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Best Non-Toxic Hair Serums

We vetted hair serums against the Welpr Standard and here are our top picks.

Camille May

Cofounder & Product Curator

Olushola M. Awoyemi

Medical Reviewer, PhD

Here's what we look for:

Formulas made with natural or synthetic ingredients that meet our standard
Free from parabens, PEGs, phthalates, harsh sulfates, BHA/BHT, artificial dyes, formaldehyde and formaldehyde-releasing ingredients, and undisclosed fragrance
Minimal, well-chosen preservatives
Trusted third-party certifications when available
Transparent sourcing, ingredients, and manufacturing practices

Best Non-Toxic Hair Serums

On Welpr, terms like "non-toxic," "safer," "cleaner," "healthier," and "vetted" are editorial labels based on our own standard for product assessment. They are not guarantees, certifications, or medical claims. Learn more.

Captain Blankenship Nourish Hair & Scalp Serum

Meets the Welpr Standard

Top Pick

Captain Blankenship

Nourish Hair & Scalp Serum

Free From: BPA Free, BPF Free, BPS Free, Cruelty Free, Dye Free, Formaldehyde Free, Heavy Metal Free, Paraben Free, PFAS Free, Phthalate Free, Sulfate Free
Certified: Certified B Corp, Leaping Bunny, Made Safe
Highlights: Vegan, Cruelty-free, Made in USA, No synthetic fragrance, Recyclable packaging, Recycled materials, For Scalp health, Overnight treatment, Heat protection

8.4

Performance score

Where to buy

Amazon
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Captain Blankenship
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An oil-based serum that doubles as a daily finishing product or a deeper scalp treatment. A few drops smooth frizz and add shine on dry or damp hair; applied more generously to the roots and left on for a few hours (or overnight), it works as a scalp-nourishing mask.
The formula is built around botanical oils that closely mimic the scalp's natural sebum, so it hydrates without disrupting your scalp's oil balance. A blend of wild-harvested Maine seaweeds adds vitamins, minerals, and amino acids.
Lightweight for an oil-based serum, but a little goes a long way. Start with just a few drops; using too much too quickly is the easiest mistake to make with this one.
Scent leans herbal and woodsy: rosemary, cedarwood, and sweet orange. The fragrance comes entirely from the essential oils in the formula, so intensity can vary slightly between batches.
Captain Blankenship is a small, women-run company in the Hudson River Valley. The seaweeds are wild-harvested from the Maine coast, and the products are manufactured in an organic-certified facility in Minneapolis that runs on renewable energy.
Among non-toxic hair serums, this one keeps its ingredient list notably short: thirteen ingredients total, all either certified organic or wild-harvested, with no silicones or synthetic preservatives.

Camellia Oleifera Seed Oil
Argania Spinosa Kernel Oil
Simmondsia Chinensis (Jojoba) Seed Oil
Helianthus Annuus (Sunflower) Seed Oil
Rosmarinus Officinalis (Rosemary) Leaf Oil
Citrus Aurantium Dulcis (Orange) Peel Oil
Abies Balsamea (Balsam Canada) Needle Oil
Laminaria Digitata Extract
Fucus Vesiculosus Extract
Ascophyllum Nodosum Extract
Porphyra Umbilicalis Extract
Alaria Esculenta Extract
Juniperus Virginiana Oil

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Under Luna Deep Magic Hair + Scalp Serum

Meets the Welpr Standard

Budget Pick

Under Luna

Deep Magic Hair + Scalp Serum

Free From: Cruelty Free
Highlights: Vegan, Cruelty-free, Pregnancy safe, Breastfeeding safe, Recyclable packaging, For Scalp health, Leave-in, Heat protection

8.2

Performance score

Where to buy

Amazon
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Under Luna
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Marketed as a 4-in-1: scalp treatment, anti-frizz serum, heat protectant, and texturizer. The base is an herb-infused jojoba oil, so it functions more like a multipurpose hair oil than a traditional silicone-based serum.
Particularly suited for dry, irritated, or flaky scalps. It can be applied directly to the scalp before a shower or left on overnight as a deeper treatment.
The scent is warm and woodsy with citrus notes (grapefruit, clove, cabreuva). It does contain essential oils, which is worth noting if you're sensitive to them.
Most non-toxic hair serums use a longer ingredient list with carrier blends and botanical extracts. This one has only eight ingredients, all plant-derived, with no added preservatives or synthetic stabilizers.
Under Luna is a woman-owned, small-batch operation out of Portland, Oregon. Their packaging is glass and aluminum rather than plastic, and orders ship in recycled materials.

