Authored by Harmonie Hernandez, founder of Ceremony Hair Care, Kaua'i. I formulate by removing things, not by adding them. This article explains why our hair growth oil contains exactly three actives, none of which are the four ingredients you'll see in nearly every other "natural hair growth" product on the shelf.

Open ten "natural hair growth" products at Whole Foods, Sephora, or your local apothecary. Eight of them will list rosemary essential oil. Seven will list castor oil. Five will list jojoba. Most will list all three. The marketing copy on each one will tell you these ingredients are time-tested, research-backed, the gold standard for hair growth.

I formulated our pre-shampoo oil with none of them.

This article is the long version of why. Not because I think rosemary or castor are evil, they aren't. Because I think the conversation around hair growth has gotten lazy. The same four oils get recycled because they're cheap, available, and have folk-medicine credibility. None of those reasons are formulation reasons. And for a meaningful percentage of customers, those ingredients are actively the source of the scalp problems they're trying to solve.

The rosemary essential oil problem

Rosemary essential oil sits at the center of natural-hair-growth marketing because of a 2015 study (Panahi et al.) showing it performed comparably to 2% minoxidil for androgenetic alopecia. That study is real. It got picked up by every wellness blog and beauty editor for a decade. It's now treated as settled science.

What's missing from the marketing copy is the rest of the literature on rosemary essential oil and skin contact.

Rosemary essential oil at typical product concentrations (1 to 5%) is one of the more sensitizing botanical extracts in cosmetic chemistry. It contains 1,8-cineole, camphor, and α-pinene at high concentrations, three compounds with documented histories of contact dermatitis in dermatology literature. The European Scientific Committee on Consumer Safety (SCCS) has reviewed rosemary oil multiple times and consistently flags it for sensitization risk above 0.1% leave-on.

The clinical reality I see in customer messages: maybe 15 to 25% of people who try a high-rosemary product develop scalp irritation, redness, itching, or paradoxical shedding within 4 to 6 weeks. The original Panahi study didn't measure this, because it wasn't designed to. Hair growth was the endpoint. Scalp tolerance wasn't.

If you're in the 75% who tolerate it, rosemary essential oil might be helping your hair growth. If you're in the 25% who don't, rosemary is likely making your hair worse than doing nothing, and the symptoms (irritation-induced shedding) look identical to the very problem you bought the product to solve. There's no good way to know which group you're in until you try it. And the fairer formulation strategy, in my view, is to skip ingredients with this risk profile when there are alternatives that don't carry it.

The castor oil problem

Castor oil is the other ingredient that won't die. Its hair-growth reputation traces back to 19th-century apothecary advertising, which is to say, it traces back to nothing scientific.

What we actually know about castor oil:

  • It's a triglyceride dominated by ricinoleic acid, an unusual hydroxy fatty acid that gives castor its distinctive thick, tacky texture.
  • It has antimicrobial properties at high concentration (which is why it's in so many "scalp clarifying" products).
  • There is no peer-reviewed clinical study showing castor oil grows hair. None. The closest thing is a single 2003 paper showing in-vitro prostaglandin pathway interaction, interesting, not clinical.
  • It's strongly comedogenic on skin. The same ricinoleic acid that gives castor its texture forms a sticky barrier that clogs follicles and traps sebum, debris, and product residue.

That last point matters a lot. The follicle is where hair grows. If you're putting a substance on your scalp that has a documented tendency to clog follicles, you are working against the goal at the mechanism level. I have customers who came to Ceremony after a multi-month folliculitis flare from heavy castor-oil use elsewhere. The story repeats often enough that I treat it as a pattern, not a coincidence.

The other complication: castor oil is so thick that it doesn't rinse cleanly with anything except sulfate shampoos. So the "natural hair growth routine" that combines castor oil with sulfate-free shampoo creates a gradual, invisible buildup at the scalp that takes weeks of clarifying to undo. People often describe it as their hair "stopped working", that's the buildup speaking.

Why jojoba isn't bad, just not a growth ingredient

Jojoba gets a kinder treatment from me because it isn't problematic, it's just not pulling its weight in a hair-growth formulation.

Jojoba (technically a wax ester, not a true oil) has a fatty-acid profile that mimics human sebum. That makes it useful as a skin moisturizer because the body recognizes and tolerates it well. It's a fine carrier oil. It's a fine moisturizer. It's a fine ingredient.

What it isn't: a hair growth driver. Jojoba doesn't influence DHT, doesn't change microcirculation, doesn't deliver clinically meaningful antioxidants at typical concentrations. It's there because it's there, because every "natural hair growth" formulation copies the same recipe and jojoba is on the recipe.

I left jojoba out for the same reason I leave out filler ingredients in our shampoo. If something isn't doing real work, it's a place where a more useful ingredient could be. Formulation is subtraction, not addition.

