Cynomel and Cynoplus: The Mexican T3 Sourcing Question (Research Context)

For roughly two decades - from the mid-2000s through the early 2020s - Cynomel was the de facto T3 source for the bioenergetic-research community. A 25 mcg liothyronine tablet manufactured by Laboratorios Grossman in Mexico, priced in pesos and available through Mexican pharmacies and online export channels, Cynomel filled a specific gap: it was inexpensive, it was a direct T3 product (not a T4 prohormone requiring conversion), and it was accessible to self-directed researchers who either could not obtain a US Cytomel prescription or found the price differential compelling enough to source south of the border. Cynoplus - the companion T4+T3 combination product from the same manufacturer - served a related but distinct role for researchers who preferred a synthetic desiccated-thyroid-hormone equivalent.

Both products developed a genuine following in the Ray Peat community and in the broader bioenergetic-research forums that discussed T3 optimization, cyclic T3 protocols, and the Wilson's WT3 approach. The Grossman's brand became synonymous with accessible liothyronine in that community context. It is discussed in the Ray Peat protocol complete 2026 research guide as a landmark in the community's T3-sourcing history.

The sourcing picture has shifted substantially since approximately 2022. Mexican pharmacy export restrictions have tightened, US Customs enforcement of personal-import quantity limits has become less predictable, Grossman's has experienced intermittent manufacturing pauses, and a secondary problem has emerged: counterfeit "Cynomel-style" products circulating in online channels that bear the name but not the quality. The community that built protocols around Cynomel is now navigating a sourcing landscape that is less reliable than it was at the product's peak accessibility.

This post reviews Cynomel and Cynoplus from a research context: what they are, why the bioenergetic community adopted them, what the supply chain looks like now, and where the pharmacokinetic case for sustained-release T3 (SR-T3) as the modern research-grade alternative sits.

Research framing. This article reviews Cynomel and Cynoplus from a research-context standpoint. All compounds discussed are sold strictly for laboratory research and not for human consumption. See our FAQ legality page for full terms.

What Is Cynomel?

Cynomel is a brand of liothyronine sodium tablets manufactured by Laboratorios Grossman, a Mexican pharmaceutical company established in the mid-twentieth century. Each tablet contains 25 mcg of liothyronine sodium - the synthetic, bioidentical form of T3 (triiodothyronine), the active thyroid hormone that binds to nuclear thyroid hormone receptors (TRalpha and TRbeta) to regulate metabolic gene expression. Cynomel was developed and approved for clinical use in Mexico as a treatment for hypothyroidism and is a recognized pharmaceutical product within the Mexican regulatory system.

Its adoption by the bioenergetic-research community outside Mexico was a function of practicality rather than any unique pharmacological distinction from Cytomel or generic liothyronine sodium. The active molecule is identical: liothyronine sodium at 25 mcg per tablet. What differentiated Cynomel was its price point (substantially lower than US-market Cytomel, particularly prior to generic liothyronine becoming widely available in the US), its availability through Mexican pharmacy channels that did not require a US physician prescription, and the community-knowledge network that emerged in bioenergetic forums around sourcing logistics. By the mid-2010s, Cynomel was the most frequently discussed T3 source in Ray Peat community contexts, Wilson's WT3 protocol forums, and related thyroid-optimization research communities.

Cynomel is immediate-release liothyronine. It dissolves rapidly after oral administration and enters systemic circulation quickly, producing the pharmacokinetic profile characteristic of all immediate-release T3 formulations: a sharp serum peak within 2-4 hours of dosing, followed by a trough as the dose clears the bloodstream. This pharmacokinetic behavior - the same behavior that characterizes Cytomel and generic liothyronine - is a central limitation that the bioenergetic research community has discussed extensively, and it is examined in detail in the pharmacokinetic section below.

What Is Cynoplus?

Cynoplus is the companion product in Laboratorios Grossman's thyroid line: a T4+T3 combination tablet containing 50 mcg of levothyroxine (T4) and 12.5 mcg of liothyronine (T3) per tablet. It is a synthetic two-hormone preparation that approximates, in its T4:T3 ratio, the thyroid hormone output of the human thyroid gland - though the ratio of approximately 4:1 T4:T3 by weight in Cynoplus is somewhat lower in T4 proportion than the gland's native 20:1 ratio, reflecting a deliberate elevation of the T3 fraction.

