This is not a list of everything the supplement industry wants you to buy. It’s a ranked list of what I’ve actually used, researched, and found worth the money, with an honest assessment of the evidence behind each one.
The ranking criteria: strength of the research, real-world results I’ve noticed, quality of what’s available, and value relative to cost.
1. Creatine
Creatine moved to the top of my list the moment I understood what it does specifically for women over 40 on a weight loss protocol. GLP-1 medications suppress appetite and create a caloric deficit — which means some of the weight you lose will be muscle unless you actively protect it. Creatine supports muscle energy production, improves recovery from resistance training, and has decades of safety research behind it.
5 grams daily, taken consistently. The form matters — standard creatine monohydrate works, but nano-creatine dissolves completely and absorbs faster. The version I use is Arq8 FullDissolve. Read the full creatine post here.
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2. Berberine
Berberine activates AMPK, an enzyme that regulates metabolism and blood sugar. Clinical trials show reductions in fasting blood glucose, improvements in insulin sensitivity, and meaningful effects on body weight. It’s the supplement I’d recommend first to someone who isn’t on GLP-1 and is dealing with blood sugar swings or stubborn weight despite clean eating.
500mg capsules, standardized extract, taken with meals to reduce GI side effects. Read the full breakdown: Berberine for weight loss: does it actually work?
3. Cortisol Support (Ashwagandha-Based)
Chronic cortisol elevation drives abdominal fat storage, increases cravings, and disrupts sleep — three mechanisms that work directly against weight loss. Ashwagandha has the strongest evidence for reducing cortisol in chronically stressed individuals among available supplement ingredients. Combined with other adaptogens in a cortisol-specific formula, the effect on stress eating and sleep is more pronounced than any fat burner I’ve tried.
The cortisol supplement I use is Harmonia. Read the full review here.
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4. Protein Powder
Protein powder isn’t exciting, but it’s one of the most evidence-backed tools for weight loss and body composition. High protein intake preserves lean muscle during a calorie deficit, increases satiety, and has a higher thermic effect than carbs or fat. If you’re over 40 and in a calorie deficit without adequate protein, you’re likely losing muscle alongside fat.
What to look for: whey isolate for highest protein per calorie and fast absorption, plant-based blend (pea plus rice) if you’re dairy-free. Avoid products with a lot of added sugar or fillers. Full breakdown: best protein powder for weight loss.
5. Collagen
Collagen production declines after 40. During weight loss, the joint stress from exercise and the skin changes from losing fat both benefit from consistent collagen supplementation. It also contributes to daily protein intake — useful when appetite is reduced on GLP-1. Adding a scoop to morning coffee takes ten seconds.
The collagen I use is from Physician Crafted — Nu-Derma Gold, which pairs collagen with Vitamin C and Hyaluronic Acid. Full post: collagen for weight loss.
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6. Probiotics
Specific probiotic strains — particularly Lactobacillus gasseri and Lactobacillus rhamnosus — show meaningful effects on body fat and appetite hormones in clinical studies. Gut health increasingly connects to metabolic function and weight management in ways that weren’t well-understood a decade ago.
Multi-strain formula with at least 10-20 billion CFU, guaranteed potency at expiration. Full post: probiotics for weight loss.
7. Magnesium
Magnesium is involved in over 300 enzymatic reactions, including insulin signaling and blood sugar regulation. Most people are deficient. Take it for sleep quality and the weight-related benefits follow: better cortisol regulation, less evening cravings, improved recovery.
Magnesium glycinate before bed, 300 to 400mg. Avoid magnesium oxide. Full breakdown: magnesium for weight loss and sleep.
What I Don’t Recommend
Garcinia cambogia: weak research, clinically insignificant results. Raspberry ketones: compelling in animal studies, irrelevant in human doses. Most “fat burner” blends: stimulant effect from caffeine, nothing else doing real work. CLA: small effect size, inconsistent results.
If you can’t find a clear mechanism for why a supplement would work, that’s usually your answer.
The Bigger Picture
Supplements support a working system. If the fundamentals are off, no supplement compensates. If the fundamentals are solid and you’ve plateaued, targeted supplementation can move things forward. Start with creatine and protein. Add cortisol support if stress is a factor. Build from there.
If you’re at the point where diet and supplements have taken you as far as they can, the GLP-1 guide is worth reading. That’s a different tier of intervention with meaningfully different results.
Explore the Full Supplements Series
Highest-impact supplements
- Creatine for weight loss: why it’s not just for bodybuilders
- Arq8 creatine gummies review
- Best protein powder for weight loss
- Berberine for weight loss: does it actually work?
- Best supplements to take while on GLP-1
Cortisol and hormonal weight gain
- Cortisol and weight gain: what’s actually happening
- Ashwagandha and cortisol: what the research shows
- Harmonia cortisol support: full review
Foundations and support nutrients
- Magnesium for weight loss and sleep
- Vitamin D and weight loss: what the connection is
- Omega-3 and fat loss: does it actually help?
- Collagen for weight loss: what it does
- Probiotics for weight loss
Specific audiences