Every guide, graded
Browse by category, or scan the full list. Each grade reflects the strength of human trial evidence when we last checked. Where that evidence is thin, the grade says so.
Creatine monohydrate: what it actually does
The most researched supplement in sports science, and one of the few with a real effect size behind it.
Vitamin D3: when supplementing actually moves the needle
Genuinely useful if you're deficient, mostly irrelevant otherwise. Knowing which one you are is the whole trick.
Omega-3 (EPA/DHA): fish oil that isn't a waste of money
Most fish oil sold is underdosed. Here's what the actual trial doses look like and why the ratio on the label matters.
Magnesium glycinate: the form matters more than the marketing
Magnesium is genuinely under-consumed, but which compound you buy determines whether it helps or just sends you to the bathroom.
Ashwagandha: a real adaptogen with real caveats
One of the few herbal supplements with decent randomized trial data behind it, mostly for stress and cortisol, not the miracle it's sold as.
Popular supplement questions
Every guide below is written to answer a specific question. These are the ones readers ask most.
- Creatine monohydrate dosage
- Creatine side effects
- Do you need to cycle creatine
- How much vitamin D should I take
- Vitamin D3 vs D2
- Can you take too much vitamin D
- How much EPA and DHA per day
- Best fish oil supplement
- Algae omega-3 vs fish oil
- Magnesium dosage for sleep
- Magnesium oxide absorption
- When to take magnesium
- Ashwagandha side effects
- KSM-66 vs Sensoril
- How long does ashwagandha take to work
Which supplements are actually worth taking?
Short answer: far fewer than the shelf suggests. Of the five supplements covered here, only creatine monohydrate earns a strong evidence grade outright. Vitamin D3, omega-3 EPA and DHA, magnesium glycinate and ashwagandha all sit at moderate, which usually means they work well for a specific group of people and do very little for everyone else.
That distinction is the whole point of the grades. Correcting a genuine vitamin D deficiency is worth doing. Adding vitamin D on top of an already-normal blood level is not the same intervention, and the trials show it. The same logic runs through the magnesium and omega-3 guides.