Cynoplus occupied a particular niche for researchers interested in a desiccated-thyroid-hormone-style protocol - the combination of T4 and T3 that characterized natural desiccated thyroid (NDT, Armour Thyroid) - but who preferred a fully synthetic formulation with consistent dosing. Desiccated thyroid, derived from porcine or bovine thyroid glands, contains T4, T3, T2, T1, and calcitonin in biologically variable ratios depending on the source animal. Cynoplus strips the combination down to T4 and T3 with pharmaceutical-grade standardization while retaining the T3 component that T4-only levothyroxine protocols lack. For researchers following protocols that required both hormones but wanted the predictability of synthetic formulation, Cynoplus was a logical Mexican-market alternative to the US NDT products.

Like Cynomel, Cynoplus is immediate-release: both the levothyroxine and liothyronine components dissolve rapidly after ingestion, producing a T3 peak within 2-4 hours and the characteristic T3 spike-and-trough pattern.

The Bioenergetic-Research Community's Adoption

The bioenergetic research community's adoption of Cynomel was not incidental to the Ray Peat framework - it was a direct consequence of it. Peat's foundational argument was that T3, not T4, was the operationally active thyroid hormone, and that relying on T4 (levothyroxine) and expecting adequate tissue T3 was a systematic error in standard thyroid management: the deiodinase enzymes required for T4-to-T3 conversion are impaired in the chronic-illness population by selenium deficiency, inflammation, elevated cortisol, and reverse T3 dominance. The practical implication was that direct T3 supplementation was preferable to T4 administration, and that Cytomel or an equivalent liothyronine product was the correct research tool.

When Peat's writing began circulating widely online through the 2000s - archived newsletters, podcast interviews, the network of blogs and forums that developed around his framework - a community formed that was motivated to source direct T3 products. In the US, Cytomel required a physician prescription that many community members either could not obtain (practitioners unwilling to prescribe T3 monotherapy) or found economically inaccessible. Generic liothyronine was not yet broadly available at low prices. Cynomel, accessible through Mexican pharmacies and a handful of online export channels, filled this gap for a substantial portion of the community.

The Wilson's WT3 protocol - a cyclic T3 protocol developed by physician E. Denis Wilson and designed to normalize body temperature through carefully structured T3 dosing cycles - added a second dimension of Cynomel demand. The WT3 protocol uses direct T3 (not T4) in a gradually titrated, twice-daily dosing schedule, and community members following the protocol needed a reliable, affordable, consistent T3 source. Cynomel became the canonical source for WT3 protocol followers outside the clinical setting. The bioenergetic community's general distrust of T4-only protocols - well-grounded in the deiodinase literature - meant that Cynomel was filling genuine research demand, not merely a cost-arbitrage opportunity. This broader T3 sourcing and research context is reviewed in the full liothyronine sourcing guide for 2026.

The Supply Chain Problem

The Cynomel supply chain that served the bioenergetic-research community reliably through the 2010s has become substantially less reliable since approximately 2022. Several factors have converged.

Mexican pharmacy export restrictions have tightened. Mexico's regulatory environment for pharmaceutical exports has evolved, and the informal network of online Mexican pharmacies that would ship liothyronine to US addresses has contracted. Some channels that operated openly through 2019-2021 have closed or become more restrictive in response to regulatory pressure. The infrastructure that made Cynomel accessible to US researchers has degraded.

US Customs enforcement of personal-import limits for prescription medications is notoriously inconsistent but has become less predictable for thyroid products in the 2022-2025 period. Packages that previously cleared without incident are now seized at a higher rate at certain ports of entry, particularly for shipments that trigger any inspection. The practical effect is that research subjects relying on Cynomel import face supply unpredictability at the border that did not exist to the same degree five years earlier.

Grossman's has experienced intermittent manufacturing pauses. The company is a real manufacturer producing a real product, but it is not a large multinational pharmaceutical operation. Manufacturing pauses - inventory gaps at the manufacturer level - have translated into availability gaps in the export market. Researchers who sourced Cynomel consistently through 2018-2021 began reporting difficulty obtaining reliable supplies by 2023 in multiple bioenergetic and WT3 research forums.

