A Scalp That Flakes and Itches Even When You’re Washing Regularly
Not all flaking is dandruff, and not all dandruff is a fungal issue, even though that’s what most people assume. When someone tells me their scalp has been itchy and irritated and they’ve already tried the Nizoral and the Head and Shoulders and nothing is really solving it, I ask about zinc. Zinc deficiency shows up on the scalp in a really specific way, more of a dry, inflamed flaking rather than the oily, yellowish flaking you’d associate with seborrheic dermatitis, and women who eat a mostly plant-based diet or who have digestive issues that affect absorption are particularly susceptible.
Zinc plays a role in cell turnover and the health of the scalp tissue itself, and when it drops, you get that uncomfortable tight, itchy feeling along with visible flaking that doesn’t respond to antifungal treatments because fungus isn’t what’s driving it. Biotin supplements often get credit for scalp improvements, and while biotin has its place, I’d argue zinc is doing a lot of work that doesn’t get discussed nearly enough in beauty spaces.
If you want something topical while you’re sorting out the internal piece, I’ve had genuinely good results recommending zinc pyrithione scalp treatments to clients, which address the symptom directly. For the supplementation side, zinc supplements for women are widely available, but I’d encourage you to get tested before you start high-dose supplementation because zinc and copper compete for absorption and you don’t want to throw one off while fixing the other. Your GP can run this as part of a standard panel.
6. Hair That Looks Dull and Lifeless No Matter What Products You Use
There’s a particular kind of dullness I can spot pretty quickly, the kind that isn’t about damage or build-up, where the hair just looks flat and matte even right after a fresh color or a blowout. It doesn’t have the dimensional quality healthy hair has, that slight variation in how the light hits each strand. I’ve learned to ask those clients about their protein intake and, more specifically, whether they’ve been under a lot of stress, because cortisol and protein malnutrition often come as a package deal.
Hair is made of keratin, which is a protein, and when your body is stressed or not getting enough dietary protein, it starts deprioritizing non-essential functions like hair growth and quality. The strand gets thinner in diameter, which is part of why the hair looks limp, and the cuticle, which is what creates that light reflection we associate with shine, becomes rougher and less compact. You can throw every hair gloss treatment on the market at this and get temporary improvement, but the underlying issue keeps expressing itself.
Collagen supplements have gotten a lot of attention, and I don’t think they’re hype. Vital Proteins Collagen Peptides is what I personally use, and I do think it makes a difference in the texture and body of my hair, especially since I’m in my late 40s and protein synthesis just isn’t what it was. The distinction worth knowing is that collagen provides amino acids that your body can use to build keratin, it’s not keratin itself, so it’s a building block rather than a direct deposit. Still worth it, in my opinion.
5. Premature Gray or Color That Fades Weirdly Fast
Okay, this one I find genuinely fascinating and it doesn’t get talked about enough in the context of nutrition. Gray hair is a normal part of aging and I’m not here to tell you it can be reversed by taking a supplement. But premature graying, meaning significant gray before your mid-40s, has been linked in research to deficiencies in B12, folate, copper, and selenium. And here’s the thing I notice in the salon all the time: clients who are deficient in these nutrients also often have color that just doesn’t hold. It fades faster, it doesn’t deposit as evenly, and the gray that is there resists the dye in a way that’s disproportionate to normal gray coverage challenges.
B12 in particular is one I think about constantly with my older clients, because B12 absorption decreases with age regardless of diet, and women who have been on metformin for diabetes or on long-term acid reflux medication have even more trouble absorbing it. The connection to melanin production is real, because B12 is involved in the enzymatic pathways that produce pigment. I’m not a doctor and I want to be clear about that, but I’ve seen clients whose graying slowed noticeably after getting their B12 up from deficient to optimal levels.
If you color your hair and you’re frustrated by how quickly it fades or how uneven your coverage is, it’s worth asking your doctor specifically about B12 and folate alongside your iron. Sublingual B12 supplements are generally better absorbed than the standard pill form, which is why most nutritionists recommend them, and they’re inexpensive and easy to find.
4. A Widening Part Line or Overall Thinning That Seems to Be Spreading
When a woman points to her part and says it looks wider than it used to, I take that seriously, because that kind of diffuse thinning across the top of the scalp is one of the most emotionally difficult changes women deal with, and it very often has a nutritional component that’s being overlooked while she spends money on volumizing sprays that can’t do what she needs them to do.
Iron deficiency is the one I check first, always. Specifically ferritin, which is stored iron, not just hemoglobin. A lot of women have hemoglobin levels that look technically normal on a standard blood test and their doctor says everything is fine, but their ferritin is very low, and ferritin is what hair follicles actually draw from. There’s a threshold that keeps coming up in the research, somewhere around 70 ng/mL being the ferritin level where hair loss stabilizes for most women, but the standard “normal” range often goes down to 12 or even lower. You have to specifically ask your doctor to check ferritin and to tell you the actual number.
Vitamin D deficiency also shows up as this kind of diffuse thinning, and it’s incredibly common especially in women who live in northern climates, work indoors, or have darker skin tones. For anyone dealing with thinning at the crown, I recommend looking into women’s hair vitamins that include iron and biotin as a starting point, though real supplementation should follow actual testing. Topically, women’s minoxidil treatments have good evidence behind them for the physical regrowth side while you address the nutritional deficits, and the two approaches together tend to work better than either one alone.
