Mushroom coffee and sleep: the half life maths of a 2pm cup
Nobody needs telling that a late coffee can keep you up. What is less obvious is how late is late, and how much a smaller dose changes the answer. This article does the arithmetic, plainly, so you can set your own cut off rather than take a rule of thumb.
The half life
Caffeine is cleared by the liver at a rate that is usually described as a half life of about five hours in a healthy adult. That means five hours after a coffee, roughly half the caffeine is still in your system; ten hours after, about a quarter; fifteen hours after, about an eighth. The range is wide, from around three hours in fast metabolisers to eight or more in slow ones, and it stretches out with pregnancy, some medications and the contraceptive pill. Five is the number we will use. Adjust it for yourself if you know you are at one end.
A cafe coffee at 2pm
Take a double shot latte at around 150mg. At 7pm there is about 75mg left. At midnight, about 37mg. At 5am, about 19mg. Thirty seven milligrams at midnight is about the caffeine in a cup of green tea, and for a lot of people that is enough to shave the deep sleep off the first half of the night even if they fall asleep fine. This is why a 2pm flat white is the cup that people most often discover they should not have had.
A mushroom coffee at 2pm
Now take a serve of Mello Mushroom Coffee at about 48mg. At 7pm, about 24mg. At midnight, about 12mg. At 5am, about 6mg. Twelve milligrams at midnight is less than a cup of decaf tea and, for most people, below the level that shows up in sleep quality. The mushroom coffee is not doing anything clever here; it simply starts from a number about a third the size, so every point on the curve is about a third the size too.
The table
Hours after the cup, 150mg coffee, 48mg mushroom coffee. Zero: 150, 48. Five: 75, 24. Ten: 37, 12. Fifteen: 19, 6. Twenty: 9, 3. Both curves have the same shape; one just runs a lot lower.
Where the cut off lands
A common guideline is no caffeine within eight to ten hours of bed. For a 10pm bedtime that means a full strength coffee should be finished by about noon to 2pm, and even at 2pm you are carrying 37mg into midnight. For a 48mg serve, the same eight to ten hour rule gets you to about 12mg at midnight, and pushing the cup to 3pm or 4pm only moves that to about 15mg. So the practical rule most of our customers settle on is: full strength coffee in the morning only, a mushroom coffee is fine until mid afternoon, nothing with caffeine after about 4pm. Our guide to the best time to drink mushroom coffee goes through the morning versus afternoon question in more detail.
Why the second cup is the problem
People rarely get into trouble with one coffee. They get into trouble with the second, because caffeine stacks. A 150mg cup at 8am and another at 2pm means about 19mg from the first and 75mg from the second at 7pm, close to 100mg still on board in the early evening. Swap only the afternoon one for a 48mg serve and the 7pm figure drops to about 43mg. Swap both and it is about 27mg. The afternoon cup is where the lever is.
What about Reishi
Reishi is the mushroom in the blend with the strongest traditional association with evening and rest, and people sometimes ask whether it offsets the caffeine. We are not going to claim that. The human research on Reishi and sleep is small and used amounts that are not comparable to a blended coffee. Reishi is in the blend for its traditional use and its place among the six; the caffeine arithmetic above stands on its own and is the honest reason a smaller serve sits better in the afternoon. Our Reishi research page lists what the studies actually measured.
Matcha for the late afternoon
If you want something at 4pm, Mello Mushroom Matcha is about 48mg as well, with the L theanine from the tea leaf that many people find takes the edge off. It is the same caffeine number, so the same half life maths applies; the difference is in how the lift feels, not how long it lasts.
The caveats
The five hour half life is an average. If you are a slow metaboliser, or pregnant, or on medication that slows caffeine clearance, the numbers above should be roughly doubled and your cut off moved earlier. Anyone pregnant, breastfeeding, on medication or managing a medical condition should talk to a GP or pharmacist about caffeine and about mushroom extracts before adding either. Anyone with a mushroom allergy should avoid both Mello blends, and the coffee blend contains coconut milk and MCT oil, so anyone with a coconut allergy should choose the matcha or skip both.
The short version
Caffeine halves about every five hours. A 150mg coffee at 2pm leaves about 37mg at midnight; a 48mg mushroom coffee at 2pm leaves about 12mg. Keep full strength coffee to the morning, use a smaller serve for the afternoon, stop everything by about 4pm, and the second cup stops costing you the first half of the night.