Meets the Welpr Standard

Innersense

Hair Renew Daily Active Serum

Free From: Cruelty Free, Dye Free, Formaldehyde Free, Gluten Free, Paraben Free, Phthalate Free, Sulfate Free
Highlights: Soothes scalp, Reduces flaking, Fortifies hair follicles, For all scalp types, Daily use, Peppermint fragrance, Vegan

8.2

Performance score

Where to buy

Amazon
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Innersense
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Built around dry, itchy, flaky scalp concerns: tea tree oil and hemp seed oil replenish moisture and help reduce flaking and itching due to dryness.
Antioxidant-rich pea sprout extract supports the scalp at the root by helping fortify hair follicles and revitalize roots.
The serum is suited to all skin and scalp types, including scalps that need both moisture support and relief from dryness-related irritation.
Peppermint is the stated fragrance note, giving the scalp serum a mint-forward scent profile.

Water/Aqua/Eau
Propanediol
Glycerin
Caprylyl/Capryl Glucoside
Pyrus Malus (Apple) Fruit Extract
Citric Acid
Sodium Levulinate
Potassium Sorbate
Ethanol
Angelica Archangelica Root Extract
Chamomilla Recutita (Matricaria) Flower Extract
Mentha Piperita (Peppermint) Oil
Lactic Acid
Sodium Gluconate
Glycolic Acid
Lavandula Angustifolia (Lavender) Oil
Vaccinium Myrtillus Fruit/Leaf Extract
Pisum Sativum (Pea) Sprout Extract
Gevuina Avellana (Hazelnut) Oil
Melaleuca Alternifolia (Tea Tree) Leaf Oil
Oenothera Biennis (Evening Primrose) Oil
Euterpe Oleracea Fruit Oil
Helianthus Annuus (Sunflower) Seed Oil
Saccharum Officinarum (Sugar Cane) Extract
Calendula Officinalis Flower Extract
Citrus Aurantium Dulcis (Orange) Fruit Extract
Citrus Limon (Lemon) Fruit Extract
Acer Saccharinum (Sugar Maple) Extract
Cannabis Sativa (Hemp) Seed Oil
Malic Acid
Hydrolyzed Adansonia Digitata Seed Extract
Tartaric Acid
Equisetum Arvense Extract
Prunus Persica (Peach) Gum
Menthyl Lactate
Tocopherol
Sodium Benzoate
Limonene

Meets the Welpr Standard

Living Libations

Organic Seabuckthorn Styling Serum

Free From: Cruelty Free
Highlights: Cruelty-free, For Frizz control, Leave-in

8.2

Performance score

Where to buy

Amazon
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More liquid gel than traditional serum. It has a thin, silky consistency that doesn't get sticky or weigh hair down, so it works as a lightweight styling product rather than a heavy leave-in treatment.
Built around a base of plant-derived hold agents (tree resin and seaweed extract) instead of synthetic polymers, which is unusual even among non-toxic hair serums. The hold comes from botanicals historically used for styling rather than lab-created film formers.
Works on both damp and dry hair. Can be layered over multiple days without making hair look greasy or feel crunchy, which makes it practical for people who don't wash daily.
Particularly suited to curly, wavy, or frizz-prone hair. The formula is designed to define curl pattern and smooth flyaways while keeping moisture levels balanced.
Scent comes entirely from the essential oil blend: expect herbal and citrus notes (think peppermint, rosemary, grapefruit) rather than anything perfume-like. It's noticeable during application but doesn't linger strongly.
Living Libations sources essential oils directly from small-scale distillers and farmers they've worked with for over 20 years, and produces in small batches. Slight variation in color, consistency, and scent between batches is normal.

