Biotin
Helps enzymes process fats, carbohydrates, and proteins.
Why it matters
Biotin helps enzymes break down fats, carbohydrates, and proteins. It also supports gene regulation and cell signaling.
- Supports metabolism of carbohydrates, fats, and protein.
- Contributes to normal cell signaling.
- Helps several carboxylase enzymes function.
If intake is too low
Biotin deficiency is rare, but when it happens it can affect the skin, hair, nervous system, and mood.
- Hair thinning and scaly rash around the eyes, nose, and mouth.
- Lethargy, depression, or hallucinations in severe deficiency.
- Tingling in the arms and legs.
If intake is too high
No upper limit has been set for biotin, but high-dose supplements can still be risky because they interfere with important lab tests.
- No established upper limit.
- Can distort blood test results and mislead care decisions.
- High-dose hair-and-nails products are the usual problem.
No adult upper limit established
No tolerable upper intake level has been established, but the lab-test interaction risk is a major real-world safety issue.
Common food sources
Biotin is found in a variety of foods, so deficiency is rare when overall intake is adequate.
- Egg yolks, salmon, pork, and liver
- Nuts, seeds, and legumes
- Sweet potatoes and some whole grains
Who may need closer attention
Deficiency stays rare, but certain life stages and unusual exposures can raise concern.
- People who are pregnant
- People regularly consuming large amounts of raw egg whites
- Anyone taking high-dose hair, skin, and nails products before lab testing
Use extra caution if
Small details change the risk picture with nutrients more than most people expect.
You take a hair, skin, and nails supplement or you are about to have lab work. Always tell the clinician or lab about biotin before testing.
Supplement and label notes
Useful context when this nutrient shows up across more than one product.
- Biotin megadoses are common in beauty supplements and can be far above the DV.
- The biggest real-world issue with biotin is lab-test interference, not classic toxicity.
- If you use biotin, tell the lab or clinician before bloodwork rather than assuming the dose is too small to matter.
Daily Value targets in SuppMap
These are the same label-style Daily Value targets used in the app.
Official references
These pages were used to draft the summaries on this guide.
Educational only. These pages are not a diagnosis or a substitute for personal medical care.
More guides
Keep moving through the rest of the Daily Value chart from here.