Top Vitamins That Support Hair Growth

If your hairbrush is suddenly collecting more strands than usual or your ponytail feels thinner, you’re not alone. Hair growth is deeply tied to nutrition, and vitamins play a bigger role than most people realize. While genetics, hormones, age, and stress matter, the right nutrient status can be the difference between sluggish growth and stronger, denser strands. As a nutrition professional who’s worked with hundreds of clients on hair health, I’ve seen the same pattern again and again: fix the underlying vitamin gaps and hair often follows suit—just not overnight. Here’s a practical, evidence-informed guide to the vitamins that truly support hair growth, how to use them wisely, and where people commonly go wrong.

How Hair Grows—and Why Vitamins Matter

Your hair grows from follicles, tiny factories in the scalp that produce keratin-based strands. Each follicle cycles through:

• Anagen (growth) for 2–7 years

• Catagen (transition) for a few weeks

• Telogen (rest/shedding) for 2–3 months

At any time, roughly 85–90% of hairs are in anagen, 10–15% in telogen, and 1–2% in catagen. Hair typically grows about 1 to 1.25 cm per month. That rate depends on adequate nutrient delivery to rapidly dividing cells in the follicle matrix. Vitamins fuel cell division, collagen synthesis, hormone balance, and antioxidant defense. Without them, follicles can prematurely shift into shedding mode.

I always remind clients: hair is a “non-essential” tissue in survival terms. When nutrients run short, your body prioritizes heart, brain, and liver. Hair gets whatever is left. That’s why even borderline deficiencies can show up on your head before anywhere else.

Vitamin D: The hair-cycle regulator most people are low in

What it does:

• Helps regulate the hair cycle and may stimulate dormant follicles

• Supports immune balance in the scalp and general hormone signaling

What the evidence says:

• Low vitamin D status is common (roughly 35–40% of U.S. adults run low) and consistently appears in studies of diffuse hair shedding and alopecia areata.

• While supplementing vitamin D isn’t a cure-all for pattern hair loss, restoring a deficiency often reduces shedding and improves hair quality over time.

Practical targets:

• Recommended intake: 600–800 IU/day for adults

• Many people need 1,000–2,000 IU/day to maintain healthy blood levels, especially if indoors or living in northern latitudes.

• Blood test: 25(OH)D. I aim for 30–50 ng/mL for general health; some dermatologists prefer 40–60 ng/mL for hair concerns.

• Safety: Upper limit without medical supervision is 4,000 IU/day. Overdoing vitamin D can raise calcium and cause problems—get labs and adjust.

Food sources:

• Fatty fish (salmon, sardines), cod liver oil, egg yolks, fortified dairy or plant milks, sun exposure when appropriate.

Insider tip: Clients who start vitamin D often notice reduced shedding within 8–12 weeks if low to begin with. Pair with a meal containing fat for better absorption.

Biotin (Vitamin B7): Great if you’re deficient—less helpful if you’re not

What it does:

• Supports keratin infrastructure and energy metabolism in follicle cells

The catch:

• True biotin deficiency is uncommon in the general population. It shows up after long-term use of raw egg whites (avidin binds biotin), heavy alcohol use, pregnancy, certain genetic disorders, and after bariatric surgery. In those cases, biotin helps dramatically.

• For people with normal biotin status, high-dose biotin hasn’t shown consistent hair growth benefits in robust studies.

Dosing and safety:

• Typical supplement doses range from 30–100 mcg/day in multis. High-dose hair products often contain 2,500–10,000 mcg (2.5–10 mg).

• Big warning: Biotin interferes with common lab tests, including thyroid labs and cardiac troponins, sometimes even at doses of 5–10 mg/day. Tell your clinician if you take it and pause before labs (usually 48–72 hours, but follow your lab’s guidance).

Food sources:

• Eggs (cooked), liver, salmon, nuts, seeds, sweet potatoes, legumes.

Professional take: When clients bring me a “hair vitamin” with mega-biotin, I almost always ask for labs first. If there’s no deficiency and other nutrients are low, biotin is rarely the real fix.

B12 and Folate (B9): DNA builders for fast-dividing hair cells

What they do:

• Enable DNA synthesis and red blood cell formation—critical for rapidly growing follicle cells

• Support oxygen delivery to the scalp via healthy hemoglobin levels

Who’s at risk:

• Vegans and many vegetarians (B12 is primarily in animal foods)

• Adults over 50, those on metformin or acid-reducing medications (PPIs/H2 blockers)

• People with pernicious anemia or malabsorption

Practical targets:

• B12 RDA: 2.4 mcg/day. For low levels or absorption issues, daily 250–1,000 mcg can help via passive diffusion (work with your clinician).

