Does Vitamin C Affect Adderall?

Updated on January 15, 2024
 by — reviewed by Jason Williams, PhD (Contributor: George Collins / Editor: Yoko Hill)
An article exploring the complex interaction between Vitamin C and Adderall.

How does vitamin C affect Adderall’s effects?

Adderall is a commonly prescribed medication for Attention Deficit Hyperactivity Disorder (ADHD), helping individuals manage symptoms such as inattention, hyperactivity, and impulsivity.

Vitamin C, also known as L-ascorbic acid (or ascorbic acid), is an essential nutrient that supports various bodily functions, including immune system health and antioxidant protection.

But, does vitamin C interfere with Adderall? In this article, we will explore the effects of vitamin C on the absorption and effectiveness of Adderall and discuss considerations when using them together.

Read on to learn how to get enough vitamin C to maintain optimal health, whilst still getting the best out of your ADHD treatment regimen!

Understanding Adderall and Its Effects

Adderall is a stimulant medication that contains a combination of amphetamine and dextroamphetamine components. It works by increasing the levels of certain neurotransmitters in the brain, which can help improve focus, attention, and cognitive functioning.

Commonly prescribed for individuals with ADHD, Adderall also provides cognitive enhancement benefits for those without the disorder. Some of the most notable effects of Adderall include:

  1. Improved Focus and Concentration: Adderall is known for its ability to enhance focus and concentration in individuals with ADHD. It stimulates the central nervous system, allowing individuals to effectively maintain their attention on tasks and reduce distractions.
  2. Increased Alertness and Energy Levels: Adderall stimulates the release of dopamine and norepinephrine in the brain, which can result in heightened alertness and increased energy levels. This can be particularly beneficial for individuals with narcolepsy, a condition characterized by excessive daytime sleepiness.
  3. Enhanced Cognitive Function: Adderall has been shown to improve cognitive function, including memory, problem-solving, and decision-making abilities. This can be particularly helpful for students or individuals in high-pressure, demanding professions.
  4. Improved Academic and Work Performance: By improving focus, concentration, and cognitive function, Adderall can contribute to improved academic and work performance. It can help individuals stay on task, complete assignments or projects more efficiently, and achieve better overall results.
  5. Reduction of Hyperactivity and Impulsivity: For individuals with ADHD, Adderall can effectively decrease hyperactivity and impulsivity, leading to improved behavior and self-control. This can greatly enhance their ability to function in various settings, including school, work, and social environments.
  6. Part of a Comprehensive Treatment Plan: Adderall is often prescribed as part of a comprehensive treatment plan for ADHD or narcolepsy. It is typically used in conjunction with psychological, educational, and lifestyle interventions to optimize outcomes and improve overall quality of life.

Adderall is a controlled substance and should only be used under medical supervision.

While Adderall can be highly effective for managing ADHD symptoms, it is not without its side effects. Some common side effects of Adderall include insomnia, loss of appetite, dry mouth, headaches, and increased heart rate.

The Role of Vitamin C in the Body

Vitamin C, also known as ascorbic acid, is one of the most well-known and widely consumed vitamins.

It is crucial for various bodily functions, including the production of collagen, a protein that supports healthy skin, bones, and connective tissues. 

Additionally, Vitamin C acts as an antioxidant, protecting the body against harmful free radicals and supporting the immune system’s function. 

Here are some key functions of Vitamin C in the body:

  • Boosts the immune system: Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune systems. It helps in protecting against environmental oxidative stress and promotes the oxidant-scavenging activity of the skin.
  • Fights free radicals: As an antioxidant, Vitamin C fights harmful free radicals in the body. It neutralizes these unstable molecules, which can cause damage to cells and DNA. By doing so, it may help prevent or delay certain cancers and heart diseases.
  • Supports wound healing: Vitamin C is essential for the growth and repair of tissue all over the body. It plays a vital role in wound healing and helps maintain healthy bones, teeth, skin, and cartilage.
  • Enhances iron absorption: Vitamin C helps the body better absorb non-heme iron, which is found in plant-based foods. This can benefit vegetarians and vegans by ensuring they get enough iron from their diet.
  • Promotes healthy aging: Due to its antioxidant properties, Vitamin C may help promote healthy aging. It helps fight oxidative stress and reduces the risk of cartilage loss in individuals with osteoarthritis.

Some great sources that are rich in Vitamin C are oranges, grapefruits, lemons, and limes. 

This is the vitamin that all of us are aware of and we turn to this vitamin whenever we are experiencing a knock to our immune system. It’s also found in vegetables like broccoli, which is exactly why most of our parents insisted, ‘Eat your greens!’.

Vitamin C is a water-soluble vitamin, which means the body cannot store it. Therefore, it’s crucial to incorporate Vitamin C-rich foods into your daily diet to ensure an adequate intake.

Interaction Between Vitamin C and Adderall

Yes, Vitamin C (ascorbic acid) can impact the effectiveness of Adderall. Consuming foods or drinks high in Vitamin C can hinder the absorption of Adderall, both IR and XR, into the body. This is due to the high levels of citric acid and ascorbic acid in these items.

This includes some of your favorite citrus snacks and fruit juices. It also includes caffeine – a popular drink that many individuals rely on to stay stimulated throughout the day. A high intake of these substances will affect how much vitamin C interferes with Adderall and how many of its effects get dulled. 

So, how much vitamin C makes Adderall not work? 

Individuals need to consume an average of 60mg or less of vitamin C in order for this drug to continue working like normal. If users consume more than this, they are going to interfere with the effectiveness of their Adderall supplementation. 

