Muscle loss on sema — the protein target nobody wants to commit to

F
Joined 2026
19 posts
2/5/2026 · 6833 views

Going to put a stake in the ground: if you're on a GLP-1 and not eating 1g protein per lb of goal body weight AND doing resistance training 3x/wk, you are losing meaningful muscle. The weight loss is real but the body composition question is separate and it's being under-discussed in sema threads.

Data I care about:

  • STEP trials showed ~40% of lost weight was lean mass in the non-training arm. Forty percent. That's not a rounding error, that's a body composition problem.
  • Studies with resistance training + adequate protein on GLP-1s show LBM preservation closer to 10-15% of loss. Still not zero, but enormously better.

My frame: the drug makes you eat less. You have to actively engineer the diet you do eat around protein-first. Appetite suppression makes that mechanically hard — you don't want 180g protein when you don't want to eat at all. Solutions I've seen work:

  • Protein shakes as the 'meal' on peak side effect days. 2 scoops whey in water is 50g and mostly liquid.
  • Greek yogurt, cottage cheese, skyr as fallback when real food is unappetizing.
  • Egg whites (cooked) as the highest density per kcal.
  • Protein-forward soup on the worst nausea days.

And yes: lift heavy things. Two compound movements + accessory per session is enough. Don't program for hypertrophy volume on a 500kcal deficit — program for retention.

Who's tracking LBM objectively? DEXA? BIA? Any data to share?

20 Replies

D
Joined 2026
45 posts
2/5/2026

Serial DEXA here. 42M, 218 -> 181 over 9 months on 1.0 sema. LBM dropped from 158 to 152 — so 6lb of lean for 37lb total. That's 16% of loss as lean, which tracks with trained-and-protein-fed literature. I'm lifting 4x/wk, averaging 180g protein on 215lb goal weight. Confirming the playbook works.

F
Joined 2026
19 posts
2/6/2026

@recomp_rex fair. 0.8g/lb goal weight + lifting is the floor. 1g is the ceiling where further gains taper. I push the ceiling because under-shooting on a GLP-1 is so easy.

R
Joined 2026
37 posts
2/6/2026

The 1g/lb target is widely pushed but for most people 0.8g/lb of goal weight is adequate when combined with resistance training. Above 0.8 the muscle-retention curve is flat in the literature. 1g is a margin-of-safety target, which is fine, but don't let people think 0.8 is inadequate.

S
Joined 2026
36 posts
slow_loseMember
2/6/2026

I am NOT hitting 0.8g/lb. I'm hitting maybe 0.5. I'm also not training. I'm losing weight and I feel fine. Is my LBM dropping? Probably. Do I care enough to force 150g/day of food I don't want? Not right now.

H
Joined 2025
205 posts
hexaclinicContributor
2/7/2026

@slow_lose that's a legitimate choice but state it as a choice. You're trading future metabolic floor and physical resilience for present-day convenience. Both are real. The issue is people who think they're not making the trade.

Q2 stack
  • CJC-1295 no DAC · 100 mcg · pre-bed · sub-Q
  • Ipamorelin · 200 mcg · pre-bed · sub-Q
  • BPC-157 · 500 mcg · 2x/day · sub-Q
M
Joined 2026
31 posts
2/7/2026

Protein powder take: whey isolate > concentrate on sema. Isolate is faster-clearing from the stomach. On a slowed-gastric-emptying drug, anything that clears faster is a win for tolerability. Casein at night is the exception — you want that slow.

N
Joined 2025
31 posts
2/8/2026

Counterintuitive lift suggestion: train 2x/wk full-body, not 4x/wk split. On a deficit the limiter is recovery, not frequency. I kept every compound lift +/- 5% through a 40lb cut on sema running 2x/wk, 5x5 rep range, no accessory volume.

