Best Hair Growth Serums: The Ordinary Leads

The best growth hair serum for oily hair is The Ordinary Multi-Peptide Serum for Hair Density, a clear 2.02 Fl Oz leave-in that's alcohol-free and silicone-free and is meant to sit on a dry scalp overnight. If your scalp runs dry and flaky instead, the Botanic Hearth Rosemary Oil for Hair Growth at 6.7 Fl Oz gives you far more product per bottle and a conditioning oil base. The deciding factor here isn't the active list. It's texture. Six serums, three different formats, and only some of them belong on a scalp that shines by lunchtime.

Best growth hair serum for oily hair at a glance

How six serums survived the cut

Three things knocked listings out before I looked at a single ingredient.

First, no published size. If a listing won't tell you how much liquid is in the bottle, you can't work out whether it lasts a month or a season, and a growth product is a months-long commitment or it's nothing.

Second, blended claims that mix supplements with topicals. A capsule and a scalp serum do different jobs and get judged differently. Anything that couldn't say plainly whether you swallow it or apply it was out.

Third, no stated format. "Serum" covers a water spray, a cold-pressed oil and a clear peptide drop, and those three feel completely different on a greasy scalp. Every survivor had to declare which it was.

What came through is six products across four categories on Amazon: two filed under hair regrowth treatments, one under regrowth tonics, one under scalp treatments, one under styling serums, and one under relaxers. That spread tells you something useful. There is no tidy shelf for this. You're comparing across departments, which is exactly why sizes run from 1 Fl Oz to 6.7 Fl Oz and formats run from a mist to an oil.

I then ranked on the things a shopper can actually verify: format, volume, stated actives, and where each sits against the others on price. Everything else in this guide is comparison, not measurement.

Water, oil or peptide: which texture suits an oily scalp?

Here's the trick with a best growth hair serum for oily hair search. Amazon's results don't filter for oily scalps. The qualifier is mostly ignored, so no product in this set can honestly be described as formulated for grease. What you can do is read the format and judge for yourself, and that turns out to be the whole decision.

Three textures are represented:

• Clear leave-in drops. The Ordinary's serum is listed as Clear, alcohol-free and silicone-free, applied as a few drops to a clean dry scalp once daily. No carrier oil in the description, no styling polymers.
• Cold-pressed oil. Botanic Hearth blends rosemary with biotin, jojoba and castor oils. Castor is heavy. The brand's own pitch is deep hydration and improved texture, which is a benefit if your scalp is dry and a problem if it isn't.
• Water-based spray. AROMATICA's Root Enhancer is a 3.38 Fl Oz rosemary water spray. The listing specifically mentions targeting scalp buildup and oily scalp, the only product here to raise the subject.

Two sit in between. Bare Anatomy states its serum is lightweight, non-greasy and absorbs without making hair greasy. THORN & BERRY describes a peptide and niacinamide complex, and niacinamide is a familiar ingredient in oil-control skincare, though the listing makes no oil-control claim.

The pattern is simple. Anything built on an oil base adds oil. If you already wash every day or two because your roots go flat, a water or clear-serum texture is the safer starting point, and you can always add an oil later on a weekend when you're washing anyway.

1. The Ordinary Multi-Peptide Serum for Hair Density — Best overall

A clear, alcohol-free and silicone-free leave-in with the longest published actives list here, and the only one that names six separate peptide and botanical technologies.

Best for: nightly use on a scalp that turns greasy by day two Skip it if: you want an oil you can also run through the ends

What sets this apart within the set is the combination of a clear texture and a named actives roster. The Ordinary lists REDENSYL, Procapil, CAPIXYL, BAICAPIL, AnaGain and high-solubility caffeine, plus larch wood, pea and green tea leaf extracts. No other pick names six technologies. The brand also states the formula is alcohol-free and silicone-free, which matters more than it sounds: silicones are what make some scalp products feel slick and coated after a few days of build-up.

