The role of ingestibles
One of the most consistent patterns we see at A3 across hundreds of clients and thousands of data points is chronic stress. Not the acute, productive kind, but the low-grade, always-on kind that shows up in suppressed HRV, cortisol that never quite normalizes, and performance that degrades over time. We think of it as the unsung tax on high achievement. This series is a deep dive into a full stack of evidence-based interventions for doing something about it. As we said in Part 1, the research is clear: while there may not be a single magic bullet, multiple moderate interventions quickly add up.
First, a quick recap: Part 1 covered breathing and mental practices. Part 2 tackled exercise and sleep. Part 3 covered your environment: temperature, physical surroundings, and social connection. Those posts addressed what you do and what you're surrounded by.
This one is about what you put in your body.
Before we hop in, we should also say up front: this is the area where we're most cautious. While nutrition research gives us a lot of big-picture insights, the evidence gets less clear the more we hone in on short-term impacts. Medicines are powerful, but they're sometimes a bigger hammer than simple lifestyle problems require. And while supplements are a cornerstone of the wellness industry, marketing often aggressively outpaces evidence; most are backed by little more than optimistic extrapolation from animal studies or underpowered trials with questionable methodology.
That said, there's signal in the noise. Some interventions have genuine evidence behind them: powerful effect sizes, replication across multiple trials, and benefits that well outweigh the costs. The trick is separating the truth from the hype.
This post covers three categories:
Foundational nutrition: the dietary patterns and blood sugar dynamics that everything else builds on;
Supplements and adaptogens: what's actually worth considering, what the evidence supports, and what we skip; and,
Pharmaceuticals: a brief, honest look at the prescription options. What they do, what they don't, and where they fit.
Let's get into it.
Foundational Nutrition
Before we get to supplements and pharmaceuticals, it's worth addressing the substrate they're built on. No supplement will compensate for a diet that's working against you, and the foundational patterns here are both well-evidenced and often overlooked.
Blood Sugar Stability: The Invisible Mood Lever
If you've ever felt anxious, irritable, or foggy a few hours after a carb-heavy meal, you've experienced reactive hypoglycemia (and your body's stress response activating in real time).
Here's what's happening: a rapid blood sugar spike (from refined carbs, sugar, or a large meal without protein or fat to slow absorption) triggers a large insulin release. Blood sugar then crashes below baseline in response to that insulin, so your body responds with a sympathoadrenal response. Adrenaline and cortisol flood your system to mobilize glucose and bring levels back up. The subjective experience of that hormonal rollercoaster is often indistinguishable from anxiety: racing heart, jitteriness, difficulty concentrating, irritability.
For some people, this is a daily occurrence. Case studies document anxiety symptoms resolving within days to weeks simply from stabilizing glycemic patterns. No supplements, no medication. Just avoiding the rollercoaster in the first place.
The practical fixes are straightforward:
Pair carbohydrates with protein, fat, or fiber. This slows absorption and flattens the glucose curve. A piece of fruit with nuts hits differently than a piece of fruit alone.
Avoid refined carbs on an empty stomach. A pastry for breakfast with nothing else is a setup for a mid-morning crash.
Prioritize lower glycemic index foods when possible. Whole grains over refined, whole fruits instead of juices or smoothies, etc.
This isn't a prescription for any particular diet—keto, paleo, Mediterranean, or otherwise. (Depending on clients' particulars, we often recommend all of the above.) It's simpler than that: avoid the patterns that trigger your stress response multiple times a day. For some clients, this single change produces more noticeable improvement in day-to-day stress and energy than any supplement we've recommended.
The Mediterranean Pattern
When it comes to overall dietary patterns and mental health, the Mediterranean diet has the strongest evidence base.
The landmark SMILES trial put this to a rigorous test: adults with moderate-to-severe depression were randomized to either dietary counseling (toward a Mediterranean pattern) or social support. The dietary intervention group showed a Cohen's d of -1.16 for depression reduction, a very large effect size, with 32% achieving remission compared to 8% in the control group. Subsequent trials and meta-analyses have largely supported these findings.