The counterfeit problem has amplified the core sourcing issue. As authentic Cynomel became harder to obtain through legitimate Mexican pharmacy channels, fraudulent products began appearing in the supply chain - products marketed under the Cynomel name or in packaging mimicking Grossman's labeling that contain misdosed, adulterated, or entirely substituted active ingredient. This is not speculation: the phenomenon of counterfeit liothyronine marketed to online buyers is well-documented in harm-reduction discussions in the bioenergetic and thyroid optimization research communities.

Quality Variability and Counterfeit Concerns

Authentic Cynomel - genuine Grossman's product sourced through verified Mexican pharmacy channels - was generally regarded as a well-formulated, consistent product by the bioenergetic research community throughout its peak availability period. The dose accuracy of authentic Grossman's liothyronine was considered reliable, and the formulation held up under the informal quality-verification that community members applied (consistent effects at consistent doses, tablet weight uniformity).

The problem is that without HPLC (high-performance liquid chromatography) verification of dose accuracy and purity, any liothyronine product sourced from unverified online channels is pharmacologically uncharacterized from the buyer's standpoint. This has always been true; it has become more consequential as the fraction of "Cynomel" circulating in online research channels that is counterfeit has increased. Counterfeit liothyronine products have been documented at a range of quality failures: misdosed tablets (potency ranging from near-zero to several times stated dose), contaminated active ingredient, tablet formulations that do not dissolve appropriately, and products containing no liothyronine at all. A research subject who calibrated a protocol on authentic Grossman's Cynomel and then sourced a counterfeit batch is running a dose that is pharmacologically undefined.

This quality uncertainty is distinct from the pharmacokinetic limitations of immediate-release T3 - it is an upstream supply chain problem that the bioenergetic research community did not face to the same degree when authentic Cynomel was consistently available. For protocol research requiring dose accuracy, this distinction matters. The pharmacokinetic behavior of a 25 mcg liothyronine dose can be modeled; the pharmacokinetic behavior of a tablet of unknown composition cannot.

The Pharmacokinetic Critique: Why Cynomel/Cytomel Spike-and-Crash

Even setting aside the modern supply chain problems, authentic Cynomel carries a pharmacokinetic limitation that the bioenergetic research community has discussed since the Wilson's WT3 framework was first formalized. Cynomel is immediate-release liothyronine. Its pharmacokinetic profile is well-characterized in the peer-reviewed literature: Tmax (time to peak serum concentration) of approximately 2-4 hours after oral dosing; half-life of approximately 2.5 hours. The result is a 3-5x elevation in serum T3 above baseline within hours of dosing, followed by a decline back toward baseline as the dose clears.

This spike-and-crash profile is the default behavior of any immediate-release T3 formulation - Cytomel, generic liothyronine, and Cynomel are all subject to it. The bioenergetic-research community has historically attributed the cardiovascular and adrenergic side effects associated with immediate-release T3 - palpitations, anxiety, the "wired" feeling followed by fatigue, temperature dysregulation during the trough period - to dose-titration errors: too much T3, or an incorrect dose split. There is something to this: dose calibration genuinely matters. But a substantial part of the acute-side-effect profile of immediate-release T3 is intrinsic to the formulation, not correctable by titration, because the serum spike is built into immediate-release kinetics at any dose above a threshold. The cortisol-stimulating effect of a rapid T3 serum spike - an adrenergic response to a sudden hormonal surge - occurs at doses that are individually tolerated from a metabolic standpoint. This is not a dose-finding problem; it is a pharmacokinetic formulation problem.

Sustained-release T3 (SR-T3) was developed to solve exactly this problem. An SR-T3 formulation using a hydroxypropyl methylcellulose (HPMC) sustained-release matrix delivers T3 over a 4-8 hour window rather than as an immediate bolus, producing a significantly attenuated serum peak and a correspondingly extended release curve. The AUC (area under the curve - total T3 exposure) is comparable to the immediate-release equivalent, but the peak is lower and the serum residence time is longer. The cardiovascular and adrenergic effects associated with the spike are reduced because there is no spike; the trough-period fatigue is reduced because the decline is gradual rather than precipitous. This is the pharmacokinetic rationale reviewed in detail in the sustained-release T3 complete guide.

