The Best Nootropics for Cognition

Lion's Mane (Hericium erinaceus) is a mushroom long used in Chinese and Japanese cooking and herbal traditions. It contains compounds called hericenones and erinacines that researchers are studying for their possible role in nerve growth factor (NGF) activity, which is why it's become a popular pick for memory and focus support.

Typical dosage: Capsule products typically range from 500mg to 2,000mg per day, often split with meals. Extract strength varies a lot by brand, so follow the label rather than assuming doses are equivalent between products.

Things to know: Generally well tolerated. Skip it if you have a mushroom allergy, and check with a doctor before combining it with other supplements or medications.

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Bacopa Monnieri is an Ayurvedic herb used for centuries in traditional Indian medicine, mainly studied for memory and learning support. Its active compounds, bacosides, are thought to support communication between nerve cells.

Typical dosage: Studied doses generally range from 300mg to 450mg/day of a standardized extract. Unlike caffeine or L-theanine, effects are usually reported after 8-12 weeks of consistent daily use, not immediately.

Things to know: Can cause mild stomach upset in some people when taken on an empty stomach — try it with food. Not recommended during pregnancy or breastfeeding without medical advice.

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Rhodiola Rosea is an adaptogenic root that grows in cold, high-altitude regions of Europe and Asia. It's traditionally used to help the body handle physical and mental stress, and is often reached for during periods of fatigue.

Typical dosage: Common doses range from 200mg to 600mg/day, standardized to rosavins and salidrosides. Most research uses a roughly 3:1 rosavin-to-salidroside ratio — worth checking the label for.

Things to know: Some people find Rhodiola mildly stimulating, so it's often taken earlier in the day. Check with a doctor if you're on medication for mood or blood pressure.

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L-Theanine is an amino acid naturally found in green and black tea leaves, known for promoting calm, focused alertness without sedation. It's commonly paired with caffeine to take the edge off jitters while keeping the alertness.

Typical dosage: Typical doses range from 100mg to 400mg, and it can be taken any time of day since it isn't sedating by itself.

Things to know: Generally very well tolerated with a strong safety record. Some people notice the calming effect more than others.

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Tongkat Ali (Eurycoma longifolia) is a root native to Southeast Asia, traditionally used to support energy, stamina and healthy testosterone levels in men.

Typical dosage: Standardized extracts are commonly dosed at 200mg to 400mg/day. Look for the extraction ratio (e.g. 100:1, 200:1) on the label — potency varies a lot between raw root powder and concentrated extracts.

Things to know: Not recommended for anyone under 18, during pregnancy or breastfeeding, or alongside hormone-sensitive conditions without medical guidance.

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Shilajit is a sticky, tar-like resin that seeps from rocks in the Himalayas and other high-altitude mountain ranges, formed over centuries from slowly decomposed plant matter. It's used in Ayurvedic medicine as a general tonic, and modern interest centers on its fulvic acid and trace mineral content.

Typical dosage: Resin forms are typically dosed at 300mg to 500mg (roughly a pea-sized amount) once or twice daily, usually dissolved in warm water or milk. Purity matters a lot here — look for third-party lab testing for heavy metals, since it's a mineral resin harvested from rock rather than grown.

Things to know: Because Shilajit is mined rather than grown, heavy metal contamination is the main safety concern — stick to brands that publish lab testing. Not recommended during pregnancy or breastfeeding, and check with a doctor if you have hemochromatosis (iron overload) or another condition affected by mineral intake.

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Ashwagandha (Withania somnifera) is a shrub whose root has been used for centuries in Ayurvedic medicine as a tonic. It's usually described as an adaptogen, and most modern research looks at stress and sleep, using extracts standardized for compounds called withanolides.

Typical dosage: Root extracts such as KSM-66 are typically taken at 300mg to 600mg per day, once or split into two doses, often in the evening. Studies usually ran for 6 to 12 weeks, so judge it over weeks rather than days.

Things to know: Not for use during pregnancy or breastfeeding. Talk to a doctor first if you have a thyroid condition, liver problems or an autoimmune condition, or take sedatives or medication for blood sugar or blood pressure. Rare cases of liver injury have been reported, so stop and seek advice if you notice yellowing skin or dark urine.

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Maca (Lepidium meyenii) is a root vegetable from the cabbage family, grown high in the Peruvian Andes and eaten there for thousands of years. It's mainly studied for libido, mood and energy; notably, studies that measured hormones generally didn't find it changes testosterone.

Typical dosage: Studies commonly used 1.5g to 3g of powder per day (roughly half to one heaped teaspoon) for 6 to 12 weeks. Gelatinized maca has been heat-treated to remove starch, which makes it easier to digest. Capsules vary in strength, so follow the label.

Things to know: Can cause bloating or stomach upset, especially raw powder. Check with a doctor if you have a thyroid condition or a hormone-sensitive condition, and avoid it during pregnancy or breastfeeding, as there isn't enough safety data at supplement doses.

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L-carnitine is a nutrient your body makes from the amino acids lysine and methionine, and gets from red meat. It carries fatty acids into the mitochondria to be burned for energy. Acetyl-L-carnitine (ALCAR) crosses into the brain more readily and is the form usually chosen for focus; L-carnitine tartrate is the form most studied for exercise recovery.

Typical dosage: Acetyl-L-carnitine is typically taken at 500mg to 1,500mg per day, and L-carnitine or L-carnitine tartrate at 1,000mg to 2,000mg per day. Larger amounts are often split into two doses with food to avoid stomach upset.

Things to know: High doses can cause nausea, diarrhea or a fishy body odor. Talk to a doctor first if you have an underactive thyroid or take thyroid medication, take blood thinners such as warfarin, have a history of seizures, or have kidney disease.

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Fadogia agrestis is a shrub from West Africa, traditionally used as an aphrodisiac and now marketed for testosterone. Almost all of the research behind it comes from rat studies; there are essentially no controlled human trials, so its effects and safety in people are largely unknown.

Typical dosage: Products commonly provide around 600mg per day of a stem extract, but this isn't based on human research. It's usually taken in cycles with breaks rather than continuously, and many people get bloodwork before and during use to check hormone levels and general health markers.

Things to know: Rat studies that found hormone effects also reported changes in testicular tissue, and there's no human safety data. Avoid it if you're under 18, trying to conceive, pregnant or breastfeeding, or have prostate problems or a hormone-sensitive condition. Talk to a doctor before using it.

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