The 3 Supplements I Recommend (and How to Choose Them)

Originally published March 2008. Last reviewed and updated by the Precision Nutrition editorial team, May 2026.

Nowadays, a good portion of my face-time with clients and athletes is spent discussing nutritional supplements.

Which ones work, which don’t. Which ones are safe, which ones may be dangerous. Which ones are “clean,” and which may contain banned substances.

Sometimes, the more information that’s put out there regarding supplements, the more confused they can get.

However, my supplement approach is really simple…and I want to share it with you today.

There are 3 basic supplements that all my clients and athletes have on hand – especially when traveling.

The short answer to the supplements question

If you only take three supplements, take:

They fill the three nutritional gaps most adults actually have — not enough plants, not enough omega-3s, not enough protein — and they’re backed by decades of research. Everything else (creatine, vitamin D, magnesium, etc.) is situational and depends on individual needs. More on that soon.

But first, a practical word on supplement quality

Before we get into the specifics: The supplement industry is still only loosely regulated in many countries.

So, the single most useful thing you can do, regardless of what you take, is buy from a brand that pays for independent third-party testing.

Look for one of these certifications on the label:

Certification	What it means
NSF Certified for Sport	Tested for label accuracy and screened against ~280 banned substances. The standard for competitive athletes.
Informed Sport / Informed Choice	Batch-by-batch testing against the WADA banned list. Common in Europe.
USP Verified	Independent verification that what’s on the label is what’s in the bottle, at the dose listed, and free of harmful contaminants.

A certified product costs a bit more. It also means you’re not gambling on whether the bottle actually contains what it claims, or whether it’s contaminated with something that could fail a drug test.

Now, without further ado, here’s why I recommend greens, proteins, and fish oils, plus how to choose a high quality version of each supplement.

Green food supplement

The 2020–2025 Dietary Guidelines for Americans recommended at least five servings of produce per day, ideally with two of those servings coming from fruit and three coming from vegetables.¹

However, a mere 10 percent of adults meet the minimums for veggie consumption, and only 12 percent meet the minimums for fruit consumption.²

Enter: Greens supplements.

Don't avoid meat, just eat more of this

Greens supplements — what to know

Greens powders concentrate the nutrients from fruits, vegetables, and sometimes algae and edible grasses into a convenient scoop you can mix with water, a smoothie, or juice. They’re a useful insurance policy if you struggle to hit 5+ servings of produce on a regular day.

However, greens powders are not a substitute for actually eating plants.

The fibre content per scoop is modest, the polyphenol profile is narrower than a varied diet, and the long-term clinical research is thinner than the marketing suggests. They narrow a gap — they don’t close it.

If you can hit your vegetable intake from food, you don’t need this supplement.

What to look for:

A short, recognizable ingredient list. If you can’t tell what most of it is, skip it.
Third-party tested (especially because greens powders are a frequent source of heavy-metal contamination from poor-quality source ingredients).
No mega-dose vitamin blends — the goal is whole-food-derived nutrients, not a multivitamin in disguise.

PN has vetted a few quality brands, so you can check out that list if you want. (See: Precision Nutrition Approved:
Our favorite nutritional supplements) And for more on what greens supplements can (and can’t) do, see PN’s deeper guide: All About Greens Supplements.

Fish oil supplement

The WHO recommends 250 to 2,000 mg daily of EPA plus DHA, but the average American adult only consumes about 35 mg/day of EPA and 76 mg/day of DHA, a fraction what’s necessary for good health.³

For those who don’t know what I’m talking about, EPA and DHA are the healthy fats present in fish oils and some algae-based oils.

And that’s where fish oil supplements (or their vegan alternatives) come in.

omega_600x450

Fish oil supplements — what to know

The omega-3 intake associated with general cardiovascular health sits around 500 mg/day combined EPA + DHA,⁴ and many sports and clinical applications use higher doses (1–3 g/day).

Unless you’re eating fatty fish like salmon, sardines, or mackerel at least twice a week, you’re almost certainly under-consuming.

However, some recent trials (most notably the VITAL trial) found that giving a modest fish-oil dose in supplement form to the general population didn’t reduce cardiovascular events as much as earlier observational research suggested.⁵

So, while EPA and DHA are still essential nutrients with broad roles in heart, brain, joint, and inflammation regulation, and most people are under-consuming them — fish oil isn’t a magic pill, and food sources should come first.

What to look for:

Total EPA + DHA per serving listed clearly on the label — not just “fish oil mg.” Aim for 1–2 g combined EPA + DHA daily unless your doctor advises otherwise.
Third-party tested for purity (oxidation, heavy metals, PCBs). Rancid fish oil is common (and unpleasant). Proper formulation, packaging, and storage ensures freshness.
Triglyceride or re-esterified triglyceride form (rTG) is generally better absorbed than the cheaper ethyl ester (EE) form.
Algae-based EPA/DHA is the vegan/vegetarian equivalent and works very well.

Protein supplement

Finally, adults — particularly if they’re active, trying to lose weight while preserving muscle, and/or on GLP-1 medications — do well at 0.7–1.0 g of protein per pound of body weight (about 1.6–2.2 g/kg).¹

Nevertheless, most women only get 80 to 100g of protein per day, while most men get only 110 to 130g protein per day.

Protein supplements to the rescue!

chicken_breasts

Protein supplement — what to know

Of the three, protein has the strongest and most consistent evidence base — and the case for it has only gotten stronger over time. Protein needs for active adults sit around 1.6–2.2 g per kg of body weight per day (roughly 0.7–1.0 g per pound), and most people, especially women and older adults, fall short of the top of that range.¹

A protein supplement isn’t magical, but it sure is a convenient way to hit a target you’re probably missing.