The mechanisms are multiple. Mediterranean eating patterns reduce inflammatory markers (hs-CRP, IL-6) that are elevated in chronic stress. They support gut microbiome diversity, which increasingly appears to influence mood and stress response through the gut-brain axis. And they provide the micronutrient density that many modern diets lack.
The pattern itself is familiar: olive oil as the primary fat, nuts, fatty fish, abundant vegetables and fruits, whole grains, legumes, moderate poultry and dairy, limited red meat and processed foods. It's not about rigid rules or elimination, but shifting the center of gravity of your eating toward these foods.
We're not in the business of prescribing one-size-fits-all diets. People's preferences, constraints, and contexts vary too much for that to work consistently. But if someone asks us what dietary pattern has the best evidence for stress and mood, the answer is straightforward: this one.
Caffeine and Alcohol
We covered both of these in Part 2, so we'll keep this brief.
Caffeine has a half-life of 5-6 hours, with significant genetic variability in metabolism. The conservative recommendation is a caffeine curfew 8-10 hours before bed. If you suspect caffeine affects your sleep even when you don't feel stimulated, you're probably right. It disrupts sleep architecture even when subjective sleep onset is unaffected.
Alcohol fragments sleep, suppresses REM, and tanks HRV. OURA data from 600,000+ user-nights showed a 15.6% mean HRV decrease on nights with alcohol consumption. There's no "safe" dose for optimal sleep quality. If you drink, finishing 3-4+ hours before bed reduces (but doesn't eliminate) the impact. There are pros and cons to drinking (and we're not teetotalers ourselves), but it's worth knowing the costs so you can weigh the benefits yourself.
Both are levers that compound. Small daily habits in the wrong direction add up to chronic drag on your stress resilience.
Supplements and Adaptogens
This is where the signal-to-noise ratio gets tricky. The supplement industry is full of compelling claims backed by thin evidence. But there are exceptions: compounds with robust research, meaningful effect sizes, and reasonable safety profiles. Here's what we actually consider worth recommending.
Ashwagandha: The Standout
If we had to pick one adaptogen with the strongest evidence for stress resilience, it's ashwagandha. The data here is genuinely impressive.
Meta-analyses show cortisol reductions of 11-32% and anxiety improvements with effect sizes around SMD -1.5 (a large effect, comparable to some pharmaceuticals). The mechanism appears to involve modulation of the HPA axis, reducing the chronic overactivation that characterizes prolonged stress.
Two extracts dominate the research:
KSM-66 (root-only extract): the most studied, typically dosed at 300mg twice daily
Sensoril (root + leaf extract): effective at lower doses, 125-250mg once or twice daily
Effects typically emerge at 2-4 weeks, with optimal benefits around 6-8 weeks. This isn't an acute intervention—it's a slow build that compounds with consistent use.
A few cautions: ashwagandha may affect thyroid hormone levels, so those on thyroid medication should consult their physician. It's contraindicated in pregnancy. And while generally well-tolerated, some people report GI discomfort or drowsiness.
Cost: $15-35/month for quality extracts.
Magnesium: The Sleep and HRV Workhorse
Magnesium is one of the most common micronutrient deficiencies in Western diets, and supplementation has documented benefits, though not always where people expect.
The evidence for magnesium reducing anxiety per se is inconsistent, with strong placebo effects muddying the waters. But the benefits for sleep quality and HRV are more reliable. Magnesium supports GABA receptor function, helps regulate the stress response, and plays a role in hundreds of enzymatic processes relevant to recovery.
Two forms are worth considering:
Magnesium glycinate: well-absorbed, less likely to cause GI issues, good general choice
Magnesium threonate: specifically crosses the blood-brain barrier, some evidence for cognitive benefits
Dose: 200-400mg elemental magnesium, 30-60 minutes before bed. Effects typically emerge over 2-3 weeks of consistent use.
Cost: $10-25/month.
