The short list

Why the list is short

Most supplement cabinets grow by addition. Something gets recommended, it goes in, and nothing ever comes out. The result is a large monthly cost, low adherence, and no way to tell what is doing anything.

A short foundation is easier to take every day, easier to evaluate, and easier to build on when a specific goal or marker calls for it.

Omega-3 fatty acids, EPA and DHA

Omega-3s are structural fats used in cell membranes throughout the body, and most people eating a Western pattern diet take in far less EPA and DHA than populations with high oily fish intake.

The relevant measurement is the omega-3 index, which reports EPA and DHA as a percentage of red blood cell fatty acids. Research groups describe an optimum of about 8 to 11 percent, and typical Western values sit well below that.

Dose depends entirely on where you start. Someone eating salmon three times a week may need very little. Someone eating none may need substantially more, and the label total is not the number that matters, since only the EPA and DHA content counts.

• Read the EPA and DHA amounts per serving, not the total fish oil weight.
• Triglyceride and re-esterified triglyceride forms are generally well absorbed.
• Freshness matters. Oxidized oil smells and tastes off, and third party oxidation testing is worth looking for.
• Taking it with a meal containing fat improves absorption and reduces reflux.

Vitamin D3, and why K2 sits next to it

Vitamin D status is measured as serum 25-hydroxyvitamin D. It is one of the few supplement questions where testing is cheap, widely available, and genuinely changes the answer, because both low and unnecessarily high intakes are worth avoiding.

Dose response varies a great deal between people based on body composition, baseline level, sun exposure, and absorption. This is why a fixed dose for everyone is a poor default and why retesting after a few months is more useful than guessing.

Vitamin K2, usually as MK-7, is commonly paired with D3 because the two work in related pathways governing where calcium ends up in the body. If you take a vitamin K antagonist such as warfarin, K2 is a conversation to have with your prescriber before adding anything.

Magnesium, and why the form decides the experience

Magnesium is involved in hundreds of enzymatic reactions, and intake below recommended levels is common. Serum magnesium is a poor indicator of total body status, which is part of why intake tends to be assessed from diet rather than from a single blood value.

Form is the practical variable. Magnesium oxide is cheap and poorly absorbed, and it is the usual reason someone concludes that magnesium upsets their stomach. Glycinate is generally better tolerated, and it is the form we tend to point people toward in the evening, which is a preference based on tolerability rather than a head to head outcome trial.

• Glycinate: well tolerated, commonly taken in the evening.
• Citrate: reasonably absorbed, with a laxative effect at higher doses.
• Oxide: high elemental content on the label, low absorption in practice.
• Threonate and taurate: more expensive, chosen for specific reasons rather than as a default.

What is deliberately not on the list

Plenty of compounds have interesting early research behind them. Interesting early research is a reason to keep reading, not a reason to add a permanent monthly expense.

When something specific shows up in your labs, history, or goals, that is when the list grows, and it grows with a reason attached and a point at which it gets reviewed.