T3 – Proper Labs [100tab/25mcg]

T3 Proper Labs 100 tabs for sale in the UK

T3 by Proper Labs is a 100-tablet pack of liothyronine sodium dosed at 25 mcg per tablet — the synthetic form of triiodothyronine, the body's most metabolically active thyroid hormone. If you want to buy T3 liothyronine UK from a verified source, every batch sold here is lab-tested and shipped same working day from our UK warehouse with discreet tracked delivery.

What is Liothyronine (T3)?

Liothyronine is a synthetic, bioidentical copy of triiodothyronine (T3), the active thyroid hormone the body normally produces by converting T4 in the liver, kidneys and peripheral tissues. T3 binds to nuclear thyroid receptors and directly raises basal metabolic rate, oxygen consumption, lipolysis and protein turnover, which is why exogenous T3 produces faster and more pronounced fat loss than T4 alone. The active half-life is roughly 2.5 days, so plasma levels accumulate over the first week of dosing and the taper at the end of a cycle has to be gradual to avoid a temporary slump in endogenous thyroid output once the drug is withdrawn. Medically liothyronine is prescribed for hypothyroidism, myxoedema coma and as a diagnostic agent. In a performance setting it is used purely for cutting and contest preparation, never bulking. Proper Labs T3 is the same molecule found in pharmacy-grade Cytomel and is interchangeable with other UK lab brands.

T3 Proper Labs benefits

• Accelerates fat oxidation by directly raising basal metabolic rate
• Improves nutrient partitioning during a calorie deficit
• Useful breakthrough tool when fat-loss plateaus on diet alone
• No androgenic side effects, no aromatisation, no liver load
• 25 mcg tablets allow precise pyramidal ramp-up and ramp-down
• Synergises strongly with clenbuterol and AAS for contest prep

The 25 mcg tablet is the format most coaches recommend because it lets you adjust dose in small increments rather than jumping 50 mcg at a time, and a 100-tablet pack is enough to cover a full ramp-up, working dose and ramp-down without re-ordering mid-cycle.

T3 Proper Labs dosage and cycle

Beginners: 25 mcg/day for the first 3–5 days, then increase by 12.5–25 mcg every few days up to 50 mcg/day. Intermediate: ramp to 75 mcg/day. Advanced (contest prep): up to 100 mcg/day, split into 2–3 administrations to keep blood levels stable. Cycle length is typically capped at 6–8 weeks. The ramp-down phase is non-negotiable — taper by the same increments you ramped up, never stop abruptly. Onset of measurable BMR shift takes 3–7 days. Take on an empty stomach for absorption consistency.

Side effects and HPT-axis recovery

T3 reliably produces dose-dependent hyperthyroid-style symptoms at the upper end of the range: fine hand tremor, sweating, heat intolerance, palpitations, mild anxiety and insomnia. These are the hormone working — not an allergic reaction — but they should guide the dose ceiling. Cardiovascular load increases, so anyone with arrhythmias or untreated hypertension should not run T3. Critically, T3 is catabolic to muscle when run in isolation: BMR is up but the body will pull from lean tissue as readily as from fat, which is why nearly every protocol stacks T3 with a testosterone base or an oral AAS. Stopping abruptly can suppress the HPT-axis and trigger a transient hypothyroid rebound — always taper. PCT in the AAS sense is not relevant here; what matters is the gradual ramp-down so endogenous T4-to-T3 conversion resumes cleanly.

Stacks well with

T3 is rarely run alone. For straightforward cutting most users pair it with Clenbuterol Proper Labs on alternating-week pyramids, or use Salbutamol Proper Labs as a continuous β2 alternative. Looking for the same molecule in a different brand or strength? See T3 Pharmaqo 100 tabs or Citomed 50 mcg T3.

Frequently asked questions

How long does T3 Proper Labs take to start working?

Most users feel the metabolic shift — slightly raised resting body temperature, mild hunger increase, faster post-meal warmth — within 3 to 7 days of starting. Visible fat-loss acceleration shows from week 2 onwards, provided diet and training are already in deficit. T3 does not burn fat by itself; it amplifies an existing calorie deficit.

Is T3 Proper Labs suitable for first-time users?

It is approachable but not casual. The molecule itself is well-tolerated, but the discipline required — strict ramp-up, strict ramp-down, max 6–8 week duration and stacking with an AAS to spare muscle — makes it a poor choice for someone with no cycle experience. First-timers should start at 25 mcg, hold that dose for at least a week, and never push past 50–75 mcg.

Can T3 be detected on a drug test?

Liothyronine is a bioidentical copy of an endogenous hormone, so standard sport and workplace drug screens do not test for it. WADA does not list T3 as prohibited. Blood work will show suppressed TSH and elevated free T3 during use, which a clinician would notice but a generic drug test will not.