• Folate RDA: 400 mcg DFE/day (600 mcg during pregnancy). Many multis provide 400–800 mcg.

• Some people prefer methylfolate (5-MTHF) over folic acid due to MTHFR gene variants. If you don’t tolerate methylfolate (can feel wired), use folinic acid or lower doses.

• Don’t exceed 1,000 mcg/day folic acid from supplements without supervision; it can mask B12 deficiency.

Food sources:

• B12: clams, sardines, salmon, dairy, eggs, fortified nutritional yeast

• Folate: leafy greens, legumes, asparagus, beets, avocado, citrus

Clinical insight: A surprising number of clients with thinning report fatigue, brain fog, and cold hands—clues to low B12 or iron. Correcting these usually improves hair within a few months.

Vitamin A: Necessary in the right dose; too much can backfire

What it does:

• Supports cell differentiation in follicles and healthy sebum production for scalp moisture

The fine line:

• Mild deficiency can cause dry, brittle hair.

• Excess vitamin A (especially from retinol or isotretinoin-like supplements) often triggers hair shedding. I’ve seen this repeatedly in clients taking high-dose retinol for skin.

Targets and safety:

• RDA: 700 mcg RAE/day for women, 900 mcg RAE/day for men

• Upper limit: 3,000 mcg RAE/day (10,000 IU)

• Beta-carotene from colorful vegetables is safer; your body converts what it needs into active vitamin A.

Food sources:

• Carrots, sweet potatoes, pumpkin, winter squash, spinach, kale, eggs, dairy, liver (rich—use sparingly)

Practical rule: If your multivitamin has more than 1,500 mcg RAE of preformed vitamin A (retinyl palmitate/acetate), reconsider. Too much is a common hidden cause of hair loss.

Vitamin C: Collagen catalyst and iron’s best friend

What it does:

• Critical for collagen synthesis, which supports the hair follicle’s connective tissue sheath

• Potent antioxidant in the scalp against environmental and metabolic stress

• Increases non-heme iron absorption from plant foods—crucial if you’re prone to iron deficiency

Targets:

• RDA: 75 mg/day for women, 90 mg/day for men (+35 mg for smokers)

• In practice, 200–500 mg/day is safe and commonly used to support iron absorption

Food sources:

• Citrus, strawberries, kiwi, bell peppers, broccoli, Brussels sprouts, tomatoes

Pro tip: If you’re taking iron, pair it with 100–200 mg vitamin C and avoid coffee/tea around the dose—they inhibit absorption.

Vitamin E: Antioxidant support with some early evidence

What it does:

• Protects cell membranes from oxidative damage, including in hair follicles

• May reduce lipid peroxidation in the scalp environment

Evidence snapshot:

• A small study using mixed tocotrienols found about a 34% increase in hair count after 8 months versus placebo (n≈38). It’s not conclusive, but antioxidant support can be helpful alongside other corrections.

Targets and safety:

• RDA: 15 mg alpha-tocopherol/day

• Upper limit: 1,000 mg/day (approx. 1,500 IU) of alpha-tocopherol

• High-dose vitamin E can interact with blood thinners; stick to modest doses unless supervised.

Food sources:

• Almonds, sunflower seeds, hazelnuts, avocado, extra-virgin olive oil, wheat germ

Supplement tip: Look for “mixed tocopherols” rather than only alpha-tocopherol to better mirror food forms. You don’t need huge doses.

The Rest of the B-Complex: Small hinges that swing big doors

While biotin, folate, and B12 steal attention, the other Bs matter:

• B6 (pyridoxine): Supports amino acid metabolism and hormone balance. RDA 1.3 mg; avoid long-term doses above 50–100 mg/day to prevent neuropathy.

• Riboflavin (B2): Helps energy production in cells; deficiency can contribute to seborrheic dermatitis. RDA 1.1–1.3 mg.

• Niacin (B3): Supports microcirculation and energy production, though high-dose “flush” niacin isn’t necessary for hair. RDA 14–16 mg; upper limit for nicotinic acid flush is 35 mg/day.

