8 Best Biotin Supplements for Hair Growth and Stronger Nails

There are some instances of hereditary biotin deficiencies, and “these can cause severe medical issues and are typically diagnosed in infancy,” says Castilla. “Certain medications can lead to relative biotin deficiencies as well—most commonly anti-seizure medications.”

Does biotin really help hair and nail growth?

Biotin is essential for hair and nail growth, and that simple fact is likely why it’s become such a buzz-worthy beauty supplement. “But the science isn’t as clear-cut,” says Hernandez. “While it can help in specific cases, like brittle nail syndrome or certain types of alopecia, the evidence for its overall benefits is mixed.”

Most people get an adequate amount of this key vitamin through their diets alone, and for healthy people without a biotin deficiency, “supplements are unlikely to grow your hair longer or make your nails stronger, despite the marketing hype,” she says. But for anyone experiencing hair loss or thinning, brittle nails, or similar issues, it’s worth asking your doctor if supplementing with biotin, or any other vitamin, might be the right choice for your body.

How much biotin should you take each day?

Adults need 30 micrograms (mcg) of biotin daily to reach adequate intake, and the average diet provides 35 to 70 mcg, explains Hernandez. This important vitamin is naturally found in a wide variety of foods like eggs, dark leafy greens, fish, avocados, sweet potatoes, legumes, and nuts and seeds.

Most biotin supplements contain at least 2,000 mcg—well over the daily requirement—and some supplements have doses upwards of 10,000 mcg. While these can be beneficial to some individuals, it can be unnecessary for others.

Of course, everyone’s individual needs are different, and it’s important to keep that in mind for anyone considering supplementation, says Lee.

What is the best form of biotin to take?

In general, it’s best to get biotin by eating a well-balanced diet. However, for those who need to supplement for any number of reasons, Hernandez says that magnesium biotinate is the superior choice. “It’s 40 times more soluble than D-biotin; it absorbs better, works faster, and is safe for boosting biotin levels,” she says.

As for powder versus capsules versus gummies, there isn’t any major difference when it comes to absorption, but most nutritionists will recommend opting for a capsule or unflavored powder over gummies, to minimize unnecessary added sugar in your diet.

What are the side effects of taking biotin?

While several studies have found no adverse effects of 10,000 to 50,000 mcg of biotin per day, it’s important to note that biotin supplementation, especially at high doses, can interfere with certain blood work and lab testing. “Most commonly affected tests are thyroid tests and heart attack marker tests. Biotin can interfere with blood marker tests commonly used to diagnose a heart attack, potentially affecting your doctor’s ability to make an accurate diagnosis,” says Castilla.