3. Slow Growth That Seems to Have Stalled Completely
This is one that I end up having a long conversation about with clients because there are a lot of reasons hair growth slows, and I want to make sure we’re thinking about the right ones before someone spends a hundred dollars on a growth serum. Thyroid function is the first thing I ask about because hypothyroidism, which is vastly underdiagnosed in women over 40, affects not just the rate of growth but the texture of the hair and even the density of the eyebrows, specifically the outer third thinning out. If that sounds familiar, please push your doctor on a full thyroid panel including T3 and T4, not just TSH.
But within the purely nutritional landscape, selenium and iodine deficiencies are connected to thyroid function, and inadequate selenium specifically has been associated with a slowing of the anagen phase, which is the active growth phase of the hair cycle. Most people in the US aren’t severely deficient but they’re not optimally nourished either, and hair is one of the first places that marginal deficiency expresses itself because it’s not keeping you alive.
I also want to mention silica here, which doesn’t get nearly the attention it deserves in conversations about hair growth. Silica is a mineral that supports the strength of the hair shaft and there’s reasonable evidence it supports growth rate as well. Silica supplements for hair growth are one of the more underrated recommendations in the whole hair supplement category, in my opinion. If you want to be more proactive topically, a scalp massager used daily genuinely increases blood flow to the follicles and costs almost nothing. I tell every client dealing with slow growth to use one. It’s one of the few things I recommend without any hesitation.
2. Changes in Texture You Didn’t Ask For, Like Suddenly Wavy or Coarser
This one surprises people, the idea that a nutrient deficiency could actually change the shape or texture of their hair when it grows in. But I’ve seen it, more than once, and it’s one of the stranger presentations because clients often come in excited, thinking their hair has changed in a good way, like they finally have some wave or body, and I have to gently explain that texture shifts in adult hair that happen without chemical processing or a major hormonal event like pregnancy are worth investigating.
Iron deficiency anemia, when it’s significant, can alter the structure of the hair shaft as it grows. Same with prolonged protein deficiency, which can actually cause curly or wavy hair to grow in straighter and limp because the disulfide bonds that create curl pattern depend on adequate sulfur-containing amino acids like cysteine and methionine. Going the other way, low thyroid function can cause a coarser, drier texture in women who previously had fine, soft hair, and they often come in thinking they need more moisture treatments when what they actually need is a thyroid check.
I’m not saying every texture shift is a medical emergency, because hormones alone, especially the perimenopause transition, account for a lot of this. But if you’ve noticed a texture change that you genuinely can’t explain and it’s been more than six months, it belongs in a conversation with your doctor. In the meantime, using a strengthening protein treatment at home can help reinforce the shaft and make the hair more predictable to style. ApHogee Two-Step Protein Treatment is one that I’ve used professionally for years and it holds up.
1. Excessive Shedding That Fills Your Brush Every Single Morning
We’re talking about Sandra’s original question here, and I saved it for last because it’s the most important and the most misunderstood. Shedding is normal. You lose somewhere between 50 and 100 hairs a day under normal circumstances and that’s fine. What’s not fine, and what I see women panic about unnecessarily because no one has explained the timeline to them, is telogen effluvium, which is the kind of diffuse, all-over shedding that happens two to four months after a triggering event.
That trigger can be almost anything, a crash diet, a surgery, a major illness, a period of extreme stress, or a nutritional deficiency that dropped too low for too long. The hair shifts from its growth phase into its resting and shedding phase en masse, and then two to four months later you’re standing in the shower watching more hair than seems possible going down the drain. By the time that’s happening, the triggering event is usually already over, which is why it feels so random and scary.
Iron, ferritin specifically, is the most common nutritional driver of this kind of shedding in women. But deficiencies in vitamin D, zinc, niacin (B3), and protein can all trigger the same response. The frustrating truth is that even once you’ve corrected the deficiency, you’re looking at three to six months before you see meaningful regrowth, because the follicles that went dormant have their own timeline for returning to the growth phase. I tell clients this up front because the waiting is hard and I want them to know the absence of immediate results doesn’t mean nothing is working.
What I recommend while you’re in that waiting period: get your blood work done and be specific about ferritin, vitamin D, zinc, and B12. Add a solid iron supplement formulated for women if ferritin comes back low, and pair it with vitamin C for absorption. Use a Nioxin system shampoo to keep the scalp environment clean and well-circulated. And please, be patient with yourself. Your body is doing its best and the hair will come back.
The Bigger Picture Here
What I want you to take away from all of this is that your hair is genuinely one of the better early warning systems your body has, and it’s worth listening to. It’s not vain to pay attention to it. It’s actually smart, because the deficiencies that affect hair are often the same ones affecting your energy, your bone density, your immune function, and your mood.
I’ve spent years doing this, and I’ve watched so many women spend years and hundreds of dollars on treatments that were never going to work because the problem was internal, not on the surface of the strand. Getting a comprehensive blood panel from your doctor, asking specifically for ferritin, vitamin D, zinc, B12, and thyroid markers, is the most useful thing you can do. Take that information seriously. Advocate for yourself if the numbers come back “normal” but you know something is off, because the difference between normal and optimal is real and your hair knows it.
You deserve to have a conversation with your doctor that goes beyond the basics. And Sandra, I hope this gives you a real place to start.