Fladrafinil: Everything You Need To Know (Benefits & Risks)

Written on January 12, 2024 by | Reviewed by William Gallagher, MNeuroSci

In this article, I'll take a closer look at; Fladrafinil (CRL 40,941 or fluorafinil) which is a popular eugeroic in the biohacking-sphere. I'll cover some background information, its benefits, and risks, and finally, reveal if I would recommend it.

First off, what is Fladrafinil?

Fladrafinil is a nootropic and one of many smart drugs of the eugeroic class. It has been shown to improve cognitive function in healthy adults with little to no side effects. The drug acts as a selective wakefulness-promoting agent.

This means it will increase wakefulness and energy levels in healthy adults. It also enhances cognitive function by enhancing the effects of adenosine.

Adenosine is a chemical messenger in the brain that inhibits wakefulness, so an increase in its concentration will enhance wakefulness and energy levels.

Fladrafinil has a chemical structure that is very similar to Modafinil, which is another popular eugeroic. This similarity means that Fladrafinil is likely to produce the same effects as Modafinil.

Quick Overview of Fladrafinil:

  • Fladrafinil is also known as CRL 40,941
  • Its molecular formula is C15H13F2NO3S
  • Its molecular weight is 325.3
  • Only made for laboratory research use (not human consumption)
  • Most of the evidence available on fladrafinil (CRL 40,941) is anecdotal evidence

So what are the benefits of Fladrafinil?

The main benefit of Fladrafinil is that it increases wakefulness and energy

How does it work?

As I've mentioned, Fluorafinil acts as a Selective Wakefulness Promoting Agent. What this means is it will cause the user to feel more awake and energetic.

It is thought that the drug may act on receptors that inhibit adenosine in the brain, and so allow adenosine to increase. The mechanism for how this occurs is not fully understood.

The effects the drug has on individuals will be different. In general, healthy adults report that it increases energy levels, wakefulness, focus, and motivation. Also, users may report enhanced cognition and a sense of well-being and euphoria.


Users can expect to feel more alert without feeling overstimulated. It is not something that should be taken as a stimulant such as Adderall or modafinil, it is more of a natural energizing agent without the jitters or risk of crash/jitters than other stimulants have. In other words, it is not thought to be addictive.

Despite the potential benefits, there has been some controversy over Fladrafinil. In particular, many people have reported that the drug can cause insomnia.

This is thought to be due to the nootropic acting on adenosine receptors in the brain. The chemical is thought to make it difficult for users to fall asleep and stay asleep. Using other medications such as melatonin may help overcome this. Some people will find themselves unable to use Fladrafinil as a result of this.

On the flip side, some users have reported that Fladrafinil does not affect them in this way but only improves their sleep quality.

How effective is Fladrafinil?

Fladrafinil, CRL 40,941, has been shown to have the potential to help users stay awake. A decrease in sedation and feelings of fatigue are common. In fact, a study found that 40 mg of the drug helped users stay awake on monotonous tasks. Also, they felt more energetic and motivated to complete the task.

There is growing evidence that suggests Fladrafinil may improve cognition as well. A 2010 study examined its effects on cognitive ability in healthy adults while performing monotonous tasks. It was found that it enhanced planning ability, clarity of thought, and mental performance during cognitive tests making it suitable for maintaining wakefulness.

Adrafinil vs Fladrafinil - What's the difference?

To begin with, it is important to understand that Fladrafinil and Adrafinil are similar in some ways, but also very different in others.

Adrafinil is considered a prodrug of Fladrafinil. This means that it can be ingested to then be metabolized into Fladrafinil in the body. Through this method, users are able to bypass the first-pass metabolism system of the liver and so increase bioavailability.

In terms of what they do, they are pretty similar. Both have been shown to be effective nootropic cognitive enhancers that can improve wakefulness and reduce fatigue in users. Although both drugs appear to provide very similar benefits and side effects, there are some key differences.

The half-life of Adrafinil is around 1 on average, whereas Fluorafinil is around 2 hours. A shorter half-life means that it will wear off more quickly meaning more frequent dosing is necessary. In fact, some users report having to take Adrafinil multiple times per day.

High doses of Adrafinil can lead to side effects such as headaches and nausea. These are thought to be due to the drug's ability to increase serotonin levels in the brain. Fladrafinil, CRL 40,941, has not been shown to have this effect on serotonin levels and so some of these side effects may not occur with it.

In theory, Fladrafinil, CRL 40,941, should have a higher potency than Adrafinil due to its longer half-life. This means it could improve wakefulness for longer. However, this difference may not be significant for individuals with a lower tolerance and/or sensitivity to the drug.

Laboratory Research Use

It's worth pointing out that Fladrafinil, CRL 40,941, is not as well-researched and has a shorter history than Adrafinil.

Therefore it may be that there are effects reported with Adrafinil also possessed by Fladrafinil but they have not been extensively recorded because of the lack of research into the newer drug.

That said, some initial research into Fladrafinil has yielded promising results.

In animal studies, it was found to improve cognition and reduce locomotor activity compared to a control group.

Also, it appeared to have no effect on the sleep cycle of mice.

This is an important consideration as excessive locomotor suppression can cause problems with daytime wakefulness.

Human Consumption & Risks Involved

It's not just animal research that has looked into the effects of Fladrafinil, CRL 40,941.

In 2010 a study was published in the journal "Neuropharmacology" which examined its benefits as a cognitive enhancer.

In this study, healthy adults were given 40 mg of the drug for more than a week and asked to complete a monotonous activity.

It was found that Fladrafinil enhanced cognitive ability and performance when completing the tasks as well as having anti-aggressive effects.

Also, it reduced feelings of fatigue and sedation in test subjects compared to when they took a placebo.

As well as helping users stay awake when feeling fatigued, it's thought that Fladrafinil, CRL 40,941, may be able to improve focus and memory.

The risks involved in taking Fladrafinil, CRL 40,941, at low doses are believed to be minimal.

However, some users have reported side effects such as stomach pain and headaches.

If you experience these or other symptoms which you are not sure are related to taking this drug then consult a doctor.

Dosage & where to buy online

Anyone buying Fladrafinil powder (or capsules) should stick to the recommended dosage which is between 50 mg and 200 mg per day. Anything above this can cause unwanted side effects due to its long half-life meaning it can stay in your system for longer.

For new users start off at a low dose of around 50 mg/day which you can then increase as you get used to the drug over time.

To take Fladrafinil, simply swallow a small capsule of 50 mg or 100 mg. Make sure to take it with a full glass of water and wait for up to 2 hours before going to bed.

Remember that most of the information available on dosages is based directly on laboratory research use.

Disclaimer: It's worth noting that fladrafinil has mostly been used for laboratory research and not human consumption (research purposes only). The scientific evidence suggests that there are some risks involved when consuming fladrafinil.

FAQ - About Fladrafinil

Q: Is Fladrafinil legal?

A: It is legal to possess but not legal to sell or ingest in many countries.

Q: Is Adrafinil the same as modafinil?

A: Adrafinil is metabolized by the body into modafinil. Adrafinil is a prodrug for modafinil. Fladrafinil is also metabolized into modafinil, but not as easily which means it has a longer half-life so can stay in your system for longer.