The Science

If your progress is steady but your strength isn't, there's a physiological reason — and it's well documented.

What the research actually says about muscle during weight loss.

Most women don't hear this part until they're in the middle of it. So here it is plainly, with the studies, before the product — because the science is the reason RETAIN exists, not the other way around.

When you lose weight, you don't only lose fat. In clinical studies of weight loss, a meaningful share of what comes off is lean mass rather than fat mass. In the STEP 1 trial of semaglutide, participants lost about 15% of their body weight over 68 weeks — and body-composition analysis found that roughly 40% of the weight lost was lean mass, not fat.1 That is the finding underneath everything GLYM is built around.

~40%
of the weight lost in the STEP 1 semaglutide trial was lean mass, not fat, when no specific steps were taken to preserve it.1

"Lean mass" is not the same as "muscle."

Here is the part that almost never gets explained, and it matters because it's reassuring, not alarming. Lean mass is not only muscle. It includes the water and glycogen stored inside your muscle cells, along with connective tissue and more. During a caloric deficit, glycogen drops, and the water it holds drops with it. On a scan, that registers as lost lean mass. In the mirror, it looks like flatter, softer muscle. But much of that early change is fuel and hydration, not tissue that's gone.2

So two things are true at once: weight loss genuinely puts muscle at risk, and the raw "lean mass lost" numbers overstate how much actual muscle is disappearing. The real question isn't whether the scale says you lost lean mass. It's whether you're supporting the systems that hold onto the muscle underneath.2

What actually preserves muscle — in order.

The evidence here is clearer than the internet suggests, and the list is short. What matters most isn't a supplement.

Protein comes first. In a controlled trial, participants in a steep deficit eating higher protein lost markedly less lean mass than a matched group eating less protein — same fat loss, very different muscle outcome, with protein as the variable.3 Resistance training is second. It's the signal that tells the body the muscle is still being used and worth keeping. Together, those two do the heavy lifting.

RETAIN is built for the third layer: the specific inputs muscle and connective tissue draw on when energy is low. It doesn't replace protein or training. It supports them.

What each ingredient is for
Creatine Monohydrate — 5g
The most studied ingredient in the formula. Creatine supports cellular energy availability during exercise, which helps maintain strength output when overall fuel is lower — the situation a deficit creates. The dose reflects the 3–5g daily range the research uses.4
Hydrolyzed Collagen Peptides — 5g
Supports the connective tissue, skin, and joints that change alongside your body as weight comes off. A meta-analysis of randomized trials found hydrolyzed collagen supported skin elasticity and hydration.5
Electrolytes — Sodium, Potassium, Magnesium
When intake drops, so does the sodium and fluid that come with food. Electrolytes support the hydration and neuromuscular signaling that muscle contraction depends on.6
Vitamin C — 250mg
Required for collagen synthesis. The body cannot assemble collagen without it, which is why it's paired with the collagen rather than sold as a separate benefit.7
L-Glycine — 500mg
Supports tissue recovery. Glycine makes up roughly a third of collagen, so it works alongside the collagen and vitamin C to support the connective tissue layer.

Preservation isn't a single moment you pass through. It runs through the whole process — and the strength you keep while the weight comes off is the strength you carry into everything after.

What the research feels like from the inside

The studies describe a sequence. So does the experience of living it. Most women move through some version of these three:

"Something looks different."
Glycogen and water shift first. Muscles can look flatter and strength can feel inconsistent within the same week — usually the first thing noticed, and the easiest to misread as lost muscle when it's mostly a fuel and hydration change.
"My workouts feel off."
Strength stops showing up the same way day to day. That's the body adapting to lower energy availability, not a sign the effort has stopped working.
"What I keep is decided here."
The longest stretch, and the one that matters most. This is where muscle is either supported or quietly lost — and what you preserve here is what you carry forward.
Before you rebuild, you preserve.
Reserve RETAIN
References
  1. Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384:989–1002. Body-composition (DEXA) substudy.
  2. Reviews of body composition during caloric restriction describing lean mass as inclusive of intramuscular water, glycogen, and connective tissue; glycogen-associated water loss during deficit.
  3. Mettler S, Mitchell N, Tipton KD. Increased Protein Intake Reduces Lean Body Mass Loss during Weight Loss in Athletes. Med Sci Sports Exerc. 2010;42(2):326–337.
  4. Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation. J Int Soc Sports Nutr. 2017;14:18.
  5. Pu SY, et al. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients. 2023;15(9):2080.
  6. MedlinePlus. Fluid and Electrolyte Balance. U.S. National Library of Medicine.
  7. National Institutes of Health, Office of Dietary Supplements. Vitamin C Fact Sheet for Health Professionals.
These statements have not been evaluated by the Food and Drug Administration. RETAIN is not intended to diagnose, treat, cure, or prevent any disease.