Biotin – Vitamin B7 Source And Use

Biotin may be familiar with vitamin B7 as biotin. It is a water-soluble B vitamin that can be found naturally in some foods as well as in supplements. Biotin is essential for enzymes to break down fats, carbohydrates, and proteins in food. It also aids in the regulation of cell signals and gene activity.

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What are recommended amounts?

There is no RDA (Recommended Dietary Allowance) for biotin because there is insufficient evidence to suggest a daily amount required by most healthy people. Instead, an AI (Adequate Intake) level is assumed to ensure nutritional sufficiency.

  • AI: The AI for biotin is 30 micrograms daily for men and women aged 19 and up, as well as pregnant women. Lactating women require 35 micrograms per day.
  • Tolerable Upper Intake Level (UL): A Tolerable Upper Intake Level (UL) is the maximum daily dose that is unlikely to cause adverse side effects in the general population. There is no UL for biotin because there have been no reports of negative effects from very high intakes.

Vitamin B7 and Health:

Biotin supplements are frequently promoted as a treatment for hair loss and as a means of promoting healthy hair, skin, and nails.

Although a biotin deficiency can cause hair loss and skin or nail problems, evidence supporting the benefit of supplementation is inconclusive. A few case reports and small trials have shown a benefit, but the study designs were flawed:

  • The types of hair conditions’ diagnoses varied or were not mentioned at all. Researchers have also noted that certain hair loss conditions, such as alopecia, can resolve spontaneously without treatment, so it is unclear whether the regrowth was specifically caused by biotin supplements.
  • The studies did not assess the participants’ baseline biotin levels to determine whether they were adequate or deficient. Some research suggests that biotin supplements may be most beneficial in people who are deficient in the nutrient; however, there aren’t enough studies that have measured biotin levels before and after supplementation to confirm this conclusion.
  • There are currently no published studies indicating that biotin supplements are beneficial for the growth of normal, healthy hair and nails.

Inconclusive evidence:

Despite inconclusive evidence, biotin supplements are still widely used.

Between 1999 and 2016, the proportion of supplement users nearly tripled.

The United States Food and Drug Administration (FDA) issued a warning in November 2017 in response to reports of biotin supplements interfering with laboratory blood tests, resulting in incorrect results.

Depending on the test, high doses have resulted in either falsely elevated or decreased blood levels.

This has influenced lab results for thyroid-stimulating hormone and vitamin D, as well as troponin, a biomarker for heart attacks.

Case reports of this occurrence showed people taking biotin levels much higher than the AI level (30 micrograms daily or 0.03 mg), but in supplement doses (10-300 mg).

Biotin is frequently found in multivitamins and hair, nail, and skin supplements. The FDA recommends that people inform their doctors about all supplements and doses they are taking at each visit.

Sources of Food:

  • Liver of beef
  • Eggs (cooked) (cooked)
  • Salmon
  • Avocados
  • Pork
  • The sweet potato
  • Nuts and seeds

Toxicity and Deficiency Symptoms


Biotin deficiency is uncommon in the United States, as most people consume enough vit B7 through a varied diet. Alcoholism increases the risk of biotin deficiency.

And other nutrient deficiencies because it inhibits absorption and is also associated with poor dietary intake.

Despite adequate intakes, approximately one-third of pregnant women have a mild vit B7 deficiency, though the exact reason is unknown.

Symptoms of vit B7 deficiency include:

  • Hair thinning
  • Rashes with scaly skin around the eyes, nose, and mouth
  • Nails that are brittle


Even at high doses, there is no evidence ofΒ B7 toxicity in humans. Because it is water-soluble, any excess will be excreted in the urine. Vit B7 has no established upper limit or toxic level.

What Did You Know?

Those who frequently use raw eggs in mayonnaise, Caesar dressing, or eggnog recipes should reconsider.

Avidin, a protein found in raw eggs, can bind to vit B7 and prevent it from being absorbed. Cooked eggs are not a problem because avidin is destroyed by heat.

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