Omega-3s: The Slow Burn
Fish oil has been studied extensively, and the 2024 dose-response meta-analyses clarified the picture: there's a real effect, but it requires adequate dosing and patience.
The data shows an SMD of -0.70 per gram daily, with optimal effects around 2g/day (SMD -0.93 for mood improvements). High-EPA formulas (≥60% EPA relative to DHA) appear more effective for mood and stress than DHA-dominant products. Documented benefits include cortisol and IL-6 reductions.
The catch: effects require 8-12 weeks. This isn't something you'll feel tomorrow. It's a long-term investment in reducing systemic inflammation and supporting brain function.
Quality matters here, too. Look for third-party testing (IFOS certification is the gold standard), and store in the refrigerator to prevent oxidation.
Cost: $20-40/month for quality.
L-Theanine: The Acute Option
Unlike the supplements above, L-theanine works quickly—effects begin approximately 40 minutes after ingestion. It's the rare compound that offers immediate, noticeable benefits without sedation or cognitive impairment.
Meta-analyses show small-to-moderate improvements in attention alongside significant cortisol decreases at the one-hour mark. EEG studies document increases in alpha brain wave activity, associated with a state of "relaxed alertness": calm but focused, not drowsy.
L-theanine also pairs synergistically with caffeine. A 1:1 to 2:1 ratio of theanine to caffeine (e.g., 100-200mg theanine with 100mg caffeine) preserves the alertness and focus benefits while smoothing out the jitteriness and anxiety that caffeine can produce. If you're caffeine-sensitive but want the cognitive benefits, this combination is worth experimenting with.
Dosing: 100-400mg alone, or 100-200mg paired with your morning coffee.
Cost: $10-20/month.
Melatonin: Less Is More
Melatonin is widely used, and widely misunderstood. The key insight: it's a timing signal, not a sedative. And the doses in most commercial products are much higher than necessary.
Research from MIT established that 0.3mg is sufficient to produce physiological effects equivalent to 3mg, but with fewer side effects. Commercial doses of 3-10mg often cause receptor desensitization, which is why many people report that melatonin "stops working after a few days."
Start with 0.1-0.3mg. If that's insufficient, increase to 0.5-1mg. Take 30-60 minutes before bed. And remember: higher isn't better here, it's often worse.
Cost: negligible ($5-10/month).
Glycine: The Sleep Bargain
Glycine is one of the best-kept secrets in sleep supplementation. It's cheap, effective, and works from the first night.
At 3g before bed, glycine improves subjective and objective sleep quality (validated by polysomnography). The mechanism involves core body temperature: glycine induces peripheral vasodilation, dropping core temp by approximately 0.3°C within 40 minutes (the same temperature drop that initiates deep sleep, as we discussed in Part 2).
Unlike melatonin, there's no receptor desensitization issue. Unlike many sleep supplements, the effects are noticeable immediately rather than requiring weeks to build.
Cost: $5-15/month. Possibly the best value in this entire list.
Other Adaptogens Worth Mentioning
A few others have evidence worth noting, though not as robust as the above:
Rhodiola rosea: moderate evidence for reducing mental fatigue, with mild stimulating effects. Unlike most adaptogens, it can work acutely (within hours). Typical dose: 370-555mg of standardized extract. Best taken in the morning given its activating properties.
Phosphatidylserine: specifically effective for blunting cortisol response during physical or mental stress. Doses of 300-800mg/day show effects in studies. More targeted than general adaptogens—useful for specific high-stress contexts.
Holy basil (Tulsi): some studies show cortisol reductions up to 36%. Dose range is broad (300-1,200mg/day). Generally well-tolerated, though less studied than ashwagandha.
Bacopa monnieri: strong evidence for cognitive enhancement, but requires 12+ weeks minimum to show effects. Not a quick fix, and more relevant for cognition than acute stress.
What We Skip
Not everything popular is worth taking. A few common recommendations we don't typically make:
Lion's mane: promising for neurogenesis and cognition in preclinical research, but insufficient human data specifically for stress in healthy adults. May be worth watching as research develops.