Aqua (Water)
Aloe Barbadensis (Aloe Vera)
Hippophae Rhamnoides (Seabuckthorn)
Acacia Senegal (Acacia) Gum
Fucus Vesiculosus (Bladderwrack) Extract
Tussilago Farfara (Coltsfoot)
Aesculus Hippocastanum (Horse Chestnut)
Equisetum Arvense (Horsetail)
Urtica Dioica (Stinging Nettle)
Rosa Canina (Rosehips)
Mentha Piperita (Peppermint)
Rosmarinus Officinalis (Rosemary)
Pogostemon Cablin (Patchouli)
Citrus Paradisi (Grapefruit)
Salvia Officinalis (Sage) Extract
Rosmarinus Officinalis (Rosemary) Extract

Meets the Welpr Standard

Typology

Calming Scalp Treatment

Free From: Cruelty Free, Fragrance Free
Highlights: Soothes scalp, Reduces itchiness, Hydrates scalp, Non-greasy finish, For sensitive scalps, 99% naturally derived, Vegan, Made in France

8.2

Performance score

Where to buy

Typology
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1% bisabolol works directly at the source of inflammation to relieve irritation and feelings of scalp discomfort. Cotton extract adds a softening, repairing role that helps the skin regenerate.
Built for sensitive, irritated scalps and for people prone to dry dandruff. Dryness can stem from too little sebum production, leaving the scalp more susceptible to irritation and discomfort.
The light emulsion absorbs quickly with a non-greasy, non-sticky finish, and does not leave hair greasy after application.
Plant glycerine holds water at the skin’s surface to help prevent dehydration and soften the scalp. Sweet almond oil contributes omega 6 and omega 9 fatty acids that rebalance the scalp’s hydrolipidic film.

Meets the Welpr Standard

Typology

Restorative Hair Serum R41 1% Hyaluronic Acid + Plant Keratin

Free From: Cruelty Free
Certified: Certified B Corp, PETA Certified, PETA Vegan
Highlights: Vegan, Made in EU, Recyclable packaging, For Damage repair, Leave-in

8.2

Performance score

Where to buy

Typology
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A leave-in serum applied via dropper to lengths and ends of dry or damp hair. It uses a low molecular weight humectant to penetrate the hair fiber and retain moisture, paired with plant-derived amino acids that bind to damaged areas of the cuticle to fill gaps and smooth the surface.
Formulated for all hair types but especially useful for dry, damaged, or brittle hair. Safe for color-treated, bleached, or highlighted hair since it skips silicones entirely.
Most hair serums use silicones to create smoothness and shine. This one relies on a water-based formula instead, which means active ingredients absorb into the fiber rather than just coating it. The tradeoff: no instant silicone-slick feel.
Contains pearlescent pigments that reflect light to give hair a satin finish. The shine is partly optical, not just from hydration.
Among non-toxic hair serums, Typology keeps the ingredient count relatively low at 19, with 99% naturally derived. Packaged in a recyclable glass bottle with a glass pipette.
Typology is a French brand certified B-Corp, and all products are manufactured in France.

Meets the Welpr Standard

RANAVAT

Mighty Majesty Fortifying Hair Serum

Free From: Cruelty Free
Highlights: Vegan, Cruelty-free, Pregnancy safe, Breastfeeding safe, No synthetic fragrance, For Scalp health, Pre-shampoo treatment, Heat protection

8.1

Performance score

Where to buy

Amazon
See price

Pros

Leaves hair feeling soft, smooth, and silky after use.
The jasmine scent is strong and consistently praised as one of the standout features.
The oil has a lightweight, non-thick consistency that absorbs without weighing hair down.

Cons

The jasmine scent is very intense, which may be overpowering for people who prefer subtle fragrances.
One person reported that the pump and lid on the newer packaging was stuck and unusable.
One person saw no visible hair results after several months of use.

Rooted in Ayurvedic hair oiling tradition, this is a three-ingredient oil serum meant primarily as a pre-shampoo scalp and hair treatment. You massage it in, leave it for a few hours (or overnight), then wash it out.
Works for all hair types, including curly, textured, and chemically treated hair, and is considered safe during pregnancy and breastfeeding.
The scent comes from steam-distilled jasmine oil, so expect rich, grounding floral notes rather than anything synthetic or perfume-like.
Versatile enough to use two ways: as a deep pre-wash treatment for scalp hydration and strengthening, or just a half-pump smoothed over dry hair to tame flyaways and add shine.
Among non-toxic hair serums, the formula is unusually minimal. The entire product is three organic botanical oils with no added preservatives, emulsifiers, or silicones.
RANAVAT's formulas are made in India using traditional Ayurvedic processing methods that take days rather than hours. The founder, a first-generation Indian American, developed the line after experiencing severe postpartum hair loss.

