Not all hair heroes wear capes (some come in pills or protein packs)
Keratin. Biotin. If you’ve spent any time scrolling through haircare TikTok, reading supplement labels, or deciphering salon menus, you’ve definitely seen these two buzzy ingredients pop up. They’re often treated like interchangeable magic bullets for fixing everything from split ends to hair loss, but they’re not even in the same category.
Biotin is a vitamin. Keratin is a protein. One works from the inside out, the other smooths things over on the surface. And while they both promise longer, stronger, shinier hair, they take very different routes to get there.
So, which one do you need? That depends on what your hair is going through—and what your goals are. If you’re battling frizz, recovering from a bleach phase, or trying to grow your hair out post-summer shedding, this guide will help you figure out where to focus your energy (and your budget).
Spoiler: more isn’t always better. And you probably don’t need both.
What is biotin, really?
Biotin is one of those ingredients that seems to appear on every “hair growth” label ever, but what actually is it? Scientifically speaking, biotin is a water-soluble B-vitamin (vitamin B7, if we’re being precise) that plays a key role in converting the food you eat into energy. It's essential for metabolism, but it's also linked to the health of your hair, skin, and nails—hence its popularity in the beauty world.
What makes biotin especially interesting for hair is its connection to keratin production. Your body uses biotin as part of the process to build keratin naturally, which explains why biotin often gets lumped into the “stronger, longer hair” conversation. But that doesn’t mean more = better.
You’ll find biotin in lots of foods—eggs, nuts, seeds, salmon, leafy greens—and it’s also in just about every multivitamin and hair supplement gummy on the market. Most people who eat a varied diet get plenty of biotin without even trying.
Still, it’s become a go-to for those hoping to reverse thinning or boost growth. And while biotin deficiencies are rare, they can happen, and they often show up as brittle nails, dry skin, or hair that’s shedding more than usual.
But here’s the myth-busting bit: biotin is not a magic pill. Taking more than your body needs won’t suddenly make your hair grow twice as fast. In fact, over-supplementing biotin can mess with lab tests (like thyroid or hormone panels), and there’s little evidence it helps if you’re not deficient in the first place.
So yes, biotin plays an important supporting role in healthy hair growth. However, if you’re already getting enough from your diet, piling on more might be expensive hype rather than actual help.
What is keratin?
If biotin works behind the scenes, keratin is the front-of-house showstopper. It’s a fibrous structural protein: a literal building block of your hair, skin, and nails. In fact, your hair is made up of about 90% keratin, which is why so many products and treatments are designed to “restore” or “boost” it.
When hair looks dull, frizzy, or damaged, what’s often happening is the keratin layer has been compromised—thanks to heat styling, chemical treatments, sun exposure, or, let’s be honest, life. That’s where keratin-infused products and keratin treatments come in: they aim to smooth and strengthen the hair shaft by replenishing that lost protein.
You’ll find keratin in everything from deep conditioners and serums to professional salon treatments that promise weeks of frizz-free shine. But it’s important to note: not all keratin is created equal. Those in-salon keratin treatments (the kind that usually involve flat ironing and a bit of downtime) are more intense—and not without controversy, especially around the use of formaldehyde. On the other hand, keratin-based shampoos, masks, and leave-ins can offer gentler, daily repair without the commitment.
Unlike biotin, which works internally, keratin is more about external support. It smooths the hair’s cuticle, fills in gaps along the shaft, and helps reduce breakage and split ends. It’s especially useful if you’ve got damaged, colour-treated, or textured hair that’s prone to frizz or snapping.
So if you’re dreaming of shinier, more manageable hair (not necessarily more hair), keratin could be your go-to. Just know it’s a styling and repair solution, not a growth booster.
Keratin vs. biotin: What’s the actual difference
They’re often mentioned in the same breath, but keratin and biotin are completely different players in the hair game.
First off, biotin is a vitamin (B7), while keratin is a protein your body naturally produces. Biotin helps your body create keratin—it’s part of the internal production line. Keratin, on the other hand, is the end product: it’s what your hair, skin, and nails are actually made of.
Biotin works from the inside out, supporting overall hair growth and scalp health as part of your nutritional intake. You’ll often find it in supplements and gummies, especially those marketed for longer, thicker hair.
Keratin works on the outside, mostly through topical products or treatments. It’s applied directly to the hair to smooth, repair, and strengthen strands that have been damaged by heat, colour, or weather.
In simpler terms, Biotin is the support crew, helping your body build healthy hair. Keratin is the structure, holding everything together and making your hair look polished and strong.