In general, a more acidic environment can alter any amphetamine-based drug’s bioavailability, which refers to the fraction of the drug that reaches the bloodstream and produces its desired effects.

Additionally, Vitamin C increases the rate of urinary excretion of ADHD medication, further reducing its effectiveness in the body.

So, how long after ADHD meds can you have vitamin C? 

This answer – you need to have less than 60mg of vitamin C in your body by the time you take your medications. In order to ensure this, it’s best to avoid all sources of vitamin C at least an hour before and after taking Adderall.

If you have vitamin C roughly 30 minutes before taking Adderall, it will reduce the effects throughout the day, meaning you cannot effectively manage your ADHD.

Does vitamin C cancel out ADHD meds entirely? Possibly. It depends on how high the percentage of vitamin C is in your body, and the higher the dose, the more of an ‘off’ switch to your Adderall it will become. This includes both Adderall XR (extended-release) and Adderall IR (immediate release).

Some people even wonder if vitamin C actually makes Adderall last longer. Unfortunately, it doesn’t. The interaction between these two substances decreases the half-life, duration, and potency of Adderall.

Impact of Vitamin C on Adderall Effectiveness

The pH level of the gastrointestinal environment plays a crucial role in the absorption of medications. Adderall has a highly alkaline pH, while Vitamin C is acidic. When these substances come into contact in the stomach, the acidic nature of Vitamin C neutralizes the active ingredients in Adderall, such as dextroamphetamine and amphetamine.(1)

This interaction can ultimately decrease the absorption of both immediate-release (IR) and extended-release (XR) forms of Adderall.

The reduced absorption of Adderall can have implications for its effectiveness in treating conditions like attention deficit hyperactivity disorder (ADHD) and narcolepsy. Patients taking Adderall may experience a decrease in its therapeutic effects if they consume high amounts of Vitamin C or acidic foods and beverages.

While the clinical significance of the Adderall and Vitamin C interaction is still a topic of debate, it is crucial to be aware of this potential drug interaction.(2)

However, for patients who are not responding to Adderall as expected, it may be necessary to explore potential drug interactions, including the interaction between Vitamin C and Adderall.

Considerations and Precautions

If you are taking Adderall and considering supplementing with Vitamin C, then there are some tips that you will need to keep in mind in order to get the best out of your treatment regimen.

The relationship between vitamins and mental health is significant,(3) and a deficiency in any super vitamin will only lead to further complications in your symptom management.

Although vitamin C can reduce the absorption of Adderall and make it less effective, it’s also essential that you still consume a healthy dose of it daily. 

The average dose of vitamin C needed daily for optimal health is shown in the table below:

AgeRequired Daily Dosage of Vitamin C (mg)

Unlike animals, the human immune system cannot synthesize vitamin C on its own, so it’s vital to eat foods that contain this vitamin in order to maintain health and avoid getting sick. 

Here are a few considerations and precautions to consider:

  • Timing: To minimize any potential interaction between Vitamin C and Adderall, it is recommended to avoid taking Vitamin C supplements or consuming high doses one hour before and one hour after taking your supplement to make Adderall work.
  • Drug Safety and Effectiveness: It’s important to balance the potential benefits of Vitamin C supplementation with the known effectiveness of Adderall in managing ADHD symptoms. Find the right balance and ensure you are receiving the optimal benefits from both interventions. 
  • Switch Your Medication: If necessary, you may need to try alternatives to Adderall in order to maintain a healthy vitamin C intake. This is a personal decision, but it’s an option for those who want to use a medication that potentially isn’t amphetamine-based. There are some alternatives that better support your ability to regularly eat foods rich in vitamin C. They do not interact with this super vitamin the same that Adderall does. Options such as Modafinil(4) or Vyvamind(( are nervous system stimulants that are not impacted by the intake of vitamin C.


While Vitamin C is essential for overall health, its potential impact on the absorption and effectiveness of Adderall should be taken into consideration. Consider the timing of your supplementation in order to avoid the negative impact of vitamin C on the absorption of Adderall.

Additionally, if you do not want to cut back on your vitamin C count and prefer not to time your intake of this vitamin, then consider switching to alternative ADHD treatment options. You can try an option that does not interact with vitamin C.

Overall, it’s possible to metaphorically, ”Have your cake and eat it”. Or should we say fruit?

Remember: If you are currently taking Adderall or considering switching your medication, it is important to discuss any plans for Vitamin C supplementation with your healthcare provider. A doctor will provide personalized advice and guidance to help you optimize your treatment plan while ensuring your safety and well-being.

Sources, Studies, and Scientific Research
  1. Kiely, M E et al. “Effect of ascorbic acid on brain amphetamine concentrations in the rat.” Progress in neuro-psychopharmacology & biological psychiatry vol. 11,2-3 (1987): 287-90. doi:10.1016/0278-5846(87)90072-8 
  2. Stevens, Jonathan R et al. “Using stimulants for attention-deficit/hyperactivity disorder: clinical approaches and challenges.” The primary care companion for CNS disorders vol. 15,2 (2013): PCC.12f01472. doi:10.4088/PCC.12f01472 
  3. Joshi, Kalpana et al. “Supplementation with flax oil and vitamin C improves the outcome of Attention Deficit Hyperactivity Disorder (ADHD).” Prostaglandins, leukotrienes, and essential fatty acids vol. 74,1 (2006): 17-21. doi:10.1016/j.plefa.2005.10.001 
  4. Greenblatt, Karl. and Ninos Adams. “Modafinil.” StatPearls, StatPearls Publishing, 6 February 2023.