The best supplements for hair growth are those that support your body’s natural renewal systems from the inside out. Vitamin D, iron and vitamin C are the most evidence-backed nutrients for healthier hair; vitamin D helps create new follicles, iron supports oxygen delivery to the scalp and vitamin C boosts collagen production while improving iron absorption. Other key nutrients like zinc, biotin and vitamin E also contribute to healthy growth. A balanced diet should cover most needs but supplements can help fill the gaps, especially if you’re low in specific vitamins or minerals.

Both biotin and vitamin B12 play vital roles in supporting healthy hair but they work in different ways. Biotin helps strengthen hair by supporting keratin production, the protein that makes up each strand, while B12 fuels cell growth and boosts oxygen delivery to the scalp through red blood cell production.

Biotin can support hair regrowth only if you’re deficient, which is rare. Low biotin levels can cause thinning hair, brittle nails and dry skin, and correcting that deficiency can help restore healthy growth. If you're following restrictive diets like keto, make sure you’re still getting enough biotin to keep your hair strong.