The Modern Alternative: Sustained-Release T3 (SR-T3)

SR-T3 formulated in an HPMC + MCC (hydroxypropyl methylcellulose + microcrystalline cellulose) matrix represents the research-grade T3 format that directly addresses the pharmacokinetic limitation of Cynomel and Cytomel. The HPMC polymer forms a hydrophilic gel layer as the capsule hydrates in the GI tract, slowing liothyronine diffusion out of the matrix and producing a controlled-release dissolution curve over 4-8 hours depending on the HPMC viscosity grade. The result is the flat, extended serum T3 curve that Peat's pharmacokinetic critique of immediate-release T3 was pointing toward as the target: continuous T3 availability at a stable concentration rather than the cycle of spikes and troughs that immediate-release dosing produces.

The practical advantages for protocol research over Cynomel are substantial on two dimensions. First, HPLC-verified purity and dose accuracy per batch - every capsule in a research-grade SR-T3 batch is manufactured from verified API and HPLC-tested for potency. The dose uncertainty that characterizes modern "Cynomel" supply does not exist. Second, the pharmacokinetic profile genuinely differs: SR-T3 produces a different, more favorable serum curve than any immediate-release liothyronine product at equivalent daily dose, without any dependency on Mexican pharmacy channels, customs enforcement patterns, or counterfeit-avoidance logistics.

The Wilson's SR-T3 Combo Kit is the reference product for bioenergetic-framework and WT3 protocol research, formulated specifically for the cyclic T3 protocol context: SR-T3 in HPMC + MCC matrix, clean excipient profile, HPLC-verified. The SR-T3 catalog covers five dose strengths (7.5, 15, 22.5, 45, 90 mcg) - the full titration ladder required by the Wilson's WT3 protocol, from the initial low-dose entry at 7.5 mcg twice daily through the higher-dose phases used in the latter stages of the titration cycle. The SRT3-15 entry-strength product is the common starting point for researchers transitioning from Cynomel or from immediate-release Cytomel who are calibrating their protocol baseline.

For researchers who have built their protocols around Cynomel and are evaluating alternatives: the pharmacology is equivalent (identical active molecule, liothyronine sodium), the daily dose arithmetic is straightforward (total daily dose in mcg carries over directly), and the formulation upgrade is not a protocol change - it is a delivery-system improvement on the same underlying compound.

Cynomel and the T3→T2 Conversion Bottleneck

There is a distinct and more advanced limitation of Cynomel-based protocols that is not a supply chain problem and not a pharmacokinetic problem: the T3→T2 conversion bottleneck. Even under the best-case Cynomel sourcing scenario - authentic Grossman's product, reliable dose, optimally titrated immediate-release protocol - research subjects with impaired DIO1 deiodinase activity face a downstream conversion failure that Cynomel cannot address.

The bioenergetic framework correctly identified the T4→T3 conversion bottleneck: deiodinase impairment blocks the conversion of T4 prohormone to active T3, making direct T3 supplementation (Cynomel, Cytomel, SR-T3) the appropriate response. What the framework predates is the downstream step: T3→T2. The same DIO1 enzyme family that converts T4 to T3 also converts T3 to 3,5-diiodothyronine (3,5-T2, T2) - the downstream thyroid metabolite that acts directly on cytochrome c oxidase (Complex IV of the electron transport chain) through a non-nuclear, non-genomic mechanism. 3,5-T2 bypasses nuclear thyroid hormone receptors entirely and stimulates aerobic respiration acutely, on a minutes timescale, through direct binding to the mitochondrial enzyme itself.

A research subject whose DIO1 activity is impaired - the same impairment that drove the original need for direct T3 supplementation - cannot reliably generate adequate 3,5-T2 from exogenous T3. Cynomel provides T3 substrate, but if DIO1 is suppressed by selenium deficiency, inflammatory cytokines, elevated cortisol, or reverse T3 competition, the T3→T2 conversion step fails regardless of how much T3 substrate is available. This explains the T3 protocol plateau pattern that is well-documented in bioenergetic and WT3 research forums: metabolic markers stall despite apparent T3 adequacy. The full mechanism and deiodinase dysfunction overlap are analyzed in the T3→T2 conversion problem guide. For researchers hitting this plateau, the Wilson's T3+T2 Combo addresses the bottleneck directly by providing both T3 and T2 in the same sustained-release format - bypassing both conversion steps simultaneously.

