Melatonin, Magnesium, L-Theanine and Other Evening Ingredients: What They Are

By the nutrima editorial team · Last reviewed October 2026 · How we research and write

Short answer: Evening supplements usually combine a few familiar ingredients: melatonin (a hormone the body makes in response to darkness), magnesium (an essential mineral), L-theanine (an amino acid found in tea leaves), GABA (an amino acid the body also makes), and botanicals such as valerian, chamomile, lavender and lemon balm. The NIH's National Center for Complementary and Integrative Health (NCCIH) describes the research on several of these as limited, mixed or inconclusive, and it advises talking with a health care provider before giving melatonin to children or using it during pregnancy or breastfeeding. This guide explains what each ingredient is, the amounts you will typically see on labels, and the safety notes official sources give.

In this guide:

The ingredients at a glance

The amounts below are what we commonly see on US supplement labels. They are not recommendations, and none of these ingredients except magnesium has an official RDA or upper limit set by the National Academies.

Ingredient What it is Amounts commonly seen on labels What official sources say about the research
Melatonin A hormone made by the pineal gland in the brain, mainly at night; supplements are usually made synthetically About 0.5 mg to 10 mg per serving NCCIH summarizes studies by use (jet lag, sleep-wake timing disorders, insomnia, children) and notes findings differ by use and that long-term safety information is lacking
Magnesium An essential mineral, always sold as a compound such as glycinate or citrate Often 100 mg to 350 mg elemental magnesium ODS fact sheet covers intake, deficiency, upper limit and interactions
L-theanine An amino acid found naturally in tea leaves (Camellia sinensis) Often 100 mg to 200 mg We did not find a dedicated ODS or NCCIH fact sheet on L-theanine at the time of review
GABA Gamma-aminobutyric acid, an amino acid the body makes and uses as a chemical messenger in the nervous system Often 100 mg to 750 mg We did not find a dedicated ODS or NCCIH fact sheet on GABA supplements at the time of review
Valerian The root of Valeriana officinalis, a flowering plant native to Europe and Asia Often 200 mg to 600 mg of root or extract NCCIH describes the evidence for sleep as inconclusive
Chamomile Dried flowers of German chamomile (Matricaria recutita), a daisy-family plant Often 100 mg to 500 mg in capsules, or as tea NCCIH says there is not enough reliable evidence to draw conclusions for sleep
Lavender Flowers and oil of Lavandula angustifolia, a mint-family plant Varies widely; oils and extracts are measured differently NCCIH notes research has been limited

Melatonin

What it is

Melatonin is a hormone. NCCIH explains that your brain produces it in response to darkness and that it helps with the timing of your circadian rhythms (your 24-hour internal clock) and with sleep. Light at night can block its production. In the United States, melatonin is sold as a dietary supplement; NCCIH notes that in many other countries it is available only with a prescription.

What NCCIH says about the research

NCCIH reviews melatonin research separately for different situations, including jet lag, sleep-wake phase disorders, insomnia, and sleep problems in children, and the findings are not the same for each. NCCIH notes that some results are modest or mixed and that more research is needed for several uses. Because the findings depend so much on the specific situation, we do not summarize them as a single claim here. If you are considering melatonin for a sleep problem, NCCIH's page and your health care provider are the right places to start.

Typical label amounts

Labels commonly list 1 mg, 3 mg, 5 mg or 10 mg per serving, with some products as low as 0.5 mg. Melatonin is measured in milligrams (mg); a few low-dose products list micrograms (mcg), where 1,000 mcg equals 1 mg. There is no official RDA or upper limit for melatonin.

Safety notes from NCCIH

  • Short-term vs. long-term use. NCCIH says melatonin appears to be safe for most people when used short term, but information on the long-term safety of melatonin supplements is lacking.
  • Side effects. In adults, NCCIH lists headache, dizziness, nausea and sleepiness as the side effects most commonly reported. In children, reported side effects include drowsiness, increased bedwetting or urination at night, headache and agitation.
  • Children. NCCIH advises talking with your child's health care provider before giving melatonin. It also notes a large rise in reports of children accidentally swallowing melatonin, so store it out of reach, especially gummies and other candy-like formats.
  • Pregnancy and breastfeeding. NCCIH notes that little is known about the safety of melatonin during pregnancy or breastfeeding. Talk to your doctor first.
  • Label accuracy. NCCIH cites research in which the melatonin content of many products differed from the amount stated on the label. Buying from a seller that shows the full Supplement Facts panel lets you at least compare what is declared.
  • Medicines. MedlinePlus lists sedative medicines among the drugs that may interact with melatonin, because taking both may cause too much sleepiness. It lists other interactions too, including some blood-thinning and diabetes medicines. If you take any prescription medicine, ask your pharmacist before using melatonin.

