What helps, what’s hype, and when to get checked
Hair and nails often reflect what’s happening in the body. Because hair growth and nail formation depend on steady nutrition, hormones, sleep, and overall health, changes like shedding, thinning, splitting, or brittleness can sometimes be an early clue that something else needs attention. Mayo Clinic notes that certain nail changes can be linked with issues such as iron deficiency, infection, inflammatory skin conditions, or other health problems.
That said, not every hair or nail change means “you’re deficient.” Stress, illness, new medications, harsh grooming, frequent handwashing/chemicals, hormonal shifts, and ageing can all play a role.
Why hair and nails change
Common contributors include:
- Stress or illness (hair shedding can increase after a major stressor or sickness)
- Dieting/very low-calorie intake (can reduce protein and micronutrients needed for growth)
- Iron deficiency (can be linked with hair issues and nail changes like “spoon nails”)
- Thyroid problems, postpartum changes, and other hormone shifts
- Skin/scalp conditions (eczema, psoriasis, fungal infections)
- Autoimmune hair loss such as alopecia areata
If you’re seeing sudden or significant change, it’s worth discussing with a GP—often the best “vitamin” is treating the underlying cause.
The nutrients that matter most
Hair and nails are made largely of keratin, and the body needs adequate building blocks plus key vitamins/minerals to support normal growth.
1) Protein (the foundation)
Hair is primarily protein, so inadequate protein intake can contribute to weak, thinning hair.
Food sources: eggs, fish, poultry, lean meat, Greek yoghurt, tofu/tempeh, lentils, beans.
2) Iron
Iron supports oxygen delivery to tissues. Iron deficiency is a well-known contributor to certain nail changes and may be linked with hair concerns in some people.
Food sources: red meat, chicken, fish, lentils/beans, spinach; pair plant iron with vitamin C foods (citrus, capsicum) to improve absorption.
3) Vitamin D
There’s growing interest in vitamin D and hair health—Harvard Health notes that if someone has hair loss and low vitamin D levels, a clinician may recommend supplementation.
Food sources: sunlight exposure (safely), oily fish, eggs; many people need testing to confirm low levels.
4) Zinc
Zinc is involved in cell growth and repair, but high-quality evidence for zinc supplements in hair/nail concerns is limited unless a deficiency exists. A dermatology evidence review found insufficient evidence to recommend routine zinc (or biotin) supplementation in dermatology.
Food sources: meat, shellfish, dairy, legumes, nuts/seeds.
5) B vitamins (especially B12 and folate)
These support normal cell turnover and red blood cell production. Deficiency is more likely in people with restricted diets or absorption issues (e.g., some gut conditions, certain medications). If you’re concerned, testing is better than guessing.
6) Vitamin C
Vitamin C supports collagen formation and helps the body absorb iron from plant foods.
7) Essential fatty acids (healthy fats)
Healthy fats support skin/scalp barrier function and “moisture lock-in.”
Food sources: salmon/sardines, extra virgin olive oil, avocado, nuts, seeds.
What about “Hair, Skin & Nails” supplements (biotin, collagen, etc.)?
Biotin: popular, but evidence is limited
Biotin is heavily marketed for hair and nails, but the NIH Office of Dietary Supplements says there is little scientific evidence to support biotin supplements for hair/skin/nails in people who aren’t deficient.
Some small studies suggest biotin may help brittle nails in certain cases, but this doesn’t mean everyone needs high-dose biotin.
Important safety note: biotin can interfere with blood tests
The FDA warns that biotin can interfere with some lab tests (including certain troponin tests used in heart-attack assessment), potentially causing falsely low or inaccurate results.
If you take biotin, tell your doctor and the pathology collector—especially before blood tests.
Food-first: the simplest “vitamin plan”
Before buying supplements, aim for a consistent base:
- Protein at each meal (eggs, yoghurt, lean meats, legumes)
- Colourful fruit + veg daily (vitamin C, antioxidants)
- Iron + zinc sources a few times per week (depending on diet)
- Healthy fats (fish, olive oil, nuts/seeds)
- Hydration + gentle grooming (heat/chemical damage can mimic “deficiency”)
Mayo Clinic Health System highlights that lacking essential nutrients can worsen hair/nail quality, especially with very restrictive diets.
When supplements make sense
Supplements are most useful when you’ve identified a real gap, such as:
- low iron/ferritin
- low vitamin D
- low B12/folate
- inadequate protein intake
- diagnosed absorption issues
A GP can guide which blood tests are appropriate and what dosing is safe. Avoid “mega-doses” unless prescribed—more isn’t always better.
When to see a GP sooner
Book a check if you notice:
- sudden, heavy shedding or bald patches
- new, unusual nail changes (spooning, separation, deep lines, significant discoloration)
- symptoms like fatigue, shortness of breath, dizziness, or heavy periods (possible iron issues)
- scalp pain, scaling, or inflammation
- hair loss linked with new medications or major life events
Takeaway
Healthy hair and nails usually come from the basics: adequate protein, key micronutrients (iron, vitamin D, B12/folate, zinc where needed), healthy fats, and addressing underlying health or stressors. “Hair and nail vitamins” can help when there’s a deficiency, but routine high-dose supplements—especially biotin—often have limited evidence and can create avoidable risks with lab testing.
General information only — not medical advice. If symptoms are persistent, sudden, or worrying, speak with your GP or a dermatologist.