GABA supplements: GABA is an inhibitory neurotransmitter, but oral GABA's ability to cross the blood-brain barrier is uncertain. Effects may be peripheral rather than central. The mechanism is unclear, which makes us hesitant to recommend it.
5-HTP: precursor to serotonin, which sounds appealing, but there are safety concerns with long-term use (potential cardiac valve issues) and significant drug interactions. We'd rather people work with their (or our) physicians if serotonin modulation is the goal.
Most "stress blend" products: proprietary blends take an 'everything above' approach, and underdose each of the ingredients as a result. They also make it nearly impossible to figure out what's actually making an impact. Our advice here (and in general): dial in supplements one by one, or you'll never know what's actually making a difference.
Pharmaceuticals
We should be clear upfront: despite having a medical team in-house who can prescribe when appropriate, we almost never reach for pharmaceuticals for stress management. The behavioral, environmental, and supplement interventions in this series usually get the job done. When they don't, and the situation suggests something beyond lifestyle optimization, we typically refer out to psychiatrists who can provide more comprehensive care.
That said, there are pharmaceutical options worth understanding, both so you can have informed conversations with your own physician, and so you know what the research actually shows versus what's commonly assumed.
Propranolol: Physical Symptoms Only
Propranolol is a beta-blocker that's widely used off-label for performance anxiety: the racing heart, trembling hands, and shaky voice that show up before a big presentation or high-stakes meeting.
The research confirms it works for these physical symptoms. RCTs show significant reductions in heart rate, tremor, and other somatic manifestations of anxiety. Musicians, surgeons, and public speakers have used it for decades.
But here's what's often misunderstood: propranolol does not reduce the psychological experience of anxiety. You'll still feel nervous, you just won't have the physical symptoms broadcasting that nervousness to yourself and others. For some people, that's enough; the absence of physical symptoms breaks the feedback loop. For others, it's not what they're looking for.
Typical dosing: 10-40mg taken about an hour before the anxiety-provoking event. Effects last 3-6 hours. It's not a daily medication for most users, it's event-specific.
Contraindications include asthma, bradycardia (slow heart rate), and hypotension (low blood pressure). No dependency risk.
Best for: predictable, event-specific physical anxiety symptoms.
Buspirone: The Slow Build
Buspirone is an anxiolytic that works differently from benzodiazepines. It effectively treats generalized anxiety disorder with efficacy comparable to benzos—but without the sedation, cognitive impairment, or dependency risk that make benzodiazepines problematic for long-term use.
The critical caveat: buspirone requires 2-4 weeks to reach full effect. It's completely useless for acute or situational anxiety. If you're looking for something to take before a stressful event, this isn't it.
But for chronic, underlying anxiety (the kind that's always there at a low hum) buspirone is worth discussing with a physician or therapist. It can serve as a bridge while behavioral interventions take hold, or as a longer-term option for those who need more support than lifestyle changes alone provide.
Best for: generalized, chronic anxiety. Not performance contexts or acute stress.
Modafinil: Modest and Overhyped
Modafinil (and its close relative armodafinil) is often discussed in optimization circles as a cognitive enhancer. The reality is more modest than the reputation.
Meta-analyses in healthy, non-sleep-deprived adults show statistically significant but small effects on cognition, with an SMD around 0.12. That's barely noticeable in practical terms. Where modafinil shines is for fatigue and wakefulness; it's FDA-approved for narcolepsy, shift work disorder, and sleep apnea-related sleepiness. If you're sleep-deprived, it helps. If you're well-rested, the benefits are marginal.
Side effects include headache (around 34% of users in trials), along with rare but serious reactions including Stevens-Johnson syndrome. It's a Schedule IV controlled substance, requiring a prescription.
One critical caution: modafinil may produce subjective confidence that exceeds actual performance improvement. You might feel sharper without being sharper, a dangerous combination for high-stakes decisions.
Best for: diagnosed sleep disorders, shift work, or managing unavoidable sleep deprivation. Not recommended as a general cognitive enhancer for well-rested individuals.