The bottle holds 2.02 Fl Oz and weighs 3.17 oz filled, in a 5.14 x 1.53 x 1.53 in dropper. Directions are a few drops on a clean, dry scalp once daily, preferably at bedtime, so it's an overnight product that gets rinsed at your next wash. That rhythm suits an oily scalp well, since you're not layering product onto hair you plan to wear out.

The trade-off is position and access. This is the most expensive pick here and only two sellers list it, which gives you less room to shop around. It's also scalp-only by design, so if you wanted one bottle to treat roots and condition dry ends, you'll be buying something else too.

Pros:

• Six named peptide and botanical technologies
• Clear texture, no carrier oil in the description
• Stated alcohol-free and silicone-free
• 2.02 Fl Oz dropper for measured drops
• Sells faster here than every other pick

Cons:

• The most expensive pick in this set
• Only two sellers list it
• Scalp-only, no conditioning benefit for lengths
• Nightly application means an extra step every day

2. Botanic Hearth Rosemary Oil for Hair Growth — Runner-up

By far the biggest bottle here at 6.7 Fl Oz, and the pick to choose when your scalp is dry and flaky rather than greasy.

Best for: dry, flaky scalps that tolerate an oil layer Skip it if: your roots look oily within a day of washing

Volume is the headline. At 6.7 Fl Oz and 6.98 oz on the scale, this holds more than three times what the 1 Fl Oz serums do, and more than three times The Ordinary's 2.02 Fl Oz. If you're treating a full head of long hair, or two people are using it, that difference is the whole argument.

Botanic Hearth describes a cold-pressed blend of organic rosemary with biotin, jojoba and castor oils. The brand says it helps thicken strands by strengthening follicles, helps soothe dandruff by reducing dryness, and delivers deep hydration to improve texture. It's also listed as ethically sourced, cruelty-free, paraben-free and sulfate-free. Those are the manufacturer's claims, and they point clearly at a dry-scalp product.

Which is exactly why it sits at number two rather than number one in a guide about oily hair. Castor and jojoba are conditioning oils. They will add slip and weight at the root, and on a scalp that already produces plenty of sebum you're likely to be washing sooner, not later. The listing also publishes no dimensions and no model number, so there's less detail on the bottle itself than several cheaper picks give you. Treat this as the pick that wins on volume and loses on texture.

Pros:

• 6.7 Fl Oz, the largest bottle in this set
• Cold-pressed rosemary with biotin, jojoba and castor
• Brand claims dandruff and dryness relief
• Paraben-free, sulfate-free, cruelty-free per the listing

Cons:

• Oil base is the wrong texture for a greasy scalp
• Second-most-expensive pick here
• No published dimensions or model number
• Only two sellers stock it

3. AROMATICA Root Enhancer Rosemary Water for Hair Growth — Best for heavy use

The only spray in the group, and the only listing that names oily scalp and scalp buildup as targets.

Best for: daily spraying over a large area of scalp Skip it if: you want measured drops rather than a mist

Format is the differentiator. This is rosemary water in a 3.38 Fl Oz spray, weighing 3.88 oz filled, in a slim 6.34 x 1.97 x 1.1 in bottle. A mist covers a wide area of scalp in seconds, which is why it's the pick if you're treating thinning across the crown rather than a single part line. AROMATICA lists a six-part Black Food Complex including black rice and rosemary water, plus organic rosemary oil, and describes the product as a scalp moisturiser and scalp tonic.

The relevant detail for this guide sits in AROMATICA's own copy: it says the tonic targets scalp buildup and the root causes of an oily scalp. That's the brand talking, not a tested result, and the same listing also positions it for dry scalps, which muddies the message. Still, it's the only one of the six that mentions grease at all.

The honest weakness of a spray is control. Drops let you count what you've used and put it exactly where you want it. A mist drifts onto hair you weren't treating, and on fine hair that can read as damp roots for an hour. Volume also sits in the middle here, well under Botanic Hearth's 6.7 Fl Oz, and the price position is mid-range, so you're paying more per ounce than the oil.

