Many supplements market themselves as the best for hair growth. But do any of them work?
Research into the benefits of supplements for hair growth has produced mixed results. Nutrition as a whole is vital for hair growth. However, supplements containing specific vitamins and minerals may be warranted in some cases to correct nutrient deficiencies associated with hair loss.
This article discusses how much zinc you need daily for hair growth and whether supplements may be suitable.
Zinc for hair growth
Supplement use should be individualized and supervised by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or health care provider. No supplement is intended to treat, cure, or prevent disease.
Zinc is a mineral that the body needs in small amounts (micronutrients). Zinc helps with immune function, cell renewal and wound healing.
Zinc helps keep hair healthy by supporting the hair follicle cycle. Hair loss (alopecia) is a symptom of low zinc levels, and some research suggests that zinc supplementation may promote hair regrowth in people with hair loss. Zinc supplements can reduce hair loss by bringing low nutrient levels within the normal range. However, not all research supports this.
There is some evidence to support 50 milligram (mg) zinc supplements to reduce hair loss. A study in women with hair loss found that 50 mg of zinc per day improved hair thickness.
In another study of women with normal zinc levels and polycystic ovary syndrome (PCOS), less hair loss was observed in women who consumed a 50 mg zinc supplement daily for eight weeks than in those who took a placebo (an ineffective substance given to a control group). ). Hair loss can be a side effect of PCOS.
Ultimately, there is not enough information to support supplementing with zinc to prevent or reverse hair loss in people without low levels or underlying health conditions related to zinc status.
Hair from comb in hand.
burakkarademir / Getty Images
Power supply
The average daily amount of zinc needed to meet the nutritional needs of most healthy adults (recommended dietary allowance, or RDA) includes the following:
Zinc can be obtained through diet. It occurs naturally in meat, fish and seafood and is added to many breakfast cereals. Foods that contain the most zinc include:
- Oysters: 32 mg per 3 ounces
- Beef: 3.8 mg per 3 ounces
- Cereal and oats: 2.3 mg per cup
- Pumpkin seeds: 2.2 mg per ounce
You only absorb between 5% and 50% of the zinc from food. This amount may vary depending on the food source of zinc and the meal composition.
Plant foods contain less zinc than their animal counterparts. In addition, certain substances found in plants (phytates) influence zinc absorption. So it may be more challenging to absorb zinc on a plant-based diet.
Zinc deficiency is less common in the United States because most people meet their needs through food or supplements. Insufficient zinc levels are more common in low- and middle-income countries.
Safety
It’s possible that a zinc supplement could do more harm than good, especially if you take too much. Always consult a healthcare provider before starting any new supplement.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Precautionary measures
Avoid zinc if you are allergic to zinc or its components. Get medical help right away if you have a severe allergic reaction (itching, hives, shortness of breath).
People with Wilson’s disease (hepatolenticular degeneration, a condition of excess copper) should consult a doctor before starting zinc supplements.
- The Food and Nutrition Board (FNB) of the Institute of Medicine (IOM) has approved the acceptable upper intake limit for zinc 40mg per day for any adult, including those who are pregnant or breastfeeding
The Tolerable Upper Limit (UL) reflects the maximum daily amount a person can ingest without risk of adverse health effects for most individuals.
The FNB does not recommend using doses of 50 mg zinc or more for a longer period of time. Excessive zinc can affect copper absorption and reduce immune function.
Side effects
Too much zinc can cause adverse effects. While it is difficult to exceed recommendations through diet alone, toxicity is possible with zinc supplements.
Side effects include:
Long-term side effects, such as decreased immune function, are also possible.
Excessive zinc supplementation can also affect the absorption of other essential micronutrients such as copper and iron.
Interactions
Zinc can interact with certain medications, and medications can affect zinc levels. These medications include the following:
- Antibiotics: Antibiotics treat or prevent bacterial infections. Some antibiotics can interact with zinc supplements in the digestive tract, affecting the absorption of both medications.
- Cuprimine (penicillamine): Penicillamine removes large amounts of heavy metals from the body. It can treat rheumatoid arthritis and Wilson’s disease, a condition in which copper levels in the body are too high. Zinc supplements may decrease the absorption and effect of penicillamine. Taking zinc and penicillamine at least one hour apart may reduce this interaction.
- Diuretics: Diuretics prevent the accumulation of excess fluid and help remove it from the body. Specific types of diuretics can promote the removal of zinc through the urine, contributing to lower nutrient levels.
It is essential to read a supplement’s ingredient list and nutritional information panel carefully to know what ingredients it contains and how much of each ingredient it contains. Discuss the supplement label with your healthcare provider to discuss possible interactions with foods, other supplements, and medications.
Similar supplements
Other nutrients contribute to healthy hair. However, limited research supports using these supplements for hair growth only if you are not deficient in these nutrients.
Egg white
Hair consists mainly of proteins. Not eating enough protein can contribute to hair loss.
It is unclear whether supplementation with a specific amino acid (protein molecule) can improve hair loss. Much research on amino acids also includes other nutrients, so it is difficult to draw a clear link between individual amino acids and hair loss.
The RDA for protein is at least 0.8 grams (g) of protein per kilogram (kg) of body weight (g/kg). However, some individuals may need more protein.
Protein-rich foods include the following:
- Animal meat
- Seafood
- Dairy
- Tofu
- Tempeh
- Legumes
Iron
Hair loss is associated with iron levels. Hair cells are among the most active in the body and require sufficient iron to function properly. However, there isn’t much evidence to support the benefits of iron supplements for hair growth without low iron levels.
The FNB of the IOM of the National Academies recommends the following daily iron intake in adults:
- 8mg for men
- 18 mg for women aged 19 to 50
- 8 mg for women over 51 years of age
- 27 mg for people who are pregnant
- 9 mg for people who are breastfeeding
Food sources of iron include lean meats, seafood and fortified grains and grains.
Omega-3 fatty acids
A deficiency of omega-3 fatty acids has been linked to hair and eyebrow loss. A randomized controlled trial of women with hair loss found that a supplement containing 460 mg of fish oil (a source of omega-3 fatty acids) reduced hair loss and improved hair thickness. But the supplement also contained antioxidants, which fish oil is weak in, and the added antioxidants may have contributed to the favorable results.
There is no set recommended dietary level for omega-3 fatty acids. However, it is recommended that adults consume the following amounts of omega-3 fatty acids daily to ensure dietary adequacy:
- 1.6g for men
- 1.1 g for females
- 1.4 g for people who are pregnant
- 1.3 g for breastfeeding people
Foods rich in omega-3 fatty acids include:
Resume
If you are concerned about hair loss, contact a healthcare provider to determine the underlying cause.
A healthy diet with sufficient nutrients and proteins provides the best support for hair growth. Sometimes a nutrient deficiency can contribute to hair loss. If you have low zinc or iron levels, taking a supplement can help restore nutrient levels and promote hair growth. But if your levels of these minerals are already within the normal range, a supplement likely won’t support hair growth or prevent hair loss.
Taking zinc when it is not necessary can cause more harm than good, contributing to unwanted side effects and affecting the absorption of other minerals essential to health.