The purity guide · By Dr. Marisol
What "hexane-free" really means, and why your castor oil bottle matters
Cold-pressed, hexane-free, glass: the three things to look for on a castor oil label, explained in plain words.
Hi, I'm Marisol. When women ask me which castor oil to buy, I always say the same thing: look past the front of the bottle.
Words like pure and natural are easy to print. Two other words tell you much more: hexane-free and cold-pressed.
Here is what they mean, how castor oil is actually made, why the bottle matters, and how to check your own oil. I have listed every source at the end.
The basicsHow castor oil is made
Castor oil comes from the seeds of the castor plant. Up to 90% of the oil is one fatty acid, called ricinoleic acid. That is what makes it so thick and rich[1].
To get the oil out, the seeds are pressed. Pressing at low temperatures gets out less than half of the oil. Pressing hotter gets out more[1].
The leftover seed pulp, called seed cake, still holds some oil. To get that last part out, factories can soak it in a solvent such as hexane[1].
How castor oil is made
3 ways to get oil out of a seed
Cold-pressed
Seeds are pressed slowly. No chemicals, no added heat.
Below 122°F (50°C)
- SolventNone
- HeatKept low
- Oil per seedLess
Expeller-pressed
Seeds are pressed hard and fast. The pressure makes heat.
Often 140 to 210°F (60 to 99°C)
- SolventNone
- HeatFrom pressure
- Oil per seedMore
Solvent-extracted
Seeds or leftover seed cake are soaked in a solvent like hexane.
Heated after, to remove the solvent
- SolventHexane
- HeatTo remove solvent
- Oil per seedAlmost all
Pressing and solvent extraction: Patel et al., 2016 [1]. Temperatures: our pressing guide [2].
Research also shows a small difference you can see: cold-pressed castor oil is usually lighter in color than solvent-extracted oil[1]. The temperatures above come from our own guide to pressing methods[2].
Know the wordWhat is hexane, and why is it used?
Hexane is a solvent made from crude oil. Its main use is pulling oil out of seeds and crops, like soybeans and corn[3]. It is fast and cheap, and it gets almost every last drop.
After extraction, the oil is heated to remove the hexane. The goal is to take it all out. Hexane is mostly a concern for factory workers who breathe it over long periods[3].
Still, many women would simply rather skip it. Especially for an oil they put on their skin every evening. That is your choice to make, and a good label makes it easy.
You asked
Does organic mean hexane-free?
In the US, organic rules do not allow volatile synthetic solvents in organic handling[4]. The USDA's organic board lists hexane as one of these solvents[5]. So certified organic castor oil should be hexane-free.
Look for the actual USDA Organic seal, not just the word "organic". Anyone can write the word. Only certified oils can use the seal.
Dr. Marisol
You asked
Is cold-pressed castor oil always hexane-free?
Cold pressing uses pressure, not solvents. So the pressing itself is hexane-free.
But "cold-pressed" is not a certified term. A brand can print it without proof. That is why I like to see a lab report too.
Dr. Marisol
You asked
Is castor oil safe on skin?
An expert panel that reviews cosmetic ingredients looked at castor oil and found it safe for use in cosmetics[6].
As with any oil, do a patch test first if you are new to it.
Dr. Marisol
Check it yourselfHow to tell if your castor oil is hexane-free
5 easy checks
-
Read the label
Look for the words "hexane-free" and "cold-pressed".
-
Find the seal
The USDA Organic seal means the oil is certified, not just described.
-
Ask for lab results
A good brand can show you a test for leftover solvents.
-
Smell it
Fresh castor oil smells faintly nutty, almost like nothing at all.
-
Check the bottle
Amber glass, a seal under the cap, and a batch number or date.
The bottle matters tooGlass, plastic and light: what the research says
A bottle of castor oil can sit on your shelf for months. What it sits in, and where you keep it, matter more than most people think.
Oil and plastic. Some plastics contain softeners called phthalates. These are "fat-loving": they mix easily into oils and fats. Food scientists have found that oily foods tend to pick them up from packaging more easily than watery foods do[7].
Not every plastic contains them, and rules limit how much can move into food[7]. But glass does not react with oil at all. It simply takes the question away.
Oil and light. Light makes oils age faster. In one study, olive oil was kept on a sunny windowsill for five weeks. Oil in clear glass changed the most. Amber glass helped, but only partly. Oil kept fully in the dark did not change at all[8].
Another study kept oil under shop lights for months. Even dark glass only slowed the change down. Oil kept in the dark changed very little, even after two years[9].
The lesson is simple: amber glass is good, and a dark cupboard is better. That is why our oil is always bottled in amber glass, at every size, and why I always say: keep it somewhere dark.
What the research shows
Glass, plastic and light
Clear glass
Changed the most
Amber glass
Changed less
Fully in the dark
No change
Amber glass is good. A dark cupboard is better.
Light studies: Kishimoto, 2019 [8] and University of Perugia [9]. Plastics: Food Packaging Forum [7].
How to keep your castor oil fresh
- Keep it dark: a drawer or cupboard is perfect. Not a sunny windowsill.
- Keep it cool: away from the stove, the heater and hot cars.
- Cap it: close the bottle after each use, so less air gets in.
- Smell it now and then: fresh oil smells faintly nutty, almost like nothing at all.
