Supplements for skin and hair: what actually helps hair loss, acne, dry skin and eczema

Short answer

Most "hair, skin and nails" supplements only help if you are deficient in something. For people with normal levels, the evidence for biotin, collagen and most skin vitamins is weak or absent.

What the evidence supports:

• Hair loss: the deficiencies most worth checking are iron (ferritin), vitamin D, zinc and thyroid function. Correcting a real deficiency can help; taking these when your levels are normal has not been shown to (1).

• Biotin: helps hair only in rare true deficiency. High doses can distort blood tests, including thyroid tests (7) and troponin, a test used to diagnose heart attacks (2).

• Collagen: a 2025 meta-analysis of 23 trials found no benefit for skin ageing once industry-funded and lower-quality studies were set aside (3).

• Acne: people with acne tend to have lower zinc levels, and zinc reduced inflamed spots in a meta-analysis (4). It is an add-on, not a replacement for proven acne treatment.

• Eczema: evening primrose and borage oil do not help (5).

Hair shedding, breakouts and skin that suddenly feels different are distressing, and wanting to fix them is not vanity. These changes often reflect something happening in the body, such as stress, illness, hormones or a deficiency, and they deserve a proper look rather than another bottle of gummies.

Note: this article is for general education and is not medical advice. Sudden or patchy hair loss, scarring acne or widespread rashes should be checked by a doctor or dermatologist.

Why supplements rarely change healthy skin and hair

Hair and skin are made of protein and need a steady supply of nutrients, energy and hormones. When something is missing, the body prioritises vital organs, and hair growth is one of the first things to slow down. That is why deficiencies, crash diets and serious illness can cause shedding.

But the reverse is not true. If you already have enough of a nutrient, taking more does not make hair grow faster or skin look younger. A review of vitamins and minerals in hair loss concluded that supplements should be guided by testing and used to correct deficiency, since there is little evidence of benefit otherwise and some nutrients, such as vitamin A and selenium, can cause hair loss in excess (1).

Hair loss: which deficiencies matter

What vitamin deficiency causes hair loss?

The nutrient problems most often linked to hair loss are (1):

• Iron deficiency. The most common nutritional link, especially in women with heavy periods, vegetarians and frequent blood donors. Iron deficiency hair loss usually shows as diffuse thinning or increased shedding. Low ferritin (the iron stores marker) is common in women with hair shedding, even without anaemia. Many dermatologists aim for ferritin well above the lower lab limit, though the exact target is debated.

• Vitamin D. Low vitamin D is common in people with alopecia areata (patchy hair loss) and in some with diffuse shedding. Whether supplements help regrowth is not proven, but correcting a deficiency is reasonable. Our guide to the vitamin D test explains the results.

• Zinc. Deficiency can cause hair loss, and is more likely with gut conditions, very restrictive diets or heavy alcohol use.

• Protein and calories. Crash dieting, eating disorders and rapid weight loss, including after weight-loss surgery or with weight-loss medicines, can trigger shedding a few months later.

• B12 and folate. Deficiency causes anaemia and fatigue and may contribute to hair changes.

• Biotin. True deficiency is rare.

Too much vitamin A or selenium from supplements can itself cause hair loss.

Not every hair loss is a deficiency

The most common causes of hair loss in women are not nutritional:

• Telogen effluvium: sudden shedding 2–4 months after a trigger such as illness, fever, surgery, childbirth, a crash diet or major stress. It usually recovers within 6–9 months once the trigger has passed.

• Female pattern hair loss: gradual thinning on the top of the head, related to genetics and hormones.

• Thyroid problems: both underactive and overactive thyroid can cause thinning.

• Hormonal conditions: polycystic ovary syndrome (PCOS) can cause thinning on the scalp with acne and extra facial hair. See how to know if you have PCOS.

• Medicines: some blood pressure medicines, antidepressants, retinoids and starting or stopping hormonal contraception.

• Alopecia areata: an autoimmune condition causing round bald patches.

Perimenopause hair loss

Perimenopause hair loss is common. Falling oestrogen and the relative effect of androgens can cause thinning on the top of the head and sometimes more facial hair. Iron deficiency from heavy, irregular perimenopausal periods and thyroid changes, which become more common in midlife, can add to it. These are worth checking before buying hair supplements. Our articles on menopause symptoms and how perimenopause is diagnosed cover the wider picture.

Vitamins for hair growth: what's worth trying

Vitamins for hair growth and vitamins for hair loss are among the most searched supplement terms. Here is how the main options compare.

The best vitamins for hair growth are the ones you are actually low in. That is why a blood test (full blood count, ferritin, vitamin D, thyroid, and sometimes zinc and B12) is a better first step than a hair gummy.

Some "hair, skin and nails" products also contain high amounts of vitamin A, selenium or vitamin B6. Stacking them with a multivitamin can push intake above safe limits.

Biotin: why it's so popular and what it really does

Biotin benefits are real for people who lack it: deficiency causes thinning hair, brittle nails and a scaly red rash around the eyes, nose and mouth. But deficiency is rare, mostly linked to certain genetic conditions, long-term raw egg white consumption, some anti-seizure medicines and heavy alcohol use.