• Pantothenic acid (B5): Involved in coenzyme A and lipid metabolism; popular in “hair-skin-nails” formulas. Adequate intake is 5 mg/day.

Food-first approach generally covers these, but if your diet is inconsistent or you’re under high stress, a balanced B-complex at or near RDA levels can help.

Minerals and Co-Factors That Make Vitamins Work

Vitamins don’t work in isolation. A few minerals are indispensable for hair growth:

• Iron: Low iron (especially low ferritin) is one of the most frequent drivers of diffuse hair shedding in women. I aim for ferritin of 40–70 ng/mL for hair health if there’s no inflammation. Work with your clinician—iron overload is harmful. Food: red meat, clams, lentils, pumpkin seeds, spinach (with vitamin C).

• Zinc: Supports keratin formation and follicle function. RDA 8–11 mg; avoid chronic doses above 30–40 mg/day to prevent copper deficiency. Food: oysters, beef, pumpkin seeds, chickpeas, cashews.

• Iodine and Selenium: Crucial for thyroid hormone production and conversion. Both low and excessive intakes can impair hair. RDA iodine 150 mcg; selenium 55 mcg (UL 400 mcg). Food: seaweed (iodine—watch amounts), dairy, eggs; Brazil nuts (selenium—1–2 nuts can cover a day).

• Copper: Supports iron metabolism and collagen cross-linking. RDA 900 mcg. Excess zinc can induce copper deficiency and hair loss.

• Protein: Not a vitamin, but hair is protein. Aim for 0.8–1.0 g/kg body weight daily, more if active. Skimping on protein can stall growth even if you supplement vitamins.

When clients insist on a single “hair vitamin,” I gently redirect: check iron and vitamin D first, then zoom out to diet quality.

How to Evaluate Your Needs: A Step-by-Step Plan

Step 1: Identify your hair pattern and timeline

• Diffuse shedding (lots in the shower/brush) often points to telogen effluvium triggered by stress, illness, postpartum, or nutrient gaps.

• Patchy loss or scarring requires a dermatologist promptly.

• Gradual thinning at the crown or receding hairline suggests androgenetic alopecia; nutrition still helps hair quality, but you might also consider topical minoxidil or other medical therapies.

Step 2: Get baseline labs

Ask your clinician for:

• 25(OH)D (Vitamin D)

• Ferritin, CBC (to check iron status and anemia)

• B12 and folate

• TSH (± free T4/T3) for thyroid

• Optional: Zinc, CRP (inflammation), CMP (liver/kidneys), fasting glucose/A1C if metabolic concerns

Helpful reference ranges for hair:

• Ferritin: aim 40–70 ng/mL if possible

• Vitamin D: aim 30–50 ng/mL, sometimes up to 60 ng/mL

• B12: above 400 pg/mL often feels better for energy and hair (functional symptoms can occur with higher “normal” values, so interpret with your clinician)

Step 3: Audit your diet

For 3 days, log your food. Did you eat:

• 2–3 servings of high-quality protein daily?

• 2 cups of colorful vegetables and 1–2 cups fruit?

• A source of healthy fats (nuts, seeds, olive oil, avocado)?

• Iron-rich foods at least once daily (especially if menstruating)?

• Fortified or animal foods for B12 (or a supplement if plant-based)?

Step 4: Choose targeted supplements

Base these on your labs and diet:

• Vitamin D3: 1,000–2,000 IU/day for maintenance; higher short-term if deficient, guided by labs.

• B12/Folate: If low or vegan, use B12 (250–1,000 mcg/day) and 400 mcg folate (or 5-MTHF) in a multi.

• Vitamin C: 200–500 mg/day if iron intake is plant-based or you need antioxidant support.

• A balanced multi: Opt for one that keeps vitamin A moderate (no more than 1,500 mcg RAE from retinol) and provides RDA-level Bs and zinc (8–11 mg).

• Iron: Only if you’re low, in forms like ferrous bisglycinate or ferrous gluconate; take with vitamin C and away from coffee/tea/dairy.

Step 5: Adjust lifestyle bottlenecks

• Sleep 7–9 hours; hair is sensitive to chronic sleep debt.

• Manage stress: breathing practices, walking, strength training—stress shifts hair to telogen.

• Treat scalp issues (seborrheic dermatitis, psoriasis) since inflammation can disrupt growth.

Step 6: Recheck and track

• Expect reduced shedding in 8–12 weeks if you corrected a deficiency.

