How to Measure Muscle Mass at Home: Methods Compared

Not directly. Even a DXA scan, which experts consider the reference standard for measuring muscle mass, though not a gold standard ^[1], measures lean soft tissue: muscle plus water, organs and other non-fat tissue ^[2]. European sarcopenia guidelines also note that body measurements are not a good measure of muscle mass on their own, and that hydration can affect both DXA and smart-scale readings ^[3].

Most GLP-1 apps do not measure this either: of 19 we checked, only one tracks fat and lean mass. If you want a rough idea of the split before you measure anything, our muscle loss calculator applies the range from 36 trials ^[17] to the weight you have lost, and says plainly what it cannot tell you.

You don't need an exact number, though. What you need to know is whether your muscle is holding up, and a few simple checks repeated the same way will show you that.

Grip strength is the easiest strength test to repeat, and it says something about your health overall. In the PURE study of 139,691 adults, every 5 kg lower grip strength was linked to a 16% higher risk of death over a median of 4 years ^[6]. That is an association, not proof that a stronger grip makes you live longer.

You need a handheld grip dynamometer. In a study of 1,064 adults over 50, a low-cost digital model agreed well with the Jamar device clinics use, reading about half a kilogram lower on average ^[7].

How to do it

1. Sit in a chair with your feet flat, your upper arm against your side and your elbow bent at a right angle.
2. Squeeze the handle as hard as you can for a few seconds.
3. Do 3 tries with each hand, resting briefly between them, and write down your best result.
4. Test the same way, at a similar time of day, every time.

What the numbers mean

European guidelines treat grip strength below 27 kg for men or 16 kg for women as low ^[3]. Asian guidelines use below 28 kg for men and 18 kg for women ^[8]. Both were designed to screen older adults for sarcopenia, so a low reading at home is a reason to talk to your doctor, not a diagnosis.

For tracking, compare yourself with your own past results. A drop that lasts several weeks tells you more than any single test.

The chair stand test checks your leg strength with nothing but a chair and a timer. There are two versions.

The 30-second chair stand

This is the version the US Centers for Disease Control and Prevention (CDC) uses to check fall risk ^[9]:

1. Use a sturdy chair with a straight back and no arm rests, with a seat about 17 inches (43 cm) high.
2. Sit in the middle of the seat with your feet flat, your back straight, and your arms crossed at the wrists with your hands on opposite shoulders.
3. When you start the timer, stand up fully and sit back down, as many times as you can in 30 seconds.
4. Count your full stands. If you are more than halfway up when time runs out, count it. If you have to use your arms, stop: your score is 0.

The CDC treats these scores as below average, a sign of higher fall risk ^[9]:

30-second chair stand: below-average scores by age

Fewer full stands in 30 seconds than these counts as below average, a sign of higher fall risk

14

12

60–64

12

11

65–69

12

10

70–74

11

10

75–79

10

9

80–84

8

8

85–89

7

4

90–94

MenWomen

The table starts at 60. If you are younger, there is no official benchmark, so treat your first result as your baseline and aim to hold or beat it.

The 5-times chair stand

Time how long it takes you to stand up and sit down 5 times, as fast as you safely can, without using your arms. European guidelines count more than 15 seconds as low strength ^[3]. Asian guidelines use 12 seconds or more ^[8].

Have someone nearby the first time you try either test, and stop if you feel dizzy or unsteady.

A tape measure is cheap, but it measures size, not muscle. When you lose fat, your arms, thighs and calves get smaller too, so a smaller number doesn't mean you lost muscle. Read it next to your strength results.

Calf circumference

Calf size is one of the better body measurements for muscle. In a US study of 17,789 adults, calf circumference was strongly linked with lean mass in the arms and legs measured by DXA ^[2]. That study set these cut-offs ^[2]:

• Moderately low: under 34 cm for men, under 33 cm for women
• Severely low: under 32 cm for men, under 31 cm for women

Fat around the calf makes it bigger, so the study adjusts for BMI. Subtract about 3 cm if your BMI is 25 to 29.9, 7 cm if it is 30 to 39.9, or 12 cm if it is 40 or above. Add about 4 cm if it is below 18.5 ^[2]. For example, a woman with a BMI of 32 whose calf measures 39 cm would compare 32 cm with the cut-offs.

To measure, sit with your foot flat on the floor and wrap the tape around the widest part of your calf, level and snug but not squeezing ^[2]. Use the same leg every time.

