Hair loss is a normal part of life. We shed anywhere from 50 to 100 hairs a day, and shifts in seasons, cortisol levels, or even diet can temporarily bump that number higher. But when shedding feels excessive or persistent, it may be time to dig deeper—starting with your body’s nutritional health.
“Hair loss can signal an underlying issue, such as a vitamin or mineral deficiency,” says Anabel Kingsley, consultant trichologist and brand president at Philip Kingsley. “Hair is incredibly sensitive because it’s nonessential tissue. When your body lacks nutrients, hair is often the first thing to suffer.”
If you’re worried about thinning or heavy shedding, a blood test ordered by your doctor is key. One of the most frequent—and fixable—culprits? Vitamin deficiency.
The upside: Correcting those deficits through diet or supplements often makes a noticeable difference. Below, Kingsley and Margo Gkini, MD, consultant dermatologist and hair loss expert, break down the vitamins most closely linked to hair health—and how to bring them back into balance.
Which vitamin deficiency causes hair loss?
“Everyone’s nutritional needs vary by age, sex, diet, and activity level,” Kingsley explains. “That said, iron, vitamin B12, zinc, vitamin D, and biotin are widely recognized as pillars of healthy hair.” Here’s what to know about each:
Iron and Ferritin (Stored Iron)
“Iron and ferritin deficiency are among the most common causes of excessive daily shedding in women,” Kingsley says. Iron helps produce red blood cells, which ferry oxygen—including to your hair follicles.
Low ferritin is a frequent trigger for Telogen Effluvium, especially in people who menstruate or follow vegetarian or vegan diets. Symptoms can include fatigue, pallor, and—of course—hair loss.
“Supplementation may help, whether through dietary tweaks or oral iron taken for three to six months,” Dr. Gkini notes. “In severe cases, iron injections deliver faster results.” Discuss testing and options with your doctor.
Vitamin B12
“Vitamin B12 metabolizes amino acids—the building blocks of hair—and keeps red blood cells healthy,” Kingsley says. Because B12 comes primarily from animal sources, vegetarians and vegans must monitor their intake. Deficiency can cause thinning, fatigue, and neurological symptoms.
Biotin
Often called “the hair vitamin,” biotin helps convert proteins, fats, and carbs into energy—vital for hair cells, which divide rapidly. Kingsley stresses, however, that true biotin deficiency is rare: “A standalone biotin pill won’t stop shedding unless the loss is directly tied to a biotin shortfall.” A balanced, multi-nutrient supplement is usually more effective.
Zinc
“Zinc deficiency can leave hair weak and brittle,” Kingsley warns. Dr. Gkini adds that zinc supports several follicle functions, potentially preventing regression and speeding recovery. Load up on zinc-rich foods like nuts, seeds, and whole grains.
Vitamin D
Known as the sunshine vitamin, vitamin D is crucial for follicle health. Low levels can disrupt the growth cycle, causing more strands to enter the shedding phase. Regular outdoor time and fortified foods help maintain optimal levels.
Do vitamin supplements help with hair loss?
Supplements can be part of the solution, but both experts emphasize pinpointing the root cause first. “Start with a well-formulated base supplement, then add extras if needed,” Kingsley advises. She cites Philip Kingsley Density Healthy Hair Complex as an example, noting the formula reflects the deficiencies most often seen in the brand’s London and New York clinics. You should always talk to your doctor before starting any new supplements.
Still, moderation matters. “Re-test your levels after three months,” she says. “If your hair loss isn’t nutrient-related, piling on vitamins won’t help.”
The bottom line: Supplements can bolster hair health, but a diet rich in protein, vegetables, and whole grains is just as critical—and often enhances nutrient absorption. For persistent or alarming hair loss, consult a healthcare professional to find the most effective, personalized plan.