Pros:

• Water-based spray, no added carrier oil
• 3.38 Fl Oz covers a wide scalp area fast
• Names scalp buildup and oily scalp in the listing
• Slim 1.1 in deep bottle travels easily

Cons:

• A mist gives you less control than drops
• Listing pitches both dry and oily scalps, which is confusing
• Mid-range price for a middling volume
• Brand states results vary by hair type

4. Bare Anatomy Advanced Hair Density Serum — Best for beginners

The only pick that publishes percentages for its actives, which makes it the easiest one to compare against anything else you're considering.

Best for: a first try at percentage-listed actives Skip it if: you go through product quickly

Numbers are the reason this one earns a place. Bare Anatomy states 3% Redensyl, 4% Anagain, 3% Baicapil and 1% Capilia Longa, alongside rosemary, biotin and rice extract. Every other listing here names ingredients without saying how much. If you're new to growth serums and want to build a baseline you can measure future purchases against, a percentage is far more useful than a marketing adjective.

The brand also states the serum is lightweight, non-greasy and absorbs without making hair greasy, and lists it as sulphate-free, paraben-free, mineral-oil-free, alcohol-free and dye-free. Those are claims from the listing rather than verified performance, but the non-greasy positioning is at least aimed at the right problem.

Two things hold it back. The bottle is 1 Fl Oz, weighing 1.06 oz, in a 3.94 x 1.89 x 1.89 in package. That's the joint-smallest here and half of The Ordinary's volume, so a daily habit empties it fast. Only one seller lists it, which is the thinnest availability in the set. And the listing leads with a "214% hair growth in 10 days" figure carrying an asterisk. Treat that as advertising copy and judge the product on its published percentages instead.

Pros:

• Publishes 3% Redensyl and 4% Anagain figures
• Stated lightweight and non-greasy
• Sulphate-, paraben- and alcohol-free per the listing
• Compact 3.94 in bottle

Cons:

• 1 Fl Oz, joint-smallest volume here
• Only one seller lists it
• Headline growth percentage is unverifiable marketing copy
• Mid-range price for the least product

5. Marc Anthony Grow Long — Best budget pick

The cheapest of the six, and the only one designed to be applied to the lengths as well as the scalp.

Best for: long-hair goals where breakage is the real problem Skip it if: you only want to treat the scalp

This one reframes the problem. Marc Anthony's pitch is length retention, not follicle stimulation: the brand says it strengthens hair fibres at the root and reduces breakage along the length. If your hair grows but never seems to get longer, breakage is often the reason, and this is the only pick in the set that addresses both ends of the strand.

The formula is described as rosemary oil, caffeine, ginseng, biotin and vitamin E, and it's listed as free from sulfates, parabens and phthalates. Directions say to apply in sections on damp or dry hair, massaging as you go, then work it through the lengths for moisture and shine. The bottle holds 2 Fl Oz, matching The Ordinary's volume almost exactly, in a 1.65 x 6.3 x 1.95 in package, released in 2023.

Here's the catch for anyone with an oily scalp. Applying a moisturising serum to damp hair and then combing it through is precisely the routine that leaves fine roots looking limp. You can still use it scalp-only, but you're paying for a dual-purpose formula and using half of it. Its slower sales position here also means fewer shoppers are choosing it than the top three, and no weight figure is published.

Pros:

• Cheapest pick in this comparison
• 2 Fl Oz, double the smallest bottles
• Targets breakage as well as the scalp
• Free from sulfates, parabens and phthalates per the listing

Cons:

• Lengths application risks weighing down oily roots
• No published weight figure
• Sells more slowly than the top three picks
• Filed under styling serums, not scalp treatment

6. THORN & BERRY Hair Growth Serum for Thinning Hair — Best for families

The second-cheapest option here, and the only formula built on a niacinamide and copper peptide pairing.

Best for: two people sharing one unscented bottle Skip it if: you need published size and weight figures before you buy

The ingredient story is the most distinctive here. THORN & BERRY names copper tripeptide-1, acetyl tetrapeptide-3 and niacinamide, plus hydrolysed keratin, amino acids, caffeine, zinc, vitamin E, hyaluronic acid and arginine. Niacinamide is the one worth noting: it's a staple of oil-control skincare, even though the brand makes no oil-control claim. The listing also describes a botanical DHT blocker and positions the product for both women and men, which is why it works as a shared bottle in a household treating two heads of thinning hair.