What actually drives hair growth (mechanism, not marketing)

Before I tell you what's in our oil, here's the framework I formulated against. Hair growth in adults is gated by four things, in roughly this order of impact:

  1. Genetic predisposition, the dominant factor for hair density and pattern. Topical products do not override this. Anyone selling you that is overpromising.
  2. Hormonal signaling, especially DHT, dihydrotestosterone is the dominant signal in androgenetic hair loss for both men and women. Some topical actives modulate this pathway modestly. The effect is real but partial.
  3. Scalp inflammation and microbiome health, chronic low-grade scalp inflammation suppresses the growth phase (anagen) and accelerates the shedding phase (telogen). Fix the scalp, and you remove a brake.
  4. Microcirculation and nutrient delivery, the follicle needs blood supply. Anything that improves scalp circulation marginally helps. Massage helps. Some botanicals do too.

A useful pre-shampoo oil should target categories 2, 3, and 4, the levers topical products can actually move. Category 1 is your parents.

That gave me my formulation brief: one active for DHT modulation, one for microcirculation and scalp tone, one antioxidant carrier to keep the formula shelf-stable and bring its own scalp-supportive properties. Three things, each doing something the others don't.

Pumpkin seed oil and DHT (the real research)

Pumpkin seed oil is the one ingredient where the literature actually shows up.

The relevant clinical paper is Cho et al. 2014, published in Evidence-Based Complementary and Alternative Medicine: a 24-week randomized, double-blind, placebo-controlled trial of oral pumpkin seed oil (400 mg/day) in men with androgenetic alopecia. The treatment group showed a 40% mean increase in hair count vs 10% in placebo. That's a real effect size from a real trial.

The mechanism is plausible: pumpkin seed oil contains delta-7-sterols that appear to inhibit 5α-reductase, the enzyme that converts testosterone to DHT. Lower DHT exposure at the follicle means less miniaturization, more anagen-phase growth. This is the same mechanism finasteride works through, at vastly lower potency and zero systemic side effects.

Two honest caveats. First, the Cho study was oral, not topical, there is less direct clinical data on topical pumpkin seed oil specifically. Second, the effect is partial; this is not minoxidil-level efficacy. But the mechanism is sound, the active compounds are present in the oil, and topical application puts the active where the follicle is. For a pre-shampoo oil that sits on the scalp for 20 to 30 minutes before being washed in, the math is reasonable.

We use cold-pressed pumpkin seed oil at the highest concentration the formula will tolerate while remaining non-comedogenic. It's the lead active in our pre-shampoo. Cold-pressing matters because heat degrades the sterols.

Nettles and scalp circulation (traditional plus modern)

Nettle (Urtica dioica) is the second active. The traditional medicine literature on nettle for hair is centuries deep across European, Ayurvedic, and Indigenous American traditions. Modern dermatological literature is thinner but converging on a few mechanisms.

Nettle leaf extract contains beta-sitosterol, another phytosterol with documented 5α-reductase activity, similar to pumpkin seed but with a different binding profile. It's also high in flavonoids (quercetin, kaempferol) that act as topical anti-inflammatories. And it contains silica, which supports keratin formation when absorbed.

The reason I included nettles alongside pumpkin seed instead of doubling up on pumpkin alone: complementary spectrum. Pumpkin seed is targeting the hormonal axis. Nettles are reinforcing on that axis but adding scalp anti-inflammatory action and trace minerals. Two different angles on the same problem produce more reliable real-world results than one angle at higher dose.

Nettles also have a long anecdotal record of improving scalp itch and seborrheic-like flaking. I won't claim that's clinically proven. I will say that customer feedback strongly tracks the traditional claim.

Vitamin E (the unsexy essential)

The third active is vitamin E (mixed tocopherols), and I include it for two reasons that aren't glamorous enough to put on a label.

First, oil-based hair products oxidize. Oxidation degrades the active phytosterols in pumpkin seed and nettles, turning the oil from a functional formulation into a rancid one over months on a shelf. Vitamin E is a fat-soluble antioxidant that protects the formula from this. Without it, our oil would have a useful shelf life of maybe 3 to 4 months. With it, we get 18 to 24.

Second, vitamin E itself has scalp benefits, modest but real. A 2010 trial in Tropical Life Sciences Research showed mixed-tocotrienol supplementation produced a 34.5% increase in hair count over 8 months. The mechanism is antioxidant protection of the hair follicle from oxidative stress, which is one of the contributors to age-related hair thinning.

So vitamin E is doing double duty: keeping the formula stable and contributing to the active goal. Three ingredients, three jobs.

The protocol: how to use a pre-shampoo oil correctly

Most people use pre-shampoo oil wrong. The instructions on the bottle are usually two lines, and two lines isn't enough for an unfamiliar ritual. Here's the longer version.

