Biotin vs. Collagen: What’s the Difference?

Take a walk down your pharmacy’s supplement aisle, and you’ll see hundreds of products aiming to do everything from boost muscle growth and regulate hormones to improve brainpower, reduce inflammation, and make you an overall healthier person. Among those so-called wonder pills are ones touting biotin and collagen to improve your skin and nails.

You may be wondering about the difference between the two and whether you should be taking them alone, together, or at all. Here, two experts break it down.

(Related: What You Need to Know Before Taking Biotin Supplements)

What is biotin, and what are its benefits?

Biotin sounds fancy, but it’s really just another term for vitamin B7. According to Rajani Katta, MD, a Houston-based dermatologist and author of Glow: The Dermatologist’s Guide to a Whole Foods Younger Skin Diet, people who take certain antiepileptic medications may develop a biotin deficiency. Eating a lot of raw eggs can also cause a biotin deficiency because avidin, a protein found in raw egg whites, binds to biotin, so it isn’t absorbed by the body. “There are genetic causes of biotin deficiencies, and this can lead to hair loss; red, flaky rashes on the skin; and brittle nails,” she says. “Other factors that might lead to lower levels of biotin are smoking, excessive alcohol intake, and pregnancy.”

Because biotin can be produced by bacteria in the intestines, some people who have conditions that affect the bacteria in their intestines may also develop a deficiency, Dr. Katta says. Inflammatory bowel disease, small intestinal bacterial overgrowth, and other conditions might affect the balance of microbes in the intestines and thus may increase your risk of biotin deficiency.

The fact that biotin deficiencies often lead to hair loss, skin rashes, and other problems may be why manufacturers began adding it to skin, hair, and nail supplements, says Dr. Katta. “However—and this is a really important point—in the years since, we just haven’t had strong evidence that biotin can help strengthen skin, hair, or nails in the absence of a deficiency,” she says. If you are deficient, you can get more biotin through the diet. Dr. Katta recommends increasing your intake of biotin-rich foods, including egg yolks, nuts and seeds, and sweet potatoes, as well as salmon, lean meat, and organ meats such as liver.

(Related: 7 Hacks for Strong and Healthy Nails)

Should you take a biotin supplement for better hair?

There is little evidence that supplementing biotin can help if you don’t have a deficiency, says Dr. Katta. Unless you are deficient, she does not recommend taking extra biotin. “There have been a few very small studies indicating improvement in brittle nails, but, importantly, we do not know these patients’ baseline biotin status, and the studies did not include a placebo group,” she says. All of that indicates the study wasn’t super high quality.

It’s also important to be mindful of potential side effects, the biggest one being that large doses of supplemental biotin can interfere with medical lab tests, such as tests for thyroid values and tests for heart attacks, Dr. Katta says. “Apart from that, extra biotin does not seem to cause side effects in most people, although some people have reported digestive upset,” she says. “However, we also don’t understand exactly how large doses affect insulin function and blood sugar levels in different people, so that is an area that definitely needs further research.”

(Related: What to Know About Liquid Collagen and Its Potential Benefits)

What is collagen, and what benefits does it offer?

You’ve probably heard of collagen. It’s the protein responsible for cushioning your joints, plumping your skin, and giving you stronger bones, hair, and nails—and more. Here’s how it works: When you eat, your body breaks down the protein in your food into amino acids. These are the building blocks of protein, and when combined with vitamin C, copper, and zinc, they create collagen. You’ll find it in your body’s connective tissue and its extracellular matrix—essentially a network that gives structural support to tissues.

Most collagen in the body is type I, II, and III. “Type I collagen is present in most connective tissues with bone, ligaments, tendon, and skin,” says Amy Gorin, a registered dietitian nutritionist and owner of Plant-Based Eats in Stamford, Connecticut. “Type II collagen is found mostly in cartilage, and type III collagen is found in the skin, lungs, the walls of blood vessels, and intestinal walls.” Food sources of collagen include bone broth and meat that contains connective tissue, Gorin says. You can also buy collagen supplements—pills, powders, even collagen-containing foods—in stores.

