Night-Time Fat Burners: What They Do, and What's Actually in Them

"Night-time fat burner" sounds like the best deal in the supplement aisle: take a capsule, go to sleep, wake up leaner.

The reality is less dramatic, and more useful. Here is what these products actually are, what the common ingredients do, and what to avoid.

What a night-time fat burner actually is

Strip away the marketing and most night-time fat burners are two things in one capsule: a sleep formula, plus one or two stimulant-free ingredients aimed at metabolism.

The key word is stimulant-free. A daytime fat burner usually runs on caffeine. A night-time one must not, or it defeats its own purpose.

Why sleep is the main event

The strongest reason to care about sleep on a diet isn't a supplement ingredient. It is a 2010 study in which people on the same calorie deficit lost a similar amount of weight whether they slept about eight and a half hours or five and a half — but on short sleep, far more of what they lost was muscle rather than fat. We cover it in Sleep and Fat Loss.

That is the honest case for a night formula. Its biggest job is protecting the quality of your sleep while you are in a deficit, because sleep decides whether the weight you lose is the weight you wanted to lose.

The common ingredients

• Melatonin. The hormone that tells your body it is night. It helps you fall asleep sooner. Doses range from 0.5mg to 10mg; some people feel groggy the next morning on higher doses, so take it only when you can get a full night.
• L-theanine. An amino acid from tea that supports relaxation without sedation.
• GABA. The body's main calming messenger. How much oral GABA reaches the brain is debated, but it is a staple of sleep formulas.
• Magnolia bark. Traditionally used to support relaxation and a calmer response to stress.
• Passion flower. A climbing plant long used in herbal tradition to support calm and restful sleep.
• Rhodiola rosea. An adaptogen used to support the body's response to stress.
• Grains of paradise (Paradoxine®). The seed of a West African plant related to ginger. Small human studies suggest it may modestly increase energy expenditure by activating brown fat — without any stimulant effect, which is why it suits a night formula.
• Schisandra. A berry from traditional Chinese medicine, used as an adaptogen.

Lean Sleep combines all eight in two capsules, with no stimulants: GABA (400mg), rhodiola (200mg), schisandra (200mg), magnolia bark (200mg), L-theanine (150mg), passion flower (100mg), Paradoxine® (25mg) and melatonin (5mg).

What to avoid on the label

Hidden stimulants. Green tea extract (which contains caffeine unless it says decaffeinated), guarana, yohimbine or synephrine have no place in something you take before bed.

Proprietary blends. If the label lists one total weight for a long list of ingredients, you can't tell whether anything is properly dosed. More on that in Proprietary Blends: What Labels Hide.

Big promises. "Lose X pounds while you sleep" is not something any capsule can deliver. Fat loss still comes from a calorie deficit, training and time.

Who it suits, and who should skip it

It suits people who are dieting, training hard and sleeping worse than they would like — especially if caffeine is part of their day and the evening is when it catches up with them.

Skip it, or talk to your doctor first, if you are pregnant or breastfeeding, take sedatives, antidepressants, blood pressure medication or other sleep aids, or have a diagnosed medical condition. Don't drive or operate machinery after taking it, and don't combine it with alcohol.

How to take one

In the evening, roughly an hour before bed, on a night when you can get a full night's sleep. Lean Sleep is two capsules with water.

It covers the night. For the meal side of a fat-loss plan, a glucose disposal agent such as Block supports how your body handles your biggest carbohydrate meal. Together they are our Fat Burn Stack.

The short version

A night-time fat burner is mostly a sleep formula with a metabolism angle. The sleep part is what matters most, so judge one by its sleep ingredients, make sure it contains no stimulants, and ignore any promise about pounds lost overnight.

—
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your physician before use if you are pregnant, nursing, taking medication, or have a diagnosed medical condition.