Collagen and biotin are popular supplements for healthy hair, skin, and nails. Collagen is a protein that supports the structure and strength of skin, hair, nails, and other body tissues. Biotin (vitamin B7) is an essential nutrient that helps your body turn food into energy and supports healthy hair and nail growth.

Collagen may be more helpful for improving skin health and reducing signs of aging, while biotin may be best for promoting hair growth. Some people may benefit from taking both.

How They Compare

Collagen and biotin both support healthy hair and skin, but they work in different ways and offer distinct benefits.

Which Is Better?

For Skin Health

Collagen is more directly involved in skin health than biotin, particularly for aging-related concerns.

Collagen levels decline with age, causing skin to lose firmness and moisture. Research shows that taking collagen supplements for 90 days can improve skin elasticity, hydration, and smoothness, effectively reducing the appearance of fine lines and wrinkles.

Biotin supplementation can replenish biotin levels and improve skin health in people with a deficiency, but it may not be as effective for people who are not deficient in the nutrient and get enough biotin from their diet.

For Hair Growth

Biotin may be the better choice if you’re concerned about hair thinning, shedding, or breakage—especially if your diet is low in biotin.

It helps your body produce keratin, the protein that makes up hair, skin, and nails. A lack of biotin can lead to thinning hair or hair loss. Research shows that biotin supplementation can improve hair thickness and promote growth, especially in people with low biotin levels.

While biotin offers more direct support for hair growth, collagen can still be helpful by supplying the nutrients your body needs for overall hair strength and health.

What Does Collagen Do?

Collagen provides structural strength and support to many body tissues, including bones, muscles, skin, hair, and ligaments. It is the main structural protein in humans, making up about 30% of all proteins.

Benefits of collagen include:

• Improves skin elasticity and moisture
• Keeps blood vessel walls strong and provides structural support to internal organs
• Reduces visible signs of aging like wrinkles
• Strengthens nails and reduces brittleness
• Supports bone strength and may help prevent bone loss
• Supports joint health and may reduce pain

Your body produces less collagen as you age, typically declining by about 1% annually starting in early adulthood. Environmental factors like sun exposure, poor diet, and smoking can also reduce collagen levels. Taking a collagen supplement can help replace what your body no longer makes.

What Does Biotin Do?

Biotin is a water-soluble vitamin that helps support many body functions, including converting food into energy and supporting other metabolic processes. The benefits of biotin include:

• Improving nail thickness and reducing brittleness and splitting
• Maintaining normal blood sugar levels
• Promoting healthy cell growth
• Strengthening hair and prevents hair loss
• Supporting healthy skin function
• Supporting the metabolism of fats and carbohydrates

Unlike collagen, your body does not produce biotin. Most people get enough biotin from food, but low levels can lead to symptoms like thinning hair, brittle nails, or dry skin. Certain medications, such as anticonvulsants (anti-seizure drugs), may increase your risk of biotin deficiency.

How to Take Them

Collagen

• Form: Collagen supplements come in several forms: powders, capsules, tablets, gummies, and ready-to-drink liquid formulations. Powders are popular because they dissolve quickly in water, smoothies, and other liquids.
• Dosage: The recommended dose of collagen ranges between 2.5 and 10 grams per day. Taking collagen with vitamin C may increase absorption since the body needs vitamin C for collagen synthesis.
• How often to take it: You can safely take collagen once daily—any time, with or without food—for up to six months.

Biotin

• Form: Biotin supplements are available in tablets, capsules, soft gels, and gummies. Biotin is often included in B-complex vitamins and multivitamins. Some hair, skin, and nail supplements combine biotin with other nutrients like zinc or vitamin C.
• Dosage: The recommended daily intake for adults is 30 micrograms, but supplements often contain much higher amounts. Supplements may contain daily doses ranging from 1,000 to 5,000 micrograms (mcg), equal to 1 to 5 milligrams (mg). While some supplements contain higher amounts, lower doses of 2.5 mg daily are more common.
• How often to take it: Biotin is safe for most people when used in doses of up to 300 mg daily for up to six months, but such high doses are rarely needed. You can take biotin at any time of day; consistent daily use is most important for seeing results, which typically appear after three to six months.

Taking Them Together

You can take collagen and biotin supplements together. In fact, some supplements combine biotin and collage into one product. Because collagen and biotin offer distinct benefits, combining them may offer more complete support for hair and skin health.

Before starting any supplement, read the label carefully and talk with a healthcare provider if you have any health conditions or take medications to ensure you can safely take the supplement.

Side Effects

Collagen and biotin are generally safe for most people when taken as directed.

Collagen may cause minor side effects in some people, such as:

• Bad taste in the mouth
• Diarrhea
• Dizziness
• Headache
• Skin rash
• Trouble sleeping
• Upset stomach or indigestion

People with fish allergies should avoid marine (fish) collagen supplements. These supplements may trigger allergic reactions, such as anaphylaxis, a severe, even life-threatening reaction to a substance.

Biotin is not known to cause side effects in most people, even when taken in large amounts. It’s a water-soluble vitamin, so excess amounts are usually passed through the urine. However, very high doses of biotin can interfere with lab tests, including blood tests for thyroid function, heart health, and hormone levels. If you are taking a biotin supplement, inform your provider before getting lab work to avoid incorrect results.

Food Sources

Collagen

Your body can make collagen from protein-rich foods, such as:

• Bone broth
• Chicken with skin
• Citrus fruits (for vitamin C, which the body needs for collagen synthesis)
• Egg whites
• Fish with skin
• Gelatin
• Leafy green vegetables

Biotin

Many fresh, whole foods contain biotin, including:

• Bananas
• Dairy foods, including cheese and milk
• Eggs
• Fish
• Meats, especially liver, and other organ meats
• Nuts and seeds (almonds, peanuts, walnuts)
• Sweet potatoes

Summary

Collagen and biotin can support skin and hair health, but they work in different ways and offer complementary benefits. If your main goal is to improve skin firmness or reduce signs of aging, collagen may be the better choice. If you are dealing with hair thinning or loss, biotin may help—but only if you are not getting enough biotin from food. You can safely take both. A healthy diet with collagen- and biotin-rich foods can also improve skin and hair health.