What Research Has and Hasn't Established

Established:

Liothyronine pharmacokinetics for immediate-release formulations are well-characterized in peer-reviewed literature: oral Tmax of 2-4 hours, plasma half-life of approximately 2.5 hours, with the resulting spike-and-trough serum curve documented across multiple pharmacokinetic studies. The spike-and-crash profile of immediate-release T3 at standard doses is an established pharmacological finding, not a community hypothesis. HPMC matrix sustained-release formulations are well-characterized in pharmaceutical science as a mechanism for controlled dissolution and extended drug release. The T4→T3 conversion dependence on DIO1 and DIO2 deiodinase activity, and the impairment of those enzymes by selenium deficiency and inflammatory signaling, are documented in the peer-reviewed endocrinology literature. The existence of Cynomel as a genuine Grossman's pharmaceutical product manufactured in Mexico and marketed for hypothyroidism treatment is a verifiable factual matter.

Hypothesis:

The SR-T3 formulation produces better protocol outcomes than immediate-release Cynomel in chronic-illness research subjects - in terms of side-effect profile, adrenergic response, and protocol consistency - consistent with the pharmacokinetic argument for a flatter serum curve. This hypothesis is mechanistically well-supported: the pharmacokinetic difference is real and documented, and the mechanism by which a lower, extended peak would reduce adrenergic and cardiovascular side effects is straightforward. What does not exist is a controlled head-to-head trial comparing SR-T3 versus immediate-release Cynomel in the chronic-illness research-subject population with protocol outcomes as the endpoint. The hypothesis is reasonable and consistent with available pharmacokinetic data; it is not yet validated in direct comparative research.

Not endorsed by mainstream endocrinology:

Cyclic T3 protocols, including the Wilson's WT3 approach and the bioenergetic-research framework's T3 optimization protocols more broadly, operate outside mainstream clinical guidelines. Standard endocrinology does not recommend T3 monotherapy for hypothyroidism management, does not endorse the deiodinase-dysfunction framework as a clinical diagnostic category, and does not support cyclic T3 titration as a treatment approach. The bioenergetic framework and its T3 protocols exist in a research-community space that is explicitly distinct from mainstream clinical practice, and the products discussed in this post are sold as research reference standards, not as approved pharmaceutical treatments.

Frequently Asked Questions

What is Cynomel?

Cynomel is a brand of liothyronine sodium tablets manufactured by Laboratorios Grossman in Mexico. Each tablet contains 25 mcg of liothyronine sodium, the synthetic bioidentical form of T3 (triiodothyronine). It was developed as a clinical hypothyroidism treatment in the Mexican pharmaceutical market and adopted widely by the bioenergetic-research community in the 2000s and 2010s as an accessible, affordable direct-T3 product. Cynomel is immediate-release liothyronine - pharmacologically identical in active molecule to US-market Cytomel and generic liothyronine sodium, but historically distinguished by its price point and Mexican pharmacy accessibility.

Is Cynomel still available?

Cynomel in the form of authentic Grossman's product is still manufactured, but its accessibility through the informal online and export channels that served the bioenergetic-research community has declined substantially since 2022. Mexican pharmacy export restrictions, tighter US Customs enforcement of personal-import limits, intermittent Grossman's manufacturing pauses, and the proliferation of counterfeit "Cynomel" products in online channels have collectively made consistent authentic sourcing significantly harder than it was through 2021. Research community forums that previously offered reliable sourcing guidance now reflect widespread supply unpredictability.

What is the difference between Cynomel and Cytomel?

The active molecule is identical: both Cynomel and Cytomel are liothyronine sodium formulated as immediate-release oral tablets. Both produce the same pharmacokinetic profile - Tmax approximately 2-4 hours, half-life approximately 2.5 hours, spike-and-trough serum curve. The differences are manufacturer (Grossman's Mexico versus Pfizer/King Pharmaceuticals US), country of origin, dosage strengths available (Cynomel is 25 mcg; Cytomel is available in 5, 25, and 50 mcg), excipient composition (different inactive ingredients in the tablet formulation), and historically, price and prescription requirements in various markets. For research purposes, their pharmacological equivalence means the primary distinctions are practical: accessibility, cost, and dose-accuracy verification.

Why does Cynomel cause anxiety or palpitations?

The cardiovascular and adrenergic effects associated with immediate-release T3 - palpitations, anxiety, the "wired then tired" pattern - are in large part a function of the pharmacokinetic spike rather than the dose per se. When 25 mcg of liothyronine enters systemic circulation as a rapid bolus, serum T3 rises 3-5x above baseline within 2-4 hours. This acute hormonal surge triggers an adrenergic response: elevated heart rate, anxiety, and autonomic activation that is the body's physiological reaction to a sharp hormonal change. These effects are often attributed to "too high a dose," but they can occur at individually appropriate doses because the magnitude of the serum peak - not the total daily dose - drives the adrenergic response. This is the pharmacokinetic problem that SR-T3 formulation directly addresses.

