NDT
| NDT (Natural Desiccated Thyroid) | |
|---|---|
| Formula | |
| Class | |
| Administration | |
| Solubility | |
| Legal status | Prescription-only in most countries |
| Brand names | Armour Thyroid, NP Thyroid, WP Thyroid |
| Bioavailability | |
| Recommended dose | |
| Upper limit | |
| LD50 | |
| Ray's verdict | Generally helps "A natural desiccated thyroid product, in the long run, is a convenient way to keep your metabolic rate where it should be." |
NDT (natural desiccated thyroid) is dried pig thyroid gland with both T4 and T3. Armour Thyroid is the best-known brand. Mainstream endocrinology largely replaced NDT with synthetic levothyroxine (T4 only).
Ray Peat, Broda Barnes, and Mark Starr favored NDT when liver conversion of T4 to T3 is poor.[1] Asked about it directly, he called it "a convenient way to keep your metabolic rate where it should be."[2] See Roadmap/05 - Supplementing T3/T4 and Harm reduction.
T3:T4 ratio
[edit]Porcine thyroid powder provides T4 and T3 together. Historical data shows Armour Thyroid U.S.P., when digested, released T3 and T4 in about a 1:3 ratio. People using it often had higher serum T3:T4 ratios than those on thyroxine alone. T4-only therapy can leave tissues under-supplied with active T3 when liver conversion is poor.[1][3]
The fact that the T3 is being used faster than T4, removing it from the blood more quickly than it enters from the thyroid gland itself, hasn't been discussed in the journals, possibly because it would support the view that a natural glandular balance was more appropriate to supplement than pure thyroxine.
— Ray Peat
Modern NDT brands differ in strength standardization. FDA reformulations of Armour (post-2009) changed tablet potency, a sourcing issue separate from the underlying physiology. Armour stopped testing every production batch on animals in the 1990s, after which glandular potency could no longer be verified from the label alone; Peat reported some glandular batches he tested had almost no thyroid activity, apparently from feed problems in the source animals. For this reason he used a standardized synthetic T3/T4 combination (Cynoplus, formulated to match Armour Thyroid U.S.P.'s original composition) for about 30 years rather than an unstandardized glandular product, treating batch standardization, not the natural/synthetic label, as what actually determines a thyroid product's reliability.[5]
Diagnosis
[edit]Clinical signs (temperature, pulse, cholesterol, symptoms) are favored over isolated modern TSH-centric rules:
Unless someone can demonstrate the scientific invalidity of the methods used to diagnose hypothyroidism up to 1945, then they constitute the best present evidence for evaluating hypothyroidism, because all of the blood tests that have been used since 1950 have been shown to be, at best, very crude and conceptually inappropriate methods.
— Ray Peat
See Basal temperature, Hypothyroidism, and Broda Barnes.
NDT vs levothyroxine
[edit]Excess T4 in tissues that convert it slowly to T3 can have antithyroid effects: in one brain-slice experiment, thyroxine suppressed respiration by 6% while T3 acts directly on mitochondria, since most T3 is produced from T4 in the liver rather than the brain.[1]
Low T3 tracks with depression severity independent of treatment choice. In a study of 32 unmedicated depression patients, 90.6% had subnormal T3 and low T3 became more common with severity, from 66.6% of mild cases to 93.3% of moderate cases to 100% of severe cases; TSH was elevated in 54.5% of patients overall, all of them severe-grade.[7] The authors proposed screening thyroid status before starting antidepressants, since unrecognized subclinical hypothyroidism could explain nonresponse to standard antidepressant therapy.
Many Peat readers use NDT, separate T3 (Cytomel), or combined T4/T3 after dietary foundations from the Roadmap. Individual response varies; monitor temperature and pulse.
Pleasure and emotional effects
[edit]Peat described a direct, felt link between thyroid dose and mood, distinct from its metabolic effects on temperature and pulse:
The first time I took enough desiccated thyroid to make my heart speed noticeably, there was a pleasure pushing up from my abdomen through my chest, making me want to smile and laugh. When I have watched suicidal women using thyroid or progesterone, there is a transformation (under an hour with progesterone, a few hours or longer with thyroid) from weeping to smiling and laughing; they speak of unbearable pain being replaced by pleasure.
— Ray Peat
References
[edit]- ↑ 1.0 1.1 1.2 Ray Peat, "Ray Peat, PhD on Thyroid, Temperature, Pulse, and TSH," functionalps.com.
- ↑ Ray Peat, Ray Peat Forum Q&A, "Thyroid, Adrenaline, Relaxation."
- ↑ Hoang TD, Olsen CH, Mai VQ, Clyde PW, Shakir MK, "Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study," Journal of Clinical Endocrinology & Metabolism. 2013;98(5):1982-90. doi:10.1210/jc.2012-4107. PMID 23539727.
- ↑ Ray Peat, "Ray Peat, PhD on Thyroid, Temperature, Pulse, and TSH," functionalps.com.
- ↑ Ray Peat, "One Radio Network: Thyroid, PUFAs, OJ, and Sugar", One Radio Network
- ↑ Ray Peat, "Ray Peat, PhD on Thyroid, Temperature, Pulse, and TSH," functionalps.com.
- ↑ Saxena J, Singh PN, Srivastava U, Siddiqui AQ, "A study of thyroid hormones (T3, T4 & TSH) in patients of depression," Indian Journal of Psychiatry. 2000;42(3):243-6. PMID 21407950. PMCID PMC2958345.
- ↑ Ray Peat, "Nutrition for Women", p. 47