For people with normal levels, there is no good evidence that biotin for hair increases growth or thickness (1). Its popularity comes largely from the fact that biotin deficiency causes hair loss, not from trials showing extra biotin helps.

The important risk is lab test interference. Many hair and nail products contain 5,000–10,000 mcg of biotin, far above the 30 mcg adults need. These doses can cause falsely high or falsely low results in tests that use a biotin-based method. The US Food and Drug Administration has warned that biotin can cause falsely low troponin results, which can delay the diagnosis of a heart attack (2). In thyroid tests, biotin can make thyroid hormone levels look falsely high and TSH falsely low, which can look like an overactive thyroid; the American Thyroid Association advises stopping biotin for at least two days before thyroid testing (7). If you take biotin, tell your doctor and the lab before any blood test and ask whether and when to pause it. In an emergency, mention it straight away.

Collagen for skin: what the 2025 evidence shows

Collagen for skin is one of the most marketed supplements, and the best collagen supplements for women are a large search category. Collagen supplements are broken down into amino acids and small peptides during digestion. The theory is that some of these peptides signal skin cells to make more collagen.

The evidence is weaker than the marketing. In 2025, a meta-analysis of 23 randomised trials with 1,474 participants initially found improvements in skin hydration, elasticity and wrinkles. But trials without industry funding showed no benefit, and when only higher-quality trials were included, there was no significant effect. The authors concluded that there is currently no clinical evidence to support collagen supplements to prevent or treat skin ageing (3). Industry groups have disputed some of the study's classifications, so the debate continues.

What does protect skin: daily sunscreen, not smoking, enough sleep, a varied diet with enough protein and vitamin C, and topical retinoids, which have much stronger evidence for wrinkles than any supplement.

Acne: supplements with some evidence

Zinc for acne

Zinc for acne has the best evidence among supplements. A meta-analysis found that people with acne had lower blood zinc levels than people without acne, and that zinc treatment significantly reduced inflammatory papules (red, raised spots), alone or alongside other treatments (4). Zinc is generally less effective than standard acne medicines, and high doses can cause nausea and, over time, copper deficiency. Typical trial doses provided around 30 mg of elemental zinc a day for about 12 weeks; the upper limit for adults is 40 mg a day unless your doctor advises otherwise (6). Zinc also reduces absorption of tetracycline antibiotics, a group that includes doxycycline and minocycline often used for acne, and of quinolone antibiotics; the NIH advises taking the antibiotic at least 2 hours before or 4–6 hours after zinc (6). Ask your pharmacist before combining them, and do not stop a prescribed acne medicine without talking to your doctor.

Other supplements for acne

• Vitamin D: people with acne often have lower vitamin D, and small trials suggest correcting a deficiency may reduce inflammatory spots. Evidence is limited.

• Omega-3 fats: small studies suggest a possible reduction in inflammatory acne; evidence is weak.

• Probiotics: early research, not enough to recommend.

• High-dose vitamin A: oral vitamin A supplements are not a safe substitute for prescription retinoids and can be toxic, especially in pregnancy.

Best vitamins for hormonal acne

Searches for the best vitamins for hormonal acne often come from adult women with breakouts around the jaw and chin, sometimes worse before periods. No vitamin reliably treats hormonal acne. If acne comes with irregular periods, extra hair growth or scalp thinning, ask about PCOS. Effective medical options include topical treatments, certain contraceptive pills and spironolactone, all decided with a doctor. Diet may play a role: some studies link high-glycaemic diets and dairy, particularly skimmed milk, with more acne.

Dry skin and eczema

Supplements for dry skin

Supplements for dry skin and vitamins for dry skin have limited evidence. Dry skin is far more often caused by weather, hot showers, harsh soaps, ageing, hormonal changes in menopause, or conditions such as an underactive thyroid, eczema or diabetes. Omega-3 fats and some vitamin D trials show small effects on skin barrier markers, but moisturising regularly with a fragrance-free emollient is much more effective than any supplement.

Persistent, unexplained dry, itchy skin can sometimes be a sign of iron deficiency, thyroid, kidney or liver problems, and is worth mentioning to your doctor.

Supplements for eczema

Supplements for eczema are widely sold, but the best-studied options do not work:

• Evening primrose oil and borage oil: a Cochrane review of 27 studies found no benefit over placebo for eczema symptoms (5).

• Vitamin D: some small trials suggest a benefit, particularly for eczema that worsens in winter or in people with low levels, but results are mixed.

• Fish oil and probiotics: no consistent benefit for existing eczema in adults.

Eczema responds best to daily emollients, avoiding triggers and anti-inflammatory treatments prescribed by a doctor.

Thyroid, iodine and selenium

The thyroid has a big influence on skin and hair: an underactive thyroid can cause dry skin, brittle nails and diffuse thinning, and an overactive one can cause fine, falling hair. People sometimes take iodine or selenium "for the thyroid". In countries with iodised salt, extra iodine is rarely needed and too much can trigger thyroid problems. Too much selenium causes hair loss and brittle nails. A thyroid blood test is the right first step, and if you take biotin, tell the lab, as it can distort thyroid results.

