- Omega-3, magnesium, vitamin D, creatine, protein — in that order.
- Skip anything not on this list until these five are dialed.
- Cheap additions beat expensive ones when bioavailability and dosing are right.
When we started Body By A, our goal wasn't to sell you 47 different supplements. It was to identify the ones with the strongest evidence, the most practical impact, and the best price-to-benefit ratio. After hundreds of hours of research and years of personal use, we've narrowed it down to five.
These aren't trendy. They're not flashy. But they work, and the science backs them up.
1. Omega-3 Fatty Acids (Fish Oil or Algae-Based)
Why: Most of us don't eat enough fatty fish. Our bodies can't make omega-3s, so we have to get them from food or supplements. They're critical for brain health, inflammation management, and cardiovascular function.
The dose: 1,000-2,000 mg EPA+DHA daily. This is the combined amount of the two active omega-3 forms. Check the label—many products list total "fish oil" but only deliver 300mg of actual EPA+DHA.
What we look for: Third-party tested, minimal fillers, and if possible, pharmaceutical-grade (meaning it's been tested for heavy metals and contaminants). We prefer brands that source responsibly.
Ajay runs on fish oil. Tessa uses algae-based when she wants a cleaner source. Both work.
Browse our picks: View our tested omega-3 options
“Five supplements, stacked right, will beat a cabinet full of everything else.”
2. Magnesium Glycinate
Why: Magnesium is involved in over 300 reactions in your body—energy production, muscle function, sleep, stress response. Most people are deficient because modern farming has depleted soil magnesium and we're all eating processed food. Even if you eat spinach and nuts, you're probably still short.
The dose: 300-400 mg daily, taken in the evening. This is the RDA (recommended dietary allowance), and it's realistic for most people. More is not better—too much magnesium causes digestive issues.
Why glycinate specifically: There are many types of magnesium (citrate, oxide, threonate, etc.), and they behave differently. Glycinate is highly absorbable, gentle on the stomach, and won't give you loose stools. This is our baseline pick for most people.
Tessa's note: I noticed sleep improvements and fewer muscle cramps within two weeks. That said, magnesium is extremely bioavailable from food if you're eating it—supplementing is more about insurance.
Browse our picks: See all magnesium types and which one to choose
3. Vitamin D3
Why: Vitamin D is actually a hormone, not a vitamin. It regulates immune function, mood, bone health, and dozens of other processes. If you live anywhere north of 35° latitude (basically anything above LA or below Florida), you cannot make enough vitamin D from sun exposure in winter. Even in sunny climates, most people don't spend enough unprotected time outside.
The dose: 1,000-4,000 IU daily. The RDA is 600-800 IU, but most research suggests that's too low. We dose based on blood levels—ideally 30-50 ng/mL. Get tested if you can; if not, 2,000 IU is a safe starting point.
What we look for: D3 (cholecalciferol), not D2. D3 is more bioavailable and what your body naturally produces. It should be in a fat (olive oil, coconut oil, etc.) because vitamin D is fat-soluble.
Browse our picks: Choose the right D3 for your needs
4. Creatine Monohydrate
Why: Creatine is one of the most studied supplements in the world. It works. It increases muscle strength, power, and endurance during resistance training. It also has emerging benefits for brain health and mood. The science is overwhelming.
The dose: 5 grams daily, any time of day. No loading phase is necessary (some people load 20g/day for 5 days, but it's not required). With consistent dosing, you'll see results in 2-4 weeks.
Who should take it: Anyone doing resistance training, and especially women (because the hormone-boosting effects are particularly beneficial for female athletes). Creatine doesn't cause hormonal disruption—that's a myth. It's one of the safest supplements available.
Ajay's note: I've been taking creatine for 7 years. My lifts are stronger, my recovery is better, and my brain feels sharper. It's boring because it just works.
Tessa's note: I was skeptical because of the myths around "bulking." Then I read the actual research. I've been taking it for 3 years. No weird side effects, just better workout performance and easier muscle maintenance.
Browse our picks: Explore our third-party tested creatine options
5. Protein Powder
Why: If you're training (resistance or cardio), you need adequate protein. The RDA is 0.8g per kg of body weight, but that's for sedentary people. If you're active, you need 1.6-2.2g per kg. For most people, that's 100-150g daily. Whole food can get you there, but it's inconvenient and expensive. Protein powder is efficient, affordable, and when chosen wisely, clean.
The dose: Variable, but aim for 20-40g per serving. Use it as a tool to hit your daily protein target, not as a replacement for whole food.
What we look for: Whey isolate or concentrate (if tolerated), or plant-based blends with complete amino acid profiles. Minimal fillers. Minimal sweeteners (we avoid stevia and artificial sweeteners in protein powders). Third-party tested for heavy metals and protein content.
The flavoring issue: Most protein powders are vanilla, chocolate, or strawberry, which means they need sweetening. Given emerging research on stevia and cardiovascular health, we’ve moved away from it entirely. Our preference: unflavored whey/isolate, or clean-flavored options sweetened only with monk fruit, cocoa, or real vanilla.
Browse our picks: Find a clean protein powder that fits your needs
That's It
These five supplements cover the bases: omega-3 for brain and heart health, magnesium for sleep and stress, vitamin D for immune and bone health, creatine for strength and possibly cognition, and protein for muscle. Everything else—fancy nootropics, adaptogenic blends, proprietary complexes—is nice to have, not need to have.
The other piece is real food. No supplement replaces a solid diet. But these five address gaps that even a good diet struggles to fill for most people in the modern world.
Start here. See how you feel in 4-6 weeks. Then, if you want to experiment with something else, you'll have a clean baseline to measure from.
Ready to Get Started?
We've sourced and vetted versions of each of these five supplements. No sponsorships, no affiliate nonsense. Just what we actually recommend and use ourselves.