That shared-use angle is also its limit. The bottle is 1 Fl Oz, joint-smallest with Bare Anatomy, so two people using it daily will finish it quickly. Price position softens that, since it's the second-cheapest pick and cheap enough to buy in pairs.

The bigger problem is what the listing leaves out. Only a size and a count are published. No weight, no dimensions, no model number, no release date. Every other pick here gives you at least one more figure. It's also the slowest-selling of the six by a wide margin, which means fewer shoppers have found reason to choose it over the alternatives above. If you want a documented purchase, look higher up the table.

Pros:

• Second-cheapest pick in this set
• Copper tripeptide-1 with niacinamide, unique here
• Listed for both men and women
• Adds keratin, zinc and hyaluronic acid

Cons:

• Thinnest published specifications of all six
• 1 Fl Oz runs out fast with shared use
• The slowest seller of the six by a wide margin
• No weight or dimensions to judge bottle size

How long does one bottle actually last?

Volume is the specification most shoppers skip, and it's the one that decides whether you finish a three-month trial or give up in week five. A growth serum needs consistency, and consistency needs product in the bottle.

Here's the range across this set, smallest to largest:

1. Bare Anatomy Advanced Hair Density Serum: 1 Fl Oz
2. THORN & BERRY Hair Growth Serum: 1 Fl Oz
3. Marc Anthony Grow Long: 2 Fl Oz
4. The Ordinary Multi-Peptide Serum: 2.02 Fl Oz
5. AROMATICA Root Enhancer: 3.38 Fl Oz
6. Botanic Hearth Rosemary Oil: 6.7 Fl Oz

That's a 6.7x spread from bottom to top. The two 1 Fl Oz serums are the same volume as a small perfume sample, and both are applied daily.

Three factors push consumption up. A bigger treatment area, so a receding hairline uses less than thinning across the whole crown. A spray rather than drops, since a mist inevitably lands on hair as well as scalp. And two people sharing, which halves everything.

The practical move is to match volume to format. Drops are the most economical because you can count them, which is why The Ordinary's 2.02 Fl Oz goes further than the number suggests. Sprays and oils get used generously by nature, so the two largest bottles here are the two you'd expect to empty fastest anyway. If you're on a 1 Fl Oz bottle, buy the second one before the first runs dry.

What the listings won't tell you about oily hair

Choosing the best growth hair serum for oily hair means reading between the bullets, because the listings weren't written for you.

Nobody states an oil-control claim. AROMATICA mentions oily scalp, Bare Anatomy says non-greasy, and that's the extent of it. Nothing in this set is formulated to reduce sebum, and any guide telling you otherwise is inventing a specification.

Application timing does more than the formula. Four of these six are meant for a clean scalp, and The Ordinary specifically says clean, dry scalp at bedtime. Applying to a scalp that's already had two days of oil means you're layering onto sebum, which is where the coated feeling comes from.

"Free from" lists matter more than active lists here. Alcohol-free is comfort. Silicone-free is the one to look for if things feel slick after a week, since silicones are what build up. The Ordinary states both. Bare Anatomy states alcohol-free and mineral-oil-free.

Category placement is a clue, not a rule. These six sit in four different Amazon categories, and one is filed under hair relaxers. That tells you the shelf is chaotic, not that the product is wrong.

Volume beats hype. Two of these hold 1 Fl Oz. A serum you run out of in three weeks can't do anything at all.

When a different pick wins

Three concrete conditions flip the recommendation.

Your scalp flakes rather than shines. Then the texture logic inverts. Botanic Hearth's 6.7 Fl Oz rosemary blend with jojoba and castor is built for exactly that, and the brand claims dandruff and dryness relief. Buy the oil, not the peptide drops.

You're treating a wide thinning area daily. Drops become tedious across a whole crown. AROMATICA's 3.38 Fl Oz spray covers it in a few passes, and its slim 1.1 in bottle fits a gym bag. You trade precision for speed.

