Blood Sugar & Metabolism
Leptin
Blood Sugar & Metabolism
Leptin is the hormone that is supposed to tell your brain you are full. When it stops working, willpower is not the problem — your hormones are.
VAT-exempt medical service
Ever feel like your body just refuses to cooperate with weight loss? Meet leptin. It is a hormone produced by your fat cells, and its job is beautifully simple: tell the brain when you have enough energy stored so you stop eating. When leptin signalling works, your appetite and weight stay in balance. But here is the twist — in people with excess body fat, the brain can become deaf to leptin's signals. That is leptin resistance. Your leptin levels are sky-high, but your brain thinks you are starving. So it cranks up hunger, slows your metabolism, and stores more fat. It is not a willpower problem. It is a signalling problem. The Wellth leptin test is analysed at a Karolinska-affiliated Swedish lab, giving you precise, trustworthy results.
Because if you have been eating well, moving your body, and still cannot shift the weight — there might be a hormonal explanation. Leptin testing shines a light on the hidden machinery behind appetite and metabolism. It is also clinically important for women who have lost their period due to low energy availability (hypothalamic amenorrhoea) and for anyone investigating insulin resistance or cardiovascular risk. Understanding your leptin level takes the blame off willpower and puts it where it belongs: on biology you can actually do something about.
What a high value can mean
High leptin sounds like it should suppress appetite, right? Unfortunately, it often means the opposite. When leptin resistance sets in, the brain ignores those satiety signals. Result: you stay hungry, you overeat, and your body keeps storing fat — even though leptin is screaming at it to stop. High leptin is also linked to chronic low-grade inflammation, insulin resistance, metabolic syndrome, and increased cardiovascular risk. It is a hormone worth paying attention to.
What a low value can mean
Low leptin typically shows up in people who are underweight, in a state of very low energy intake, or who have unusually low body fat. It is your brain's famine alarm — triggering increased appetite, reduced metabolic rate, and hormonal disruptions including loss of menstruation in women. Rare genetic leptin deficiency exists but is uncommon. If you are an athlete or very lean and experiencing fatigue or hormonal issues, this marker is especially relevant.
Fast for at least 10 hours (12 is ideal) — water only. Important: leptin samples can only be taken at Karolinska-affiliated clinics, and analysis runs 1-2 times per month. Bring valid ID to your appointment.
Order your test
Choose your test and pay online. Your lab referral is created straight away.
Give your sample
Visit any of our partner sampling locations. No appointment needed at most of them.
The lab analyses it
Your sample is analysed at an accredited Swedish laboratory.
Get your results
Your values appear in your account with reference ranges and an explanation of each marker.
Leptin resistance is when your brain stops listening to the 'I am full' signal — even though leptin levels are high. Your body has plenty of stored energy, but your brain acts as if you are starving. It ramps up hunger, slows metabolism, and promotes fat storage. It is considered one of the key hormonal drivers of obesity, and it explains why willpower alone so often fails.
Yes. Regular movement, cutting back on processed food and added sugar, quality sleep (poor sleep is one of the biggest leptin disruptors), stress management, and gradual fat loss can all help restore leptin sensitivity. Some research points to anti-inflammatory eating patterns as particularly helpful.
Leptin requires specialised lab equipment and methods. In Sweden, Karolinska-affiliated labs are among the few that run this analysis, typically in batches 1-2 times per month. That is what ensures top-tier accuracy and consistency in your results.
They feed off each other — literally. Chronically high leptin (from excess fat) can contribute to insulin resistance, and insulin resistance can worsen leptin resistance. It is a vicious cycle. The good news? Addressing one often improves the other. That is why a comprehensive metabolic panel covering both is so valuable.