Sebastian Dark Oil: The Complete Range, Explained by a Stylist

Sebastian Dark Oil is a seven-product range built around one hero: a lightweight argan-based styling oil that smooths and adds shine without weighing hair down. If you only buy one thing, buy the oil. The rest of the range exists to make the oil work better and last longer.

Dark Oil is the product people walk into the salon asking for by name. It's also the one they most often buy the wrong version of — the shampoo when they wanted the oil, the 30ml when they use it daily, the Taming Elixir when their hair is fine. This is the whole range, what each piece actually does, and who each one is for.

What is Sebastian Dark Oil?

Dark Oil is a styling and finishing oil built on argan and jojoba with a warm sandalwood-and-cedarwood fragrance. The thing that separates it from the hundred other hair oils on the shelf is its weight: it's genuinely light. You can use it on fine hair without it going flat, and on thick hair without it going greasy. Sebastian claim up to 48 hours of smoothness from a single application — take the number with a pinch of salt, but the frizz control is real and it does last past the first wash.

Because it's this light, it does three jobs. On damp hair it's a blow-dry primer that cuts drying time and stops the ends going fluffy. On dry hair it's a finisher that kills flyaways and adds shine. And a tiny amount worked through the mid-lengths before bed is the cheapest overnight treatment you'll find.

The styling oil: 30ml or 100ml?

The Styling Oil comes in two sizes. The 30ml is the right buy if you're trying it for the first time, if you have fine or short hair and use two drops at a time, or if you want one for a travel bag. The 100ml is the right buy for everyone else — at daily use on medium-to-long hair a 30ml is gone in six weeks, and per millilitre the big bottle is roughly a third cheaper.

How much to use is where most people go wrong. Start with one pump into your palm, rub your hands together until they're almost dry, then run them through the ends and mid-lengths only. Never the roots. If your hair looks oily afterwards you used too much; the fix is less, not a different product.

Shampoo, conditioner and mask: do you need them?

Honest answer: not to make the oil work. The oil is a standalone product. What the Shampoo, Conditioner and Mask do is carry the same smoothing and shine effect into the wash, so hair comes out of the shower already halfway to where the oil is trying to take it. If your hair is frizzy or dull by nature, the wash trio makes a visible difference. If it's already well-behaved and you just want polish, skip them and put the money into the 100ml oil.

Wella have started renaming the shampoo "Silky Shine" on the new bottles. Same formula — don't let the name change confuse you.

The Mask is the piece to prioritise if you buy any of the three. Once a week, damp hair, mid-lengths and ends, ten minutes. It's a smoothing mask rather than a repair mask — if your hair is breaking, you want Penetraitt instead.

Taming Elixir or Silkening Mist?

These two get confused constantly, and they suit opposite hair.

The Taming Elixir Serum is the heavier of the two. It's a cream-serum for thick, coarse or very frizzy hair — the hair that laughs at a light oil. Damp hair, before you blow-dry, worked through the lengths. It's also the one to reach for in humidity.

The Silkening Hair Mist is the lighter one — a fine aerosol spray for fine, medium or already-smooth hair that wants shine and a bit of slip without any weight at all. It's also a good detangler on damp hair, and a quick refresh on day-two hair. Because it's an aerosol, several NZ retailers can't courier it — we can.

Which Dark Oil product for your hair type?

• Fine or flat hair: the Styling Oil (two drops, ends only) and the Silkening Mist. Skip the Elixir — it'll flatten you.
• Medium hair with frizz: the Styling Oil daily, the Mask weekly. Add the Shampoo and Conditioner if the frizz is stubborn.
• Thick, coarse or curly hair: the Taming Elixir on damp hair, the Styling Oil on dry hair to finish, the full wash trio if you can. This is the hair the range was built for.
• Colour-treated or blonde: everything in the range is colour-safe. The Mask is worth it for shine on blonde, which dulls fastest.
• Curls: Dark Oil works as a finishing oil on dry curls but it isn't a curl product. For definition go to Twisted and use Dark Oil over the top.

Dark Oil vs Potion 9: which one?

People ask this a lot because they're the two Sebastian heroes. They aren't rivals. Dark Oil is a finisher — it goes on last, mainly on dry hair, for smoothness and shine. Potion 9 is a leave-in treatment — it goes on damp hair to condition, restore moisture and give soft hold before you style. Plenty of clients use both: Potion 9 in, blow-dry, Dark Oil to finish.

How to get the most out of it

• Less is always more. One pump. You can add; you can't take away.
• Rub it into your palms until they're nearly dry before touching your hair. This is the difference between shine and grease.
• Ends and mid-lengths only. The roots make their own oil.
• If you heat style, put Trilliant on before the iron and Dark Oil on after. Oil under a 200°C plate isn't protection, it's frying.
• Store it out of the sun. Argan oil goes off.

Sebastian questions we get asked

Is Sebastian Dark Oil good for fine hair?

Yes, if you use it correctly: one or two drops on the ends only, on dry hair. It's one of the lightest salon oils available. Skip the Taming Elixir on fine hair — that one's built for thick, coarse hair.

What's the difference between Dark Oil 30ml and 100ml?

Same product, different bottle. The 30ml is for trying it, for very fine or short hair, or for travel. The 100ml is better value for daily use on medium-to-long hair, roughly a third cheaper per millilitre.

Can I use Dark Oil every day?

Yes. A single pump on dry ends every day is how most of our clients use it. It's light enough that it doesn't build up as long as you keep it off the roots and wash normally.

Do I need the Dark Oil shampoo and conditioner for the oil to work?

No. The oil works on its own. The shampoo, conditioner and mask carry the same smoothing effect into the wash, which helps if your hair is naturally frizzy or dull, but they aren't required.

Is Dark Oil a heat protectant?

Not really. It gives a small amount of protection but it isn't designed for it. Use Sebastian Trilliant before heat and Dark Oil afterwards to finish.

Where can I buy Sebastian Dark Oil in New Zealand?

UKIYO is an authorised Sebastian Professional stockist and ships the full Dark Oil range NZ-wide from our Wānaka salon, free over $75. Several online retailers only carry old packaging or can't courier the aerosol Silkening Mist — we stock the current range and ship all of it.

See the full Dark Oil collection, or the complete Sebastian range we stock in NZ.

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Free NZ shipping over $75, and every order over $59 comes with a free Kérastase travel-size gift added at checkout. Genuine salon stock, shipped from our Wānaka studio — UKIYO is an authorised Sebastian Professional stockist.

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More Sebastian guides

• Potion 9: the cult leave-in
• NO.BREAKER: bond building explained
• NO.BREAKER vs Olaplex
• Penetraitt: repair for damaged hair
• Hydre: moisture for dry hair
• Twisted: curls without the crunch
• Volupt Max for fine hair
• Hairsprays: Re-Shaper vs Zero Gravity vs Fierce
• Every Sebastian styling product
• Trilliant: heat protection with shine
• Where to buy Sebastian in NZ

Shop the full Sebastian Professional range