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Microdose, BMI 18

21 replies16 peopleAug 24, 2026☆ Follow
Summary

Is microdosing tirzepatide safe and useful at BMI 18 for joint inflammation or cartilage benefits?

The original poster began at 1 mg weekly but found it excessive and plans to drop to 0.75 mg split across two doses while monitoring appetite and weight. Several replies warn that BMI 18 is already low and that GLP-1s risk further muscle loss unless protein intake and resistance training are prioritized. Others note preliminary data suggesting possible cartilage effects independent of weight loss, yet stress that evidence is early and pain or stiffness improvements were not clearly shown in humans.

What this discussion establishesWhere people disagree

Whether tirzepatide meaningfully regenerates cartilage versus merely slowing inflammation, and whether any microdose benefit justifies use at already low BMI.

Still open

Long-term safety of continued use below BMI 18 and the actual clinical value of any cartilage changes seen so far.

Nothing here is advice.

21 replies · 16 people
QuietCinder66archiveopening postAug 24

Started with 1 mg for the first two weeks but felt it was too strong. It did seem to ease some unexplained swelling in my left hand. Planning to cut the dose and split it into 0.375 mg twice a week for a total of 0.75 mg, hoping to skip appetite suppression while keeping any other gains. Tirz might lower inflammation and even support cartilage growth. I want to stay more active in my fifties, but past experience shows injuries and joint problems quickly halt any exercise push.

NorthWillow72archiveAug 24

Try adding some resistance work and maybe a few supplements; staying too low on BMI gets riskier with age.

PatientBeacon15archiveAug 24

Focus on training the parts that still feel good, especially the legs if they allow it. The big muscles below the waist deliver broad health payoffs when worked. Begin gently to stay safe, then increase effort over time. Check Dr. Ford Brewer on YouTube for extra detail.

RustMarble22archiveAug 24

Fine as long as there is no eating-disorder history and weight stays monitored.

CopperSignal27archiveAug 25

Using tirz at a BMI of 18 carries real risks; 18 sits at the edge of most anorexia cutoffs, so deliberately getting leaner than that is rarely wise. The microdose angle is somewhat reassuring, yet careful weight tracking and readiness to stop if the scale drops further will probably be needed.

BrightCompass57archiveAug 25

Other peptides exist for inflammation if that is the main target.

PatientPebble79archiveAug 25
↳ replying to @QuietCinder66 (opening post)

What goals are you chasing with the GLP-1? Beyond the weight-loss and appetite effects it was made for, what improvements do you hope to see, and is there a more direct route to those same results?

WarmSparrow92archiveAug 25

What is your body fat percentage?

CopperBeacon14archiveAug 25

At a BMI of eighteen there's really no point in taking tirz.

GreenMeadow54archiveAug 25

BMI 18 is already concerning. Any eating-disorder history would clearly argue against it. At that level there cannot be much muscle, and muscle matters most for staying active into the fifties and beyond; resistance training cannot be stressed enough. Tirz is usually the pick, but reta might let a higher dose be used without as much appetite drop. Skeptical that under 1 mg of tirz will do much for cartilage regrowth, and any inflammation relief may stay modest.

BrightSparrow36archiveAug 25

I've started rotating my sessions between klow and kpv/ghkcu as the alternative.

QuietAlder65archiveAug 25
↳ replying to @QuietCinder66 (opening post)

Not sure of height, but that BMI is low for an average adult. Other options exist for osteoarthritis and type II collagen.

BrightMeadow15archiveAug 29
↳ replying to @QuietCinder66 (opening post)

I am F49 with knees that complain a lot. Muscles must be protected when using GLP-1s. Must. Muscle is already hard to gain at this age, and these drugs tend to strip it unless protein stays high and resistance training is consistent. Have seen nothing claiming tirz regrows cartilage; would have started yesterday if it did. With arthritis, less inflammation mainly means less ongoing breakdown, which is still helpful. Faster recovery and quicker adaptation to new movement are realistic; actual cartilage regrowth probably is not. The real danger for older adults is not the initial fall or break but the inactivity that follows, leading to lost muscle and lasting mobility trouble.

QuietBramble77archiveAug 29

During my transition into menopause I noticed that carrying a few extra pounds actually helped me feel better.

RustMarble22archiveAug 30
↳ replying to @BrightMeadow15

Some early data may point that way. One study found semaglutide produced notable cartilage-protective effects in metabolic osteoarthritis, separate from weight-loss benefits.

GreenAlder66archiveAug 30

Also a bit more context on GLPs and cartilage regeneration. Cartilage apparently has GLP-1 receptors, so joint improvement may not come only from less body weight; actual regeneration could occur. One MD microdoses for the non-weight-loss effects.

BrightMeadow15archiveAug 31

That word basically signals it keeps the condition from advancing any further. The shrug shows my doubt, yet easing the swelling still amounts to a major plus for OA.

CopperLedger37archiveAug 31
↳ replying to @GreenAlder66

Here is the full text of that article. The study used both mice and people; humans gave informed consent. Human results showed cartilage thickening. This looks very preliminary. My take is do not start GLP-1 drugs just to protect or repair cartilage, but if already using them for other reasons they might offer some cartilage help.

CopperLedger37archiveAug 31
↳ replying to @BrightMeadow15

Included the full text link above. Pain and joint stiffness did not improve much in the human part of the study. Cartilage thickness rose about 17 percent in the combined group versus under 1 percent with the other treatment alone. The authors list several reasons to treat the regrowth findings cautiously.

QuietCinder66archiveSep 12
↳ replying to @WarmSparrow92

Probably somewhere from 12-17 percent; low enough that a few pounds of added weight after good resistance sessions can come from inflammation. Visible abs and thigh veins. One month into the 0.75 mg per week microdose I am holding weight steady while adding calorie-dense foods like olive oil or nuts most days. The only weight gain I want is muscle. Protein intake is adequate, yet full workout energy is not always there. Past experience lets me keep good form even when not at peak.

QuietCinder66archiveSep 12
↳ replying to @BrightMeadow15

It is pretty multivariable; could just as easily argue it is not the fall but balance and mobility that matter most. Lower balance means slower movement and less force, which makes everyday tasks take longer so people drive instead, which then reduces balance further until a fall happens without obvious cause. Balance work includes carrying heavy groceries, sometimes uneven loads, treadmill spins, backward walking, and lateral moves. Everyone should agree resistance training belongs in any routine; the muscle benefits are huge. I tend to favor single-leg moves because they load the spine less.

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