Copaiba essential oil is attributed with a great number of medicinal properties—from healing arthritis to clearing acne. There should be some truth to all these claims, as it is said to have been in use for almost 400 years. Let's take a brief look at its history, uses, and also what science says
"Copaiba" is but one name of several that refer to the tree genusCopaifera. The tree grows most prolifically in the South Americas, almost 100 feet high, and produces a reddish fruit and yellow flowers.
Copaiba essential oil is made from an oleoresin gathered from the tree trunk.
The tree's resin has most probably been in use for a very long time by the indigenous tribes in the Amazon.
The first European settlers in Central and South America reported the native American Indians to apply the resin to the navels of newborns, and also to the wounds of warriors after battle. Apparently, the indigenous people started using the oil this way after observing animals rubbing their injuries on the stems of the trees.
However, its first mention in European medicine dates back to the 1600s, when it was brought back from the Amazon by the Jesuits. It was first called Jesuit's balsam according to Raintree, an online tropical plant database. The Amazon tribes used it for chronic cystitis, bronchitis, chronic diarrhea, and as a topical preparation for hemorrhoids, among other applications. It is also used in ceremonies for spiritual and physical healing.
Between 1820 to 1910, copaiba resin was listed in the U.S. Pharmacopeia as an official medicine for the treatment of infections, constipation, and water retention. It was also used as a stimulant.
In the U.S. today, it is mainly used in perfumes and cosmetic preparations for its sweet fragrance, such as in soaps, creams, lotions, bubble baths, and detergents. The products are sometimes also advertised as antibacterial or antiseptic, but these cannot, of course, be seen as medical claims. 
As with most herbal medicine, a portion of claims about copaiba essential oil's healing powers is largely anecdotal and not backed by science. While this doesn't automatically discredit its efficacy, it is true that the oil should be used with caution. Copaiba essential oil can be very harmful if you take too much of it.
Copaiba oil benefits are advertised as:
But does science back up these claims? Some animal and small human studies do seem to.
Indigenous tribes have used copaiba oil to treat pain and associated inflammation for centuries. Anecdotes and preliminary (meaning animal) studies seem to suggest that orally administered copaiba has the potential for treating pain and inflammation in arthritis.
Testing on rats with adjuvant-induced arthritis, the researchers of a study conducted in Brazil concluded that copaiba oil showed anti-inflammatory and antioxidant action.
However, they also cautioned:
"These beneficial effects, however, were counterbalanced by harmful modifications in the liver cell metabolism and morphology of healthy control rats."
This potential of copaiba oil to harm the liver cannot be seen as a blanket reason to dismiss its healing potential. The side effect in this particular study could be due to any number of reasons, including dosage size, the method of administration, etc. However, the toxic effects should not be discarded, either. More about this later. 
Another Brazil-based clinical study looked into the potential of copaiba essential oil for the treatment of acne. Volunteers were recruited at a clinic and were treated with either the oil or a placebo.
The research team's findings were positive:
"Our results indicate that the essential oil of copaiba might have utility as a topical treatment of mild acne."
They attribute this to the oil's anti-inflammatory and antioxidant action. The author also notes that more study is needed to see if it is effective against acne vulgaris and severe outbreaks of acne. 
Yet another Brazil-based, controlled study on rats demonstrated that copaiba oil resin can protect nerve tissue. This is done through the resin's anti-inflammatory action.
"The results suggest that COR [copaiba oil-resin] treatment induces neuroprotection by modulating inflammatory response following an acute damage to the central nervous system." 
Copaiba resin has been shown to have an antibacterial effect, but no traceable study showed that copaiba in an essential oil formulation has the same property. 
All of this is promising, but as said—these studies cannot be taken as scientific proof that copaiba essential oil is safe and efficacious just yet. As noted by the authors in one recent article inIntegrative Medicine, regarding its use for anti-inflammatory arthritis:
"...the research challenge is to test topical copaiba versus a placebo for IA [inflammatory arthritis] patients against a background of usual care in RCTs [randomized control trials] of sufficient size, dose, and duration. If such trials show positive results, a logical next step might be head-to-head comparisons against NSAIDs and COXIBs. Evidence from RCTs may support more widespread use or, to paraphrase Huxley, conclude that copaiba is yet another beautiful hypothesis slain by ugly facts." 
The same argument goes for all the other alleged copaiba oil benefits.
Furthermore, if you choose to ignore the fact that much more robust, well-designed clinical research is necessary, there are always the side effects to consider.
As noted on WebMD:
"Copaiba balsam can cause side effects such as stomach pains, vomiting, diarrhea, rash, tremor, groin pain, and sleeplessness (insomnia). When used on the skin, it can cause redness, itching, and a rash that might leave brown spots after healing." 
RELATED: How Safe Is Cannabidiol?
For these reasons, full spectrum organic CBD oil might well be the better option in almost every respect. It is also a natural compound, but it has been more thoroughly tested than copaiba essential oil. Furthermore, it appears to be completely safe even in high doses.