1. Apply to a dry scalp, not damp hair

The point is contact with the scalp surface. Damp hair dilutes the oil and prevents it from reaching the scalp. Section your hair, apply small drops directly to the scalp surface, front, crown, behind ears, nape, and rub in with the pads of your fingers, not your nails.

2. Massage for at least three minutes

This step is half the value. The mechanical action of massage is what improves microcirculation. Three minutes minimum. Five is better. Longer is fine. You can do it while watching something or at the end of a shower the night before. The oil should disappear into the scalp; if you're left with a slick film, you used too much. Half a teaspoon for shoulder-length hair is plenty.

3. Let it sit for 20 to 60 minutes

This is the contact time the actives need. Twenty minutes is the floor. Sixty is the ceiling beyond which more time doesn't help. I do mine 30 minutes before a shower, or overnight on a towel-covered pillow once a week.

4. Wash out with a real shampoo

This part matters. Skipping wash-out, or using a cleanser that's too gentle, leaves residual oil on the scalp that can cause buildup over time (the same pattern I described with castor). Our organic shampoo powder rinses pre-shampoo oils cleanly because the SCI surfactant is strong enough to cut oil while staying gentle on the cuticle. Other sulfate-free shampoos can also work; pure soaps cannot.

5. Frequency: once or twice a week

More isn't better. The follicle needs time off between treatments. Once a week for maintenance, twice a week if you're actively addressing thinning. Patience is the protocol's silent ingredient, visible changes show up at month 2 to 3, not week 2.

Who this oil is for, and who should skip it

Pre-shampoo oils with our composition are most useful for:

  • Anyone in the early stages of androgenetic thinning (women's diffuse pattern, men's frontal/crown recession) who wants a topical intervention before considering minoxidil or finasteride.
  • Postpartum hair shedding, though here the value is more about scalp recovery and reducing further insult than about reversing the shed. Postpartum shedding largely resolves on its own; gentle support helps it resolve cleaner.
  • Anyone whose scalp has reacted poorly to rosemary essential oil products and who wants the same hair-growth goal with a different active profile.
  • Long-time castor oil users dealing with buildup who want to switch to something that rinses cleanly.

It's less useful for:

  • Acute medical hair loss (alopecia areata, post-chemotherapy regrowth, thyroid-related shed). See a dermatologist; topicals are not the lead intervention here.
  • Anyone who responds well to their current rosemary-based product. Don't fix what isn't broken.

Frequently asked questions

Why no rosemary at all? What if I want it?

You can buy a rosemary product anywhere. We're choosing to fill the gap that nobody else is filling: a clinically thoughtful hair growth oil for the people for whom rosemary doesn't work. If you're in the rosemary-tolerant majority and your current product is helping, our oil isn't the upgrade you need.

Is this minoxidil?

No. Minoxidil is a synthetic vasodilator with strong clinical evidence and real side effects (scalp irritation, unwanted facial hair, dependence, stopping use returns hair loss to baseline). Topical pumpkin seed and nettles are gentler and slower-acting. They're complementary tools, not replacements. Some customers stack them; that's a conversation for your dermatologist.

How long until I see results?

Eight to twelve weeks of consistent use, twice a week. Hair growth biology is slow, the active growth cycle is 2 to 6 years, and any topical change has to outwait the existing cycle. Photo evidence from week 1 is not real. Photo evidence from month 3 is.

Can I use it on my eyebrows or beard?

Yes, same protocol, smaller amount. Pumpkin seed and nettle work the same way wherever DHT-driven thinning is happening.

Will it leave my hair greasy?

Not after wash-out. The pre-shampoo step is specifically designed to be cleared by your shampoo. If your hair feels greasy after washing, your shampoo isn't strong enough, switch to one that is.

Is it safe during pregnancy and breastfeeding?

The ingredients are commonly considered safe, but I never give pregnancy advice. Confirm with your OB or midwife. There are no known issues with topical pumpkin seed, nettles, or vitamin E in standard concentrations during pregnancy.

Why is it more expensive than castor oil from the grocery store?

Cold-pressed pumpkin seed oil is roughly 12x the per-ounce cost of castor oil. We're paying for an active that does the work, not a filler. One bottle of our oil at twice-weekly use lasts roughly 4 months for shoulder-length hair. The math works out to less per month than most "natural hair growth" products at the same use rate.

Ready to try it?

Our Organic Hair Growth Oil is hand-pressed in small batches on Kaua'i. Three actives, pumpkin seed, nettles, vitamin E. Nothing else. Castor-free, rosemary-free, jojoba-free.

If your scalp has reacted to the standard "natural hair growth" formulas, this is the alternative built specifically for you. If those formulas have been working, keep doing what works. We aren't trying to be everything to everyone.

Pretty hair is healthy hair. The oil is the lever. The scalp is the soil. Take care of the soil.

Continue reading: