You have read the research. You understand that T3 is the active thyroid hormone your cells actually use. You may have already read our Slow Release T3 Guide and decided that supplementing with liothyronine is the right next step. Now the question that matters most: what t3 dosage should you actually take, and how do you dial it in safely?
Every person's ideal t3 dosage is different. There is no single number that works for everyone. What works is a systematic approach: establish a baseline, begin at a conservative dose, titrate gradually, monitor closely, and stop when your body tells you it has enough. Whether you are starting T3 for the first time, adding it to levothyroxine, or switching from Cytomel to slow release, the principles are the same — start low, go slow, and let your body temperature guide you.
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SRT3-7.5 Slow Release T3
Before You Start: Getting Your Baseline
Before you take your first dose of T3, you need a snapshot of where you are right now. Without a baseline, you have no way to measure progress or confirm that changes you feel are real improvements.
Baseline Blood Work
Get the following labs drawn before starting. Request them specifically — most standard thyroid panels only include TSH:
- Free T3 — The most important marker. Many hypothyroid patients on levothyroxine alone show low or low-normal Free T3 despite "normal" TSH.
- Free T4 — The storage hormone. Useful for understanding conversion and monitoring combination therapy.
- Reverse T3 (rT3) — The inactive metabolite that competes with T3 at the receptor. An elevated Reverse T3 relative to Free T3 is one of the strongest indicators for T3 supplementation.
- TSH — The standard screening marker. TSH will decrease as you add T3 — this is expected. TSH alone is a poor guide for T3 dosing.
Write these numbers down. You will retest every 6-8 weeks during titration.
Five-Day Basal Body Temperature Log
Your basal body temperature (BBT) is the single most useful tool for guiding your t3 dosage during titration. Before starting, establish your baseline average:
- Place a digital thermometer on your nightstand before bed.
- Each morning, before getting up, moving, or speaking, take your oral temperature.
- Record the reading immediately.
- Do this for five consecutive days.
- Calculate the average.
Most hypothyroid patients will find their average falls between 96.4°F and 97.6°F (35.8-36.4°C) — well below the healthy target of 98.2-98.6°F (36.8-37°C). This gap is what you are working to close.
Symptom Documentation
Rate the following on a scale of 1-10 and write them down: fatigue level, brain fog severity, current weight, joint/muscle pain, mood, cold intolerance, and sleep quality.
This "before snapshot" is something you will be grateful for in 8-12 weeks when you are trying to remember how bad things actually were. Memory is unreliable. Written records are not.
Choosing Your Starting Dose
The cardinal rule of thyroid hormone supplementation is start low and go slow. This applies doubly to T3, which is roughly four times more potent than T4 microgram for microgram. A conservative t3 starting dose protects you from overstimulation and gives your body time to adjust.
SRT3-7.5 (7.5mcg) — The Recommended Starting Point
For the majority of people, 7.5mcg of slow release T3 per day is the right place to begin. This includes:
- First-time T3 users who have never taken liothyronine before
- Sensitive individuals who tend to react strongly to medications
- Elderly patients or those with cardiovascular concerns
- People with suspected adrenal insufficiency — weak adrenals cannot handle sudden increases in metabolic rate, and starting too high with T3 can cause crashes, anxiety, or worsened fatigue
The SRT3-7.5 delivers a gentle, sustained release over 8-12 hours. Most people feel little to nothing in the first few days at this dose — and that is exactly what you want.
SRT3-15 (15mcg) — For Experienced Users
A 15mcg starting dose with SRT3-15 is appropriate only for:
- People already taking T3 (Cytomel, compounded T3, or another slow release product) who are switching formulations
- Those with confirmed severe T3 deficiency (very low Free T3 combined with high Reverse T3)
- Patients whose clinician has recommended a higher starting point
If you are unsure, start with 7.5mcg. You can always increase. You cannot undo the anxiety or palpitations from starting too high.
Full Product Range
Our complete slow release T3 lineup provides flexibility for every stage of your titration:
- SRT3-7.5 (7.5mcg) — Starting dose
- SRT3-15 (15mcg) — Moderate dose
- SRT3-22.5 (22.5mcg) — Mid-range dose
- SRT3-45 (45mcg) — Higher dose for established protocols
As you titrate upward, you can combine tablets to hit your target liothyronine dosage precisely, or switch to a higher-strength tablet for convenience.
The Titration Protocol: Step by Step
Titration is the process of gradually increasing your t3 dosage until you reach your optimal level. It is not a race. Expect the full process to take 6-12 weeks.
Weeks 1-2: Establish Your Foundation
- Take your chosen starting dose (7.5mcg for most) at the same time each morning.
- Continue measuring basal body temperature every morning before rising.
- Record symptoms daily — even if nothing has changed.
- Do not increase the dose during this period. Your body needs time to adjust.
What to expect: Most people notice subtle changes by the end of week two — slightly warmer hands, marginally better energy, perhaps a 0.2-0.3°F rise in morning temperature. Some notice nothing. Both responses are normal.
Weeks 3-4: First Increase (If Indicated)
Evaluate your progress at the two-week mark. Increase your dose by 5-10mcg only if:
- Your morning temperature is still consistently below 98.0°F (36.7°C)
- You have experienced no adverse effects (racing heart, anxiety, tremor, insomnia)
- You do not feel overstimulated at your current dose
If your temperature has risen meaningfully and you feel better, hold your current dose. There is no obligation to increase. The goal is the lowest effective slow release t3 dosage that normalizes your temperature and resolves symptoms.
A 5mcg increase means adding half an SRT3-7.5 tablet (they are scored for splitting). A 7.5mcg increase means adding one full SRT3-7.5 tablet to your existing dose.
Weeks 5-8: Continue Gradual Titration
Continue the same pattern: hold for two weeks, assess temperature and symptoms, increase by 5-10mcg if needed.
Common dose ranges where patients find their sweet spot:
- 15-25mcg/day — Most common for those adding T3 to levothyroxine
- 25-50mcg/day — Typical for T3-only protocols
- 50-75mcg/day — Less common; usually for Wilson's Protocol or severe T3 deficiency
- 75mcg+ per day — Rare; requires careful monitoring
When to Stop Increasing
Hold your dose when your morning basal temperature reaches and stays in the 98.2-98.6°F (36.8-37.0°C) range for at least three consecutive days. This is your signal. Your cells have enough T3. Further increases will push you into over-replacement territory.
Temperature Monitoring: Your Most Important Tool
During titration, your thermometer is more valuable than any blood test. Here is why — and how to use it properly.
Why Temperature Beats Blood Tests During Titration
Blood tests measure hormone levels in your bloodstream. Body temperature reflects what is happening at the cellular level — inside your mitochondria, where T3 drives metabolic rate. To learn more about this connection, read our guide on Low Body Temperature and Thyroid Function.
A blood test might show a "normal" Free T3, but if your temperature is still 97.2°F every morning, your cells are not getting enough. Conversely, if your temperature has normalized at 98.4°F, your cells are satisfied regardless of lab numbers.
Blood tests still matter for safety — recheck every 6-8 weeks. But day-to-day dosing decisions should be guided by temperature and symptoms.
How to Monitor Correctly
Take your temperature three times daily at consistent times:
- Morning (basal) — Before rising, before any activity. This is the most important reading.
- Mid-day — Around noon or early afternoon, before eating.
- Afternoon — Around 3-4 PM, the metabolic peak of the day.
Use the same thermometer each time. Digital oral thermometers are fine. Record every reading.
What a Rising Temperature Pattern Looks Like
In a successful titration, you will see a gradual staircase pattern — for example, baseline 96.8°F rising to 97.1°F after two weeks at 7.5mcg, then 97.5°F at 15mcg, 97.9°F at 22.5mcg, and finally 98.3°F at 30mcg (target reached — hold here).
The rises may not be linear. Day-to-day variation is normal. Focus on the three-to-five-day average, not individual readings.
Warning Signs: When to Hold or Reduce
Hold your dose if: resting heart rate consistently exceeds 90 BPM, morning temperature exceeds 98.8°F (37.1°C), you feel anxious or "wired," or sleep quality deteriorates.
Reduce by 5-10mcg if: resting heart rate exceeds 100 BPM, temperature exceeds 99.0°F (37.2°C) without illness, or you develop persistent insomnia or palpitations.
These warning signs indicate you have exceeded your optimal t3 dosage. More is not better. Back off, let things settle, and find the level where your temperature is in range without overstimulation.
The Wilson's Protocol: Cycling for Metabolic Reset
Some patients follow the Wilson's Temperature Syndrome protocol, which uses T3 to actively reset the body's metabolic thermostat. For a comprehensive overview, see our Wilson's Temperature Syndrome Guide.
The Ramp-Up / Hold / Taper Approach
Dr. E. Denis Wilson developed a specific cycling protocol based on the observation that some patients can "reset" their metabolism with a temporary course of T3:
Phase 1 — Ramp Up: Begin at a low t3 starting dose (typically 7.5-15mcg of slow release T3, taken twice daily). Increase by 7.5mcg every two days until morning temperature reaches 98.6°F (37°C) or a maximum tolerated dose. The slow release formulation is essential — immediate-release T3 creates peaks and valleys that work against the protocol.
Phase 2 — Hold: Once temperature has normalized, hold at that dose for 4-6 weeks. This sustained period of normal body temperature is what allows the metabolic set point to recalibrate. Take your dose at the same time every day without variation.
Phase 3 — Taper: Gradually reduce your dose by 7.5mcg every two days, mirroring the ramp-up in reverse. Monitor temperature throughout.
After the Taper
Three typical outcomes emerge:
- Temperature stays normal after discontinuation — The thermostat has reset. No ongoing T3 needed.
- Temperature drops slightly but stays improved — A low maintenance dose (often 7.5-15mcg daily) maintains the improvement.
- Temperature returns to baseline — The cycle can be repeated. Some patients require 2-3 cycles before a sustained reset occurs.
The Wilson's Protocol is not for everyone, but for those with classic Wilson's Temperature Syndrome — low temperatures with normal blood work — it offers a structured path beyond simple supplementation.
Common Dosing Scenarios
How much T3 to take depends significantly on your current thyroid treatment and goals. Here are the most common situations.
Adding T3 to Existing Levothyroxine (Combination Therapy)
The most common scenario. You are on levothyroxine but still have symptoms despite "normal" TSH. Adding T3 addresses the conversion problem directly.
- Keep your levothyroxine dose the same when starting T3 (or reduce by 25mcg if your doctor advises).
- Begin with 7.5mcg of slow release T3.
- Most patients find their optimal liothyronine dosage falls between 7.5-22.5mcg daily in combination therapy.
- Some practitioners recommend a T4:T3 ratio of roughly 4:1 (e.g., 100mcg T4 + 25mcg T3), but individual needs vary.
See our guide on T3 vs T4: Understanding the Difference for more detail.
T3-Only Protocols
Some patients — particularly those who convert T4 poorly or have high Reverse T3 — do better on T3 alone. T3-only dosing requires higher total doses since you are providing all thyroid hormone as T3.
- Typical T3-only doses range from 25-75mcg/day, split into two doses (morning and early afternoon).
- Titration is the same: start at 7.5mcg, increase by 7.5mcg every two weeks, guided by temperature.
- Free T4 will drop significantly on T3-only therapy — this is expected. TSH will also suppress, which is not inherently harmful when guided by symptoms and temperature.
Switching From Cytomel to Slow Release T3
If you are currently taking immediate-release Cytomel, switching to slow release T3 is straightforward:
- The dose conversion is approximately 1:1 — 25mcg of Cytomel equals 25mcg of slow release T3.
- The same dose often feels smoother in slow release form because sustained delivery avoids the peaks and crashes of immediate-release T3.
- Some patients reduce their total daily dose by 5-10mcg after switching because more hormone reaches cells during the sustained release window.
For a detailed comparison, read Slow Release T3 vs Cytomel. Our Slow Release T3 Guide covers the pharmacokinetics in depth.
Signs You've Found Your Optimal Dose
Finding your ideal t3 dosage is one of the most satisfying moments in the thyroid optimization process. Here is what it looks and feels like when everything clicks into place:
- Consistent body temperature — Morning readings hold steady at 98.2-98.6°F (36.8-37.0°C) without the wide day-to-day swings you saw during titration.
- Sustained energy — The 2 PM crash disappears. Steady, reliable energy from morning to evening without feeling wired or jittery.
- Mental clarity restored — Brain fog lifts. You can concentrate, recall words, and stay focused. Many patients describe this as "getting their brain back."
- Weight stabilization — The unexplained weight gain stops. The scale begins moving in the right direction without dramatic dietary changes.
- Improved sleep — Hypothyroid insomnia resolves. You wake feeling genuinely rested.
- Reduced pain and inflammation — Joint stiffness improves. Morning pain decreases.
Compare these observations against the baseline symptoms you documented before starting.
Safety and Monitoring
T3 is a powerful hormone, and responsible use requires ongoing monitoring. Here is how to stay safe throughout your titration and beyond.
Regular Lab Work
Recheck your thyroid panel (Free T3, Free T4, TSH, and Reverse T3) every 6-8 weeks during active titration. Once you have found your stable dose, testing every 3-4 months for the first year is prudent, followed by every 6 months thereafter.
Signs of Over-Replacement
Learn to recognize when your t3 dose for hypothyroid treatment has crossed from optimal to excessive: anxiety or nervousness, heart palpitations, insomnia (especially feeling "wired" at bedtime), unexplained rapid weight loss, hand tremor, excessive sweating, or increased bowel frequency.
If you experience any of these, reduce your dose by 5-10mcg immediately and reassess after one week.
Treat by Symptoms and Temperature, Not Lab Numbers
During T3 supplementation, TSH will decrease — often below the standard reference range. A suppressed TSH does not automatically mean over-replacement. It means the pituitary is sensing adequate T3 and reducing its signal.
The relevant question is: "Is my temperature in range? Do I feel well? Are there signs of over-replacement?" If your temperature is 98.4°F, you feel good, and your heart rate is normal, a TSH of 0.3 does not mean you need to reduce your dose. That said, a TSH below 0.1 combined with Free T3 above range does warrant evaluation with a practitioner experienced in T3 therapy.
When to Seek Medical Guidance
Consult a healthcare professional if you experience chest pain, shortness of breath, or a resting heart rate consistently above 100 BPM. Those with a history of heart disease, atrial fibrillation, or osteoporosis should work closely with a practitioner. Seek guidance if you are pregnant, if symptoms worsen despite careful titration, or if you are unsure about medication interactions.
T3 supplementation is not a substitute for medical care. It works best when used with knowledge, caution, and appropriate oversight.
Ready to begin your T3 optimization journey? Our full SRT3 range provides the flexibility you need for precise dosing at every stage:
- SRT3-7.5 (7.5mcg) — Ideal starting dose
- SRT3-15 (15mcg) — Moderate dosing
- SRT3-22.5 (22.5mcg) — Mid-range protocols
- SRT3-45 (45mcg) — Higher dose requirements
All products are HPLC-verified for purity and potency, 50 tablets per bottle. Discreet Canadian shipping. Bitcoin accepted.
Frequently Asked Questions
Can I take too much T3?
Yes. Excessive T3 causes real symptoms — anxiety, rapid heartbeat, insomnia, tremor, and in extreme cases, cardiac arrhythmias. This is why the "start low, go slow" approach is non-negotiable. By increasing in small increments (5-10mcg) every two weeks and monitoring temperature and heart rate, you dramatically reduce the risk. If you overshoot, the effects of slow release T3 resolve within 12-24 hours. Reduce your dose and reassess.
What if I miss a dose?
If you realize within a few hours of your usual time, take it then. If most of the day has passed, skip that dose and resume your normal schedule the next day. Do not double up. One missed dose will not undo your progress — thyroid hormones have cumulative tissue effects. Consistency over weeks and months matters far more than any single day.
Should I take T3 in the morning or evening?
Most people do best taking slow release T3 in the morning, ideally upon waking. T3 supports metabolic activity and energy — things you want during the day, not at bedtime. Some patients on higher doses split their slow release t3 dosage into two doses — morning and early afternoon (no later than 2 PM). Evening dosing is generally not recommended as it can interfere with sleep.
How should I time T3 with coffee, food, and supplements?
Take your T3 on an empty stomach with water, at least 30 minutes before eating or drinking coffee. Coffee, calcium, iron, and high-fiber foods can interfere with absorption. Separate calcium or iron supplements from your T3 by at least 4 hours. This applies whether you are taking our Slow Release T3 or any other thyroid hormone.
How long until I feel better on T3?
Some people notice subtle improvements — warmer extremities, slightly better energy — within the first 1-2 weeks. More significant changes in energy, brain fog, and mood typically emerge during weeks 3-6 as you titrate upward. Full optimization — including weight changes, sleep improvement, and pain reduction — often takes 8-12 weeks at the right level. If you have been on T3 for 12 weeks with no improvement, reassess your protocol, consider whether Reverse T3 dominance is a factor, and evaluate adrenal function as a potential barrier.