What to look for:

Around 20–30 g of protein per serving from a high-quality source: whey isolate or blend, casein, or a complete plant blend (pea + rice, or soy). (If whey bothers your stomach or you’re intolerant, you’ll want to read this: Whey sensitivity and intolerance: When whey protein just isn’t for you)
A short ingredient list — protein, a little sweetener, maybe cocoa or vanilla. Long mystery lists usually mean fillers.
Third-party tested for label accuracy and (if you compete) banned substances.

For deeper guidance on choosing a powder, see PN’s protein-powder buying guide: “What’s the best protein powder?” Your complete guide to choosing the right supplement for you.

When to talk to your doctor first

Supplements are not medications, but they’re not completely harmless either.

Talk to your doctor or pharmacist before starting any of these if you:

Take blood thinners (warfarin, apixaban, etc.). Fish oil can increase bleeding risk; vitamin-K-rich greens powders can interfere with warfarin dosing.
Have kidney disease. Protein intake should be discussed with your nephrologist.
Are pregnant or breastfeeding.
Take prescription medications of any kind — many supplements have interactions worth checking.
Have a known allergy or intolerance to fish, shellfish, dairy, soy, or other common protein sources.

How to know if you need anything beyond the three

This is the part of the supplement question most internet advice skips.

PN’s approach has always been “needs analysis first, supplement second.”

What’s a needs analysis? Well, it’s simple. We evaluate the client’s individual needs with respect to health, body comp, and/or performance and then introduce additional supplements only if there’s a specific need.

After all, why use a testosterone booster (such as tribulus) if your testosterone is already high?

Why use a fat burner (any fat burner) if your metabolism is already very fast?

Why use creatine if you have a high creatine intake from food and are already “creatine saturated?”

Why use a NO2 product for “bigger pumps” when you’re a sport athlete who isn’t training “for the pump” in the first place?

And why use something to buffer muscle acidity (such as beta alanine or bicarbonates) if you’re not building up high amounts of lactate during your training?

Translation: Before you add a fourth, fifth, or fifteenth bottle to the shelf, ask whether you actually have the gap that supplement is designed to fill.

A few supplement that often (but don’t always) earn a spot for specific people:

Supplement	Consider it if…
Vitamin D	You live above ~40° latitude, get little sun, have darker skin, or test low for serum Vitamin D on a blood panel.
Creatine monohydrate	You strength train, do high-intensity sport, or want a small but real muscle (and possibly cognitive) benefits. One of the most-studied supplements in existence.
Magnesium	You consistently fall short on leafy greens, nuts, seeds, and whole grains, or you have poor sleep, cramps, or low magnesium on a blood test.
Probiotic	Recovering from antibiotics or working through a specific GI issue with a clinician. Otherwise, you can get these beneficial bacteria mostly food (yogurt, kefir, fermented vegetables).
Multivitamin	As cheap insurance if your diet is genuinely inconsistent. Choose one without mega-doses.

Notice what’s not on that list: fat burners, testosterone boosters, workout “pumps,” and BCAAs if you’re already getting enough protein. Almost everything the supplement industry markets hardest is the stuff with the weakest evidence.

Frequently asked questions

What are the most important supplements to take daily?

For most adults, the three with the broadest evidence and the most common nutritional gaps are a greens or fruit-and-vegetable supplement, a fish oil supplement providing EPA and DHA, and a protein supplement. Anything else depends on your individual diet, training, age, and health status — and is worth a conversation with a registered dietitian or doctor.

Do I actually need supplements if I eat well?

If your diet consistently delivers 5+ servings of varied produce, fatty fish twice a week, and adequate protein at every meal, you can probably skip them. Most people don’t hit all three on a typical week — supplements close the gap on the days that don’t go to plan.

How much fish oil should I take?

A common general-health target is around 1–2 grams of combined EPA + DHA per day, with higher doses (2–3 g/day) used for specific situations under clinical guidance. Check the EPA + DHA total on the label, not just the total “fish oil” milligrams.

Is whey protein better than plant protein?

Whey is slightly more efficient gram-for-gram for muscle protein synthesis, but a quality plant blend (pea + rice, or soy) at adequate dose closes most of that gap and works well for the great majority of people. The best protein powder is the one you’ll actually use.

How do I know if a supplement brand is trustworthy?

Look for independent third-party testing — NSF Certified for Sport, Informed Sport, or USP Verified are the most common marks. They mean someone outside the brand has confirmed the bottle contains what it says, at the dose stated, without contaminants.

Are greens powders worth it?

They’re a reasonable insurance policy if you struggle to eat 5+ servings of vegetables daily, but they’re not a replacement for real produce. Fibre content per scoop is modest and the long-term clinical research is thinner than the marketing implies. Eat vegetables first; use the powder to top up.

The bottom line

Of the thousands upon thousands of supplements on the market, three earn the right to be on most people’s shelves: a greens or fruit-and-vegetable supplement, a fish oil supplement for EPA and DHA, and a protein supplement. They map to three nutrient gaps almost everyone actually has.

Buy from a brand with independent third-party testing, treat them as a top-up rather than a fix, and have a quick conversation with your doctor before starting any of them if you take medications.

Everything beyond that should pass a needs-analysis test — does the gap you’re trying to fill actually exist for you? — before it earns a spot on your counter.