Arm and thigh

There are no reliable home cut-offs for arm or thigh size. They still work as a trend: if they shrink while your strength holds or rises, the change is more likely to be fat.

Waist

Your waist tells you about fat, not muscle, but it helps you read your other numbers. The UK's National Institute for Health and Care Excellence (NICE) advises measuring halfway between the bottom of your ribs and the top of your hips after breathing out normally, and, for adults with a BMI under 35, keeping your waist to less than half your height ^[10].

For every tape measurement: same time of day, same spot, measure twice and use the average.

A smart scale does not see muscle. It sends a weak electrical current through your body and estimates fat and lean mass from how easily it travels, using its maker's equations.

In a study comparing three consumer smart scales with DXA, weight was accurate to within 0.3 kg, but all three underestimated fat mass, by 2.2 to 4.4 kg, and the authors concluded the scales were not accurate for body composition ^[4].

The European clinical nutrition society (ESPEN) adds two warnings for this kind of measurement ^[11]:

• Changes in lean or fat mass smaller than about 1.5 to 2 kg are hard to detect.
• Tracking change is less reliable when a lot of weight is being lost.

Averages can look better than individual readings. In a 12-month study of 19 adults losing weight, a home body composition monitor estimated average fat loss at 7.0 kg and muscle loss at 1.0 kg, close to DXA's 7.0 kg and 1.4 kg ^[12].

To get a useful trend:

• Weigh at the same time of day, after using the bathroom ^[11].
• Don't measure soon after eating, drinking or exercising ^[11].
• Compare weekly or monthly averages, not single readings.

There is more on this in are smart scales accurate?

Skinfold calipers pinch the fat under your skin at a few spots, and an equation turns those readings into a body fat percentage. They estimate fat, not muscle, errors of 3 to 9 percent are usual, and results depend a lot on who takes the measurements ^[5].

You can turn any body fat estimate into fat-free mass: multiply your weight by 1 minus your body fat percentage. For example, 80 kg at 30% body fat gives 56 kg of fat-free mass. That number includes bone, water and organs as well as muscle, and it carries all the error of the body fat estimate.

Progress photos can't separate fat from muscle either, but they are useful next to your strength log. Take them every few weeks in the same light, clothes, pose and distance, at the same time of day.

A DXA scan uses low-dose X-rays to separate fat, lean soft tissue and bone. It is considered the reference standard for measuring muscle mass, though not a gold standard ^[1]. The radiation dose of a whole-body scan is very small, about 0.004 to 0.008 mSv on common machines ^[13].

A scan is most useful when:

• You are about to lose a lot of weight and want a starting point.
• You are a few months in and want to check how much of the loss was lean mass.
• Your home checks disagree, for example strength falling while your measurements look fine.
• A home test, such as grip strength or the chair stand, came out below the cut-offs.

Go back to the same clinic and machine each time so your results can be compared.

SARC-F is a 5-question screen for sarcopenia risk. Score each question from 0 to 2 and add them up. A total of 4 or more suggests you should be assessed properly ^[14]. European guidelines recommend it as a way to find people who may need testing ^[3].

SARC-F was built for older adults. A low score in a younger adult who is losing weight says little, so rely on strength tests instead.

Weight loss makes home measurements harder to read. Some lean mass loss is expected: in the SURMOUNT-1 body scan study of tirzepatide (Zepbound®, Mounjaro®), about 25% of the weight lost was lean mass ^[15]. Tape measurements shrink as fat comes off, and smart-scale estimates are less reliable when a lot of weight is lost ^[11].

That makes strength your most useful signal. In a trial of 160 older adults with obesity who lost 9% of their body weight over 6 months, strength rose 19% in the group doing resistance training and 4% in the aerobic-only group, and lean mass fell 2% compared with 5% ^[16]. Strength can rise while you lose weight.

A simple routine:

No guideline sets how often to measure. Monthly body checks make sense because changes smaller than 1.5 to 2 kg are hard to detect with a smart scale ^[11].

On a GLP-1 medication? See does Zepbound cause muscle loss? and does Ozempic cause muscle loss? for what the body scan studies found.

Read your checks together:

If you need to act, start with protein and training. The free protein calculator gives you a daily range, and the 12-week GLP-1 workout plan works for anyone starting strength training. For the warning signs to watch between checks, see signs you're losing muscle, not fat.

See a doctor promptly if weakness comes on suddenly, gets worse quickly or affects one side of your body.