Living with skin and hair changes: the questions people ask next

How long until I see a difference in my hair?

Hair grows about 1 cm a month, and shedding from a trigger often continues for a few months before recovery. Expect at least 3–6 months after correcting a deficiency before judging the result.

Should I take a "hair, skin and nails" supplement just in case?

There is little evidence of benefit without a deficiency, and some products contain high doses of biotin, vitamin A, selenium or B6. A blood test is a better investment.

Is collagen worth it?

Based on the 2025 evidence, collagen supplements have no proven benefit for skin ageing. If you want to try it, give it 3 months and judge honestly; sunscreen and topical retinoids have stronger evidence.

Can stress cause hair loss?

Yes. Major physical or emotional stress can trigger telogen effluvium, with shedding 2–4 months later. It usually recovers within 6–9 months once the stress passes.

Why is my skin breaking out in my 30s or 40s?

Adult acne is common, particularly in women, and is linked to hormones, stress, some medicines and skincare products. It can also be an early sign of PCOS or hormonal changes in perimenopause.

Can weight-loss medicines cause hair loss?

Rapid weight loss from any cause, including medicines and surgery, can trigger shedding a few months later. Eating enough protein and checking iron and other nutrients can help.

Before you blame yourself

Many people feel embarrassed to raise hair loss or acne with a doctor, worried it sounds trivial. It is not vanity. Hair and skin changes affect confidence and wellbeing, and they can be the first sign of iron deficiency, thyroid disease, PCOS or hormonal change.

If you have spent a lot on supplements that did not help, that is not a personal failing either. The marketing is persuasive, and the real causes often need testing to uncover.

When to see a doctor

See a doctor or dermatologist if:

• you notice sudden, heavy shedding, round bald patches or a widening parting;

• hair loss comes with tiredness, heavy periods, feeling cold, weight changes or palpitations;

• you have acne with irregular periods or extra facial or body hair;

• acne is painful, cystic, scarring or affecting your mood;

• you have eczema that disturbs your sleep or does not improve with emollients;

• you have dry, itchy skin without an obvious cause;

• you take biotin and need a blood test.

How to bring this up with your doctor

What to ask for, by name. "Could we check a full blood count, ferritin, vitamin D, thyroid function and, if relevant, zinc and B12?" For acne with irregular periods: "Could this be PCOS?"

What to bring. Photos of your hair or skin over time, dates when shedding or breakouts started, any recent illness, stress, diet changes or new medicines, and a list of all supplements, especially biotin.

What to say, out loud. "I've noticed [more hair in the shower / thinning at the parting / breakouts on my jaw] since [when]. It's affecting my confidence. I'd like to find out if there's a medical cause before trying more supplements."

If you're told it's "just stress" or "just age". Ask: "Could we check ferritin and thyroid first, so we can rule out a treatable cause?"

How long until you notice a difference? Most supplements take weeks, not days. See how long supplements take to work, and how to tell if one is working.

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How Welltory helps — and what it cannot do

The limits first. Welltory is a general wellness product, not a medical device. It cannot assess hair or skin, measure iron, vitamin or hormone levels, or diagnose any condition.

What it can do is help you connect skin and hair changes with the stress, sleep and life events that often come before them, which is useful because shedding typically starts months after a trigger.

Tag events and changes. On iOS with an Apple Watch or Oura, when Welltory marks a stress or rest episode on the Today screen and asks "What happened?", tap, type or talk: "fever", "exam week", "new pill", "started iron", "breakout". Over weeks, My Patterns shows which tags tend to appear with stress and recovery; some sections need a paid plan.

Stress and sleep over months. Sleep Analysis uses Apple Watch or Oura data on iOS and on Android works with Samsung Health, or with Fitbit and Garmin Connect through Health Connect (Sleep Analysis for Android). On the iOS Today screen (with Apple Watch or Oura), Battery starts each morning from your resting heart rate on waking and your sleep (Today screen). HRV measurements show how your body handles stress over time.

A record for your doctor. From the web app you can export a CSV (Dashboard → choose a chart → Export) (export guide) to show periods of high stress or poor sleep in the months before shedding started. These are associations to discuss, not proof of cause.

How we made it

We based this article on a review of vitamins and minerals in hair loss, a 2025 systematic review and meta-analysis of collagen supplements for skin ageing, a meta-analysis of zinc in acne, a Cochrane review of evening primrose and borage oil for eczema, US Food and Drug Administration warnings and American Thyroid Association advice about biotin interference with lab tests, and NIH Office of Dietary Supplements guidance on zinc. Search questions came from what women in the United States most often ask about supplements for hair, skin, acne and eczema. For the product section, we checked every function against the Welltory Help Center on October 21, 2026.

Made with AI tools, then edited and fact-checked by the Welltory team. See our Editorial & AI policy.

Jane Smorodnikova, co-founder of Welltory, built the methodology behind how we read physiological data.

Written by Tatsiana Yashyna.

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