• Baby hairs and density changes take 4–6 months to notice, with fuller changes around 9–12 months.

• Re-test vitamin D and ferritin at 8–12 weeks if they were low, then adjust.

Realistic Expectations: What Faster Growth Actually Looks Like

Hair growth rates are biologically capped. Vitamins won’t turn 1 cm/month into 3 cm/month. What you can expect:

• Less shedding, stronger strands, more baby hairs along your hairline within 2–4 months

• Improved shine and elasticity as protein and vitamin C support collagen and keratin

• Denser feel by the 6–9 month mark if you corrected deficiencies

Postpartum shedding peaks around 3–4 months after delivery and can affect 30–50% of women. Nutrients won’t stop it completely—it’s hormonally driven—but optimized vitamin D, iron, and overall intake help recovery and regrowth.

Practical Scenarios and Supplement Blueprints

These are examples, not prescriptions. Always use labs to tailor.

Scenario 1: Vegan, 28, increased shedding and fatigue

• Labs: B12 low-normal, ferritin 20 ng/mL, vitamin D 22 ng/mL

• Plan:

• Vitamin D3: 2,000 IU/day with a meal; recheck in 12 weeks

• B12: 500–1,000 mcg/day methyl- or cyanocobalamin

• Iron: 25–45 mg elemental iron/day (ferrous bisglycinate) with 200 mg vitamin C; retest ferritin in 8–12 weeks

• Folate from foods plus a multi with 400 mcg

• Protein target: 70–80 g/day using tofu, tempeh, lentils, hemp seeds

• Notes: Pair iron with vitamin C; avoid coffee/tea 1 hour before and after iron.

Scenario 2: Indoor-working man, 45, thin hair and dandruff

• Labs: Vitamin D 18 ng/mL, zinc low, normal thyroid and iron

• Plan:

• Vitamin D3: 4,000 IU/day short-term with clinician oversight; retest in 8–12 weeks then drop to 2,000 IU/day maintenance

• Balanced multi with 10–15 mg zinc and 1–2 mg copper

• Omega-3s from diet or supplement for scalp inflammation (not a vitamin, but helpful)

• Anti-dandruff shampoo (zinc pyrithione or ketoconazole) 2–3x/week to calm inflammation that disrupts follicles

Scenario 3: Postpartum, 35, heavy shedding at 4 months

• Labs: Ferritin 28 ng/mL, vitamin D 24 ng/mL

• Plan:

• Continue prenatal or switch to a quality multi with iron

• Iron: 25–30 mg elemental/day with vitamin C

• Vitamin D3: 2,000 IU/day

• Protein 90–100 g/day and hydration

• Expectation setting: Shedding will ease by months 6–7; focus on regrowth and energy.

A Food-First Plan That Actually Covers Your Bases

Here’s a one-day template I use with clients to cover vitamin needs without a pharmacy’s worth of pills:

Breakfast

• Greek yogurt (or soy yogurt fortified with B12 and vitamin D)

• Handful of strawberries and kiwi (vitamin C)

• 2 tbsp pumpkin seeds (zinc, iron)

• Drizzle of honey and chopped almonds (vitamin E)

• Coffee after breakfast if taking iron later

Lunch

• Large spinach and arugula salad (folate) with roasted sweet potatoes (beta-carotene), chickpeas (iron), bell peppers (vitamin C), avocado (vitamin E), and olive oil-lemon dressing

• Side of sardines on whole-grain toast (B12, vitamin D, omega-3s) or marinated tofu if plant-based

Snack

• Carrot sticks with hummus

• A Brazil nut or two (selenium)

Dinner

• Grilled salmon or lentil-mushroom loaf (protein + iron/B12 in salmon)

• Quinoa and steamed broccoli (vitamin C)

• Optional: small portion of liver once every few weeks for a nutrient bomb—if you like it, go sparingly to avoid vitamin A excess

Evening

• If supplementing iron, take it now with a small glass of orange juice or 200 mg vitamin C

This kind of day easily hits the RDA for vitamins A, C, E, and most Bs, plus gives supportive minerals. Rotate foods to keep it interesting.

Common Mistakes That Sabotage Hair Growth

• Mega-biotin without labs: If your ferritin is 15 ng/mL and vitamin D is 20 ng/mL, 10,000 mcg biotin won’t fix the root problem—and can mess with lab tests.