What We Don't Cover Here
A few categories are beyond the scope of this post:
Benzodiazepines (Xanax, Valium, Ativan, etc.): effective for acute anxiety, but carry significant risks including dependency, rebound anxiety, cognitive impairment, and withdrawal difficulty. Not appropriate for long-term use or optimization contexts. If these are on the table, you should be working with a psychiatrist.
SSRIs/SNRIs: first-line treatments for clinical anxiety and depression, with strong evidence and generally favorable safety profiles. But these are treatments for diagnosable conditions, not optimization tools, and they require careful medical supervision for initiation, dosing, and discontinuation.
Ketamine and psychedelics: emerging research shows promise for treatment-resistant depression and anxiety, but these remain outside mainstream clinical practice, so you may not get great advice on them from your GP. If you're interested, seek out legitimate clinical trials or ketamine clinics operating under proper medical oversight.
Things to Try Today
We've covered a lot, from blood sugar dynamics and adaptogens to pharmaceuticals most people misunderstand. Here's how to actually start:
If you suspect blood sugar is affecting your mood: Pay attention to how you feel 2-3 hours after meals, especially carb-heavy ones without much protein or fat. If you're consistently foggy, irritable, or anxious in that window, experiment with pairing carbs with protein and fat, and notice what changes. It costs nothing, and can produce noticeable results within days.
If you're new to supplements and want to start simple: Magnesium glycinate is the lowest-risk entry point. Broad benefits for sleep and HRV, well-tolerated, inexpensive. 200-400mg before bed for 2-3 weeks, and see what you notice.
If you want something for acute stress: L-theanine is the most accessible option. Effects within 40 minutes, no sedation, no dependency. Try 100-200mg before a stressful meeting or on a high-anxiety day. If you're caffeine-sensitive, pair it with your morning coffee to smooth out the jitters.
If sleep is the main issue: Glycine (3g before bed) is cheap, effective from night one, and works through the temperature mechanism we discussed in Part 2. Stack it with low-dose melatonin (0.3mg, not 5-10mg) if sleep onset is the problem. Both are low-risk and easy to test.
If you're ready to commit to a longer-term adaptogen: Ashwagandha (KSM-66, 300mg twice daily) has the strongest evidence for sustained cortisol reduction and anxiety improvement. Give it 6-8 weeks before judging. Not a quick fix, but a meaningful one if you stick with it.
If you're considering omega-3s: Look for high-EPA formulas (≥60% EPA), aim for 2g/day, and commit to 8-12 weeks. Check for IFOS certification and store in the fridge. This is a slow burn, not an acute intervention.
If pharmaceuticals are on your radar: Have an informed conversation with your physician. Propranolol for event-specific physical symptoms, buspirone for chronic underlying anxiety (not acute), and be skeptical of modafinil hype if you're already sleeping well. And if the situation calls for more than lifestyle optimization, a psychiatrist referral is usually the right move.
The non-negotiable minimum: Fix your foundation before adding supplements. Blood sugar stability costs nothing. The Mediterranean eating pattern doesn't require buying anything new; it's a shift in emphasis, not a purchase. Supplements work best as additions to solid fundamentals, not replacements for them.
What's Next
We've now covered the full toolkit:
Part 1: Breathing and mental practices
Part 2: Exercise and sleep
Part 3: Temperature and environment
Part 4 : Nutrition, supplements, and pharmaceuticals
That's a lot of interventions. The question now is: where do you start? How do you prioritize across the stack? What matters most for your particular stress profile?
Part 5: Building Your Protocol will pull it all together: a framework for sequencing, prioritization, and personalization. Because "do everything" isn't a strategy.
The interventions in this post work for most people—but "most people" isn't the same as you specifically. At A3, we combine biomarker data, genetic insights, and ongoing coaching to help clients figure out exactly which protocols will move the needle for their particular physiology and goals. If you want help building a personalized stack rather than experimenting on your own, we're here to help.