Vitamin B7 (biotin)
Helps the body use fats, carbohydrates and protein; needed for healthy skin, hair and nails.
If you are short of it
Possible signs
- Hair thinning or loss
- Brittle or ridged nails
- Skin rash or dermatitis
- Tingling or numbness in hands and feet
- Tiredness, low energy
These signs are common and have many other causes. They are clues, not proof; a blood test and a doctor can tell.
Who is more at risk
Eating many raw egg whites (avidin binds biotin), pregnancy, alcohol, long-term anticonvulsants, rare genetic disorders.
Foods rich in Vitamin B7 (biotin)
| Food | Serving | Amount | women 19–50 | men 19–50 |
|---|---|---|---|---|
| Beef liver | 85 g cooked | 31 NIH | 103% | 103% |
| Eggs | 2 large eggs | 20 NIH | 67% | 67% |
| Salmon | 100 g cooked | 5 NIH | 17% | 17% |
| Beef (lean) | 100 g cooked | 4.5 NIH | 15% | 15% |
| Sweet potato (baked) | 1 medium | 2.4 NIH | 8% | 8% |
| Sunflower seeds | a small handful (28 g) | 2.1 NIH | 7% | 7% |
| Almonds | a small handful (28 g) | 1.2 NIH | 4% | 4% |
| Tuna (canned, light) | 85 g, half a can | 0.6 NIH | 2% | 2% |
| Cheese (cheddar type) | 40 g, about 2 slices | 0.5 NIH | 1.7% | 1.7% |
| Spinach (cooked) | ½ cup (90 g) | 0.5 NIH | 1.7% | 1.7% |
| Broccoli (cooked) | ½ cup (80 g) | 0.4 NIH | 1.3% | 1.3% |
| Milk (fortified) | 1 cup (240 ml) | 0.3 NIH | 1% | 1% |
| Plain yogurt (low-fat) | 1 cup (245 g) | 0.2 NIH | 0.7% | 0.7% |
| Banana | 1 medium | 0.2 NIH | 0.7% | 0.7% |
Unit: mcg. Share of the daily amount. Values marked NIH were checked against the food tables of the NIH Office of Dietary Supplements; the others are approximate and unchecked. Real foods vary with variety, brand, soil and cooking.
As a supplement
Hair-and-nail products are common, but benefit is proven only when you are truly deficient.
Too much
No upper limit, but biotin supplements can falsify blood tests (including troponin for heart attacks and thyroid tests). Tell the lab and your doctor; many labs advise stopping 2 days before testing.
How much you need each day
| Group | Recommended | Upper limit |
|---|---|---|
| Infants 0–6 months | 5 | — |
| Infants 7–12 months | 6 | — |
| Children 1–3 years | 8 | — |
| Children 4–8 years | 12 | — |
| Children 9–13 years | 20 | — |
| Boys 14–18 years | 25 | — |
| Girls 14–18 years | 25 | — |
| Men 19–30 years | 30 | — |
| Women 19–30 years | 30 | — |
| Men 31–50 years | 30 | — |
| Women 31–50 years | 30 | — |
| Men 51–70 years | 30 | — |
| Women 51–70 years | 30 | — |
| Men over 70 | 30 | — |
| Women over 70 | 30 | — |
| Pregnant 14–18 years | 30 | — |
| Pregnant 19–30 years | 30 | — |
| Pregnant 31–50 years | 30 | — |
| Breastfeeding 14–18 years | 35 | — |
| Breastfeeding 19–30 years | 35 | — |
| Breastfeeding 31–50 years | 35 | — |
Unit: mcg. US/Canada Dietary Reference Intakes (National Academies), as summarised by the NIH Office of Dietary Supplements. Other countries’ values differ slightly. These are amounts for healthy people, not treatment doses.
Medicines and habits to mention to your doctor
Anti-seizure medicines (phenytoin, carbamazepine, valproate)
They can lower folate, vitamin D, vitamin K and biotin. Ask about bone health and folate, especially before pregnancy.
Page updated: 2026-10-08 · By Prof. E. Shalaan, Applied Sciences and AI (ASAI)