DMSO and Castor Oil Ratios Explained: 10/90 to 75/25

A DMSO and castor oil ratio simply describes how much DMSO is blended with how much castor oil, written as DMSO first (a 30/70 blend is 30% DMSO and 70% castor oil). Lower DMSO ratios such as 10/90 or 20/80 are the mildest and are traditionally chosen for sensitive areas, while higher ratios such as 50/50 or 75/25 are traditionally used for larger muscle and joint areas. Many people find it easiest to start low and move up only as their comfort allows.

If you have been searching for how to mix, how to compare, or which ratio to pick, this guide breaks it down in everyday language. We are a small, family-run company, so we will also show how our own ready-made blends map to each ratio.

What does a DMSO and castor oil ratio actually mean?

DMSO (dimethyl sulfoxide) is a clear, naturally derived solvent that is traditionally used as a carrier. Castor oil, especially Jamaican black castor oil, is a thick, nourishing oil that people have used for generations in skin and body care. When the two are combined, the castor oil supplies richness and the DMSO changes how quickly the blend spreads and absorbs on the skin.

The ratio is just the percentage of each. A 50/50 blend is half DMSO and half castor oil by volume. A 10/90 blend is only one part DMSO to nine parts castor oil. Because DMSO is the more active part of the pair, the ratio is the main way a blend's strength is described. You can read more about the ingredient itself in our guide Understanding DMSO: history, uses, and safety, and about the oil in Castor oil packs: traditional use for muscle & joint comfort.

How do the common ratios compare?

Here is a simple side-by-side look at the ratios people ask about most. These descriptions reflect how each strength is traditionally used and how we describe our own blends; they are not medical guidance.

Notice that the jump from one step to the next is meaningful. Going from 30/70 to 50/50 raises the DMSO share by two thirds, so it is wise to move one step at a time rather than skipping ahead.

How do you choose the right ratio for you?

The best starting ratio depends on three things: the area of the body, your skin's sensitivity, and your experience with DMSO.

For sensitive skin or your very first time, many people begin with a 10/90 or 20/80 blend on a small patch of skin and wait a day to see how their skin feels. If that goes well, a 30/70 blend is a comfortable everyday middle ground. For broader areas such as the lower back, knees, or shoulders, people who are used to DMSO often reach for a 50/50 blend. The 75/25 strength is generally kept for experienced users with larger areas of persistent achiness.

Whatever you choose, a few habits matter more than the exact number. Use clean, dry skin. Apply to the skin only, never near open wounds. Avoid applying over lotions, perfumes, or anything you would not want carried along by the DMSO. Wash your hands before and after. And if your skin feels warm or itchy, go to a lower ratio or pause. We cover more of these basics in our DMSO safety overview.

If you are weighing pain-focused options, our Pain Care collection groups the 50/50 and 75/25 blends together with our Pain Free Body Butter with DMSO, and the DMSO Pain Relief Bundle lets you compare strengths in one order.

Can you mix DMSO and castor oil at home?

People do ask this, and the honest answer is that it is possible but easy to get wrong. The quality of each ingredient matters a great deal. DMSO should be a pure, high-grade product, and the castor oil should be a clean, unadulterated oil. Anything dirty, contaminated, or poorly stored in the mixing process can be carried along with DMSO, which is why many people prefer a ready-made blend made in a controlled setting.

If you do blend your own, measure by volume with clean glass or stainless tools, never plastic that could react with DMSO, and label the bottle with the ratio and date. Store it tightly closed, away from light and heat. Because DMSO attracts moisture from the air, keep the lid on whenever you are not pouring.

Our blends are mixed in set ratios so that every bottle matches the number on the label. That consistency is the main reason many customers choose a pre-blended option over mixing at the kitchen counter.

Which castor oil should the blend use?

Most people who like this pairing prefer Jamaican black castor oil. It is roasted before pressing, which gives it a deep color and its signature thick feel, and it has a long history in traditional body and hair care. Our blends use Jamaican black castor oil, and some use organic oil. If you are curious about the oil on its own, see Castor oil beyond the bottle: skin, hair, and full-body uses, or our overview of why castor oil and DMSO are paired for joint comfort.

Frequently Asked Questions

What is the most common DMSO and castor oil ratio?

Among the ratios people search for, 50/50 and 30/70 come up most. A 50/50 blend is a balanced choice for everyday muscle and joint comfort, while 30/70 is a milder, gentler step.

Can you mix DMSO with castor oil yourself?

Yes, people do, but purity and cleanliness matter. Use high-grade DMSO, clean glass tools, and exact measurements, or choose a ready-made blend so the ratio is consistent every time.

What is the difference between a 50/50 and a 75/25 blend?

A 75/25 blend contains half again as much DMSO as a 50/50 blend. It is traditionally used for deeper, more persistent discomfort on larger areas, so most people work up to it gradually.

Should I do a patch test first?

Yes. Apply a small amount to a small patch of clean skin and wait about a day. If your skin feels comfortable, you can continue; if not, try a lower ratio or stop using it.

These statements have not been evaluated by the FDA. This product/content is not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary.