Hydrafinil: Review of Nootropic Benefits, Dosage, & Side Effects

Updated on February 10, 2024
 by — reviewed by Jason Williams, PhD (Contributor: George Collins / Editor: Yoko Hill)
A comprehensive review of Hydrafinil, covering its nootropic benefits, dosage guidelines, and potential side effects.

This relatively new, yet effective, nootropic drug known as Hydrafinil is a cognitive enhancer that belongs to a class of drugs known as eugeroics. These are stimulants that produce wakefulness and alertness without the peripheral body effects typically associated with stimulants.

This fluorene derivative is often compared to its relatives, Adrafinil and Modafinil, in terms of effectiveness and usage. Hydrafinil’s primary claim to fame is its cognitive benefits, including improved attention, memory, and cognitive performance.

Unlike Modafinil, Hydrafinil is not approved by the FDA for human consumption, but it has gained attention in the world of nootropics for its potency and shorter half-life compared to other nootropic drugs.

Could this powerful smart drug be the answer you’re looking for to boost your dopamine levels?

Let’s have a closer look and find out!

What is Hydrafinil?

Hydrafinil powder, (also known as Fluoreno, 9-fluorenol, or 9-hydroxyfluorene) is a potent compound that falls under the category of eugeroics, a class of drugs known for pharmacokinetic properties that promote alertness and wakefulness. The idea behind the production of these drugs is to enhance alertness for people facing sleep deprivation, as well as for people who have sleep apnea, narcolepsy, or shift work sleep disorder.

Hydrafinil is a derivative of fluorene and is structurally similar to the analog of Modafinil and Adrafinil.(1) Its chemical structure is distinct but related, which influences its effects and mechanisms of action. Hydrafinil’s impact on the dopamine pathways is far less substantial which means that it is less likely to be addictive as a stimulant substance.

Like other eugeroics, Hydrafinil is thought to work by stimulating certain neurotransmitter systems in the brain. It is believed to function as a dopamine reuptake inhibitor, which increases the concentration of dopamine in the brainleading to enhanced alertness, attention, and information processing.

Hydrafinil is primarily known for its wakefulness-promoting properties. It’s used by some individuals seeking to enhance cognitive abilities, improve concentration, and reduce fatigue.

Hydrafinil is not approved by the FDA or WADA for use and is often categorized as a research compound.(2) Like Modafinil, its legality may vary by country, and it is typically available through a specialized supplier of nootropic supplements or research chemical products.

In summary, Hydrafinil is an efficacious synthetic compound that offers a nootropic impact that’s more effective than Modafinil. It’s popular with people due to its ability to enhance wakefulness without causing a crash.


  • Improves cognition to boost productivity and focus
  • Enables better information processing and learning abilities
  • Reduces fatigue and promotes wakefulness and alertness
  • Less addictive than other eugeroic nootropics


  • Not approved by the FDA
  • Limited human trials and research studies on its long-term safety profile

Mechanism of Action

The mechanism of action of Hydrafinil (9-fluorenol) is not as thoroughly researched or understood, but it is believed to influence cognitive function and wakefulness through several potential pathways:

  • Dopamine Reuptake Inhibition: Hydrafinil’s stimulation of dopamine pathways is one of its key effects. It works by inhibiting the reuptake of dopamine: it increases the concentration of this neurotransmitter in the brain. The dopamine receptor (DAT) in your brain plays a crucial role in mood, motivation, attention, and the reward system, which contributes to enhanced alertness and cognitive function. 
  • Enhanced Neurotransmitter Activity: Besides its impact on dopamine, Hydrafinil may also influence other neurotransmitter systems. This includes effects on serotonin, norepinephrine, choline, and other neurochemicals that are integral to cognitive processes and wakefulness.
  • Stimulation of Wakefulness Centers: Like other eugeroic compounds, Hydrafinil is thought to stimulate certain areas of the brain associated with wakefulness and alertness. This may involve the hypothalamus or other regions that regulate sleep-wake cycles and arousal levels.
  • Indirect Effects on Cognitive Function: By promoting wakefulness and reducing fatigue, Hydrafinil may indirectly enhance cognitive performance. This can manifest as improved concentration, better decision-making, and increased ability to focus on tasks without succumbing to distractions or tiredness.
  • Neuroprotective Effects: Some preliminary research suggests that compounds like Hydrafinil have neuroprotective properties, protecting the brain from oxidation.

Nootropic Benefits of Hydrafinil

While scientific research on Hydrafinil is limited compared to more established nootropics like Modafinil, its use is often based on anecdotal evidence and its theoretical pharmacological profile.

Here are the nootropic benefits attributed to Hydrafinil.

1. Enhanced Cognitive Function

Anecdotal reports from people who take Hydrafinil have shown that its ability to boost cognitive performance, such as faster information processing and better memory recall, is effective.

Overall, users experience better mental function that allows them to be more productive at work, during study sessions, or going about daily activities.(3)

2. Wakefulness Promotion

Hydrafinil promotes mental arousal, leading to wakefulness and alertness during daytime and nighttime shifts, allowing you to experience improved cognitive function no matter your sleep schedule.

Additionally, Hydrafinil is able to enhance alertness without necessarily eliciting the peripheral body effects, meaning that you do not experience a crash after its effects have worn off.

3. Increased Concentration and Focus

Hydrafinil works to increase your ability to concentrate and focus on tasks, especially those requiring sustained mental effort. This is due to its impact on your dopamine receptors (DAT), which stimulates a more efficient reward signal that will give you the energy you need to stay on your mental game.(4)

4. Mood Enhancement

Some people who use Hydrafinil report mood improvement, possibly due to its influence on dopamine and serotonin levels. This is also beneficial for people who are often sleepy, as it allows them to beat the natural irritation that comes with a lack of rest. 

5. Neuroprotective Properties

The neuroprotective effects of Hydrafinil, although not extensively studied, contribute to long-term brain health. This allows your neurons to be protected from oxidative stress, thus preventing cognitive decline.(5) 

Uses of Hydrafinil

Hydrafinil’s uses are largely based on anecdotal reports and its pharmacological profile, as there is limited clinical research specifically on it.

The primary uses of Hydrafinil include:

  • Promoting Wakefulness: Similar to other eugeroics like modafinil, Hydrafinil is used for its wakefulness-promoting effects. It’s particularly sought after by individuals needing to stay awake and alert, such as those working in shift jobs or facing demanding academic or professional schedules.
  • Enhancing Cognitive Function: Users often turn to Hydrafinil for its potential cognitive benefits, such as improved memory, increased mental clarity, and enhanced learning capabilities.
  • Improving Focus and Concentration: Hydrafinil is believed to aid in maintaining focus and concentration, especially during tasks that require prolonged mental effort.
  • Mood Enhancement: There are anecdotal reports of Hydrafinil having mood-enhancing effects, which could be beneficial for overall mental well-being and productivity.
  • Combating Fatigue: For those experiencing fatigue, whether due to sleep deprivation, medical conditions, or lifestyle factors, Hydrafinil is used to help alleviate tiredness and boost energy levels.

Where to Buy Hydrafinil

It’s tricky to find good quality nootropic supplements sold online. This task is not for the faint-hearted, and there are many scammers out there looking to sell you below-average Hydrafinil powder. 

Luckily, we have done the work of trying out various options and testing products from many companies.

Our top pick for the best place to order Hydrafinil is Science.bio.

This reputable company provides third-party tested nootropics, with worldwide shipping, and a 30-day return-or-exhange policy.

Hydrafinil Dosage

The commonly reported dosage for Hydrafinil is within the range of 50 mg to 150 mg per day. This range is based on user experiences and may vary depending on individual tolerance and desired effects.

It is often recommended to start with a lower dose, such as 50 mg, to assess tolerance and effects. This is particularly important for individuals who are new to nootropics or have sensitivities to stimulants.

Additionally, to prevent potential sleep disturbances, it is generally advised not to take Hydrafinil late in the day.

Hydrafinil Side Effects & Safety

Due to this lack of comprehensive scientific studies, the side effects and safety profile of Hydrafinil are not fully understood. However, based on its pharmacological profile and anecdotal reports from users, several potential side effects and safety considerations have been noted:

  • Insomnia or sleep disturbances
  • Headaches
  • Nausea
  • Digestive discomfort
  • Anxiety
  • Dry mouth

These side effects typically are short-lived and can also be avoided with responsible usage. Combining Hydrafinil with natural nootropics like Rhodiola Rosea supplements enhances its effects and promotes a decrease in anxiety. Additionally, drinking lots of water whilst using this nootropic supplement will decrease the chances of dry mouth. 

Some important notes on Hydrafinil’s safety profile include:

  • Potential for Tolerance or Dependence: While there is some suggestion that Hydrafinil might have a lower risk of dependence compared to other eugeroics, the potential for developing tolerance or dependence cannot be completely ruled out.
  • Unknown Long-Term Effects: The long-term safety and effects of Hydrafinil are not well-documented, which is a significant consideration for anyone thinking of using it regularly.


This next-generation Modafinil successor is a potent nootropic supplement for anyone who wants to get the best of their mental performance.

Hydrafinil is especially beneficial for those with a terrible sleep schedule, insomnia, or sleep disorders like sleep apnea. Fluorenol is no different to other eugeroic compounds in it’s mechanism of action, however it does not cause a crash after its effects have worn off.

Hydrafinil’s appeal lies in its potency and shorter half-life compared to more established eugeroics like Modafinil. This, along with its powerful benefits such as enhanced cognitive function, improved focus, and mood elevation, with a lower risk of side effects and dependence, have made Hydrafinil an effective solution for many people seeking increased mental function.


How long does Hydrafinil take to work?

The time it takes for Hydrafinil to start working can vary based on individual metabolism, dosage, and other personal factors. Generally, nootropics may take anywhere from 30 minutes to 2 hours to manifest noticeable effects.

What is the elimination half-life of Hydrafinil?

The elimination half-life of Hydrafinil is around 7 – 8 hours. This is the time it takes for the concentration of the drug in the blood to be reduced to half its initial value. Typically, a full dose lasts 12 hours, and in some cases, up to 15 hours. 

Should you cycle Hydrafinil?

Cycling nootropics, which involves taking them for a period and then taking a break, is often recommended to prevent tolerance and potential side effects. While there is no specific guideline for cycling Hydrafinil due to the lack of extensive research, following general nootropic cycling principles is advisable.

Can I stack Hydrafinil with other nootropics?

Stacking, or combining different nootropics, is common in nootropic communities. However, due to the limited research and understanding of Hydrafinil, it’s difficult to predict its interactions with other substances. Typically, users experience enhanced effects when Hydrafinil is stacked with Modafinil.

How should I store Hydrafinil?

Like many chemical compounds, nootropics should generally be stored in a cool, dry place away from direct sunlight. This helps to maintain their stability and potency.

Sources, Studies, and Scientific Research
  1. Tanda, Gianluigi et al. “Modafinil and its structural analogs as atypical dopamine uptake inhibitors and potential medications for psychostimulant use disorder.” Current opinion in pharmacology vol. 56 (2021): 13-21. doi:10.1016/j.coph.2020.07.007 ↩
  2. Knoop, Andre et al. “Mass spectrometric characterization of urinary hydrafinil metabolites for routine doping control purposes.” Drug testing and analysis vol. 13,11-12 (2021): 1915-1920. doi:10.1002/dta.3137 ↩
  3. El-Ghundi, Mufida et al. “Insights into the role of dopamine receptor systems in learning and memory.” Reviews in the neurosciences vol. 18,1 (2007): 37-66. doi:10.1515/revneuro.2007.18.1.37 ↩
  4. Nieoullon, André. “Dopamine and the regulation of cognition and attention.” Progress in neurobiology vol. 67,1 (2002): 53-83. doi:10.1016/s0301-0082(02)00011-4 ↩
  5. Malík, Matěj, and Pavel Tlustoš. “Nootropics as Cognitive Enhancers: Types, Dosage and Side Effects of Smart Drugs.” Nutrients vol. 14,16 3367. 17 Aug. 2022, doi:10.3390/nu14163367 ↩