Your Pregnancy Matters

Biotin and lab tests: Beauty supplement poses risks for pregnant women

Your Pregnancy Matters

Missing that pregnancy "glow"? Think twice before taking biotin beauty supplements – the risks may outweigh the benefits.

Biotin, also known as vitamin B7, is found in many beauty supplements that are marketed as hair, skin, and nail enhancers. But biotin – also known as vitamin B7 – can cause serious errors in medical test results.

In the past two decades, the percentage of adults taking biotin supplements has significantly increased. In 1999, just 0.1% of all adults took 1 mg/day of biotin. By 2016, consumer totals rose to 2.8%. Women tend to take even more biotin – one in 20 (4.7%) reported taking the supplement in a 2020 study.

In 2019, the U.S. Food and Drug Administration (FDA) issued an updated advisory about interference between biotin supplementation and common blood tests. High levels of biotin in a patient's blood or urine samples can cause significantly incorrect lab test results. This can lead to incorrect diagnoses and improper treatment of conditions, such as ectopic pregnancy, miscarriage, or heart and thyroid issues.

How much biotin is safe?

The Institutes of Medicine recommends a daily biotin allowance of 30 mcg (0.03 mg) for most adults. Unfortunately, supplement labeling is not strictly regulated, and your product may include more B7 than you might think.

Many products offer mega-doses, with some touting 10,000 mcg (10 mg) or higher. That's more than 300 times the recommended allowance. If you're also taking a general multivitamin, you may be getting an even higher daily dose.

How biotin interferes with lab testing

Some lab assays use biotin during the testing process. Increased biotin from a patient’s blood sample can bond to specific proteins during the testing process, leading to inaccurately high or low test results.

3 lab tests women should know about (and how biotin affects them)

1) b human chorionic gonadotropin (hCG): That’s right, the pregnancy hormone. Having a high level of hCG can be an early indicator of pregnancy. We also test for hCG levels to determine whether a patient might be experiencing an ectopic pregnancy or miscarriage.

Biotin supplements can cause false low levels in blood tests. That means you may be pregnant or experiencing an ectopic pregnancy or miscarriage and might not know it. In urine tests, high levels of biotin may prevent the control line on your home pregnancy test from appearing, yielding invalid results.

2) Thyroid stimulating hormone (TSH): Thyroid dysfunction is common – 1 in 8 women has a thyroid problem. To diagnose new thyroid disease or assess an existing condition, we measure TSH levels. Too high and you may have hypothyroidism. Too low, you may have hyperthyroidism. Taking too much biotin can cause false low levels of TSH, which may prompt unnecessary treatment that can lead to actual thyroid issues.

Related reading: What women need to know about thyroid conditions

3) Troponin: Troponins are proteins found in muscles, including the heart. Elevations of certain troponins aid in the diagnosis of heart attacks. However, biotin supplementation can lead to falsely low troponin levels, which can delay diagnosis. This is especially alarming for female patients, since heart attack symptoms in women may be more subtle.

Missed heart attack diagnoses carry the risk of potentially serious clinical implications. The FDA has received a report that one patient taking high levels of biotin died following falsely low troponin test results.

Lab tests that involve the protein ferritin or these hormones listed here can also be skewed by biotin supplementation:

  • Cortisol
  • Estrogen
  • Progesterone
  • Testosterone

Rather than taking straight B7 or a "beauty supplement," consider continuing with your prenatal vitamin instead. The standard prenatal vitamin has everything women need for daily health – plus, you'll get a safe level of biotin to help restore your glow.

Robyn Horsager-Boeher, M.D.

Suggestions for healthy hair, skin, and nails

Some hair loss after pregnancy is normal and inevitable. But there are a few things you can do to take care of your appearance post-baby.

Rather than taking straight B7 or a "beauty supplement," consider continuing with your prenatal vitamin instead. The standard prenatal vitamin has everything women need for daily health – plus, you'll get a safe level of biotin to help restore your glow.

If you have long hair, try soft scrunchies or clips to hold up your hair instead of elastics. Less breakage leads to better-looking, more supple hair. And try to avoid blow-drying, flat-ironing, or curling your hair for a few weeks as your body adjusts – heat damage can increase hair loss. With a new baby and the COVID-19 pandemic going on, you may find yourself going more casual anyway!

You might want to invest in a thick lotion for your skin and nails. As a new mom – particularly during the pandemic – you're going to be washing your hands a lot. A good lotion can help soothe dry skin and reduce cuticle and nail damage.

And, as always, eat a healthy diet. Biotin is just one of many vitamins that support overall health and wellness – and a radiant appearance.

Related reading: Quarantine cuisine: Easy meals to support a healthy immune system

Protect yourself from biotin interference

If you've been taking biotin, talk with your provider. If they know you'll need certain labs, they might recommend you take less biotin for a while leading up to the test.


  1. Make sure you are aware of the ingredients in any supplement you are taking.
  2. Watch out for duplication of certain vitamins if you are taking more than one supplement. A doctor or pharmacist can help you compare.
  3. If you take biotin, add it to your current medication list.
  4. If possible, review copies of your lab results personally. Many labs now indicate whether a certain test may be affected by biotin supplementation.

If you're concerned about your biotin levels or recent lab work, talk with your doctor. We can help you come up with safe, healthy ways to look and feel your best without risking your health.

To visit with an Ob/Gyn, call 214-645-8300 or request an appointment online.