Hair Loss

Supplements for Hair Growth: What Works Best?

Hair loss and thinning hair is a common condition that affects both men and women. While there are many medical treatments available, some people prefer to try dietary supplements first. Certain vitamins, minerals and other compounds may support hair growth when taken as supplements.

This article reviews the evidence behind the best hair growth vitamins and supplements, including:

• Biotin
• Vitamin D
• Iron
• Zinc
• Protein
• Omega-3 fatty acids
• Saw palmetto
• Collagen

We’ll also discuss factors that contribute to hair loss, dosages for hair growth, and safety considerations.

What Causes Hair Loss and Thinning?

Before exploring supplements, it helps to understand what causes hair loss and thinning in the first place.

Some key factors include:

• Hormonal changes - Fluctuations in androgens like testosterone and DHT are linked to patterned hair loss in both men (male pattern baldness) and women. Conditions like polycystic ovarian syndrome (PCOS) may also trigger hair loss.
• Nutritional deficiencies - Low intake or absorption of iron, zinc, biotin, vitamin D and protein can affect hair health. Deficiencies may be due to low dietary intake, malabsorption issues or other conditions.
• Medications - Hair loss is a common side effect of medications like blood thinners, antidepressants, NSAIDs, birth control pills and high-dose vitamin A supplements. Chemotherapy medications are also notorious for causing temporary hair loss.
• Autoimmune disorders - Conditions like alopecia areata cause patchy hair loss when the immune system mistakenly attacks hair follicles. Thyroid disorders may also cause hair loss.
• Ageing and genetics - Hormonal changes from ageing and genetic predisposition are factors in female and male pattern hair loss. Age-related thinning usually starts around 40-50 years old.

While you can’t change your age or genetics, some supplements may help counteract nutrient deficiencies, hormonal issues and other triggers for hair loss.

8 Best Supplements for Hair Growth

Certain vitamins, minerals and compounds show potential to support hair growth and reduce shedding. Let's explore the top evidence-based options:

1. Biotin

Biotin is a B-complex vitamin involved in amino acid metabolism. It’s required for making keratin, a structural protein found in hair and nails.

Biotin deficiency is rare, but may cause brittle hair and hair loss. Biotin supplements are often marketed for “hair, skin and nails.”

Studies on biotin for hair growth show mixed results:

• A 90-day study in adult women with thinning hair found that biotin supplements increased hair volume and improved hair growth (1).
• However, two other studies found biotin was no better than a placebo for hair loss in women (2, 3).

For people without a deficiency, biotin is unlikely to improve hair more than a healthy diet. But a moderate dose may help those with a true deficiency.

Suggested dose: 2.5-5 mg per day

2. Vitamin D

Vitamin D helps regulate calcium absorption and supports immunity. Getting enough vitamin D is also crucial for the hair growth cycle.

Deficiencies are common, especially during fall and winter when daylight is limited. Low vitamin D levels are linked to alopecia areata and female pattern hair loss.

In one study, vitamin D supplementation improved hair loss in women with thinning hair. Other studies show mixed results, likely because many participants had adequate vitamin D already.

Testing vitamin D levels through a blood screening can confirm a clinical deficiency. If levels are low, try supplementing with vitamin D3.

Suggested dose: 2000-4000 IU vitamin D3 per day

3. Iron

Iron carries oxygen in the blood to tissues and cells. Low iron levels may impair oxygen delivery to hair follicles, damaging the follicles and causing shedding.

Iron deficiency is a common cause of hair loss in premenopausal women. Supplementing with iron reduces hair loss for those with confirmed iron-deficiency anaemia.

Too much iron can also cause issues. Get your levels tested before supplementing.

Suggested dose: As recommended by your healthcare provider based on lab testing.

4. Zinc

Zinc is needed for cell division and protein synthesis during hair growth. Deficiencies are uncommon, but zinc supplements may help for those with a confirmed deficiency.

Studies show mixed evidence on zinc and hair loss:

• In one study, zinc supplements reduced hair shedding in women with alopecia areata.
• However, other research shows zinc is no better than placebo for female pattern hair loss.

Zinc may also boost the effects of topical minoxidil treatment (Rogaine) when used together.

Suggested dose: 8-14 mg per day

5. Protein

Getting adequate protein is crucial for hair health, since hair follicles are made of keratin protein.

Severe protein deficiency from restrictive dieting or malnutrition can trigger excessive hair shedding . Some research suggests increasing protein intake may help reduce hair loss.

Suggested intake: 0.8-1 gram of protein per pound of body weight daily.

6. Omega-3 Fatty Acids

Omega-3s from fish oil and flaxseed may have anti-inflammatory effects that support hair growth.

One rat study found omega-3s improved hair growth by boosting follicle proliferation and keratin expression (16). Fish oil also reduced hair loss in women with patchy alopecia areata.

Getting omega-3s from whole foods like salmon, walnuts and chia seeds is ideal. Fish oil (1000-2000 mg EPA/DHA) or flaxseed oil supplements may also help.

Suggested dose: 500-1000 mg fish oil 2-3 times per day OR 1 tbsp flaxseed oil

7. Saw Palmetto

Saw palmetto is an herbal extract often used to treat prostate enlargement. It works by reducing levels of DHT, a hormone linked to male pattern baldness (18).

