Cypenamine: Everything You Need To Know (Benefits & Side Effects)

Updated May 12, 2024 by | Reviewed by William Gallagher, MNeuroSci
(Estimated reading time: 3 minutes)

N-Ethyl-Cypenamine (also known as cypenamine hydrochloride and 2-phenylcyclopentylamine), is a potent, fast acting psychostimulant.

This article will give a description of the drug, benefits, side effects as well as possible legal ramifications.

So without further ado, let's just get straight into it, shall we?

What is Cypenamine?

Cypenamine is a molecule that can be considered to have some structural similarity to fencamfamine.

Cypenamine is the result of the research performed by scientists at the William S. Merrell Chemical Company in the 1940's.

The company developed several compounds intended to enhance physical and mental performance during World War II but none were found to be suitable for use in combat.

In the 1950's a group at Merrell that was interested in finding a blood pressure lowering drug, began studying cypenamine and its pharmacological properties.

For much of the following decade the company continued to research the drug as an antihypertensive agent but eventually abandoned it in favor of other more promising drugs in this area.

How Cypenamine Works

Cypenamine works by stimulating the sympathetic nervous system.

This would occur through the same mechanisms that are associated with stimulating the central nervous system, causing a release of norepinephrine and dopamine.

The dose of cypenamine used in experiments was around 0.4 mg per kilogram of body weight for a period of four to six weeks.

This is greater than the dosage of fencamfamine. Because of the higher dosage, cypenamine produces more pronounced increases in energy and a general sense of well being.

Cypenamine vs Fencamfamine

Both drugs are based on the same amphetamine-like molecule and are considered to be psychostimulants.

However, fencamfamine is an active agent in its own right whereas cypenamine is a prodrug which must be metabolized into an active form.

Cypenamine also differs from fencamfamine in that it is more potent and has more potential side effects.

Legal Implications

Cypenamine is currently legal throughout the world.

This means that there are no regulatory laws in place to restrict its sale, production and use as there are for fencamfamine. This may be because the drug has never been developed for market.

In some countries fencamfamine is scheduled as a controlled substance under the United Nations Convention on Psychotropic Substances of 1971.

Benefits & Side effects

The main function of Cypenamine is to stimulate the sympathetic nervous system.

This property makes it an effective source of energy, and also acts as a mild euphoriant .

Another benefit of cypenamine is that when taken at the correct dosage, it has no significant drug side effects .

Though there are several reports of adverse effects, these are generally minor and are usually related to over dosage.

The most common adverse effect is insomnia.


Cypenamine is a drug that has been researched throughout most of the 20th century.

After an unsuccessful search for an antihypertensive, the company at William S. Merrell Chemical Company began researching the drug as a potential stimulant.

Throughout much of the 1950's it was studied alongside other psychostimulants such as amphetamine and methamphetamine, but finally in 1960, it was dropped from the market and rights were sold to a company in Japan.

Cypenamine is currently legal throughout most of the world with no restrictions on its sale or use. The drug has been abandoned in favor of Fencamfamin for treating depressive day-time fatigue.