Another key difference? Biotin is slow and subtle; you might see results in a few months, if at all. Keratin often delivers immediate payoff, especially in treatment form, by smoothing frizz and adding shine.
Still not sure? Think of it like this.
→ Biotin is the builder. Keratin is the brick.
What’s best for hair growth?
If your main goal is longer, fuller hair, here’s the short answer. Biotin is more closely linked to growth, but that doesn’t mean keratin has no role to play.
Let’s break it down.
Biotin supports the natural hair growth cycle by helping your body metabolise amino acids and produce keratin. If you’re low on biotin, you might notice thinning, shedding, or brittle strands. In these cases, adding biotin through food or supplements can help stimulate growth and strengthen new hair as it comes in.
However, if you already get enough biotin in your diet (which most people do), taking more probably won’t give you Rapunzel results overnight. You won’t grow inches of new hair in a week, but you might see fewer strands in your brush and stronger regrowth over time.
Keratin, on the other hand, doesn’t grow hair—it protects what you’ve already got. If your hair breaks before it gets long, adding keratin topically can help you hang onto length. It coats and reinforces each strand, reducing damage from heat styling, brushing, and chemical processing. That means less snapping, fewer split ends, and more retained growth.
So, if your hair is shedding or thinning? Try biotin. Breaking or fraying at the ends? Keratin could help.
And if it’s both? You might benefit from a combo approach… just don’t expect miracles from a bottle.
Can you take or use both?
Yes, but that doesn’t mean you need to.
Since biotin and keratin serve totally different functions, it’s safe (and sometimes helpful) to use them together, especially if you’re addressing multiple concerns like shedding and frizz. In fact, many hair supplements and products already combine the two: biotin to support hair growth internally, keratin to reinforce and smooth on the outside.
But the catch is that more isn’t always better.
If your diet already includes enough biotin-rich foods (like eggs, almonds, leafy greens, and salmon), supplementing with high-dose biotin probably won’t give you any extra benefits, and in rare cases, it can interfere with lab test results, especially hormone or thyroid panels. So, if you’re considering daily supplements, it’s worth checking in with your doctor first.
As for keratin? While it can work wonders for frizz and breakage, too much keratin, especially from intense salon treatments, can make hair feel stiff or brittle over time. If your strands are healthy and strong to begin with, layering on more protein than your hair needs might tip things out of balance.
The best approach? Be intentional.
If you’re using a keratin-rich hair mask, you probably don’t need a daily keratin shampoo, too. If you’re getting biotin from your meals, you can skip the supplements. Start small, listen to your hair, and build from there.
How to choose what’s right for you
So, keratin or biotin? The answer depends less on what’s trending and more on what your hair is asking for.
Start by thinking about your hair goals. Are you trying to grow it out? Recover from bleach damage? Tame humidity frizz? Address postpartum shedding? Your answers will help narrow things down fast.
Here’s a quick cheat sheet.
You want to grow your hair or reduce shedding?
→ Focus on biotin, particularly if you suspect a nutritional gap or you're seeing slower regrowth. Add it through supplements (if needed) or food first.
Does your hair feel dry, look frizzy, or break easily when you brush it?
→ Reach for keratin. Look for leave-in treatments, masks, or shampoos with keratin listed as a key ingredient.
Do you use a lot of heat tools or colour regularly?
→ Keratin will help smooth the cuticle and prevent breakage from styling stress.
You’re not sure what your hair needs, but it just feels... off?
→ Try adjusting your diet first. Foods rich in biotin, protein, and healthy fats can support both keratin production and overall hair health without overloading your routine.
Also, consider how you want to work it into your day.
→ Biotin = supplements or nutrition (low maintenance, but takes time).
→ Keratin = topical or treatment-based (hands-on, but fast results).
Bottom line: You don’t have to do it all. Pick one approach, stay consistent, and give it time. Hair responds best to steady, not scattered.
Biotin vs. keratin, let’s recap.
At the end of the day, keratin and biotin are teammates, not twins. Biotin works from the inside, supporting healthy hair growth and keratin production over time. Keratin, on the other hand, works on the surface, smoothing and strengthening strands you already have.
Neither is a miracle cure, but both can seriously support your hair goals if you know what you're using them for. Want stronger regrowth after shedding? Biotin might help. Need to tame frizz or repair heat damage? Keratin’s your go-to.
What matters most is choosing based on your needs, not just what’s trending. Overloading your routine with supplements and treatments you don’t need won’t do your hair any favours—and might even backfire.
If you’re after more advice on all things hair health, the LifeTYME blog is packed with expert tips, tutorials, and product know-how to help you take better care of your hair, whether you’re growing it out, smoothing it down, or just figuring out what it actually needs.