There’s limited quality evidence on saw palmetto for hair loss. Some small studies show positive effects, while others show saw palmetto is no better than placebo (19, 20).

Saw palmetto appears safe for healthy adults when taken at recommended doses. But there aren’t enough studies to confirm its effectiveness.

Suggested dose: 320 mg per day standardised to 85-95% fatty acids

8. Collagen Supplements

Collagen is the most abundant protein in hair. It provides structure to strands and strengthens hair.

Some small studies suggest collagen supplements may improve skin and hair health. But large-scale studies are still lacking (21).

Collagen peptides are safe for most people and may help support overall hair strength. But the evidence is still limited compared to other supplements.

Suggested dose: 2.5–15 grams per day of collagen peptides

In summary, biotin, vitamin D, iron and zinc have the strongest evidence for deficient individuals. Omega-3s and protein are beneficial for overall hair health. Saw palmetto and collagen show potential but need more research.

It’s best to get a lab test to check for any vitamin or mineral deficiencies before supplementing. For overall health, focus on getting nutrients from a balanced diet first before trying supplements.

Supplements for Different Types of Hair Loss

Certain supplements may be more beneficial depending on the type of hair loss:

• Female/male pattern hair loss - Saw palmetto and vitamin D show the most potential. Iron and zinc may help those with deficiencies.
• Alopecia areata - Vitamin D, zinc, and omega-3s may reduce hair shedding.
• Telogen effluvium/shedding - Iron, biotin, zinc, and protein help address common deficiencies and triggers.
• Breakage and thinning - Protein, omega-3s, iron, collagen and biotin strengthen hair and reduce breakage.

Talk to your dermatologist to identify the type of hair loss and rule out underlying conditions. Then determine which supplements may be most helpful for your specific case.

Supplements for Hair Growth Dosages

The table below summarises the standard daily dosages for each hair supplement:

Supplement	Suggested Dosage	Upper Limit
Biotin	2.5 - 5 mg	10,000 mcg (10 mg)
Vitamin D	2,000 - 4,000 IU	4,000 IU
Iron	As recommended by doctor	45 mg
Zinc	8 - 14 mg	40 mg
Protein	0.8 - 1 g per lb of body weight	Varies
Omega-3s	500 - 1000 mg EPA/DHA OR 1 tbsp flaxseed oil	3000 mg EPA/DHA
Saw Palmetto	320 mg (standardised extract)	Not determined
Collagen Peptides	2.5 - 15 g	Varies

Follow dosage instructions carefully and avoid exceeding the Upper Limit, especially for iron and zinc. Taking too much may cause adverse effects.

For omega-3s, it’s ideal to get 250-500 mg combined EPA/DHA per day from food sources like salmon. Supplements can help provide the higher end of the dosage range.

Work with a healthcare professional to determine the optimal dosage for your individual hair needs. More is not always better when it comes to supplements.

Safety and Side Effects

Supplements are not strictly regulated. Purchase quality brands following cGMP standards for safety and purity.

Avoid supplements with additives, artificial colours or unnecessary fillers. Herbal supplements may have drug interactions, so review them with your doctor.

When taken at suggested doses, the supplements above are generally well tolerated and safe for most people. However, possible side effects include:

• Biotin - Rarely, high doses may interfere with thyroid lab test results. Reduce dose at least 2 days before testing.
• Vitamin D - High doses may cause hypercalcaemia with symptoms like nausea, vomiting, weakness.
• Iron - Constipation, stomach upset, darker stools. Interacts with some medications.
• Zinc - Nausea, metallic taste, diarrhoea. Interacts with antibiotics like quinolones.
• Saw palmetto - Headache, dizziness, nausea. May interact with hormonal medications.
• Omega-3s - Fishy aftertaste, gastrointestinal symptoms. Bleeding risk at high doses.

Stop taking any supplement causing severe side effects or allergic reactions. Avoid supplements if pregnant or breastfeeding unless cleared by your OB-GYN.

And remember, dietary supplements should never replace medical treatments prescribed by your doctor.

FAQ

What are the signs of healthy hair growth?

Signs of healthy hair growth include hair that is shiny, strong, smooth to the touch and bounces back when pulled. Increased hair density, reduced splitting ends and faster growth rate (normal is 1/2 inch per month) also indicate healthy hair.

How can I tell if my hair loss is temporary or permanent?

Temporary hair loss usually reverses within 6-12 months, while permanent hair loss is progressive without regrowth. Check if hair loss follows a pattern (receding hairline, diffuse thinning). See a dermatologist who can diagnose the type of hair loss through exams and sometimes a scalp biopsy.

Do hair supplements interact with medications?

Some hair supplements like saw palmetto and omega-3s may interact with blood thinners, birth control pills and other medications. Always check with your doctor before taking supplements, especially if you are on regular prescriptions. Stop supplements 2 weeks before any surgery.

What lifestyle factors help with hair growth?

Good sleep, stress management, exercise, not smoking, staying hydrated, eating nutritious whole foods, and limiting damaging styles like tight ponytails help create the optimal environment for hair growth. Address lifestyle factors along with taking supplements.

When should I see a doctor for hair loss?

See your doctor or dermatologist if hair loss persists beyond 6 months, is sudden or severe, or is accompanied by itching, pain or other symptoms. A proper diagnosis is key before trying supplements and treatments.