• Too much vitamin A: Retinol-heavy multis or extra “skin” supplements stacking vitamin A can push you into shedding territory.

• Ignoring iron: Ferritin below 40 ng/mL is a red flag for many women with shedding. Get the lab. Treat it thoughtfully.

• Zinc overload: Chronic 50 mg zinc can deplete copper and cause hair loss. Keep zinc near 8–15 mg unless clinically directed otherwise.

• One-and-done expectations: Hair responds slowly. Give changes at least 12 weeks before judging.

• Skipping protein: Beautiful hair without adequate protein is wishful thinking. Hit your daily target.

• Gummy vitamins as a solution: Fun, but often underdosed and loaded with sugar. Use them occasionally, not as your core plan.

• Taking everything at once: Stack too many supplements, and you can’t tell what’s working—or causing side effects.

Smarter Supplement Shopping: What to Look For

• Third-party testing: Choose brands certified by USP, NSF, or Informed Choice when possible.

• Reasonable doses: RDA-level multis with modest vitamin A (prefer beta-carotene), D3, balanced Bs, and 8–11 mg zinc.

• Forms that absorb well: D3 (cholecalciferol), methylcobalamin or cyanocobalamin for B12, 5-MTHF or folinic acid for folate if you’re sensitive to folic acid, ferrous bisglycinate for gentler iron.

• Transparency: Clear labels listing amounts and forms, not proprietary blends hiding doses.

• Avoid heavy stacking: If your multi has 100% of vitamin A and you also take a skin oil with retinol and a cod liver oil, you’re likely overdoing vitamin A.

Timing tips:

• Fat-soluble vitamins (A, D, E, K) with meals containing fat

• Iron away from calcium and coffee/tea; pair with vitamin C

• B vitamins in the morning if they make you perky

Budget-Friendly Priorities

If you can’t do everything:

• Get ferritin and vitamin D tested. These two often move the needle most for shedding and energy.

• Buy a simple, well-dosed multivitamin and vitamin D3 if needed.

• Use food to cover vitamin C, E, and most Bs.

• Add iron only if you’re low; you’ll save money and avoid side effects.

A $10–$20/month plan can go far if it’s targeted.

Special Considerations

• Thyroid conditions: Both hypo- and hyperthyroidism cause hair changes. Correct the thyroid issue; then dial in iron, selenium, iodine (don’t supplement iodine high-dose without guidance), and vitamin D.

• PCOS and insulin resistance: Hair thinning can involve androgens. Nutrition helps, but consider medical therapies alongside vitamin D, B-complex, and inositol (not a vitamin, but often beneficial).

• Bariatric surgery: Higher risk of deficiencies in B12, iron, vitamin D, and others. Work with your care team; you’ll likely need tailored, long-term supplementation.

• Medications: Isotretinoin (acne) can increase shedding; talk to your dermatologist. Metformin can reduce B12. PPIs reduce B12 absorption. Anticoagulants and vitamin E have interactions.

When to See a Professional

• Sudden, dramatic shedding or patchy hair loss

• Scalp pain, redness, scarring, or intense dandruff that doesn’t respond to over-the-counter care

• Signs of anemia (fatigue, pale skin, shortness of breath) or thyroid symptoms (weight changes, temperature intolerance)

• Hair loss after a new medication

A board-certified dermatologist can evaluate the scalp and hair follicles, run targeted labs, and coordinate with a nutrition professional for a comprehensive plan.

A Simple, Sustainable Hair-Nutrition Routine

• Morning:

• Balanced breakfast with protein

• Multivitamin with D3 (if included) and a small snack with fat

• Midday:

• Colorful vegetables and vitamin C-rich foods

• Evening:

• Iron with vitamin C (only if you’re low), away from calcium/coffee/tea

• Weekly:

• 2–3 servings of fatty fish or fortified alternatives

• Leafy greens at least 5 times

• Nuts/seeds most days

• Every 8–12 weeks:

• Recheck labs if you were deficient

• Track shedding, baby hairs, and ponytail thickness

Final Thoughts

Hair responds to steady, boring consistency more than flashy supplements. Most clients who get real results do a few things well: they correct low vitamin D and iron, cover the basics with a sensible multi, keep vitamin A in check, eat enough protein, and give it time. If you take one thing from this guide, let it be this: test, don’t guess. Your follicles are remarkably resilient when they have what they need, and the right vitamins—used strategically—can help them show it.