Vitamin D vs. Biotin: Which Is Better For Hair Loss?

Hair growth starts internally, with happy, healthy follicles. You can slather on all the hydrating hair masks or scalp-stimulating serums you please, but if your body lacks essential nutrients, trust us, your mane will suffer. 

It's why many beauty fans flock toward hair vitamins when dealing with increased shedding. Now, you can find quite a few formulations on the market—from collagen powders to mineral complexes to antioxidant-rich tonics—but one growing debate has recently caught our attention: Which is better for hair growth, vitamin D or biotin?   

Vitamin D is essential for pretty much every bodily function—including, yep, your hair growth. In fact, insufficient levels of vitamin D1 have been linked to hair shedding. Considering clinical vitamin D insufficiency persists in almost half of the population (41%2, to be exact), it may be something to consider if you're dealing with hair loss. 

"Vitamin D3 directly interacts with hair follicles, and when D3 levels aren't optimal, it can decrease the volume of hair on the scalp and throughout the body," certified trichologist and founder of Advanced Trichology William Gaunitz, FWTS, previously told mbg about vitamins for hair growth.

Biotin is perhaps the more well-known player, as it's involved in keratin production3. Research even shows that not getting enough biotin4 can lead to breakage and hair shedding—however, true biotin deficiencies are quite rare. 

Still, your body cannot make its own biotin, so you must ingest it orally. Meat (especially organ meat), fish, eggs, seeds, nuts, and certain vegetables (sweet potatoes, broccoli, and spinach) are top food sources of biotin, while targeted supplements can also provide support. 

Our take: Why not combine them? As we mentioned, biotin works well with complementary nutrients, and vitamin D supports plenty of other functions of your body besides hair growth. Chances are, you'll benefit from getting more vitamin D, anyway.