Knee project
  • BPC-157 · 500 mcg · 2x/day local to knee · sub-Q
  • TB-500 · 5 mg · weekly loading · sub-Q
S
Joined 2026
28 posts
2/8/2026

Cottage cheese is the MVP food of GLP-1 protocols and I will die on this hill. 24g protein per cup, low volume, low sulfur, easy on the stomach, mixes with any fruit. Three cups a day covers a lot of protein on a day you don't want solid food.

Week 14
  • Semaglutide · 1.7 mg · weekly · sub-Q
C
Joined 2026
71 posts
2/9/2026

The STEP trials' lean mass data was DXA-based which overestimates lean loss compared to MRI-based lean measures. The 40% figure is probably an upper bound. True lean loss in STEP was likely closer to 25-30% of total weight. Still meaningful but worth the accuracy.

F
Joined 2026
19 posts
2/10/2026

@citation_required correct, and worth stating. I use 40% as a worst-case to scare people into the gym. True figure is lower but still significant.

N
Joined 2025
31 posts
2/11/2026

@wanderlite progressive overload with something, anything. Resistance bands count. Bodyweight squats, push-ups, dumbbell rows with a 15lb dumbbell. The muscle doesn't care about aesthetics of the gym, it cares about being asked to work against increasing resistance 2-3x/wk.

Knee project
  • BPC-157 · 500 mcg · 2x/day local to knee · sub-Q
  • TB-500 · 5 mg · weekly loading · sub-Q
W
Joined 2026
17 posts
2/11/2026

What counts as 'resistance training' for someone who's never lifted? Bodyweight? Resistance bands? I'm 54F and intimidated by the free weight area.

P
Joined 2026
36 posts
2/12/2026

Anecdata but grip strength is my leading indicator of LBM loss on GLP-1s. If my deadlift top set grip starts failing earlier than usual I know I've been under-eating protein for 2-3 weeks. Cheap proxy for DEXA between scans.

P
Joined 2025
71 posts
2/14/2026

Additional lever: creatine 5g/day. Widely studied, cheap, no reason not to, and preserves training performance on a deficit. It's the one supplement I'd put alongside protein for anyone on a GLP-1.

Healing + skin
  • BPC-157 · 500 mcg · 2x/day · sub-Q
  • GHK-Cu · 2 mg · nightly topical · topical
S
Joined 2026
25 posts
2/15/2026

Is there a point where the muscle loss is enough to make the drug not worth it? Like if I lose 30lb but 12 of it is lean, am I better off at my start weight with more muscle?

H
Joined 2025
205 posts
hexaclinicContributor
2/16/2026

@syringe_shy depends on start point. If you're starting with a body fat % where metabolic risk dominates (e.g. BMI >35, T2D, NAFLD), losing weight even with some lean loss nets positive on almost every health axis. If you're starting at BMI 28 trying to get to 24, the calculus shifts and lean preservation matters much more.

Q2 stack
  • CJC-1295 no DAC · 100 mcg · pre-bed · sub-Q
  • Ipamorelin · 200 mcg · pre-bed · sub-Q
  • BPC-157 · 500 mcg · 2x/day · sub-Q
D
Joined 2025
119 posts
dr_doubtRegular
2/18/2026

The correct frame: the drug enables the deficit, the protocol determines what the deficit costs you. Sema without protein and lifting is a body recomposition lottery. Sema with both is a body recomposition tool.

R
Joined 2025
36 posts
2/18/2026

Stealing dr_doubt's line. 'The drug enables the deficit, the protocol determines what the deficit costs you.' Putting that in every GLP-1 thread I reply to.

Current
  • Tesamorelin · 1 mg · daily AM · sub-Q
G
Joined 2026
22 posts
2/22/2026

Saving this whole thread. Starting sema next week at 32F, 196lb, goal 150. Wasn't going to lift. Changed my mind. Thank you.

L
Joined 2026
20 posts
2/25/2026

Came for weight loss info, leaving with a training plan. Forum at its best.

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