Meets the Welpr Standard

Annmarie

Smoothing Hair Serum

Free From: BPA Free, BPF Free, BPS Free, Cruelty Free, Non-GMO, Paraben Free, PFAS Free, Phthalate Free
Certified: Leaping Bunny, Made Safe
Highlights: Smoothes, Hydrates, Moisturizes, For all hair types, Solid-form serum, Non-greasy, 30-Day money-back guarantee

8.0

Performance score

Where to buy

Amazon
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Annmarie
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The solid serum melts when warmed between the palms, then works on damp hair or as a finishing treatment on dry hair.
Murumuru butter, the formula's primary ingredient, is a rich emollient that strengthens damaged hair. Jojoba and argan add moisture and nourishment for a silky-smooth finish.
Murumuru butter provides the smoothing role often associated with silicone, in a formula made without petroleum-based ingredients or greasiness.
Bright, soft notes of petitgrain, clary sage, and lavender create an uplifting aromatherapy scent experience.

Meets the Welpr Standard

Nutrafol

Women's Hair Serum

Highlights: Vegan, Cruelty-free, Pregnancy safe, Breastfeeding safe, No synthetic fragrance, For Growth & thickness, Leave-in

7.5

Performance score

Where to buy

Amazon
See price

Pros

Lightweight and non-greasy; absorbs quickly without leaving residue or weighing hair down.
Virtually no noticeable scent, so it layers easily with other hair products.
Multiple people report visible thickening and new growth around the hairline and thinning areas after 2 to 3 months of consistent use.
Easy to work into a daily routine since it only takes a couple of dropper applications massaged into the scalp.

Cons

Results require patience; most people didn't see visible changes until 8 to 10 weeks in, and at least one person saw no improvement after 7 months.
The paper label on the bottle peels and flakes off during normal bathroom use, and the flakes can end up in hair and on skin.
The consistency is very thin and watery, which makes it prone to running down your face during application.

Lightweight, water-based scalp serum applied with a dropper tip directly to areas of concern like the hairline, temples, or crown. It absorbs quickly without leaving a greasy residue, so you can apply it and style as usual.
Designed as a topical complement to Nutrafol's oral hair growth supplements, targeting thinning and breakage from the outside while the supplements work internally. It can be used on its own, but the brand positions the two as a paired routine.
Among non-toxic hair serums focused on thinning hair, this one takes a drug-free approach, relying on plant-based actives and a proprietary exosome delivery system rather than conventional hair loss drugs like minoxidil.
Works on wet or dry hair and is meant for daily use on the scalp only; it hasn't been tested for eyebrows or eyelashes. One bottle lasts anywhere from one to three months depending on whether you're treating specific spots or your whole scalp.
Safe for use during pregnancy and breastfeeding, and compatible with color-treated hair and extensions. Nutrafol's three co-founders all experienced hair thinning themselves, which shaped the brand's focus on natural, clinically tested formulas developed with a physician-led team.

Aqua
Glycerin
Melaleuca Alternifolia (Tea Tree) Leaf Water
Propanediol
1, 2-Hexanediol
Niacinamide
Panthenol
Hydroxyethylcellulose
Lepidium Meyenii (Maca) Root Extract
Maltodextrin
Caprylhydroxamic Acid
Equisetum Arvense (Horsetail) Extract
Hippophae Rhamnoides (Sea Buckthorn) Fruit Extract
Laminaria Saccharina (Neptune Kelp) Extract
Chondrus Crispus (Seaweed) Extract
Sodium Metabisulfite
Alcohol
Arginine
Phospholipids
Lactic Acid
Melatonin
Potassium Sorbate
Lactobacillus Ferment
Pisum Sativum (Pea Sprout) Extract
Phosphate Buffered Saline
Withania Somnifera Seed Exo Extract

