In the world of beauty supplements, collagen and biotin are popular players. It makes sense: The protein and vitamin, respectively, can both play key roles in keeping skin, hair, and nails in tip-top shape. While they have different jobs in your body, “collagen and biotin work together synergistically, along with many other nutrients,” says integrative dietitian Robin Foroutan, R.D.N., a spokesperson for the Academy of Nutrition and Dietetics.

Does one—or both—of these nutrients deserve a place in your supplement stack? We asked dermatologists and registered dietitians to give us the full breakdown on biotin and collagen, as well as who might benefit from each.

COLLAGEN

What Is Collagen?

“Collagen is an abundant protein found in bones, muscles, skin, and tendons that forms a scaffold to provide structure and strength,” explains Melissa Levin, M.D., clinical instructor at Mount Sinai Icahn School of Medicine and dermatologist at Marmur Medical in New York. Think of it as a support network in the dermis — the skin layer that helps keep skin resilient and supple, she says. “Collagen is also really important for skin turnover — basically allowing for skin renewal and repair,” adds Foroutan.

How To Add Collagen To Your Diet

Organic and pasture-raised bone broth is a great source of collagen, says Foroutan. It’s otherwise pretty tough to get from food in our modern diet.

“Some dermatologists believe that eating foods that are high in the building blocks of collagen, including amino acids like proline and lysine, and minerals like copper, can help improve your skin,” says Levin. Shellfish, nuts, and red and lean meats are all sources of copper; legumes and lean meats are good sources of lysine; and egg whites, meats, cheese, and soy all contain proline.

Vitamins That Support Collagen

Certain nutrients — like vitamin A (found in sweet potatoes, carrots, and spinach) and vitamin C (found in citrus fruits, bell peppers, and Brussels sprouts) — are thought to support collagen formation and are equally important in your diet, says Levin.

Should You Supplement With Collagen?

“As we age, we produce less collagen, which results loss of elasticity and volume, and the onset of wrinkles,” says Levin. Preliminary studies show the promise of taking bioactive collagen peptides, though more studies are needed, she says. One study published in Skin Pharmacology and Physiology found that 2.5 grams of bioactive collagen peptide daily reduced the appearance in wrinkles around the eyes in women after eight weeks.

The women in the study were between the ages of 45 and 65, suggesting a collagen supplement may be worth considering as you approach middle age.

Just keep in mind, says Levin, that we need further studies to confirm whether collagen supplements are incorporated to form new collagen or just support existing structures.

Many collagen supplements are available in capsule or chewable form, and are recently even being sold in powder form.

If you’re concerned about wrinkles and keeping the structure of your skin strong, collagen may be your MVP nutrient—especially as you age.

BIOTIN

What It Is

Also known as vitamin B7 or vitamin H, biotin is a B vitamin important in fatty acid metabolism and cell growth, says Levin. “It’s become a ‘hot’ vitamin for healthy hair and nails after a study found it improved nail brittleness,” she explains.

The study, published in Cutis, found that 63 percent of participants with brittle nails saw improvement in nail plate thickness after six months of biotin supplementation.

How To Add Biotin To Your Diet

According to Foroutan, biotin is found in egg yolks, almonds, and sweet potato.

Should You Supplement With Biotin?

While Levin doesn’t outwardly suggest biotin supplements for nail or hair problems, she doesn’t discourage them. Even though a body of data is lacking, some patients say they do see an improvement in their health and hair when taking biotin, she says.

While biotin deficiency is usually characterized by brittle hair and nails, we need more research to identify the proper dose for someone with healthy hair and nails, says Levin. Most docs simply suggest 2.5mg daily, she adds.

One caveat to keep in mind: Though there are no studies that demonstrate harm in taking biotin, Levin has seen excess biotin supplementation cause acne flare-ups in patients.

“Both biotin and pantothenic acid (vitamin B5) are absorbed through the same intestinal receptors,” she explains. “If someone takes an excess amount of biotin, the biotin can saturate these receptors and inhibit your B5 absorption. Since B5 plays a role in skin barrier function, hindered absorption may spur worsening acne.

Dealing with tons of hair breakage and weak nails? That’s your signal to talk to your doc about biotin.

If you want to show your skin, hair, and nails some extra TLC, it’s safe to take both collagen and biotin, says Levin, so don’t worry about pulling double duty.