Magnesium

Magnesium is an essential mineral. The NIH Office of Dietary Supplements describes it as a cofactor in more than 300 enzyme systems, including those involved in muscle and nerve function. It appears in many evening formulas, usually as magnesium glycinate, citrate or oxide.

The ODS fact sheet focuses on intake, deficiency, safety and interactions, and that is what we cover. Two numbers matter most on a label: the elemental magnesium per serving, and the ODS upper limit of 350 mg a day from supplements and medicines for anyone 9 and older. If you take a magnesium-containing evening formula plus a separate magnesium product, add them together. ODS also notes that people with kidney disease face a higher risk of magnesium building up, and lists interactions with some antibiotics, bisphosphonates, diuretics and proton pump inhibitors.

For forms, the full RDA table and the complete interaction list, see our magnesium forms guide.

L-theanine

L-theanine is an amino acid that occurs naturally in the leaves of the tea plant, Camellia sinensis, which is the source of green, black and oolong tea. It is not one of the amino acids your body uses to build proteins, and it is not an essential nutrient, so there is no RDA, Daily Value or official upper limit. In supplements it is usually produced by fermentation or synthesis rather than extracted from tea.

Labels commonly list 100 mg to 200 mg per serving. You will also see L-theanine paired with caffeine in daytime products, a combination we describe in the focus ingredients guide.

At the time of review, we did not find a dedicated fact sheet on L-theanine from the NIH Office of Dietary Supplements or NCCIH. Without an official summary of the research, we do not describe any effects. Safety information for use during pregnancy, breastfeeding and in children is limited, so talk to your doctor first in those situations.

GABA

GABA (gamma-aminobutyric acid) is an amino acid your body makes. In the brain and nervous system it works as a neurotransmitter, a chemical messenger between nerve cells. It is also found in small amounts in some fermented foods, and supplement-grade GABA is usually made by fermentation.

Labels commonly list 100 mg to 750 mg. As with L-theanine, we did not find a dedicated ODS or NCCIH fact sheet on GABA supplements at the time of review, there is no official intake recommendation or upper limit, and we do not describe effects. Ask your doctor before use if you are pregnant, nursing, under 18, or take medicines that act on the nervous system.

Valerian, chamomile, lavender, lemon balm and reishi

Valerian

Valerian is a flowering plant native to Europe and parts of Asia; supplements use its root. NCCIH describes the evidence on valerian for insomnia and other sleep problems as inconclusive. NCCIH says valerian appears to be safe for most adults for short periods, with side effects that may include headache, dizziness, stomach upset and sleepiness; long-term safety is not known, and safety has not been established for pregnancy, breastfeeding or young children. The ODS valerian fact sheet raises the possibility of additive effects when valerian is combined with alcohol or sedative medicines, so do not combine them without your doctor's advice.

Chamomile

Chamomile is a daisy-like plant; supplements and teas use its dried flowers. NCCIH says chamomile has been studied for sleep but there is not enough reliable evidence to draw conclusions. NCCIH notes that allergic reactions can happen, especially in people allergic to related plants such as ragweed, chrysanthemums, marigolds and daisies, and that chamomile may interact with some medicines, including cyclosporine and the blood thinner warfarin.

Lavender

Lavender is a fragrant mint-family plant. It is used as an oil for aromatherapy and skin products, and as dried flowers or extracts in oral products. NCCIH notes that research on lavender has been limited and that lavender taken by mouth may cause side effects such as constipation, diarrhea and headache. Lavender essential oil is not the same as an oral lavender ingredient; do not swallow essential oils unless a product is labeled for oral use.

Lemon balm

Lemon balm (Melissa officinalis) is a lemon-scented herb in the mint family, used as a tea and in extracts. We did not find a dedicated NCCIH or ODS fact sheet on lemon balm at the time of review, so we describe only what it is.