So, why the sudden influx of collagen supplements? “Collagen is a very important structural protein that helps provide scaffolding and support to your skin, and as you age, your collagen starts to break down and your body doesn’t produce it at the same rate,” Dr. Katta says. “This is one of the reasons that manufacturers started putting it in supplements—there’s a hope that if you eat it, your body can use it to make new collagen.”

(Related: 12 Collagen Supplements and Where to Buy Them in Canada)

Should you take a collagen supplement for better skin?

We know all of the great things our natural collagen does, but it’s not clear whether supplemental collagen will have the same benefits. Research is still preliminary. One big unknown is whether your body would use protein’s amino acid building blocks to specifically make new skin collagen. “Some of those building blocks do seem to make their way to the skin, but it’s hard to say if consuming them in the form of a supplement is any better than consuming them from foods,” Dr. Katta says.

Other researchers have looked at collagen supplements from another angle, asking whether the skin looks better after taking collagen supplements, Dr. Katta says. “With the research that’s been done so far, they all raise more questions in my mind,” she says. “Many of the research studies have been sponsored by the manufacturer or have lacked a placebo group, which is just not ideal.” Take, for instance, a study published in 2018 in Nutrition Research. Researchers found that collagen supplementation may be helpful for skin elasticity. Big caveat: the researchers work for a company that makes collagen supplements.

Some studies have used a placebo group, but they haven’t looked at wrinkles, Dr. Katta says. Instead, they’ve looked at other outcomes, such as skin moisture levels. Because there are foods that may achieve the same benefit, researchers don’t have enough evidence to say that supplements could provide any benefit. After all, you may already get everything you need from your diet. “A common issue is that when my patients ask me about supplements, they’re hoping that it will help with skin wrinkling, not just skin moisture,” Dr. Katta says. “Of the collagen research done, hardly any has looked at wrinkling.”

Considering the limited research, is it worth it to shell out money for collagen supplements? “I tell my patients that when it comes to collagen supplements, their guess is as good as mine,” D. Katta says. “The research that has been done hasn’t been that strong.” Although animal collagen products may provide amino acid building blocks that your body can use to create new proteins, Dr. Katta prefers to get those amino acids from high-quality food sources. Chicken, beef, fish, and eggs are all great sources.

(Related: Does Vegan Collagen Powder Really Work?)

Are collagen supplements safe?

A common misconception Dr. Katta encounters with her patients is that they believe collagen supplements aren’t harmful at all. They think there’s no harm in taking them, even if they don’t actually work. “I tell my patients that that’s not true: some supplements can be risky,” she says. “There is no FDA [Food and Drug Administration] approval needed for supplements, and there’s no required quality control.”

In fact, the independent lab ConsumerLab, tested 15 different collagen supplements and found that one was contaminated with the heavy metal cadmium. Heavy metals such as lead, mercury, arsenic, and cadmium are concerning because they can cause serious health effects.

“Many of my patients are really careful when they consume seafood, seeking out only low-mercury fish, but they often don’t realize that there’s limited oversight of the supplement industry,” Dr. Katta says. “In fact, many collagen supplements don’t even disclose which animals they use to source their collagen, let alone how they’re ensuring the quality of those sources.”

Should you use topical biotin and collagen products?

Biotin and collagen aren’t just sold as pills and powders. You’ve probably even come across shampoo, conditioner, and other hair products touting biotin and collagen as their active ingredients to promote long, thick, and voluminous hair.

Don’t be fooled by the marketing lingo. These aren’t holy-grail products. “I’ve seen even less research on topical application of these products, and collagen is such a large molecule, so I wouldn’t expect it to be absorbed through the hair or skin and thus wouldn’t recommend it either for hair products,” she says.

Now that you know about biotin and collagen, this is what you need to know about peptides in skincare.