Hair oil is one of the oldest hair care products, and one of the most versatile. A few drops can soften dry ends, tame frizz, add shine and protect hair during washing. Oils differ a great deal in weight and behavior, so the right choice depends on your hair type and on what you want the oil to do.
What this guide rests on
The comparisons here use general properties of each oil and the kinds of product sold, as described in hair care references and on labels. ArniSun has not tested these oils on hair, and claims about growth are assessed against published evidence.
What hair oil can do
- Soften and add shine by coating the hair.
- Reduce frizz by smoothing the cuticle.
- Reduce breakage from combing by lowering friction.
- Limit swelling of the hair in water, when applied before washing.
- Seal in moisture, when applied over a water-based product.
What hair oil cannot do
- It does not moisturize by itself. Oil contains no water. It holds in the moisture that is already there.
- It does not repair split ends. It only smooths them for a while. See Split Ends: Causes and Ways to Reduce Breakage.
- It has not been shown to make hair grow faster. Popular claims for castor, rosemary and other oils rest on limited evidence. See Scalp Massage: How to Do It and What to Expect.
Common oils compared
| Oil | Weight | Notes | Suits |
|---|---|---|---|
| Argan | Light to medium | Softening; adds shine; popular in serums | Most hair types |
| Jojoba | Light | Technically a liquid wax; similar in feel to scalp oil | Fine to medium hair; scalp use |
| Grapeseed | Light | Non-greasy | Fine hair |
| Sweet almond | Light to medium | Softening | Medium hair; dry ends |
| Coconut | Medium to heavy; solid when cool | One of the few oils shown to penetrate the hair shaft; reduces protein loss when used before washing | Thick, coarse, dry hair; can stiffen some hair |
| Olive | Heavy | Softening; pre-wash treatments | Thick, coarse, very dry hair |
| Avocado | Medium to heavy | Rich | Dry, coarse hair |
| Castor | Very heavy and sticky | Seals; adds gloss; often mixed with lighter oils | Coarse or coily hair; edges, in small amounts |
| Mineral oil | Light | Smooths and seals; does not penetrate | Dry hair; detangling |
Many "hair oils" on the shelf are blends of oils with silicones. These behave more like serums. They feel lighter and less greasy than pure oils. See Leave-In Conditioner vs Hair Serum: Which Do You Need?.
Choosing by hair type
| Hair type | Choice | Amount |
|---|---|---|
| Fine or oily | Light oil or oil-silicone blend, on the ends only | 1 drop |
| Medium | Argan, almond or a blend | 1 to 3 drops |
| Thick or coarse | Argan, avocado, olive or coconut | 3 to 6 drops |
| Curly | Medium oils, to seal after leave-in | A few drops per section |
| Coily | Richer oils and butters, for sealing. See Coily Hair Routine: Moisture, Detangling, and Styling | As needed |
| High porosity or bleached | Oils that seal, used over a leave-in. See Hair Porosity: What It Is and Why It Matters | A few drops |
Ways to use hair oil
1. As a finishing product
Rub one or two drops between your palms, and smooth over the ends of dry hair for shine and to calm flyaways.
2. On damp hair, before styling
Apply a small amount to the mid-lengths and ends after washing, over a leave-in conditioner. It helps to seal in moisture.
3. As a pre-wash treatment
Apply oil to dry hair from mid-length to the ends 20 to 30 minutes, or longer, before shampooing. This reduces the swelling and friction that washing causes. Shampoo thoroughly afterwards.
4. For the scalp
A light oil can soften a dry scalp before washing. Avoid oiling the scalp if you have dandruff or an oily scalp, because oil can make flaking worse. Always wash it out.
Reading the label
- Ingredient order. If cyclopentasiloxane or dimethicone comes first, the product is mainly silicone with some oil.
- "100% pure" means a single oil, with no additives.
- "Cold-pressed" or "unrefined" describes how the oil was extracted. It keeps more of the natural scent and color.
- Fragrance and essential oils can irritate the scalp.
- "Heat protectant". Only rely on an oil for heat protection if the label says so. Plain oils can heat up and damage hair.
Avoiding greasiness
- Start with one drop. Add more only if needed.
- Apply to the ends first, and keep oil away from the roots.
- Warm it between your palms, so that it spreads thinly.
- Use less on fine hair, and in humid weather.
- If hair looks stringy, you have used too much. A clarifying wash removes it.
Storage and safety
- Keep oils closed, and away from heat and light. Plant oils turn rancid.
- Discard any oil that smells sharp or stale.
- Oil on bathroom floors is slippery.
- Patch test if you have sensitive skin, or a nut allergy, and check the source of the oil.
Related on ArniSun
- Leave-In Conditioner vs Hair Serum: Which Do You Need?
- Hair Porosity: What It Is and Why It Matters
- Scalp Massage: How to Do It and What to Expect
- Split Ends: Causes and Ways to Reduce Breakage
- Coily Hair Routine: Moisture, Detangling, and Styling
Sources and further reading
Frequently asked questions
Which hair oil is best for dry hair?
Argan suits most dry hair. Thick or coarse hair can take richer oils, such as coconut, olive or avocado.
Does hair oil help hair grow?
There is no strong evidence that any oil speeds up growth. Oils can reduce breakage, which helps hair to keep its length.
Should I put oil on wet or dry hair?
Both work. On damp hair, it seals in moisture. On dry hair, it adds shine and smooths frizz. Use only a few drops.