Can I import Cynomel from Mexico legally?

US Customs may seize prescription medications imported without an FDA-recognized prescription, and enforcement for personal-import quantities of thyroid medications is inconsistent. The legal position for personal import of Cynomel is ambiguous and has become less predictable since 2022 as enforcement patterns have shifted. Beyond the legal uncertainty, the modern supply chain concern is quality: a substantial fraction of "Cynomel" available through online channels is not authentic Grossman's product, and there is no practical way to verify authenticity without laboratory analysis. This article does not endorse, facilitate, or advise on circumventing US prescription requirements or customs law.

What is the difference between Cynomel and slow-release T3?

Cynomel is immediate-release liothyronine: it dissolves rapidly after ingestion and produces a sharp serum T3 peak within 2-4 hours before declining. Slow-release (sustained-release) T3 - SR-T3 - is liothyronine formulated in a matrix (typically HPMC) that slows dissolution and extends release over 4-8 hours. The active molecule is the same (liothyronine sodium), but the serum curve is fundamentally different: SR-T3 produces a lower, extended peak rather than a spike. The adrenergic and cardiovascular side effects associated with immediate-release Cynomel are substantially attenuated with SR-T3 formulation, and the extended serum residence time provides more consistent receptor occupancy throughout the dosing interval. SR-T3 is not a different compound - it is a pharmacokinetically improved delivery system for the same compound.

Is slow-release T3 better than Cynomel?

From a pharmacokinetic standpoint, SR-T3 is a formulation improvement over Cynomel for the purposes that the bioenergetic research community uses T3: the attenuated serum peak reduces adrenergic side effects, the extended release provides more consistent T3 availability across the dosing interval, and the flat serum curve avoids the trough-period fatigue associated with immediate-release T3 clearance. From a supply chain and quality standpoint, research-grade HPLC-verified SR-T3 has a significant advantage over the modern Cynomel sourcing landscape: dose accuracy is verified, authenticity is not in question, and the supply is not dependent on Mexican export channels or customs enforcement variability. The relevant limitation to acknowledge: a head-to-head controlled trial comparing protocol outcomes between SR-T3 and authentic immediate-release Cynomel in the chronic-illness research population does not exist.

Where can I find a research-grade alternative to Cynomel?

HPLC-verified sustained-release T3 formulated in HPMC + MCC matrix - the research-grade Cynomel alternative optimized for the pharmacokinetic profile the bioenergetic-research community's protocols favor - is available through the Wilson's SR-T3 Combo Kit and the SRT3-15 entry-strength product. Both are sold strictly as research reference standards for laboratory use. The catalog spans the five standard dose strengths (7.5, 15, 22.5, 45, 90 mcg) that cover the full Wilson's WT3 titration ladder. All batches are HPLC-verified for potency and purity, and the excipient profile is HPMC + MCC only - no dyes, fillers, or allergen-class additives.

Closing Note

Cynomel occupied a genuine and important role in the bioenergetic research community's T3-access history. Grossman's product gave a technically engaged research community access to direct liothyronine when the US pharmaceutical infrastructure either couldn't or wouldn't provide it at accessible price points, and it enabled the development and widespread adoption of T3 protocols - including Wilson's WT3 - that continue to influence bioenergetic-framework research. That history is real and worth acknowledging. The current supply picture is different: authentic Cynomel is harder to source, counterfeit product circulates in the channels that once carried the real thing, and the pharmacokinetic limitations of immediate-release T3 have always been present regardless of the sourcing channel. SR-T3 in HPMC + MCC matrix - research-grade, HPLC-verified, formulated for the same cyclic T3 protocols Cynomel served - is the modern path forward for researchers who need dose-accurate, pharmacokinetically optimized liothyronine. The Wilson's SR-T3 Combo Kit and the Wilson's T3+T2 Combo for researchers addressing the downstream deiodinase conversion problem - along with the full catalog of bioenergetic-framework reference compounds - represent the research-grade infrastructure that the bioenergetic community now has available that it did not have when Cynomel was the primary option.