Our promiseHow I check our castor oil
Before we buy a batch, an outside lab tests it. If it does not pass, we do not buy it[2]. Here is what our Golden Castor Oil is checked for[10]:
- USDA Certified Organic: certified every year.
- Cold-pressed and hexane-free: pressed without heat or chemical solvents.
- Leftover solvents: meets USP limits for all Class 1, 2 and 3 solvents.
- Heavy metals: arsenic, cadmium, lead and mercury below detection limits.
- Phthalates: not detected.
- Amber glass: never plastic, at any size.
The oil I trust
Organic Golden Castor Oil
One ingredient. Cold-pressed, hexane-free and third-party tested, in amber glass.
- USDA Certified Organic
- 16.9, 8.45 or 3.38 fl oz, all in amber glass
- Pump on the large sizes, dropper on the small
Rated 4.93 out of 5 by 1,628 customers · 30-day money-back guarantee
You asked
Why is castor oil so thick? Is that normal?
Yes. Castor oil is one of the thickest plant oils there is[1]. That is what makes it stay where you put it.
Warm a few drops between your fingers, or apply it to damp skin. It spreads much more easily.
Dr. Marisol
Make it yoursSimple ways to use it
Face: press 2 or 3 warm drops into clean, damp skin at night.
Body: smooth it onto elbows, knees and heels after a warm shower.
Hair, lashes and brows: a few drops for a soft, glossy look.
Castor oil packs: 1 to 2 tablespoons on your pack for a quiet evening rest.
Your belly button: a few drops and slow circles before bed. Read my navel oiling guide.
"Trust is earned. So I show you where our oil comes from, how it is made and how we check it."
Why you can trust this guide
How this guide was made
- Written by
- Dr. Marisol Teijeiro, ND (inactive), founder of Queen of the Thrones®. She has worked in natural wellness since 2002 and is the author of two books.
- Based on
- 10 sources, including peer-reviewed research, an expert safety review and official sources. Each fact links to its source.
- Last reviewed
- October 30, 2026. We update this guide when new research comes out.
- Our promise
- We do not promise results that research has not shown. Where there are no studies, we say so.
- Our products
- Queen of the Thrones® makes the Golden Castor Oil in this guide. We mention them because we use them, and we keep the facts separate from the product.
- Not medical advice
- This guide is for education. It does not replace your doctor.
- Spot a mistake?
- Tell us and we will fix it.
Sources
I believe you deserve to see where information comes from. These are the sources used in this guide.
- Patel VR, Dumancas GG, Kasi Viswanath LC, Maples R, Subong BJJ. Castor oil: properties, uses, and optimization of processing parameters in commercial production. Lipid Insights, 2016 Read the source
- What is the difference between cold-pressed vs expeller-pressed castor oil? Queen of the Thrones® Read the source
- Hexane: hazard summary. U.S. Environmental Protection Agency Read the source
- 7 CFR 205.270(c)(2): Organic handling requirements, volatile synthetic solvents. U.S. Code of Federal Regulations Read the source
- Extractants and Solvents Discussion Paper. USDA National Organic Standards Board, Materials Committee, 2012 Read the source
- Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of Ricinus communis (castor) seed oil and related ingredients. International Journal of Toxicology, 2007 Read the source
- Phthalates: background article. Food Packaging Forum Read the source
- Kishimoto N. Influence of exposure to sunlight on the oxidative deterioration of extra virgin olive oil during storage in glass bottles. Food Science and Technology Research, 2019 Read the source
- Dark glass bottles are susceptible to oxidation, study finds (University of Perugia research in Food Chemistry). Olive Oil Times, 2021 Read the source
- Product transparency: organic certificate and lab results. Queen of the Thrones® Read the source
FAQs
Your castor oil purity questions, answered
It is castor oil made without hexane, a chemical solvent. The oil is pressed from the seeds instead of being pulled out with a solvent.
Look for "hexane-free" and the USDA Organic seal on the label. Then ask the brand for a lab test that checks for leftover solvents.
In the US, USDA Organic rules do not allow hexane extraction. So certified organic castor oil should be hexane-free. Look for the seal, not just the word.
Cold pressing uses pressure, not solvents, so the pressing is hexane-free. Because "cold-pressed" is not a certified term, a lab report is the best proof.
The seeds are pressed slowly so the oil stays below about 122°F (50°C), with no chemicals and no added heat.
Yes. Press 2 or 3 drops into clean, damp skin at night. Castor oil has a comedogenic rating of 0 to 1. Do a patch test first.
Amber glass keeps the oil as it is and blocks light that can make oil go stale faster. Oil can sit in its bottle for months, so the bottle matters.
Fresh castor oil smells faintly nutty, almost like nothing at all. A sharp, sour or chemical smell is a sign the oil is old or poorly made.
Some plastics contain softeners that mix easily into oils. Glass does not react with oil, and amber glass also blocks some light. That is why we always use amber glass.
Keep it somewhere dark and cool, like a drawer or cupboard, and close the cap after each use. Light and heat make oils age faster.
One ingredient. Nothing to second-guess.
Begin with one bottle.
USDA Organic, cold-pressed, hexane-free and third-party tested, in amber glass.
USDA Certified Organic · Third-Party Tested · Bottled in Glass
QUEEN OF THE THRONES®
This article is for general education only and is not medical advice. Dr. Marisol Teijeiro's naturopathic doctor license is inactive, and she does not diagnose or treat any condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. For external use only.