Amphetamine salts are a combination of four different forms of amphetamine, mixed in equal parts, that work together to increase certain brain chemicals involved in focus and alertness. You’ll most commonly see them listed on a prescription label as “mixed amphetamine salts” or by the brand name Adderall. The term “salts” refers to the specific chemical forms the active ingredient takes, not table salt or anything related to it.
The Four Salts and Why They Matter
Each tablet of mixed amphetamine salts contains exactly four compounds in a 1:1:1:1 ratio, meaning each one makes up 25% of the total active ingredient. Two of these are forms of dextroamphetamine (the “right-handed” molecular shape) and two are forms of amphetamine (the “left-handed” shape). So a 20 mg tablet contains 5 mg of each salt.
This distinction matters because the two molecular shapes behave slightly differently in your body. Dextroamphetamine is more potent at boosting focus-related brain chemicals, while the left-handed form contributes additional effects on alertness and physical energy. Combining both in one pill produces a broader, more balanced effect than using either form alone.
How They Work in the Brain
Amphetamine salts increase the levels of two key chemical messengers outside your brain cells: dopamine, which plays a central role in motivation and reward, and norepinephrine, which supports attention and arousal. But unlike some medications that simply block these chemicals from being recycled, amphetamine does something more active.
The drug enters nerve cells through the same doorways that normally pull dopamine back inside after it’s been released. Once inside, it does two things. First, it empties the tiny storage compartments where dopamine is held in reserve, flooding the interior of the cell with free dopamine. Second, it essentially reverses the direction of the recycling pumps on the cell’s surface, pushing dopamine and norepinephrine out into the space between nerve cells instead of pulling them in. The result is a substantial increase in these chemical signals, which improves the brain’s ability to sustain attention and regulate impulses.
What They’re Prescribed For
Mixed amphetamine salts are FDA-approved for two conditions: ADHD and narcolepsy. Both immediate-release and extended-release formulations carry these approvals. For ADHD, the immediate-release version is approved for children aged 3 and older, while the extended-release capsule is approved starting at age 6. Adults can use either formulation. For narcolepsy, the oral versions are approved, though the transdermal patch form of amphetamine is not cleared for this use.
Immediate-Release vs. Extended-Release
The two formulations differ mainly in how quickly they reach peak levels in your bloodstream and how long they last. With immediate-release tablets, blood levels of both amphetamine forms peak about 3 hours after you take them. Extended-release capsules delay that peak to around 7 hours, roughly 4 hours longer. This is because XR capsules contain two types of beads: one set dissolves right away, and the second set dissolves about 4 hours later, creating a two-phase release.
The elimination half-life (how long it takes your body to clear half the drug) also differs between the two molecular forms. In adults, dextroamphetamine has an average half-life of about 10 hours, while the left-handed form lingers a bit longer at around 13 hours. In children aged 6 to 12, those numbers are slightly shorter: 9 hours and 11 hours, respectively. This means a single extended-release dose can provide symptom control for most of the day, while immediate-release tablets typically need to be taken two or three times daily.
Typical Dosing
For the extended-release version, children 6 and older usually start at 10 mg once daily in the morning, with increases of 5 to 10 mg per week as needed. The maximum recommended dose for children is 30 mg per day. Adolescents aged 13 to 17 also start at 10 mg, with the option to increase to 20 mg after one week. Adults starting treatment for the first time typically begin at 20 mg per day.
Dosing is individualized. Some people respond well to low doses, while others need the upper end of the range. The goal is always the lowest effective dose that controls symptoms without producing significant side effects.
Scheduling and Prescription Rules
Amphetamine salts are classified as a Schedule II controlled substance by the DEA, the same category as oxycodone and fentanyl. This classification reflects a high potential for abuse and dependence. In practical terms, this means your doctor cannot call in or electronically send refills the way they might for most medications. You typically need a new prescription each time, and many states limit prescriptions to a 30-day supply.
Cardiovascular Considerations
Because amphetamine salts raise heart rate and blood pressure, they carry specific cardiovascular precautions. They should not be used by people with symptomatic heart disease, moderate to severe high blood pressure, advanced hardening of the arteries, or an overactive thyroid. People with known structural heart abnormalities are also generally advised against using them. Before starting treatment, a review of personal and family cardiac history is standard practice.
Long-Term Use and the Brain
One common concern is whether taking amphetamine salts for years causes lasting damage to the brain’s dopamine system. Animal research has shown that high doses of amphetamine can cause extensive, long-lasting damage to dopamine-producing nerve fibers in the brain’s movement and reward centers, with reductions persisting for months. However, even after this damage, the actual cell bodies that produce dopamine remain intact. This suggests the damage occurs at the level of wiring rather than killing off cells entirely.
It’s worth noting that these animal studies typically use doses far higher than what’s prescribed for ADHD. The neurotoxicity profile of therapeutic doses in humans over years of use is harder to pin down, and most clinical evidence does not show the same degree of damage seen in lab settings. Still, this is one reason doctors aim for the lowest effective dose and reassess the need for medication periodically.