Vitamins for hair growth are designed to promote new hair growth and strengthen existing follicles after hair loss. They’re often marketed as magic pills that will give your hair volume and a healthy glow. But is that all advertising or do they actually work?

There is truth behind supplementing vitamin deficiencies and hair health. However, the research behind miracle hair growth supplements is lacking. So, depending on why your hair is thinning, hair growth vitamins may be worth the money. Here’s what to know before you buy.

Read more: Best Vitamins for Hair Growth

Do hair growth vitamins work?

The short answer is… it’s complicated. No clinical studies definitively back vitamin supplements that restore hair growth and prevent further loss. A vitamin supplement’s ability to help hair health comes down to what is causing the hair loss. If it’s because of medications you are on or medical conditions, vitamins for hair growth aren’t going to help. Some vitamin supplements for hair growth do help strengthen and restore hair shine, but typically only if your problem is a vitamin deficiency. They will not improve your hair growth if you do not have a vitamin deficiency.

Hair growth vitamins can also contribute to keeping hair healthy. But while they can help with appearance and strength, they won’t give you Rapunzel-like hair. Many of the nutrients in these supplements are related to hair growth (like biotin and vitamins A, C and E). That doesn’t mean that taking these vitamins will make your hair grow back longer and thicker.

What vitamins are good for hair growth?

Unhealthy hair can present in several ways, though the most common characteristics are hair thinning, brittle and weak strands, dullness and lack of growth. The best vitamins for hair growth are chock-full of nutrients like biotin, vitamin C and vitamin E. There are many essential vitamins and minerals that play a role in hair health, including but not limited to:

• Biotin: Vitamin B7, aka biotin, strengthens and maintains the protein structures that make up hair, skin and nails. Many people take this to help their hair grow faster and strengthen existing hair. Biotin is one of the most important vitamins for hair growth. However, it’s not a nutrient you can stockpile. Taking more biotin than your body needs doesn’t amplify the benefits.
• Vitamin A: Vitamin A is essential for keeping your scalp moist and healthy. It also reduces hair breakage. However, you shouldn’t over-supplement vitamin A. Vitamin A is stored in the liver, where the dispersal is tightly controlled. Taking too many floods the transportation system and is associated with hair loss. You can find vitamin A in animal products and leafy greens.
• Vitamin C: Vitamin C has a few ways it helps maintain hair health. First, it’s an antioxidant that neutralizes free radical damage that can block hair growth. (Free radicals are unstable molecules with an uneven number of electrons that can damage other cells.) Vitamin C also aids collagen production and improves iron absorption. Strawberries, peppers and tomatoes are good sources of vitamin C.
• Vitamin D: Low levels of vitamin D have been associated with alopecia, among other conditions. Vitamin D also helps hair follicles regulate growth and shedding. Fatty fish, tuna and orange juice fortified with vitamin D can help you get your recommended dose.
• Vitamin E: Vitamin E is an antioxidant, like vitamin C, which helps prevent oxidative stress by free radicals. Vitamin E is found in avocados, spinach and almonds.
• Iron: An iron deficiency can contribute to hair loss, especially in women. Food sources with iron include meat, seafood, spinach, beans and nuts.
• Omega-3s: Omega-3s keep the cholesterol-derived layer of our skin cells healthy. Maintaining this layer of the skin promotes scalp circulation and prevents hair follicle inflammation. A 2015 study investigating hair loss and omega-3s found that of the participants taking omega-3 and omega-6 supplements, 90% reported less hair loss. Foods rich in omega-3s are fish and seafood.
• Zinc: Alopecia is also associated with a zinc deficiency. Zinc is essential for tissue growth and repair. Zinc cannot be naturally generated in the body and has to be supplemented through your diet. Meat, nuts and beans are excellent sources of zinc.

If you aren’t getting what you need from your diet, whether because of dietary limitations or medical conditions that impact the gastrointestinal tractvitamin supplements can help fill the gaps.

Should you buy hair growth vitamins?

The best vitamins for hair growth aren’t worth the money unless you have a vitamin deficiency. They aren’t a magic capsule key to commercial-ready hair, and they aren’t something you want to take too much of.

In some cases, changes in your lifestyle and diet can help more than vitamins can. Vitamins are supposed to be supplements to your diet, not a replacement. Diet low in calories, fat and protein can contribute to unhealthy hair and hair loss known as telogen effluvium. Don’t worry: Telogen effluvium hair loss is typically reversible once your diet is corrected.

Overall, you’d be better off focusing on what you eat and your lifestyle rather than relying on vitamins for hair growth. Make sure your diet is well-rounded and includes protein, vegetables and healthy fats. Giving your body what it needs to function properly is the best thing you can do for hair growth.

Hair growth vitamins don’t really work for the average person. However, if your hair is brittle or weak due to age or a vitamin deficiency, vitamin supplements for hair growth may help bring some of that natural shine back.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.