Yes, but high-dose vitamin C around the same time can make Adderall work less well.
The FDA prescribing information for Adderall states that acidifying agents lower blood levels and efficacy of amphetamines, and vitamin C (ascorbic acid) is the classic gastrointestinal acidifier. The effect is about dose and timing, not total avoidance: fruit at breakfast is fine, while a 500 or 1000 mg supplement or a large glass of orange juice taken with your dose can cut absorption. MedlinePlus also lists antacids and other products that interact with amphetamine salts, so the window around your dose matters in both directions.
Can I take vitamin C with Adderall? What to do
Common questions
Can I take vitamin C with Adderall?
You can take vitamin C while on Adderall, but timing matters if you take large doses. The FDA label for Adderall warns that acidifying agents, including gastrointestinal acidifiers like ascorbic acid (vitamin C), lower blood levels of amphetamine and make it work less well. This is mostly a high-dose issue: a 500 to 1000 mg vitamin C supplement or a big glass of orange juice swallowed at the same time as your dose can reduce how much Adderall your body absorbs. Normal amounts of vitamin C from food are not a problem. The simple fix is to take Adderall first and hold supplements or acidic juices for a few hours. Do not adjust your own dose to compensate. If your medication suddenly feels weaker after you started a supplement or changed your breakfast, mention it to your prescriber before changing anything.