Your hair grows but snaps before it gets long. No follicle serum fixes mechanical breakage. Marc Anthony Grow Long is the cheapest pick here and the only one designed to run through the lengths, which is where the damage is. Use it on the ends and keep a scalp product separate if roots go greasy.

Two smaller flips are worth naming. If you want an active percentage on the label so you can compare future purchases, Bare Anatomy's 3% Redensyl and 4% Anagain figures are the only published numbers in the set. And if two people need the same bottle, THORN & BERRY's men-and-women positioning plus its low price position makes buying two copies painless.

The verdict

If you have an oily scalp and you're starting from scratch, buy The Ordinary Multi-Peptide Serum for Hair Density. It's a clear 2.02 Fl Oz leave-in, stated alcohol-free and silicone-free, with six named technologies from REDENSYL to high-solubility caffeine, applied as drops to a clean dry scalp at night and rinsed at your next wash. Nothing else here gives you that combination of a light texture, a documented actives roster and enough volume to run a real trial. It's the most expensive pick and only two sellers list it, and it's still the one I'd start with.

If your scalp is dry, flaky or itchy rather than greasy, buy Botanic Hearth Rosemary Oil for Hair Growth instead. At 6.7 Fl Oz it holds more than three times the volume, and its jojoba and castor base is a genuine advantage on a scalp that needs conditioning rather than one that needs a break from it.

The cutoff is simple and you already know which side you're on: how many days after washing before your roots look oily. Two days or fewer, take the clear peptide drops. Four days or more, take the oil. In between, AROMATICA's water-based spray splits the difference at 3.38 Fl Oz.

FAQ

Which is the best growth hair serum for oily hair overall?

The best growth hair serum for oily hair overall is The Ordinary Multi-Peptide Serum for Hair Density. It's a clear 2.02 Fl Oz leave-in, stated alcohol-free and silicone-free, so there's no carrier oil or silicone film going onto a scalp that already produces plenty of sebum. Directions call for a few drops on a clean, dry scalp at bedtime.

Is a hair growth serum worth it if my scalp is already oily?

Whether a hair growth serum is worth it depends entirely on texture, not on the active list. An oil-based product on a greasy scalp usually means washing more often, which undoes your routine. A clear drop or a water spray sidesteps that. Bear in mind no product in this set claims to control oil, so you're choosing the format least likely to make things worse.

Does the rosemary oil work differently from the peptide serums?

Rosemary oil works differently in one important way: it's a conditioning oil blend, not a water-thin actives carrier. Botanic Hearth combines rosemary with biotin, jojoba and castor across 6.7 Fl Oz, and the brand pitches deep hydration and dandruff relief. The Ordinary and Bare Anatomy instead name peptide complexes like REDENSYL, Baicapil and Anagain in far lighter textures.

The Ordinary or Bare Anatomy: which should I choose?

Choose The Ordinary if volume matters, since 2.02 Fl Oz is double Bare Anatomy's 1 Fl Oz and it names six technologies rather than four. Choose Bare Anatomy if you want published percentages you can compare later, because its 3% Redensyl, 4% Anagain, 3% Baicapil and 1% Capilia Longa figures are the only concentrations stated in this whole set.

What mistake do people make buying growth serums?

The mistake people make buying growth serums is choosing a 1 Fl Oz bottle for a daily habit. Two picks here hold that little, and a serum applied every night to a full crown empties fast. Growth routines need months of consistency, so match volume to your treatment area and buy your second bottle before the first one runs dry.

Start with the texture question rather than the ingredient panel, because that's the variable you can judge from your own bathroom mirror. If your roots go greasy inside two days, The Ordinary Multi-Peptide Serum for Hair Density is the sensible default: clear, silicone-free, 2.02 Fl Oz, applied at night and washed out in the morning, which is the only routine on this list that never leaves product sitting on hair you plan to wear out. Give it a full bottle before you judge it, note how your scalp feels at day three, and adjust format from there.

Last updated: September 22, 2026. Product availability re-checked.

This page contains affiliate links. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.