Typically, urine cools down fairly quickly after leaving the body, starting at around 98.6°F (37°C). Without insulation or using a urine heating pad, it will drop to room temperature, usually 68–72°F (20–22°C), within 10 to 20 minutes. The exact timing can depend on the surrounding temperature and insulation.
To keep urine stored in a pill bottle at body temperature (around 98.6 fahrenheit or 37°C) for a test, you could attempt this using several body areas, but maintaining an accurate temperature without heat loss is challenging, at best.
Hand the sample in below the right temperature for a test
and you're going to to fail, instantly. Period.

Accuracy: Securing a pill bottle near the abdomen might seem to be the most effective option, because it's close to your core temperature, where body temperature is highest. However, the urine is only likely to stay around 96.8 - 98.6 degrees fahrenheit (36–37°C) for a while, as it is not stored within your core, as urine will be when in the bladder. So even on the warmest place on your body, you will struggle to maintain the temperature for long.
Challenge: Over time, the urine inside the bottle will begin to cool, possibly dropping to 91.4–95°F (33–35°C). Without proper insulation, the bottle could cool further. There's also a risk of leakage if the bottle isn’t sealed well, and it’s important to make sure the bottle is clean to avoid contamination by germs and leakage into your clothing.
Accuracy: Storing a pill bottle between the inner thighs might seem a good option, because this area is warmed by large blood vessels, keeping the bottle around v.
Challenge: As with the abdomen, the pill bottle may experience heat loss over time becuase it isn't inside your body, as urine is within the bladder. Movement can cause the urine to cool faster, possibly dropping below around 90 degrees fahrenheit (32°C), risking test rejection. You also need to be careful with leakage in this area, especially if the bottle isn’t secured tightly.
Accuracy: Placing the pill bottle under your arm can keep it warm for a short time, maintaining a temperature of about 91.4–95°F (33–35°C).
Challenge: The armpit is prone to cooling when you move your arm or raise it. This means the temperature in the bottle could drop below 32°C before the sample is submitted.
Accuracy: Securing the pill bottle in the waistband or lower back area works well if you’re sitting, as this traps body heat and could keep the urine in the pill bottle around 91.4–93.2°F (33–34°C).
Challenge: Without direct contact with skin, the bottle may cool quickly, possibly dropping below the required range if stored for too long. Again, there’s a chance of leakage if the pill bottle isn’t sealed properly.
Accuracy: Women sometimes consider internal storage of a small bottle of urine but this is not to be recommended. This area is warmer and closer to body temperature, so the urine may stay around 98.6°F (37°C).
Challenge: While this method could potentially be effective, there’s a higher risk of leakage or accidental spills, especially if the pill bottle isn’t secured properly. Apart from comfort and other issues, there is an additional issue of germs within the urine infecting the area if they spill from the bottle.
It's not inside your body, like urine is in the bladder.
It will cool when it's put into a pill bottle
Your pill bottle has a lot of surface area, exposed to cooling, and not touching your body
While body storage methods may help for a short time, only a digital heating unit, like a battery powered urine warmer can reliably keep the urine in the pill bottle at the exact temperature required for testing. These units ensure the urine remains at the perfect range, eliminating the risk of cooling, germ contamination, and leakage.