Meets the Welpr Standard

Hairstory

Bond Serum

Highlights: Vegan, Cruelty-free, Fragrance-free, No synthetic fragrance, Recyclable packaging, Refillable, For Damage repair, Leave-in, Heat protection

7.0

Performance score

Where to buy

Hairstory
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Leave-in serum that uses liposome delivery to target damaged sections of the hair fiber specifically, rather than coating the whole strand uniformly. The technology is designed to restore broken bonds caused by bleaching, coloring, or chemical relaxing.
Primarily built for chemically processed hair: bleached, color-treated, or relaxed. It works on all hair types, but the bond-repair mechanism is most relevant if your hair has been through chemical stress.
Unscented and lightweight with a velvety, non-greasy finish. You apply it to damp hair after cleansing (focusing on the most damaged areas first) and leave it in.
Hairstory also makes a companion product called Bond Boost that you mix into their cleanser before using this serum. The idea is that Bond Boost primes the hair to absorb the serum's actives more effectively, so the two are designed as a system.
Among non-toxic hair serums, this one takes an inside-out approach: the bond-restoring complex works within the hair fiber while a separate set of ingredients addresses the outer cuticle layer for frizz and split ends.
Hairstory launched in 2015 around the idea of detergent-free haircare, with formulas developed in collaboration with professional hairdressers rather than purely in-lab.

Water
Coco-Caprylate/Caprate
Propanediol
Betaine
Glycerin
Isoamyl Laurate
Xanthan Gum
Triolein
Castor Oil Propanediol Esters
Sodium Stearoyl Laylate
Brassica Campestris Aleurites Fordi Oil Copolymer
Sodium Anisate
Levulinic Acid
Tapioca Starch
Tetrasodium Glutamate Diacetate
Sodium Levulinate
Phosphatidylcholine
Itaconic Acid
Arginine
Mannitol
Panthenol
Algin
Polyglyceryl-10 Laurate
Linum Usitatissimum (Linseed) Seed Extract
Salvia Hispanica Seed Extract
Cetyl Alcohol
Potassium Sorbate
Sodium Benzoate
Benzyl Alcohol
Ceramide Np
Citric Acid
Xylitol
Caprylic Acid
Cetrimonium Chloride
Sodium Chloride

How to Swap to Non-Toxic hair serums:

Here's how to swap to non-toxic hair serums:

What to know about hair serum

Hair serums are leave-in products that stay on your hair and scalp for hours or even all day. Because they sit on skin and are applied close to your face, the formulation deserves a close look.

Serums often contain synthetic fragrances, silicones, and preservatives that can build up with daily use.
Welpr focuses on clean formulations, fragrance transparency, and the absence of endocrine disruptors like parabens and phthalates.

Review what you already use

Check the serum you currently use by scanning it with the Welpr Personal Care and Cosmetic Scanner. It will flag any concerning ingredients so you can see how your product stacks up.

Look at the ingredient list for the word "fragrance" or "parfum"—these can hide undisclosed synthetic ingredients.
If you use more than one leave-in hair product, scan the one you apply most often or closest to your scalp first.

Use your current serum more carefully

If you're not ready to switch yet, small changes in how you apply your serum can reduce what your skin absorbs. This is especially helpful if your serum contains synthetic fragrance or harsh preservatives.

Apply serum to the mid-lengths and ends of your hair rather than directly on your scalp.
Use a smaller amount than you normally would—a little often goes further than the bottle suggests.

Choose a cleaner hair serum

Look for serums with simple, purposeful ingredients like plant-based oils and natural extracts. Fragrance-free options are best, but if scented, the fragrance should come from essential oils or plant extracts rather than synthetic sources.

Certifications like EWG VERIFIED™ or MADE SAFE® are a good sign, but Welpr still reviews every formula individually before approving it.
Click the button above to shop Welpr Approved hair serum.

Camille May

Cofounder & Product Curator

Camille May is the co-creator of Welpr and a guide for clean living. After selling her last company in the health food space, she went non-toxic while working to heal an autoimmune condition....

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Olushola M. Awoyemi

Medical Reviewer, PhD

Olushola M. Awoyemi (aka Shola) is a board-certified toxicologist and a research scientist with a PhD in Environmental Toxicology. Shola's long-term ambition is to be recognized as a world-renowned expert in toxicology,...

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