In the world of competitive fitness, there is a common misconception that once you hit your 40s, your “best days” are in the rearview mirror. For Brittany, a former bikini bodybuilder in her 30s, the drive to return to the stage was there, but her body wasn’t responding like it used to.
Despite getting 8 hours of sleep, her energy was nonexistent. Despite a “good” diet, she was trapped in a 20lb yoyo cycle. She tried the standard “weight loss shots,” but GI distress forced her to stop.
When Brittany came to Thrive Wellness Institute, we didn’t just give her a diet; we rebuilt her metabolism from the molecular level up. One year later, the data tells a story of one of the most successful body recompositions we have ever witnessed.
The Starting Line: January 2025(fat loss after 40)
Brittany began her journey at 178 lbs with 32.8% body fat. While she had a strong athletic foundation, her metabolism was “stalled.”
- Lean Mass: 95.5 lbs
- Visceral Fat (The dangerous fat around organs): 10
- Metabolic Age: 41 (Exactly her chronological age)
Her labs revealed the “why” behind her fatigue: her Testosterone was sitting at 23 ng/dL—on the lower end for an active female—and her protein intake was insufficient at only 80g daily to support muscle protein synthesis.
The Thrive Protocol: The Science of the Transformation
To get Brittany back into “Bikini Pro” shape, we moved away from generic weight loss strategies and implemented a targeted Peptide and Hormone protocol.
1. The Metabolic Engine: Retatrutide (Reta)
After struggling with GI issues on Tirzepatide, we transitioned Brittany to Retatrutide, starting at 1mg and titrating to 3mg. Unlike its predecessors, Retatrutide is a “triple agonist” (GLP-1, GIP, and Glucagon). The addition of the Glucagon receptor agonism was the game-changer for Brittany; it increased her metabolic rate and thermogenesis while being much gentler on her digestion.
2. Hormonal Optimization: Testosterone Replacement
We optimized Brittany’s testosterone, bringing her from a baseline of 23 ng/dL to a vibrant 77 ng/dL. This wasn’t about “bulk”; it was about recovery. This shift is what allowed her to finally break the fatigue cycle and maintain her lean muscle mass even while in a significant caloric deficit.
3. The “Holy Grail” of Peptides: Tesamorelin & Ipamorelin
We cycled a combination of Tesamorelin and Ipamorelin.
- Tesamorelin is FDA-approved specifically for the reduction of visceral fat.
- Ipamorelin stimulates the natural release of growth hormone without the “hunger spikes” associated with other peptides.This duo is largely responsible for her visceral fat dropping from a 10 down to a 6.
4. Mitochondrial & Fat Oxidation Support
We rounded out her protocol with L-Carnitine (to shuttle fatty acids into the mitochondria to be burned for fuel) and 5-Amino-1MQ. 5-Amino-1MQ is a cutting-edge peptide that blocks the NNMT enzyme, effectively “turning on” the metabolism in fat cells and increasing cellular energy (ATP).
The Foundation: Protein & Resistance
Peptides are the “turbocharger,” but the diet is the “fuel.” We moved Brittany to a 120g protein target to protect her muscle tissue. We also made a counter-intuitive shift in her training: we lowered her cardio. By switching to 2-3 days of low-intensity walking and 5-6 days of heavy resistance training, we lowered her systemic cortisol (which was 16.5 ug/dL) and allowed her body to stay in an anabolic (building) state rather than a catabolic (breaking down) state.
The Results: January 2026
The “After” data is nothing short of a Masterclass in Body Recomposition.
| Metric | January 2025 | January 2026 | Change |
| Weight | 178 lbs | 130.6 lbs | -47.4 lbs |
| Body Fat % | 32.8% | 20.8% | -12% |
| Lean Mass | 95.5 lbs | 96.2 lbs | +0.7 lbs (GAINED) |
| Visceral Fat | 10 | 6 | -40% |
| Metabolic Age | 41 | 32 | -9 Years |
The most incredible stat: Brittany lost over 47 pounds of total weight, yet her Lean Mass actually increased. In traditional weight loss, you typically lose 25% of your weight from muscle. By using our peptide and hormone protocol, Brittany lost pure fat while actually getting stronger.
Summary from Thrive Wellness Institute
Brittany’s metabolic age is now nine years younger than when she started. She has reclaimed her energy, her confidence, and her “bikini-ready” physique.
Her transformation proves that with the right data, the right peptides, and a commitment to protein and lifting, your 40s can be your strongest decade yet.
Are you ready to see what your body is truly capable of? Contact Thrive Wellness Institute today for your comprehensive lab review.
FAQ
Can women really build muscle after 40?
Yes. With proper protein intake, resistance training, and hormone optimization, women can gain lean muscle well into their 40s and beyond.
Is testosterone therapy safe for women?
When prescribed and monitored correctly, female testosterone optimization improves energy, recovery, and body composition without masculinizing effects.
Why didn’t standard weight-loss injections work for Brittany?
Traditional GLP-1 medications suppressed appetite but worsened digestion and failed to address metabolic rate or hormonal decline.
What makes peptide therapy different from dieting?
Peptides restore cellular signaling, allowing the body to burn fat, preserve muscle, and improve energy rather than relying on calorie restriction alone.
How long does body recomposition take?
Meaningful metabolic transformation typically occurs over 6–12 months when protocols are personalized and data-driven.