Interactive tools
Tools for a clearer head
Small, honest calculators and checkers built on the same primary research as our articles. They run entirely in your browser, save nothing, and are educational estimates, not a diagnosis. When a tool points to something medical — iron, B12, thyroid — it tells you to go get the bloodwork.
- Symptom checkerBrain-Fog Cause FinderToggle the symptoms and context that fit you — poor sleep, low-iron risk, thyroid signs, B12/vegan diet, new medications, dehydration, post-meal slumps, perimenopause, high stress — and see the likely contributors behind your fog, each with a short evidence note and a clear prompt to get bloodwork when it matters.Find likely causes
- Caffeine & sleepCaffeine Cutoff CalculatorEstimate how much caffeine from a coffee, espresso, energy drink, or tea is still circulating at bedtime — and the last safe time to have it so residual caffeine stays under the common sleep-disruption threshold. Late caffeine is a quiet driver of next-day fog.Find your cutoff
- Calm focusCaffeine + L-Theanine CalculatorEnter a caffeine dose — or pick a coffee, matcha, energy drink, or pill — and get the L-theanine to pair with it at the commonly-studied ~1:2 "calm focus" ratio, plus a reverse mode and a timing note. The amino acid that takes caffeine's edge off, dosed honestly.Find the pairing
Start with the reading
The tools are a way in; the depth is in the articles. These are the best places to begin.
- What causes brain fogThe full map of common contributors, evidence-graded.
- How to clear brain fogWhat actually moves the needle, in order of impact.
- The afternoon crashWhy a second coffee backfires — pairs with the cutoff tool.
- Best cognitive-energy picks (2026)Our evidence-graded hub for energy and focus.
These tools are informational and not medical advice. They cannot diagnose a condition, account for your full history, or replace testing and a clinician's judgment. Persistent or worsening brain fog — especially with weight change, low mood, numbness, heavy periods, or a new medication — deserves a real evaluation. Talk to a licensed clinician.
Where to actually get clinician-supervised NAD+
These tools tell you what your body is doing. If you have decided to try NAD+, these are the partners we rank highest on published price and clinician oversight.
Every provider below is a paid partner of ours, and we may earn a commission at no extra cost to you — that is why these three and not others. See all 14 ranked, partners and non-partners alike.
- CoreAge Rx$93/mo flat
Nasal spray + injection
Nasal and injected NAD+ are marketed for cellular energy and focus with no rigorous human cognition or energy trial.
Visit CoreAge Rx - HealthRXFrom $134/mo
Sub-Q injection + nasal spray
Sub-Q and intranasal NAD+ sold for energy and focus; neither route has a rigorous human cognition trial behind it.
Visit HealthRX - RxSpan MDFrom $199/mo
Injection, nasal spray, flex-dose tablet
Injected, nasal and oral NAD+ marketed for energy; no rigorous human trial supports any of the three routes for focus.
Visit RxSpan MD