Reishi

Reishi (Ganoderma lucidum) is a woody mushroom traditionally used in East Asia, sometimes included in evening gummies. Our mushroom collection lists the products that contain it.

How to read an evening-formula label

  1. Serving size first. Two capsules, one strip or two gummies: every amount on the panel refers to the full serving.
  2. Look for each ingredient's amount. Melatonin should be listed in mg or mcg. Magnesium should be listed as elemental mg, with the form in parentheses.
  3. Check %DV. Only nutrients with a Daily Value (such as magnesium) show a percentage. Melatonin, L-theanine, GABA and botanicals show "†" or "Daily Value not established."
  4. Botanicals: check the plant part and extract type. "Valerian root extract" or "chamomile flower powder" tells you the part used. An extract ratio (such as 4:1) or standardization percentage describes how concentrated it is.
  5. Proprietary blends. A "proprietary blend" lists the ingredients in order of weight but only the blend's total amount. You cannot tell exactly how much melatonin or valerian is in a blend unless it is listed separately.
  6. Other ingredients. Gummies and strips include sweeteners, flavors and starches; capsules list the shell material.
  7. Warnings. Read the product's warnings, including any advice about driving or operating machinery.

For a row-by-row walkthrough, see our Supplement Facts label guide.

Who should check with a doctor first

  • Pregnant or breastfeeding. NCCIH notes limited safety information for melatonin and valerian in pregnancy and breastfeeding.
  • Under 18. NCCIH advises talking with a child's health care provider before giving melatonin.
  • Taking medicines, especially sedatives, sleep medicines, blood thinners, diabetes medicines, cyclosporine, antibiotics or diuretics.
  • Drinking alcohol. Ask your doctor before combining alcohol with valerian, melatonin or other products that can cause drowsiness.
  • Kidney disease, if the product contains magnesium.
  • Allergies to daisy-family plants, if the product contains chamomile.
  • Scheduled surgery. Tell your surgical team about every supplement you take.
  • Ongoing sleep trouble. Persistent sleep problems can have medical causes; a clinician can help work out why.

Storage

Store capsules, strips and gummies in their original containers, tightly closed, in a cool, dry place. Oral strips are sensitive to humidity, and gummies can soften or stick in heat. Because of the rise in accidental melatonin ingestion by children reported by NCCIH, keep these products up high and out of sight, and never call them candy.

Shop this category

Evening formulas are in our Rest & Restore collection. Each product page shows the full Supplement Facts panel and the country of manufacture.

Related reading: the magnesium forms guide, the focus ingredients guide, and all guides on our guides hub.

Frequently asked questions

Is melatonin a vitamin or a hormone?

A hormone. NCCIH explains that the brain makes melatonin in response to darkness. In the US it is sold as a dietary supplement; in many other countries it requires a prescription.

How much melatonin is in a typical supplement?

Labels commonly list between 0.5 mg and 10 mg per serving. There is no official RDA or upper limit. NCCIH notes that research has found the actual content of some products differs from the label.

Can children take melatonin?

NCCIH advises talking with your child's health care provider before giving melatonin, and reports a sharp increase in accidental melatonin ingestion by children. Keep it out of reach.

Is melatonin safe during pregnancy?

NCCIH notes that little is known about melatonin's safety during pregnancy or breastfeeding. Talk to your doctor before using it.

Can I take an evening supplement with alcohol or sleep medicine?

Ask your doctor or pharmacist first. MedlinePlus lists sedative medicines among melatonin's interactions, and the ODS valerian fact sheet raises the possibility of additive effects with alcohol and sedatives.

Is L-theanine the same as green tea extract?

No. L-theanine is one amino acid found in tea leaves. Green tea extract is a concentrate of many tea compounds, including caffeine and catechins. Check the label to see which one a product contains.

Why do evening formulas include magnesium?

Magnesium is an essential mineral that appears in many multi-ingredient products. If you take more than one magnesium-containing product, add up the elemental amounts and stay within the ODS upper limit of 350 mg a day from supplements.

Sources

These statements have not been evaluated by the Food and Drug Administration. This product information is not intended to diagnose, treat, cure, or prevent any disease. Talk to your doctor before starting any supplement.